ARTICULOS PUBLICADOS · A green synthesis of copper nanoparticles using native cyclodextrins as stabilizing agents. Journal of Saudi ... Flavone functionalized magnetic nanoparticles:

TECNOLOacuteGICO NACIONAL DE MEacuteXICO INSTITUTO TECNOLOacuteGICO DE TIJUANA

Centro de Graduados e Investigacioacuten en Quiacutemica

Maestriacutea en Ciencias en Quiacutemica

No de reg CONACyT 000261

ARTICULOS PUBLICADOS

QOFS Quiacutemica Orgaacutenica en Fase Soacutelida

La productividad de esta liacutenea de investigacioacuten en cuanto a artiacuteculos publicados durante el

periodo 2012-2017 fue de 34 artiacuteculos cientiacuteficos

A continuacioacuten se da el detalle de los artiacuteculos publicados

1) Ramirez-Herrera D E Tirado-Guizar A Paraguay-Delgado F Pina-Luis G

Ratiometric arginine assay based on FRET between CdTe quantum dots and Cresyl

violet Microchim Acta 2017 184 1-9

2) Martiacutenez-Quiroz M Loacutepez Maldonado E A Ochoa-Teraacuten A Oropeza-Guzman

M T Pina-Luis G E Zeferino-Ramiacuterez J Innovative uses of carbamoyl benzoic

acids in coagulation-flocculationacutes processes of wastewater Chemical Engineering

Journal 2017 307 981-988

3) Muntildeoz-Bustos C Tirado-Guiacutezar A Paraguay-Delgado F Pina-Luis G E Cooper

nanoclusters-coated BSA as novel fluorescence sensor for sensitive and selective

detection of mangiferin Sensor and Acuators B Chemical 2017 244 922-927

4) Martiacutenez-Quiroz M Ochoa-Teraacuten A Aguilar-Martiacutenez M Garciacutea-Eliacuteas J

Santacruz-Ortega H Miranda Soto V Pina-Luis G New fluorescent metal receptors

base on 44acute-carbonyl bis(carbamoylbenzoic) acid analogues with naphthalene

fluorophore Supramol Chem 2017 DOI

httpdxdoiorg1010801061027820161277585

5) Suaacuterez-Cerda J Espinoza-Goacutemez H Nuacutentildeez G A Rivero IA Gochi-Ponce Y Z

Flores-Loacutepez L A green synthesis of copper nanoparticles using native cyclodextrins

as stabilizing agents Journal of Saudi Chemical Society 2017 21 341-348

6) Ramiacuterez-Zatarain S D Ochoa-Teraacuten A Reynoso-Soto E A Miranda-Soto V

Feacutelix-Navarro R M Pina-Luis G Yatsimirsky A K ldquoSelective interaction of NN-

bis(aminobenzyl)naphthalenediimides with fluoride anionrdquo Supramol Chem 2017 29

446-454

7) Tirado-Guizar A Paraguay-Delgado F Pina-Luis GE A molecularly imprinted

polymer-coated CdTe quantum dot nanocomposite for tryptophan recognition based on

the Foumlrster resonance energy transfer process Methods Appl Fluoresc 2016 41-8

8) Loacutepez H S Enciso J E Ochoa-Teraacuten A Velazquez J I Sarmiento J I An easy

one-step synthesis of imidazolin-2-ones from phthalic anhydrides and their antioxidant

evaluation Mendeleev Commun 2016 26 69-71

9) Aguilar-Garciacutea D Ochoa-Teraacuten A Paraguay-Delgado F Diacuteaz-Garciacutea M E Pina-

Luis G Water-compatible corendashshell AgSiO2 molecularly imprinted particles for the

controlled release of tetracycline J Mater Sci 2016 51 5651-5663

10) De la Rosa-Romo L M Oropeza-Guzmaacuten M T Olivas-Sarabia A Pina-Luis G

Flavone functionalized magnetic nanoparticles A new fluorescent sensor for Cu2+ ions

with nanomolar detection limit Sens Actuators B 2016 233 459-468

11) Martiacutenez-Quiroz M Ochoa-Teraacuten A Pina-Luis G Santacruz Ortega H

Photoinduced electron transfer in NN-bis(pyridylmethyl)naphthalenediimides study of

their potential as pH chemosensors Supramol Chem 2016 publicado en liacutenea DOI

1010801061027820161162905

12) Soliacutes-Delgado L E Ochoa-Teraacuten A Yatsimirsky A K Pina-Luis G Colorimetric

and Fluorescent Determination of Fluoride Using a Novel Naphthalene Diimide Boronic

Acid Derivative Anal Lett 2016 publicado en liacutenea

DOI1010800003271920161147575

13) Landey-Aacutelvarez M A Ochoa-Teraacuten A Pina-Luis G Martiacutenez-Quiroz M Aguilar-

Martiacutenez M Eliacuteas-Garciacutea J Miranda-Soto V Ramiacuterez J Z Machi-Lara L

Labastida-Galvaacuten V Ordontildeez M Novel naphthalimidendashaminobenzamide dyads as

OFFON fluorescent supramolecular receptors in metal ion binding Supramol Chem

2016 publicado en liacutenea DOI1010801061027820161149180

14) Salazar-Gasteacutelum M I Lin SW Pina-Luis G E Peacuterez-Sicairos S Feacutelix-Navarro

R M Electrochemical and Spectrometric Studies for the Determination of the

Mechanism of Oxygen Evolution Reaction J Electrochem Soc 2016 163(5) G1-G7

15) Santiago-Ruiz S Torres-Pacheco L J Oropeza-Guzman M T Rivero I A

Catalytic synthesis of hydantoins derivatives by pulsed Fe electro-oxidation The

International Journal of Electrochemistry Science 2016 11 6324-6335 DOI

102096420160713 ISSN 1452-3981

16) Montes-Aacutevila J Sarmiento-Saacutenchez J I Delgado-Vargas F Rivero I A Diacuteaz-

Camacho S P Uribe-Beltraacuten M Antioxidant activity and antimicrobial evaluation of 1-

benzyl-123-triazole Acta Universitaria Multidisciplinary Scientific Journal 2016 26(3)

63-67doi 1015174au2016937 ISSN 0188-6266

17) Santiago-Ruiz S Polverini E Manjarrez J Espinoza K A Reynoso E Rivero I

A Virtual Screening of putative of anticonvulsant hydantoin derived drugs and

biological evaluation Annals of Medicinal Chemistry and Research 2016 2(1) 1016

18) Monreal I Torres Pacheco L J Oropeza Guzman M T Rivero I A In-situ Fe

electro-oxidation to Improve the Synthesis of mono and disubstituted benzimidazoles

Int J Electrochem Sci 2015 10 6743-6753

19) Tirado Guiacutezar A Pina-Luis G Paraguay Delgado F Fluorescence enhancement

study of shell-less CdTe quantum dots Mater Express 2015 5 33-40

20) Tirado Guiacutezar A Pina-Luis G Paraguay Delgado F Ecofriendly synthesis of ultra-

small metal-doped SnO2 quantum dots MRS Commun 2015 5 63-69

21) Ochoa-Teraacuten A Estrada-Manjarrez J Martiacutenez-Quiroz M Landey-Alvarez M A

Alcaacutentar Zavala E Pina-Luis G Santacruz Ortega H Goacutemez-Pineda L E

Ramiacuterez J-Z Chaacutevez D Montes Aacutevila J Labastida-Galvaacuten V Ordontildeez M A

novel and highly regioselective synthesis of new carbamoylcarboxylic acids from

dianhydrides Sci World J 2014 11 pages

22) Coacuterdova-Guerrero J Hernaacutendez-Guevara E Ramiacuterez-Zatarain S Nuacutentildeez-Bautista

M Ochoa-Teraacuten A Muntildeiz-Salazar R Montes-Aacutevila J Loacutepez-Angulo G

Paniagua-Michel A Nuntildeo Torres G A Antibacterial activity of new oxazolidin-2-one

analogues in methicillin-resistant staphylococcus aureus strains Int J Mol Sci 2014

15 5277-5291

23) Loacutepez-Maldonado E A Oropeza-Guzmaacuten M T Ochoa-Teraacuten A Improving the

efficiency of a coagulation-flocculation wastewater treatment of the semiconductor

industry through zeta potential measurements J Chem 2014 Article ID 969720 10

pages DOI1011552014969720

24) Loacutepez-Maldonado E A Oropeza-Guzmaacuten M T Jurado-Baizaval J L Ochoa-

Teraacuten A Coagulation-flocculation mechanisms in wastewater treatment plants through

zeta potential measurements J Hazard Mater 2014 279 1-10

25) Sarmiento-Saacutenchez J I Montes-Aacutevila J Ochoa-Teraacuten A Delgado-Vargas F

Wilson-Corral V Diacuteaz-Camacho S P Garciacutea-Paacuteez F Bastidas-Bastidas P

Syntesis of 1H-Benzoxazine-24-diones from heterociclic anhydrides evaluation of

antioxidant and antimicrobial activities Quim Nova 2014 37 1297-1301

26) Ochoa-Teraacuten A Guerrero L Rivero I A A Novel one-pot and one-step microwave-

assisted cyclization-methylation reaction of amino alcohols and acetylated derivatives

with dimethyl carbonate and TBAC Sci World J 2014 Article ID 634935 10 pages

DOI1011552014634935

27) Sarmiento-Saacutenchez J I Ochoa-Teraacuten A Rivero I A Synthesis and antioxidant

evaluation of enantiomerically pure bis-(123-triazolylmethyl)amino esters from

modified α-amino acids Sci World J 2014 Article ID 264762 7 pages

DOI1011552014264762

28) Tirado-Guiacutezar A Pina-Luis G Paraguay-Delgado F Ramiacuterez-Herrera D Size-

dependent enhanced energy transfer from tryptophan to CdSemercaptopropionic acid

quantum dots A new fluorescence resonance energy transfer nanosensor Sci Adv

Mater 2014 6 492-499

29) Pina-Luis G Martiacutenez-Quiroz M Ochoa-Teraacuten A Santacruz Ortega H Meacutendez-

Valenzuela E New dual emission fluorescent sensor for pH and Pb(II) ions base on

bisnaphthalimide derivatives Journal of Luminiscence 2013 134 729-738

30) Loacutepez Maldonado E A Oropeza Guzmaacuten M T Pina-Luis G Ochoa-Teraacuten A

Evaluation of the physicochemical behavior of waste water treatment polyelectrolytes

with metal ions J Environmen Prot 2013 4 270-279

31) Ortiz-Arzate Z Jimeacutenez-Bravo T S Saacutenchez-Flores N A Pacheco-Malagoacuten G

Bulbulian S Rivero-Espejel I A Adsorption of phenol and chlorophenl mixtures on

silicalite-1 determined by GC-MS method J Mex Chem Soc 2013 57 111-117

32) Kozzina A Iturbe J L Rivero I A Selective Reduction of phenylacetylene with

AlMgO particles used as an alternative water-reactive generator of hydrogen Catal

Lett 2013 143 739-747

33) Loacutepez Maldonado EA Ochoa-Teraacuten A Oropeza Guzman MT A multiparameter

colloidal titrations for the determination of cationic polyelectrolytes Journal of

Environmental Protection 2012 DOI 104236jep2012311172

34) Pina-Luis G Rosquete Pina GA Valdeacutes Gonzaacutelez AC Ochoa Teraacuten A Rivero

Espejel IA Diacuteaz-Garciacutea ME Morin functionalized Merrifieldrsquos resin A new material

for enrichment and sensing heavy metals Reactive amp Fuctional Polymers 2012 72 61-

Mendeleev Commun 2016 26 69ndash71

ndash 69 ndash

MendeleevCommunications

copy 2016 Mendeleev Communications Published by ELSEVIER BV on behalf of the N D Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences

Imidazolidinones are commonly synthesized by cyclization of 12-diamines with phosgene or 11-carbonyldiimidazole1 For the synthesis of imidazolidinones several routes have been reported2 but probably the most commonly used methodology involves the use of isocyanates ie the reaction with amino alcohols3 amines4 a-imino ketones5 vinylaziridines6 and allylamines7 Imidazolidinones are found in several natural compounds eg Biotin (vitamin B) which was isolated from yolk and is a co-enzyme in the carboxylation reaction in the biosynthesis of the fatty acids8 Imidazolidinones have been reported against b-secretase (BACE1) inhibitors in Alzheimerrsquos disease9 avb3-antagonist in the prevention and treatment of Osteoporosis10 against Schistosoma mansoni11 selective Human Enterovirus 71 inhibitors12 muscarinic M3 selective antagonists13 They possess anticancer (A549 COLO205 KATO III K562)13(c) anti bacterial and antifungal14 and antileishmanial15 activities

Recently we have reported the synthesis of small heterocyclic compounds and their antioxidant evaluation16 Currently our research is focused on the development of a simple one-pot syn-thesis of small heterocyclic compounds with potential bio logical activities In this paper an easy one-step synthesis of benzimid-azolin-2-ones from phthalic anhydride derivatives with trimethyl-silyl azide (TMSA) and their antioxidant evaluation are reported

On the treatment of phthalic anhydrides 1 with TMSA the Curtius rearrangement leads to benzoxazine-24-dione inter-mediates 2 followed by the second Curtius rearrangement and final intramolecular cyclization to provide imidazolin-2-ones 3 (Scheme 1) We started with the optimization of reaction condi-tions using phthalic anhydride 1a as a model First a comparison between the reaction efficiencies of TMSA generated in situ and commercial reagent was made with TLC monitoring until the reac tion of the phthalic anhydride was complete The reactions of TMSA generated in situ (from trimethylsilyl chloride with sodium azide) and commercial reagent in THF for 30 h at reflux provided compound 3a in 20 and 51 isolated yields respec-tively Subsequently different solvents [DMSO benzene aceto-nitrile and benzenendashacetonitrile (31 vv)] were tested under optimal reaction conditions When DMSO was used as a solvent product 3a was not formed and some non-identified by-products were obtained Probably this reaction follows a mechanism similar to that proposed by Snyder17 for the synthesis of alkyl chloride from TMSCl In contrast the employment of other above solvents

favored the expected product but gave a lower yield than THF Note that the matched conditions do not require any sophistication and can be readily accomplished The solvent was evaporated in vacuo and the product precipitated with diethyl ether to provide the corresponding imidazolin-2-ones in moderate to good yields The highest yield in THF could be associated with the solubility of reagents and intermediates in this solvent The yields of imid-azolin-2-ones 3andashg synthesized using this methodology (Table 1)dagger were 45ndash91 depending on the structure of the starting mate-rial The structures of the imid azolin-2-ones were confirmed by NMR IR spectra and GC-MS Jones and Schofield18 reported the synthesis of imidazolin-2-one by a four-step method from 1236-tetra hydro phthalic anhydride with TMSA in 72 h to give a 19 of overall yield but obtained a mixture of imidazolin-

An easy one-step synthesis of imidazolin-2-ones from phthalic anhydrides and their antioxidant evaluation

Heacutector S Loacutepeza Joseacute E Encisoa Adriaacuten Ochoa-Teraacutenb Juan I Velazquezc and Juan I Sarmientoc

a Facultad de Ciencias Quiacutemico-Bioloacutegicas Universidad Autoacutenoma de Sinaloa 80040 Culiacaacuten Sinaloa Meacutexico

b Centro de Graduados e Investigacioacuten en Quiacutemica Instituto Tecnoloacutegico de Tijuana 22510 Tijuana BC Meacutexico

c Facultad de Ingenieriacutea Culiacaacuten Universidad Autoacutenoma de Sinaloa 80040 Culiacaacuten Sinaloa Meacutexico Fax +52 667 713 4043 e-mail jsarmientouasedumx

DOI 101016jmencom201601027

Treatment of phthalic anhydride derivatives with trimethylsilyl azide affords benzimidazolin-2-ones in 45ndash91 yield which is the result of two consecutive Curtius reactions Within the series obtained 13-dihydro-2H-imidazo[45-b]pyridin-2-one showed highest antioxidant activity

R RMe3SiN3 N3

2Me3SiN3 CO2

Scheme 1

Water-compatible corendashshell AgSiO2 molecularly

imprinted particles for the controlled release

of tetracycline

Diana Aguilar-Garcıa1 Adrian Ochoa-Teran1 Francisco Paraguay-Delgado2 Marta Elena Dıaz-Garcıa3and Georgina Pina-Luis1

1Centro de Graduados e Investigacioacuten en Quiacutemica Instituto Tecnoloacutegico de Tijuana AP 1166 22500 Tijuana BC Mexico2Departamento de Materiales Nanoestructurados Centro de Investigacioacuten en Materiales Avanzados S C Av Miguel de Cervantes

120 Complejo Industrial Chihuahua CP 31109 Chihuahua CHIH Mexico3Departamento de Quiacutemica Fiacutesica y Analiacutetica Facultad de Quiacutemica Universidad de Oviedo Av Juliaacuten Claveriacutea 8 33006 Oviedo

Received 21 November 2015

Accepted 29 February 2016

Springer Science+Business

Media New York 2016

ABSTRACT

Silver nanoparticles coated with molecularly imprinted silica shell (AgSiO2-

MIP) were synthesized and their properties for the molecular recognition and

the controlled delivery of tetracycline (TC) in aqueous environments were

investigated In this study a synthesis protocol based in the entrapping of TC

into silica particles with a core of silver nanoparticles (AgNPs) was developed

These particles were examined by transmission electron microscopy scanning

electron microscopy energy dispersion spectroscopy Fourier transform infra-

red spectroscopy zeta potential and UV visible and fluorescence spectroscopy

The as-prepared AgSiO2-MIP particles were evaluated for selective recogni-

tion of TC The imprinted particles have higher TC binding ability as compared

with corresponding non-imprinted particles and have high selectivity toward

TC over other competitive antibiotics The studies of release profiles of TC-

loaded AgSiO2-MIP particles in aqueous solutions demonstrated a strong

dependence with pH and temperature The kinetic delivery of TC showed two

types of release which includes initial burst release (low-affinity sites) and slow

release (high-affinity sites) The amount of TC release from AgSiO2-MIP par-

ticles was lower at pH 2 (simulated gastric fluid) to pH 8 (simulated colonic

fluid) which makes the proposed system a good candidate for TC oral

administration The excellent biocompatibility of the silica materials the known

bactericidal properties of the AgNPs and the drug release results render the

possibility of designing a new generation of TC delivery systems for controlled

release

Address correspondence to E-mail gpinaluistectijuanamx gpinaluisyahoocom

DOI 101007s10853-016-9867-x

J Mater Sci

KMFFCC

cspcsCctmasf[t

Sensors and Actuators B 233 (2016) 459ndash468

Contents lists available at ScienceDirect

Sensors and Actuators B Chemical

jo ur nal home page wwwelsev ier com locate snb

lavone functionalized magnetic nanoparticles A new fluorescentensor for Cu2+ ions with nanomolar detection limit

uz Mariacutea de la Rosa-Romo a Mercedes T Oropeza-Guzmaacuten b Amelia Olivas-Sarabia ceorgina Pina-Luis alowast

Centro de Graduados e Investigacioacuten Instituto Tecnoloacutegico de Tijuana Blvd Alberto Limoacuten Padilla sn Campus Otay AP 1166 Tijuana BC 22500 MeacutexicoCentro de Investigacioacuten y Desarrollo Tecnoloacutegico en Electroquiacutemica CIDETEQ Carretera Tijuana-Tecate km 265 CP 22444 Tijuana BC MeacutexicoCentro de Nanociencias y Nanotecnologiacutea Km 107 Carretera Tijuana-Ensenada Apdo Postal 14 CP 22800 Ensenada BC Meacutexico

r t i c l e i n f o

rticle historyeceived 24 November 2015eceived in revised form 15 April 2016ccepted 19 April 2016vailable online 20 April 2016

eywordsagnetic nanoparticle

luorescence

a b s t r a c t

This paper presents the preparation and characterization of a new class of fluorescent core-shell mag-netic nanoparticles composed of a Fe3O4 core coated with amino-functionalized silica shell and modifiedwith morin (Fe3O4SiO2-NH2-morin) These nanoparticles were examined by transmission electronmicroscopy (TEM) Fourier transform infrared spectroscopy (FTIR) thermogravimetric analysis (TGA)zeta potential and vibrating sample magnetometer (VSM) The fluorescent magnetic nanoparticles wereanalyzed by UVndashvis and fluorescence spectroscopy The characterization data showed that the nanopar-ticle diameter is increased at each synthesis step (from 14 to 78 nm) and that all nanoparticles havesuperparamagnetic properties The fluorescence response of morin-magnetic nanoparticle towards Cu2+

lavoneopper nanomolar detectionore-shell nanoparticle

ions showed a significant and selective fluorescence quenching Morin functionalized magnetic nanopar-ticle are found to be highly selective for Cu2+ ions whereas the interference from other metal ions andbiological compounds was negligible The nanosensor not only provided a sensitive (75 nM) and selectivedetection of Cu2+ ions but a new fluorescent and biocompatible material with potential use in biologicalapplications

Introduction

Magnetic nanoparticles have demonstrated potential appli-ations in catalysis cell labelling drug delivery contaminanteparation and other owing to their magnetic features [1ndash11] Inarticular sensors based on magnetic nanoparticles have attractedonsiderable interest due to the significant improvement in sen-itivity and selectivity that can be achieved by this methodore-shell nanoparticles consisting of a magnetically responsiveore and a silica shell have some important advantages Firsthe magnetic core makes them easy to separate and recycle from

atrix with an external magnet Second they are biocompatiblend have greater stability Furthermore they are readily synthe-ized by solndashgel method and easily modified by a wide range of

unctional groups including thiol amine and carboxylate groups12ndash15] These functional groups provide sites for surface modifica-ion with various chemical and biomedical ligands The thick silica

lowast Corresponding authorE-mail addresses gpinaluistectijuanamx gpinaluisyahoocom

G Pina-Luis)

layer can act as the support of fluorescent probes to develop non-toxic biocompatible and recoverable fluorescence nanosensors

Morin (3572prime4prime-pentahydroxyflavone) is a polyphenolic com-pound derived from flavones (Fig 1) that possesses a wide range ofbioactivities and is often employed as anti-inflammatory antioxi-dant antineoplasic and as cardiovascular protector agent [1617] Ithas the ability to form complexes with some metal ions and can actas an excellent scavenger of metal ions from contaminated sam-ples Modification with morin provides fluorescent properties tothe nanoparticle and serves as a biocompatible receptor friendlyto the environment useful in the recognition and separation ofmetal ions as effective metal chelating agent and in many biologicalapplications

Morin has been immobilized on different supports and success-fully employed in the separation and preconcentration of tracemetals [18ndash20] but to our knowledge there are no reports on theuse of morin immobilized on the magnetic nanoparticle as mate-rial for the recognition of heavy metals In particular the design

of a Cu2+ ions sensor has received attention given its implicationsin a number of neurodegenerative diseases as well as ecologicalpollution Copper trace ions are vital in various enzymatic pro-cesses its deficiency may lead to several neurological problems On

Supramolecular chemiStry 2016httpdxdoiorg1010801061027820161162905

Photoinduced electron transfer in NN-bis(pyridylmethyl)naphthalenediimides study of their potential as pH chemosensors

Marisela Martiacutenez-Quiroza Adriaacuten Ochoa-Teraacutena Georgina Pina-Luisa and Hisila Santacruz Ortegab

acentro de Graduados e investigacioacuten instituto tecnoloacutegico de tijuana tijuana meacutexico bDepartamento de investigacioacuten en poliacutemeros y materiales universidad de Sonora hermosillo meacutexico

ABSTRACTThe change in fluorescent properties of a series of NN-bis(pyridylmethyl)naphthalenediimides (BIPy-NDIs) as function of pH were investigated The naphthalenediimide dyes displayed OFFndashON pH sensing properties owing to photoinduced electron transfer in the pH range from 17 to 41 The fluorescence enhancement of the chemosensors studied is based on the hindering of photoinduced energy-electron transfer (PET) from pyridine ring to the naphthalene fluorophore by protonation Moreover using density functional theory theoretical calculations of molecular orbitals it was verified that protonation nitrogen atom in pyridine ring inhibits the PET process The best selective response for monitoring pH in the presence of different metal ions was exhibited by BIPy-NDI 1B In addition 1B was applied for determination of pH in real samples of commercial vinegars The results were consistent with those obtained by glass electrode method indicating that the new probe could be a practical pH indicator in strongly acidic conditions

copy 2016 informa uK limited trading as taylor amp Francis Group

KEYWORDSNNprime-bis(pyridylmethyl)naphthalenediimides pet ph chemosensor

ARTICLE HISTORYreceived 22 June 2015 accepted 2 march 2016

CONTACT adriaacuten ochoa-teraacuten ochoatectijuanamx

Introduction

Naphthalenediimides (NDIs) are a class of compounds that have become increasingly important in the last decade with a series of applications ranging from the biomedical to material science due to their outstanding photo- and electrochemical properties (1) NDIs are excellent materi-als for studying electro- or photoinduced electron transfer reactions and can be incorporated into larger multi-com-ponent assemblies such as field effect transistors bio-logical models and supramolecular devices (2) They are excellent electron acceptors in aqueous solution and ideal for the design of synthetic derivatives that can be used as structural probes and therapeutic agents in molecular

biology and chemotherapy (3ndash5) NDIs have been used to reduce and oxidise proteins (6ndash8) and DNA (9ndash11) Most studies in aqueous solution involve the binding to nucleic acids and many of these derivatives are used as DNA inter-calators (7ndash11) They also show biological applications rely mainly on their pharmacological activity as local anesthet-ics (12 13) tumoricidals (14 15) and antivirals (16ndash18)

Photophysical characterisation of NDIs is limited to a few derivatives mainly due to their low solubility in aque-ous media However İccedilli and co-workers (19) reported the photoinduced energy-electron transfer (PET) in NDIs and demonstrated that electron donor groups in the N-substituent of the NDI quench the fluorescence emission

iaacuten

eraacuten

Full Terms amp Conditions of access and use can be found athttpwwwtandfonlinecomactionjournalInformationjournalCode=lanl20

Download by [New York University] Date 29 February 2016 At 1318

Analytical Letters

ISSN 0003-2719 (Print) 1532-236X (Online) Journal homepage httpwwwtandfonlinecomloilanl20

Colorimetric and Fluorescent Determination ofFluoride Using a Novel Naphthalene DiimideBoronic Acid Derivative

Luis Ernesto Soliacutes-Delgado Adriaacuten Ochoa-Teraacuten Anatoly K Yatsimirsky ampGeorgina Pina-Luis

To cite this article Luis Ernesto Soliacutes-Delgado Adriaacuten Ochoa-Teraacuten Anatoly K Yatsimirskyamp Georgina Pina-Luis (2016) Colorimetric and Fluorescent Determination of FluorideUsing a Novel Naphthalene Diimide Boronic Acid Derivative Analytical Letters DOI1010800003271920161147575

To link to this article httpdxdoiorg1010800003271920161147575

Accepted author version posted online 29Feb 2016

Submit your article to this journal

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Colorimetric and Fluorescent Determination of Fluoride

using a Novel Naphthalene Diimide Boronic Acid Derivative

Luis Ernesto Soliacutes-Delgado

Centro de Graduados e Investigacioacuten en Quiacutemica del Instituto Tecnoloacutegico de Tijuana Tijuana

Meacutexico

Adriaacuten Ochoa-Teraacuten

Meacutexico

Anatoly K Yatsimirsky

Facultad de Quiacutemica Universidad Nacional Autoacutenoma de Meacutexico Meacutexico

Georgina Pina-Luis

Meacutexico

Address correspondence to Georgina Pina-Luis Tel +52 664 6233772 Fax +52 664 6234042

E-mail gpinaluistectijuanamx gpinaluisyahoocom

Supertitle Spectroscopy

Received 22 September 2015 revised 25 January 2016 accepted 25 January 2016

Abstract

Novel naphthalimidendashaminobenzamide dyads as OFFON fluorescent supramolecular receptors in metal ion binding

Marco A Landey-Aacutelvareza Adriaacuten Ochoa-Teraacutena Georgina Pina-Luisa Marisela Martiacutenez-Quiroza Milagros Aguilar-Martiacuteneza Joseacute Eliacuteas-Garciacuteab Valentiacuten Miranda-Sotoa Joseacute-Zeferino Ramiacuterezc Lorena Machi-Larac Victoria Labastida-Galvaacutend and Mario Ordontildeezd acentro de Graduados e investigacioacuten en Quiacutemica instituto tecnoloacutegico de tijuana tijuana mexico bunidad acadeacutemica de ciencias Quiacutemicas universidad autoacutenoma de Zacatecas Zacatecas mexico cDepartamento de investigacioacuten en poliacutemeros y materiales universidad de Sonora hermosillo mexico dcentro de investigaciones Quiacutemicas-(iicBa) universidad autoacutenoma del estado de morelos cuernavaca mexico

ABSTRACTA series of novel naphthalimidendashaminobenzamide (NAPIM-2ABZ) dyads 3 connected by different length polymethylene chains were synthesized and studied as fluorescent supramolecular receptors in metal ion binding The photophysical properties were evaluated and compared with separated chromophores The electronic absorption spectra of dyads 3 showed no interaction between chromophores in the ground state The fluorescence quantum yields were lower in dyads 3 in comparison with N-propyl-2-aminobenzamide (8) The fluorescence quenching is attributed to a PET mechanism between fluorophores (from 2ABZ to NAPIM) which is dependent on the polymethylene chain length In metal binding study was found a response towards transition metal ions such as Hg(II) Cu(II) Zn(II) and Ni(II) Dyad 3b presented selectivity towards Cu(II) The UV-vis IR and 1H-NMR studies demonstrated the interaction with 2ABZ moiety in the ground state and interestingly dyads with shorter polymethylene chains 3a (n = 0) 3b (n = 1) and 3c (n = 2) exhibited an OFFON fluorescence behaviour due to the PET inhibition and the quenching of 2ABZ fluorescence Dyads 3d (n = 4) and 3e (n = 6) presented opposite response ONOFF in the complex with metal ions evidencing the absence of PET in these dyads

copy 2016 taylor amp Francis

KEYWORDSpet dyads naphthalimide aminobenzamide metal binding

ARTICLE HISTORYreceived 9 September 2015 accepted 28 January 2016

Introduction

2-Aminobenzamide (2ABZ) has been extensively studied as fluorescent label in order to improve the oligosaccha-ride detection and sequencing by high-performance liquid chromatography (1ndash6) The introduction of 2ABZ as fluo-rescent probe into saccharides occurs through a two-step

reductive amination The same strategy has been used in the label of monosaccharides with N-aminoethyl-2-aminobenzamide (2AEAB) (7) which has the advantage of being a bifunctional molecule and allows to develop microarrays to study the proteinndashcarbohydrates interac-tions (8) Fluorescent sensors for the detection of Zn(II) with a 2ABZ moiety as fluorophore were reported (9 10)

Journal of The Electrochemical Society 163 (5) G37-G43 (2016) G370013-46512016163(5)G377$3300 copy The Electrochemical Society

Electrochemical and Spectrometric Studies for the Determinationof the Mechanism of Oxygen Evolution ReactionM I Salazar-Gastelumz S W Lin G E Pina-Luis S Perez-Sicairosand R M Felix-Navarroz

Centro de Graduados e Investigacion en Quımica Instituto Tecnologico de Tijuana Tijuana BC 22000 Mexico

A novel study of the oxygen evolution reaction (OER) mechanism at different anode materials is shown using the two approacheselectroanalytical and spectroscopic For first time new evidence is provided for electroanalytical approach which consists of usingchronoamperometric curves to obtain Tafel plots at different detection times Besides intermediates of OER (eg bullOH) weredetected and quantified indirectly by fluorescence spectroscopy This technique detects the formation of 7-hydroxycoumarin in situfrom the reaction between coumarin and bullOH Among all anode materials tested only SnO2-Sb2O5 and boron doped diamond(BDD) electrodes showed the typically Tafel slope value of 120 mV decminus1 associated with a primary water discharge as determiningstep where bullOH is the main active intermediate The potential that provide the best detection of bullOH in several electrolytes for thesetwo electrodes were identified This spectroscopic studies support the evidence of the formation of bullOH as the rate determining step(RDS) in the OER mechanismcopy 2016 The Electrochemical Society [DOI 10114920251605jes] All rights reserved

Manuscript submitted October 1 2015 revised manuscript received December 26 2015 Published January 21 2016

In recent years electrochemical research has mostly fo-cused on pollutant degradation evaluating different electrochemicalmethods1ndash4 and process designs5 to remove trace amounts of or-ganic compounds in wastewater Among the several electrochemi-cal methodologies reported electrochemical oxidation has provideda path to total mineralization of pollutants6 However this processstrongly depends on the both the medium being treated and electrodematerials chosen for their ability to form strong oxidants7 Amongthe known oxidant species bullOH has attracted much attention be-cause of its high oxidizing power which is a highly desirable featurefor the destruction of toxic organic contaminants8 In addition bullOHis well recognized as potent reactive oxygen species in biologicalsystems which is known to cause oxidative stress and other physio-logical complications in living organisms Therefore numerous re-searchers have reported on the bullOH generation8ndash11 Methods for bullOHgeneration includes Fenton or Electro-Fenton process12 radiation ofTiO2 photocatalyst in aqueous media9 and polarization at high an-odic potentials13 Consequently polarization at high anodic potentialscan lead to mineralization of organic compounds via electrochemi-cal oxygen transfer reaction (EOTR) However the determining stepof EOTR can be attributed to anodic discharge of bullOH to O2 in theoxygen evolution reaction (OER)13

OER is an anodic process in which oxidation of water takes placevia the transference of either one electron leading to the electro-generation of bullOH (Reaction 1) or involving two transferred elec-trons leading to oxygen evolution (Reaction 2) and production of lesspowerful oxidants such as O2 O3 etc14

H2 O rarr middotOH + H+ + eminus [1]

H2 O rarr 1

2O2 + 2 H+ + 2 eminus [2]

The rate of OER at given electrode potential depends criticallyon the nature of electrode materials15 PbO21416 SnO2-Sb2O5

17 andboron-doped diamond (BDD)18 are anode materials reported withhigh overpotentials for oxygen evolution On the other hand plat-inum based-electrodes19 and dimensionally stable anodes (DSA)2021

are electrodes reported with low overpotentials for oxygen evolutionOER is a complex process and is not only a function of overpotentialvalue due to the possibility of different pathway occurring simultane-ously This process depends on several thermodynamics parameterssuch as electrolyte temperature anode material electrolyte concen-tration etc A large number of reports discuss the mechanistic aspectsof OER in terms of Tafel slope values11131519 The discussion of this

zE-mail rmfelix2003yahoocommx moi6salazarhotmailcom

reaction mechanism of OER is mostly based on the analysis of Tafelslope value supplemented by spectroscopic studies of the nature ofthe reaction intermediates15

Several mechanisms differing in molecular details have been pro-posed for OER151921 A generalized mechanism can be stated asfollows

S + H2 O rarr S minus middotOH + H+ + eminus [3]

S minus middotOH rarr S minus OH [4]

S minus OH rarr S minus O + H+ + eminus [5]

2S minus O rarr O2 + 2S [6]

The first step of the generalized mechanism is the discharge ofwater (Reaction 3) with the generation of S-bullOH which is the mainactive intermediate of OER Depending on the nature of the electromaterial a surface rearrangement of the bullOH could take place resultingin a more stable specie (Reaction 4) This stable specie is susceptibleto electrochemical oxidation (Reaction 5) and subsequently oxygenis released (Reaction 6) Thus the rate determining step (RDS) ofOER mechanism is related to Tafel slope value22

A large number of publications report the Tafel slopesfrom different materials and electrolytes using linear sweepvoltammetry1011132023 or galvanostatic polarization22 Tafel slopevalues are usually between 30 to 120 mV decminus115 Table I summarizesthe Tafel slope values founded in literature for OER The intermediateTafel slope values are interpreted in terms of mixed mechanism or ofintermediate coverage with adsorbed species15 and this phenomenonis associated with the surface rearrangement as the RDS (transforma-tion of the intermediate) Nevertheless Tafel slope values higher than120 mV decminus1 may result from the presences of species adsorbed thatact as barrier for OER11 this fact is related with the formation andadsorption of S-bullOH as RDS22 Multiple Tafel slopes can also be ob-served as function of overpotential where the transitions can be due to(a) changes in the coverage of adsorbed species for the same RDS ofthe same mechanism (b) changes in the RDS in the same mechanismand (c) changes in the mechanism15 Under the basis of a generalizedmechanism only changes in the adsorbed species or changes in theRDS are considered for further discussion

The physicochemical properties of bullOH makes it possible for theseradicals to carry out the mineralization of organic contaminants How-ever the concentration of bullOH is difficult to quantify due to a highlyactive intermediate and a lifetime of approximately 10minus9 s31 Since

) unless CC License in place (see abstract) ecsdlorgsiteterms_use address Redistribution subject to ECS terms of use (see 131111164128Downloaded on 2016-01-22 to IP

Catalytic Synthesis of HydantoinsDerivatives by Pulsed Fe electro-oxidation

110396By IA Rivero

WORD COUNT 3905 TIME SUBMITTED 31-JAN-2016 0902AM

PAPER ID 21390854

Int J Electrochem Sci 10 (2015) 6743 - 6753

International Journal of

ELECTROCHEMICAL SCIENCE

wwwelectrochemsciorg

In-situ Fe electro-oxidation to Improve the Synthesis of Mono

and Disubstituted Benzimidazoles

IMonreal1 LJ Torres-Pacheco

2 MT Oropeza-Guzman

2 I A Rivero

1Centro de Graduados e Investigacioacuten en Quiacutemica Tecnoloacutegico Nacional de Meacutexico Instituto

Tecnoloacutegico de Tijuana CP 22500 Tijuana B C Mexico 2Centro de Investigacion y Desarrollo Tecnologico en Electroquimica subsede Tijuana Carretera

Tijuana-Tecate km 265 Parque Industrial El Florido CP 22444 Tijuana B C Mexico E-mail iriverotectijuanamx moropezacideteqmx

Received 9 April 2015 Accepted 2 June 2015 Published 24 June 2015

This paper presents an innovative green organic electrosynthesis to prepare benzimidazoles in

methanol media at room temperature starting from o-phenylendiammines and benzaldehydes The

main characteristic of this proposal is the in-situ Fe electro-oxidation serving as catalyst in the

synthetic path of benzimidazoles mono and disubstituted Anodic linear sweep voltammetry of Fe wire

in methanol were used to select the supporting electrolyte among tetrabutilammonium

tetrafluoroborate (TBATFB) and tetrabutilammonium hexafluorophosphate (TBAHFP) I vs E plots

pointed toward TBATFB as a better supporting electrolyte due to the fact that Fe presents a lower

potential dissolution compared with TBAHFB Electrolysis at constant potential was performed in a

three-electrode undivided cell to prepare two different benzimidazoles (mono and disubstituted) using

1mM TBATFB in methanol In both cases good yields and easy purification were achieved Results

indicate that in-situ soft electrochemical Fe oxidation produce fresh Fe(III) to act as an effective

catalyst for benzimidazoles synthesis and succeed a green chemistry process Products were

characterized by IR NMR (1H

13C) and MS The success of the electrochemical assisted synthesis

was compared with a FeCl3Alumina previously reported

Keywords benzimidazole o-phenylenediamine Fe electro-oxidation in methanol organic

electrosynthesis

1 INTRODUCTION

Electro-organic synthesis and organic electrosythesis have been considered as promising

approaches to prepare more than a few organic compounds [1] The most common procedures are the

direct electrochemical reaction of some of the reagents corresponding to electro-organic synthesis

Delivered by Publishing Technology to University of ReadingIP 1342251226 On Thu 25 Dec 2014 162253

Copyright American Scientific Publishers

Materials ExpressArticle

Copyright copy 2015 by American Scientific PublishersAll rights reservedPrinted in the United States of America

2158-584920155033008doi101166mex20151211

wwwaspbscommex

Fluorescence enhancement study ofshell-less CdTe quantum dotsAntonio Tirado-Guizar1 Georgina Pina-Luis1lowast and Francisco Paraguay-Delgado2

1Centro de Graduados e Investigacioacuten Instituto Tecnoloacutegico de Tijuana AP 1166 Tijuana 22500 BC Meacutexico2Centro de Investigacioacuten en Materiales Avanzados SC Departamento de Fiacutesica de MaterialesAv Miguel de Cervantes 120 Complejo Industrial Chihuahua CP 31109 Chihuahua Chih Meacutexico

ABSTRACT

We report a systematic study on the synthesis of shell-less CdTe quantum dots towards the enhancement oftheir luminescence properties Reaction times and CdTe molar ratios were investigated to optimize the synthe-sis conditions It was found that these parameters have a significant influence on the quantum dots emissionwavelengths and photoluminescence quantum yields The synthesis can be carried out without the use of aninert atmosphere and pyrophoric ligands in less than an hour Water-soluble CdTe quantum dots were alsoprepared by modification of CdTeODE with mercaptopropionic acid Hydrophobic and water-soluble quantumdots were characterized by UV-visible absorption spectroscopy fluorescence spectroscopy transmission elec-tron microscopy and energy dispersive X-ray spectroscopy The optical stability of hydrophobic and hydrophilicquantum dots was tested irradiating the sample with a high power xenon lamp After 45 min of illuminationthe hydrophobic-materials showed an excellent stability (bleachinglt 10) and the hydrophilic-materials a non-reversible photo-enhancement process After 15 minutes of stopping the illumination the quantum yield ofhydrophilic quantum dots in aqueous solution was stabilized to 55 The characteristics of the synthesizedquantum dots make them suitable for use as biological fluorescent markers photocatalytic materials with highperformance and new materials for solar cells

Keywords Quantum Dots High Quantum Yield Shell-Less Photostability Enhancement

1 INTRODUCTIONNanocrystalline semiconductors have attracted consider-able attention because of their special electrical and opticalproperties such as narrow emission bands wide excitationbands large Stokes shifts high brightness and photochem-ical stability This type of nanomaterial can be consid-ered with great potential for biological applications in cellsand tissue labeling1ndash3 bioimaging4 optoelectronic56

and drug delivery7 Among IIndashVI type semiconductorcompounds CdTe presents much interest because it isa material suitable for emitting in the visible and in

lowastAuthor to whom correspondence should be addressedEmails gpinaluistectijuanamx gpinaluisyahoocom

the near-infrared (NIR) spectral range by controlling thenanoparticle sizeAn important strategy in the development of new flu-

orescent probes is the use of quantum dots due to theirabove-mentioned properties The high surface to volumeratio of the nanomaterial and its great dispersivity pro-vide large adsorptive surface that increase the interactionbetween the nanoparticle and the analyte As a result sen-sors with better selectivity and sensitivity are obtainedMoreover the fluorescence signal also offers many advan-tages over other detection system It has been reportedanalytical probes based in fluorescence detection that allowthe determination of analyte in femtomolar concentrations(10minus15 M)8

Mater Express Vol 5 No 1 2015 33

Research Letters

Ecofriendly synthesis of ultra-small metal-doped SnO2 quantum dots

Antonio Tirado-Guiacutezar andGeorgina Esther Pina-Luis Centro de Graduados e Investigacioacuten en Quiacutemica Instituto Tecnoloacutegico de Tijuana AP1166 Tijuana 22500 BC MeacutexicoFrancisco Paraguay-Delgado Departamento de Materiales Nanoestructurados Centro de Investigacioacuten en Materiales Avanzados S C Av Miguel deCervantes 120 Complejo Industrial Chihuahua CP 31109 Chihuahua Chih Meacutexico

Address all correspondence to Francisco Paraguay-Delgado Antonio Tirado-Guiacutezar at franciscoparaguaycimavedumx guizarantoniogmailcom

(Received 7 December 2014 accepted 26 February 2015)

AbstractAn ecofriendly synthesis is established to obtain ultra-small SnO2 nanoparticles (NPs) doped with metals by a hydrothermal method using onlytin tetrachloride urea and water as reagents This synthesis was done in a short period time at low temperature and without surfactantsMicroscopy analysis revealed the formation of doped tin oxide NPs with a diameter smaller than 28 nm Un-doped and doped tin oxideswere obtained with a tetragonal type rutile structure with an average surface area of 348 m2g

IntroductionCurrent research groups dedicated to the area of materialsscience have drawn interest in luminescent materials such asquantum dots (QDs) QDs are colloidal nanocrystalline semi-conductors with special luminescent properties with relativelyspherical morphology narrow emission bands (typically 20ndash30 nm full-width at half-maximum intensity) and high photo-chemical stability[1] Luminescent QDs have great applicationsin light-emitting diodes[2] biological imaging[3] and sensors[4]

Tin oxide (SnO2) is a great semiconductor material with anexciton Bohr radius of approximately 27 nm[5] In particularSnO2 has been widely used as gas sensors for monitoring theenvironment and as catalysts[6] For these types of applicationssmall size particles and large surface area are necessary to highperformance

Doping SnO2 nanoparticles (NPs) with small quantities ofmetals can improve the optoelectronic properties such as photo-luminescence and optical band gap which would result in sur-face modification providing excellent electric properties andphotocatalytic activities[7] In particular ZnndashSnO2 NPs havebeen demonstrated to be great materials for improved powerconversion efficiency in Dye-sensitized solar cell[8]

Additionally dilute magnetic semiconductors produced by dop-ing transition metal ions into non-magnetic semiconductors areof interest for potential applications in spin electronics[9]

Doped QDs also have been used as fluorescence sensorsMn-doped ZnS QDs was used for the determination of 4-nitro-phenol by QD fluorescence quenching[10] Metal-doped SnO2

has also been studied to developed luminescent NPs[11] obtain-ing particles with sizes between 71 and 162 nm without an op-tical shirt on their emission wavelength

As can be seen from the above the synthesis of doped semi-conductors is of great interest for their potential applications invarious areas In particular there are few reports of its use asphotoluminescent sensors Therefore the synthesis of dopedSnO2 QDs is an important topic in groups dedicated to opticalmaterials SnO2 NPs have been synthesized by various methodssuch as combustion[12] laser ablation[13] spray-pyrolysis[14]

and hydrothermal[15] However these methods usually need ofspecial equipment a high-cost and complicated process Eachmethod used for SnO2 can provide many NP morphologieswith different surface areas depending of these morphologiesSnO2 has been used for applications in field emissions[16]

solar cells[17] rechargeable Li batteries[18] and sensors[19]

As mentioned above hydrothermal synthesis has been re-ported however the synthesis conditions can be optimizedFor example SnO2 NPs have been obtained with temperaturesabout 180degC with prolonged reaction times[20] in another re-port a hydrothermal process involving hydrazine hydrate in-stead of NaOH has been used to produce SnO2 but stillusing high temperatures and long periods of synthesis[21]

In this work we present a simple and green method for thesynthesis of very small SnO2 NPs The synthesis does not re-quire high temperatures organic solvents or surfactants mak-ing it an environmental friendly method We developed ZnFe Co Ti-doped SnO2 NPs in a 6 h reaction with about2 nm crystalline particle size

ExperimentalSynthesis methodDoped and un-doped SnO2 NPs were synthesized following amodified methodology describe by Ye and co-workers[22] In

MRS Communications (2015) 5 63ndash69copy Materials Research Society 2015doi101557mrc201511

MRS COMMUNICATIONS bull VOLUME 5 bull ISSUE 1 bull wwwmrsorgmrc 63

54ensp ensp ensp J Mex Chem Soc 2013 57(1)ensp GabrielaenspHuelgasenspet al

Synthesis of New Chiral Monosulfonamides Prepared from (11R12R)-1112-Diamino-910-dihydro-910-ethanoanthracene and their Use as Ligands for Asymmetric CatalysisGabrielaenspHuelgas1enspHaydeeenspRojasenspCabrera1enspDomingoenspMadrigal3enspRatnasamyenspSomanathan3enspPilarenspGuzmaacuten12enspAurelioenspOrtiz2enspandenspCeciliaenspAnayaenspdeenspParrodi1

1ensp DepartamentoenspdeenspCienciasenspQuiacutemico-BioloacutegicasenspUniversidadenspdeensplasenspAmeacutericas-PueblaenspStaenspCatarinaenspMaacutertirensp72820enspCholulaenspMeacutexicoenspTelephoneensp+(55)222-2292005enspceciliaanayaudlapmx

2ensp FacultadenspdeenspCienciasenspQuiacutemicasenspBenemeacuteritaenspUniversidadenspAutoacutenomaenspdeenspPueblaensp72570enspPueblaenspPueblaenspMeacutexico3ensp CentroenspdeenspGraduadosenspeenspInvestigacioacutenenspInstitutoenspTecnoloacutegicoenspdeenspTijuanaenspApartadoenspPostalensp1166ensp22000enspTijuanaenspBenspCenspMeacutexico

ReceivedenspAugustensp1ensp2011enspacceptedenspAprilensp1ensp2013

J Mex Chem Soc 2013 57(1) 54-60copyensp2013enspSociedadenspQuiacutemicaenspdeenspMeacutexico

ISSNensp1870-249XArticle

Abstract Newenspchiralenspmonosulfonamidesensp6-16enspcontainingensp(11R12R)-diamino-910-dihydro-910-ethanoanthraceneenspasenspcarbonenspskeletonenspwereensppreparedenspCompoundsensp6-12 15 andensp16enspwereenspusedenspasenspopticallyenspactiveenspligandsenspinensptheenspenantioselectiveenspethylationenspofenspbenzaldehydeenspMoreoverensptheensp monosulfonamidesensp 6-10ensp wereensp testedensp inensp theensp asymmetricensp transferensphydrogenationensp(ATH)enspofenspacetophenoneenspwithenspRh(Cp)LenspcomplexKey wordsensp Monosulfonamideensp asymmetricensp catalysisensp enantioselec-tiveenspaddition

Resumen Nuevasensp monosulfonamidasensp quiralesensp 6-16ensp teniendoensp aensp laensp(11R12R)-diamino-910-dihidro-910-etanoantracenoenspcomoenspesqueletoenspcarbonadoenspfueronensppreparadasenspLosenspcompuestosensp6-12ensp15enspyensp16enspseensputiliza-ronenspcomoenspligantesenspoacutepticamenteenspactivosenspenensplaenspetilacioacutenenspenantioselectivaenspdeensp benzaldehiacutedoensp Ademaacutesensp lasensp monosulfonamidasensp 6-10ensp seensp probaronenspenensp laensp reduccioacutenenspasimeacutetricaenspporensp transferenciaenspdeensphidroacutegenoensp(ATH)enspdeenspacetofenonaenspconenspRh(Cp)LensputilizaacutendolosenspcomoenspcatalizadoresPalabras claveenspMonosulfonamidaenspcataacutelisisenspasimeacutetricaenspadicioacutenenspenan-tioselectiva

Introduction

Chiralensp secondaryensp alcoholsensp areensp importantensp structuresensp presentensp inenspnaturalenspproductsenspandenspinenspmanyensppharmaceuticalenspcompoundsenspandenspareenspalsoenspprecursorsenspforenspmanyenspotherenspcomplexensporganicenspmoleculesensp[1]enspHenceenspthereenspisenspneedensptoenspdevelopenspnewenspmethodsenspforenspmakingenspchiralenspsecondaryenspalcoholenspAsymmetricenspcatalysisensphasenspbeenenspaensppow-erfulensptoolensptoenspobtainenspenantiomericallyensppureensporenspenrichedenspalcoholsenspmainlyenspbyenspnucleophilicensp additionsensp toenspcarbonylensp compoundsensp [2]enspSeveralenspandenspefficientenspchiralenspligandsensphaveenspbeenenspusedenspaloneensporenspinensptheensppresenceenspofenspLewisenspacidsenspTheseenspincludeenspaminoenspalcoholsensp[3-6] α-hydroxy acids [7]enspα-amino amides [8]enspα-hydroxy amides [9]enspandensphydroxysulfonamidesensp[10-14]

Ourensp groupensp hasensp recentlyensp reportedensp theensp preparationensp ofenspbis(sulfonamide)ensp 1ensp containingensp (11R12R)-1112-diamino-910-dihydro-910-ethanoanthraceneensp asensp carbonensp skeletonensp [15]enspTheenspbis(sulfonamide)ensp1enspwasenspusedenspasenspligandenspinensptheenspasymmetricenspalkylationenspofenspprochiralenspketonesenspwithenspdiethylenspzincenspinensphighenspyieldenspandenspenantioselectivitiesenspupensptoensp99enspeeensp(Figureensp1)

SubsequentlyenspKoumlnigenspet al [16]enspdescribedensptheenspsynthesisenspofenspnovelensp tetradentateensp sulfonamideensp ligandsensp andensp usedensp themensp inensp theenspcatalyticenspasymmetricenspalkylationenspofenspaldehydesenspwithenspdiethylzincenspQuantitativeenspyieldsenspofensptheenspcorrespondingenspsecondaryenspalcoholenspandenspgoodenspasymmetricenspinductionensp(70enspyieldenspandensp74enspee)enspwereenspob-tainedenspwithenspligandsensp2a-b

Somanathanensp et al [17-18]ensp reportedensp theensp useensp ofensp monosul-fonamideensp ligandensp 3a-b derivedensp fromensp trans-(1R2R)-cyclohex-ane-12-diamineensp inensp theenspasymmetricensp transferensphydrogenationenspofensparomaticenspketonesenspEnantioselectivitiesensprangedenspfromensp70ensptoensp99enspandenspgoodenspyieldsenspforensptheenspsynthesisenspofensp1-phenylpropanolenspderiva-tivesenspwereenspachieved

RecentlyenspHiroseensp[19]enspandenspco-workersenspdescribedensptheenspsynthe-sisenspofenspchiralensp13-aminoenspsulfonamidesensp4 5

Theyenspwereensppreparedenspfromensp(-)-cis-2-benzamidocyclohexan-ecarboxylicenspacidenspandenspstudiedenspbyensptestedenspasenspligandsenspforenspcatalyticenspenantioselectiveensp additionensp ofensp diethylensp zincensp toensp aldehydesensp Theyenspprovidedenspsecondaryenspalcoholsenspinenspquantitativeenspyieldsenspandenspinenspgoodensptoenspexcellentenspenantioselectivitiesensp(upensptoensp98enspee)

Theseensp reportsensp promptedensp usensp toensp prepareensp theensp monosulfon-amidesensp6-12 15 and 16 andensptoensptestensptheirenspcatalyticenspactivityenspFirstensp

Fig 1enspChiralenspsulfonamidesenspusedenspinenspasymmetricenspcatalysis

N H H NSO 2S O 2

2a bR = a p-M eC 6H 4- b C 6H 5-

N HO 2S

M eM e

N HO 2S

M eM eO H

O H R = a p-M eC 6H 4 b C 6H 5

N HO 2S

N M e2

R = a 4 -M eC 6H 4-

R = b 4 -M eC 6H 4-

Tetrahedron Asymmetry 25 (2014) 997ndash1001

Tetrahedron Asymmetry

journal homepage wwwelsevier comlocate tetasy

Oxygenndashchlorine interactions in the transition state of asymmetricMichael additions of carbonyl compounds to b-nitrostyrene

uArr Corresponding author Tel +52 (664) 623 3772 fax +52 (664) 623 4043E-mail address rsomanathanmailsdsuedu (R Somanathan)

RCH2NO2 R1 EWG

R1 NO2

R1 EWG

R1 NO2

Scheme 1 Michael addition of nucleophiles to ab-unsaturated systems with anelectron-withdrawing group

H2N HN SO2

Scheme 2 Michael addition of acetone to nitrostyrene catalyzed bmonosulfonamides

Joseacute A Romero a Angeacutelica Navarrate a Felipe A Serviacuten a Domingo Madrigal a Andrew L Cooksy bGerardo Aguirre a Daniel Chaacutevez a Ratnasamy Somanathan auArra Centro de Graduados e Investigacioacuten del Instituto Tecnoloacutegico de Tijuana Apartado Postal 1166 Tijuana BC 22510 Mexicob Department of Chemistry and Biochemistry San Diego State University San Diego CA 92182-1030 United States

a r t i c l e i n f o a b s t r a c t

Article historyReceived 22 April 2014Accepted 9 May 2014Available online 18 June 2014

An oxygenndashchlorine interaction is reported in the transition state of the Michael addition of acetone tonitrostyrene catalyzed by enantioenriched monosulfonamides The interaction between the oxygen fromthe nitro group and the chlorine at the ortho-position of the sulfonamide moiety is supported by theoret-ical calculations Asymmetric Michael addition products catalyzed by monosulfonamides were obtainedin moderate yields and enantioselectivities

1 Introduction

The catalytic Michael reaction is an important and well-studiedprocess for stereoselective carbonndashcarbon bond formation inorganic synthesis1 In recent years the field of asymmetricorganocatalytic Michael reactions has received widespreadattention2 Among the reactions studied the conjugate additionof nitroalkanes to ab-unsaturated systems and additions involvingcarbonyl compounds to ab-unsaturated nitroalkenes are of greatinterest (Scheme 1)34 The products obtained are direct precursorsto important structural moieties such as c-aminocarbonyls2-pyrrolidones and 2-piperidones3a

Various classes of bifunctional organocatalysts have beenemployed in Michael additions such as thioureas cinchona alka-loids proline derivatives and sulfonamides4a Having a library ofenantioenriched monosulfonamides in hand5 we turned our atten-tion to using these ligands as organocatalysts in Michael additionsHerein we report the use of enantioenriched mono-sulfonamidesderived from (1R2R)-cyclohexanediamine as bifunctionalorganocatalysts to promote the addition of carbonyl compoundsto b-nitrostyrene (Scheme 2)

y chiral

The sulfonamide organocatalyst acts as a weak hydrogen bonddonor and at the same time contains a basic primary amino groupthat can activate the nucleophilic reaction partner (in this caseacetone) by generation of an enamine Thus the catalyst is pro-posed to be bifunctional in the transition state of the reaction(Fig 1A)

Digest Journal of Nanomaterials and Biostructures Vol 10 No 1 January - March 2015 p 161 - 167

SYNTHESIS AND COMPARATIVE STUDY OF N-ISOPROPYLACRYLAMIDE

(NIPAAm) HYDROGEL AND N-ISOPROPYLACRYLAMIDE-METHYL-

METHACRYLATE (NIPAAm-MMA) GEL

JA LOacutePEZ-SAacuteNCHEZa JM CORNEJO-BRAVO

b PA LUQUE

D MADRIGAL PERALTAd A OLIVAS

aPCeIM-Centro de Nanociencias y Nanotecnologiacutea - UNAM CP 22860

Ensenada BC Meacutexico bUniversidad Autoacutenoma de Baja California Facultad de Ciencias Quiacutemicas e

Ingenieriacutea Calzada Universidad SN Mesa de Otay 22300 Tijuana B C

Meacutexico cFacultad de Ingenieriacutea Arquitectura y Disentildeo Universidad Autoacutenoma de Baja

California CP 22860 Ensenada BC Meacutexico dInstituto Tecnoloacutegico de Tijuana Centro de Graduados e investigacioacuten A P

1166 22000 Tijuana B C Meacutexico eCentro de Nanociencias y Nanotecnologiacutea - UNAM CP 22860 Ensenada BC

Meacutexico

The purpose of this study was to investigate the behavior of the N-isopropylacrylamide

(NIPAAm) hydrogel and N-isopropylacrylamide-methyl-methacrylate (NIPAAm-MMA)

gel in a range of temperature close to that of the human body for potential soft tissue

repair The preparation of NIPAAm hydrogel and NIPAAm-MMA gel was done through

the free radical polymerization technique A change in the swelling of the NIPAAm

hydrogel as a function of the temperature with the time was observed but not in the

NIPAAm-MMA gel The samples were tested at 22 oC 29

oC and 37

and characterized using FT-IR Thermal stability of all the samples was studied by means

of thermogravimetric analysis and the surface morphology of the NIPAAM hydrogel is

compared with that of the copolymer of NIPAAm-MMA gel by atomic force microscopy

(Received December 14 2014 Accepted February 16 2015)

Keywords Hydrogel NIPAAm Free radical polymerization

1 Introduction

Sensitive gels change their volume depending on the properties of the environment they

are in though most are liquid This volume change is reversible and can be continuous or

discontinuous depending on the chemical structure of the sensitive hydrogel Tanaka brought

these materials to worldwide attention through his pioneering work on the temperature sensitive

N-Isopropylacrylamide (NIPAAm) polymers and copolymers and on solvent sensitive acrylamide

polymers [1-2] Hydrogels having nanoside dimensions could have many applications because of

their size As it is well known many reported hydrogels possess stimuli responsive behavior such

as thermo- and pH-sensitivity just as macrogels [3] Because many recent review papers describe

the interest in hydrogels for biomedical applications we do not aim to give a complete overview

here we only shortly highlight the advantages of hydrogels with a few appealing examples related

to potential soft tissue repair and delivery [4-7] Hydrogels are sub-micron-size water-swollen

particles composed of a three-dimensional network of hydrophilic polymer chains linked by

Corresponding author pluqueuabcedumx

Tetrahedron Letters 56 (2015) 2355ndash2358

Tetrahedron Letters

journal homepage wwwelsevier com locate tet le t

Synthesis of C2-symmetric 12-diamine-functionalizedorganocatalysts mimicking enzymes in enantioselective Michaeladdition reactions

Felipe A Serviacuten a Domingo Madrigal a Joseacute A Romero a Daniel Chaacutevez a Gerardo Aguirre aCecilia Anaya de Parrodi b Ratnasamy Somanathan auArra Centro de Graduados e Investigacioacuten en Quiacutemica del Instituto Tecnoloacutegico de Tijuana Apartado Postal 1166 Tijuana BC 22510 Mexicob Departamento de Ciencias Quiacutemico Bioloacutegicas Universidad de las Ameacutericas-Puebla Ex-Hacienda Santa Catarina Maacutertir sn Cholula Puebla 72810 Mexico

Article historyReceived 30 January 2015Revised 20 March 2015Accepted 27 March 2015Available online 2 April 2015

KeywordsMichael additionOrganocatalystsC2-Symmetric13-Benzenedisulfonamides

We report the synthesis of novel chiral wedge shaped C2-symmetric 13-benzenedisulfonamides asorganocatalysts that hydrogen bond to the nitroolefins in the transition state of the Michael additionof carbonylic compounds mimicking natural enzymes leading to products in excellent yields (up to99) and enantioselectivities (up to 99)

Introduction

The Michael reaction using organocatalysts is one of the mostefficient and broadly applicable carbonndashcarbon bond forming reac-tions known because a wide variety of acceptors and donors canbe used with high stereoselectivity12 Designing organocatalystsas small enzyme mimics to catalyze the Michael reaction has beena challenge to synthetic organic chemists over the years Variousclasses of bifunctional organocatalysts have been employed inthe enantioselective Michael addition such as thioureas cinchonaalkaloids proline derivatives and sulfonamides3 One of the mainobjectives of our research group is to design bifunctionalorganocatalysts that mimic enzymes by dual activation betweentwo functionalities in a reaction involving achiral reactants

In the search for new multifunctional catalysts that mimicenzymes we recently reported the synthesis and catalytic activityof a series of halogenated (X = Cl Br) enantioenriched monosulfon-amides as organocatalysts (Scheme 1) 4 These catalysts exhibitednovel Cl O bonding interactions (Fig 1) in addition to theexpected hydrogen bonding in the transition state of conjugateMichael addition of carbonyls to nitrostyrene4 This remarkable tri-functional interaction involving enamine formation Cl Onitro

interaction and HndashOnitro bonding in the transition state was foundcomputationally to provide structural rigidity enhancing theyields of the Michael addition product

Based on the hypothesis that multifunctional enantioselectivecatalysts would exhibit greater enantioselectivity we decided toexplore C2-symmetric organocatalysts C2 and C3-symmetric cata-lysts have been efficiently used as organocatalysts in the asymmet-ric Michael addition reactions these ligands offer two or threeactivation sites and may mimic an enzymatic catalysts5 An appar-ent advantage of C2-symmetric catalysts is that they reduce thenumber of diastereomeric transition states simplifying the analy-sis of the stereochemical outcome Based on these considerationswe synthesized a series of C2-symmetric bis-sulfonamide ligandsderived from 13-benzene sulfonyl chloride and biphenyl-440-disulfonyl chloride and tested them in the asymmetric transferhydrogenation of aromatic ketones (ATH) with Ru(II) and Rh(III)complexes (enantioselectivities up to 99 yields up to 99)6

Interestingly the structural features of these C2-symmetric bis-sul-fonamide ligands are also suitable as organocatalysts for the conju-gate Michael addition reaction with a primary amine group thatcan activate acetone by formation of an enamine intermediateand a proton donor from the sulfonamide group (NH-SO2Ar) forhydrogen bonding to the nitro group of the alkene Furthermoreprevious literature showed acetate anion recognition by similarbis-13-benzenedisulfonamides where the two acetate oxygens

Research ArticleA Novel and Highly Regioselective Synthesis ofNew Carbamoylcarboxylic Acids from Dianhydrides

Adri=n Ochoa-Ter=n1 Jesuacutes Estrada-Manjarrez2 Marisela Martiacutenez-Quiroz1

Marco A Landey-Aacutelvarez1 Eleazar Alc=ntar Zavala3 Georgina Pina-Luis1

Hisila Santacruz Ortega4 Luis Enrique Goacutemez-Pineda1 Joseacute-Zeferino Ramiacuterez4

Daniel Ch=vez1 Julio Montes Aacutevila3 Victoria Labastida-Galv=n5 and Mario Ordontildeez5

1 Centro de Graduados e Investigacion Instituto Tecnologico de Tijuana 22510 Tijuana BC Mexico2Departamento de Ingenierıa Bioquımica Instituto Tecnologico de Culiacan 80220 Culiacan SIN Mexico3 Facultad de Ciencias Quımico Biologicas Universidad Autonoma de Sinaloa 80010 Culiacan SIN Mexico4Departamento de Polımeros y Materiales Universidad de Sonora 83000 Hermosillo SON Mexico5 Centro de Investigaciones Quımicas Universidad Autonoma del Estado de Morelos 62209 Cuernavaca MOR Mexico

Correspondence should be addressed to Adrian Ochoa-Teran ochoatectijuanamx

Received 6 November 2013 Accepted 26 November 2013 Published 6 January 2014

Academic Editors C Lopez-Leonardo A Marra A Sacchetti and A Sirit

Copyright copy 2014 Adrian Ochoa-Teran et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

A regioselective synthesis has been developed for the preparation of a series of NN1015840-disubstituted 441015840-carbonylbis(carbamoyl-benzoic) acids and NN1015840-disubstituted bis(carbamoyl) terephthalic acids by treatment of 331015840441015840-benzophenonetetracarboxylicdianhydride (1) and 1245-benzenetetracarboxylic dianhydride (2) with arylalkyl primary amines (A-N)The carbamoylcarboxylicacid derivatives were synthesized with good yield and high purity The specific reaction conditions were established to obtaincarbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group Products derived from bothanhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions The chemo- andregioselectivity of products derived fromdianhydrides were determined byNMR spectroscopy and confirmed by density functionaltheory (DFT) All products were characterized by NMR FTIR and MS

1 Introduction

Some 119873-aryl 2-carbamoylbenzoic acids commonly knownas phthalamic acids are auxin transport inhibitors in plants[1ndash4] The activity of these phytotropins is directly relatedto the carboxylic acid group attached to an aromatic ringin the ortho position of a second aromatic ring through aconjugated or a planar system of atoms The spatial require-ment for a high activity is the specific distance between thetwo aromatic ring centers (73 A) Other biological effects ofthis molecule in plants include the ability to inhibit the polartransport of auxins to abolish the apical dominance effectand to prevent the geo- and phototropic response In partic-ular the119873-1-naphthyl-2-carbamoylbenzoic acid (NACBA) isknown as a potent inhibitor of auxins transport and geotropic

curvature It also has the capacity to bind to fractions contain-ing plasma membrane vesicles from maize coleoptiles

Recently the synthesis of 119873-aryl-2-carbamoylbenzoicacids under microwave assisted conditions from phthalicanhydride and aryl or heterocyclic amines in the absence ofsolvent with yields 51ndash99 has been reported [5] Significantresearch findings show that these 119873-arylphthalamic acidsinduce hyperlipidemia in Swiss white mice and also anincrease in body weight of the animals in contrast withthe hypolipidemic activity showed by their phthalimideanalogues [6]

In addition 2-carbamoylbenzoic acids and structurallyrelated compounds have shown attractive pharmaceuticaland agricultural applications as novel anti-inflammatoryimmunomodulatory antiproliferatory antithrombotic and

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 725981 11 pageshttpdxdoiorg1011552014725981

Int J Mol Sci 2014 15 5277-5291 doi103390ijms15045277

International Journal of Molecular Sciences

ISSN 1422-0067 wwwmdpicomjournalijms

Article

Antibacterial Activity of New Oxazolidin-2-One Analogues in Methicillin-Resistant Staphylococcus aureus Strains

Jesuacutes Coacuterdova-Guerrero 1 Esteban Hernaacutendez-Guevara 2 Sandy Ramiacuterez-Zatarain 2 Marco Nuacutentildeez-Bautista 1 Adriaacuten Ochoa-Teraacuten 2 Raquel Muntildeiz-Salazar 1 Julio Montes-Aacutevila 3 Gabriela Loacutepez-Angulo 3 Armando Paniagua-Michel 1 and Gustavo A Nuntildeo Torres 1

1 Escuela de Ciencias de la Salud Universidad Autoacutenoma de Baja California Ensenada Baja California 22890 Meacutexico E-Mails jesuscordovauabcedumx (JC-G) bautistamk8814hotmailcom (MN-B) arpaniaguahotmailcom (AP-M) gus_aryam19hotmailcom (GANT)

2 Centro de Graduados e Investigacioacuten en Quiacutemica Instituto Tecnoloacutegico de Tijuana Tijuana Baja California 22000 Meacutexico E-Mails ehgm10hotmailcom (EH-G) Sandy_denyshotmailcom (SR-Z)

3 Facultad de Ciencias Quiacutemico Bioloacutegicas Universidad Autoacutenoma de Sinaloa Culiacaacuten Sinaloa 80010 Meacutexico E-Mails julmontesgmailcom (JM-Aacute) gabylpz06gmailcom (GL-A)

Authors to whom correspondence should be addressed E-Mails ramusaluabcedumx (RM-S) ochoatectijuanamx (AO-T) Tel +52-646-175-0707 (ext 65305) (RM-S) +52-664-623-3772 (AO-T)

Received 30 November 2013 in revised form 12 March 2014 Accepted 17 March 2014 Published 26 March 2014

Abstract Staphylococcus aureus is one of the most common causes of nosocomial infections The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S aureus (MRSA) clinical isolates S aureus confirmation was achieved via catalase and coagulase test Molecular characterization of MRSA was performed by amplification of the mecA gene Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol using commonly applied antibiotics and the oxazolidinone analogues Only (R)-5-((S)-1-dibenzylaminoethyl)-13-oxazolidin-2-one (7a) exhibited antibacterial activity at 66 μg These results allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains

OPEN ACCESS

Research ArticleImproving the Efficiency of a Coagulation-FlocculationWastewater Treatment of the Semiconductor Industry throughZeta Potential Measurements

Eduardo Alberto Loacutepez-Maldonado1 Mercedes Teresita Oropeza-Guzmaacuten12

and Adriaacuten Ochoa-Teraacuten2

1 Centro de Investigacion y Desarrollo Tecnologico en Electroquımica (CIDETEQ) Carretera Libre Tijuana-Tecate km 265Parque Industrial El Florido 22500 Tijuana BC Mexico

2 Centro de Graduados e Investigacion en Quımica del Instituto Tecnologico de Tijuana Boulevard Alberto Limon Padilla snMesa de Otay 22500 Tijuana BC Mexico

Correspondence should be addressed to Eduardo Alberto Lopez-Maldonado eduardo a lmhotmailcom

Received 6 November 2013 Revised 11 June 2014 Accepted 12 June 2014 Published 10 July 2014

Academic Editor Saima Q Memon

Copyright copy 2014 Eduardo Alberto Lopez-Maldonado et alThis is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Efficiency of coagulation-flocculation process used for semiconductor wastewater treatment was improved by selecting suitableconditions (pH polyelectrolyte type and concentration) through zeta potential measurements Under this scenario the zetapotential 120577 is the right parameter that allows studying and predicting the interactions at the molecular level between thecontaminants in the wastewater and polyelectrolytes used for coagulation-flocculation Additionally this parameter is a key factorfor assessing the efficiency of coagulation-flocculation processes based on the optimum dosages and windows for polyelectrolytescoagulation-flocculation effectiveness In this paper strategic pH variations allowed the prediction of the dosage of polyelectrolyteon wastewater from real electroplating baths including the isoelectric point (IEP) of the dispersions of water and commercialpolyelectrolytes used in typical semiconductor industries The results showed that there is a difference between polyelectrolytedemand required for the removal of suspended solids turbidity and organicmatter fromwastewater (234mgL and 67mgL resp)It was also concluded that the dose of polyelectrolytes and coagulation-flocculation window to achieve compliance with nationaland international regulations as EPA in USA and SEMARNAT in Mexico is influenced by the physicochemical characteristics ofthe dispersions and treatment conditions (pH and polyelectrolyte dosing strategy)

1 Introduction

In the industrial wastewater treatment of semiconductorsthe most appreciated characteristic of polyelectrolytes (PE)is their solid-liquid separation efficiency with extensiveapplication in purification of drinking water industrial rawand process water municipal sewage treatment mineralprocessing and metallurgy oil drilling and recovery paperand board production and so forth [1ndash9] Polyelectrolytescan be used alone or in association with other flocculantaids such as inorganics salts surfactants or even as a secondpolymer Compared with inorganic coagulants there are

some advantages by using organic polyelectrolytes [1 6 7 1011] lower dose requirements a smaller volume of sludge asmaller increase in the ionic load of the treated water andcost savings up to 25ndash30

It is well known that the efficiency of a certain polyelec-trolytes in flocculation processes is evaluated as a function offourmain parameters the optimumflocculant concentrationwhich should be as low as possible isoelectric point (IEP)that determines the effective pH range and the flocculationwindow which must be as large as possible [12] To improvethe solidliquid separation process polymeric flocculantsmainly polycations have been used [1 6ndash9] The main

Hindawi Publishing CorporationJournal of ChemistryVolume 2014 Article ID 969720 10 pageshttpdxdoiorg1011552014969720

Journal of Hazardous Materials 279 (2014) 1ndash10

Journal of Hazardous Materials

j o ur nal ho me pa ge wwwelsev ier com locate jhazmat

oagulationndashflocculation mechanisms in wastewater treatmentlants through zeta potential measurements

A Loacutepez-Maldonado alowast MT Oropeza-Guzman ab JL Jurado-Baizaval a Ochoa-Teraacuten b

Centro de Investigacioacuten y Desarrollo Tecnoloacutegico en Electroquiacutemica Unidad Tijuana Carretera libre Tijuana-Tecate km 265sq Blvd Nogales Parque Ind El Florido CP 22444 Tijuana BC MexicoCentro de Graduados e Investigacioacuten en Quiacutemica del Instituto Tecnoloacutegico de Tijuana Blvd Alberto Limoacuten Padilla sn Mesa de Otay CP 22500 TijuanaC Mexico

i g h l i g h t s

A well planned polyelectrolyte dos-ing strategy plays a crucial role in suc-cessful coagulationndashflocculation pro-cesspZndashpH plots are a powerful toolto plan polyelectrolytes dosage andto discover coagulationndashflocculationmechanismsPreviously prepared polyelec-trolytes dispersions improvedresulting water quality after acoagulationndashflocculation process

g r a p h i c a l a b s t r a c t

r t i c l e i n f o

rticle historyeceived 19 March 2014eceived in revised form 20 May 2014ccepted 6 June 2014vailable online 21 June 2014

eywordsoagulationndashflocculation mechanismolyelectrolyte complexing capacitylectroplating wastewater

a b s t r a c t

Based on the polyelectrolyte-contaminant physical and chemical interactions at the molecular level thisarticle analyzed and discussed the coagulationndashflocculation and chemical precipitation processes in orderto improve their efficiency Bench experiments indicate that water pH polyelectrolyte (PE) dosing strat-egy and cationic polyelectrolyte addition are key parameters for the stability of metalndashPE complexesThe coagulationndashflocculation mechanism is proposed based on zeta potential () measurement as thecriteria to define the electrostatic interaction between pollutants and coagulantndashflocculant agents Poly-electrolyte and wastewater dispersions are exposed to an electrophoretic effect to determine Finallyzeta potential values are compared at pH 9 suggesting the optimum coagulant dose at 162 mgL poly-dadmac and 67 mgL of flocculant since a complete removal of TSS and turbidity is achieved Based on

ontaminantndashPE interaction the concentration of heavy metals (0931 mgL Sn 07 mgL Fe and 063 mgL Pb) treated water met theMexican maximum permissible limits In addition the treated water has 45 mg O2L chemical oxygendemand (COD) and 45 mg CL total organic carbon (TOC) The coagulationndashflocculation mechanism is pro-posed taking into account both zeta potential ()ndashpH measurement and chemical affinity as the criteriato define the electrostatic and chemical interaction between pollutants and polyelectrolytes

lowast Corresponding author Tel +52 6646453278E-mail addresses elopezcideteqmx eduardo a lmhotmailcom

EA Loacutepez-Maldonado)

1 Introduction

The electroplating wastewater in the semiconductor industrycontains dissolved and suspended heavy metals (such as Sn CrNi Pb and Cu among others) making necessary to find a suitable

Quim Nova Vol 37 No 8 1297-1301 2014

httpdxdoiorg1059350100-404220140201

e-mail jsarmientouasedumx

SYNTHESIS OF 1H-BENZOXAZINE-24-DIONES FROM HETEROCYCLIC ANHYDRIDES EVALUATION OF ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES

Juan I Sarmiento-Saacutencheza Julio Montes-Avilab Adriaacuten Ochoa-Teraacutenc Francisco Delgado-Vargasb Victor Wilson-Corrala Sylvia P Diacuteaz-Camachob Fernando Garciacutea-Paacuteeza and Pedro Bastidas-Bastidasd

aFaculty of Engineering Autonomous University of Sinaloa Blvd of the Americas SN 80040 Campus Culiacaacuten Culiacaacuten Sinaloa MeacutexicobFaculty of Chemical-Biological Sciences Autonomous University of Sinaloa Blvd of the Americas SN 80040 Campus Culiacaacuten Culiacaacuten Sinaloa MeacutexicocCentro de Graduados e Investigacioacuten en Quiacutemica Instituto Tecnoloacutegico de Tijuana Blvd Alberto Limoacuten Padilla SN 22500 Tijuana BC MeacutexicodLaboratorio de Anaacutelisis de Residuos de Plaguicidas Centro de Investigacioacuten en Alimentacioacuten y Desarrollo AC Unidad Culiacaacuten Meacutexico

Recebido em 08012014 aceito em 26052014 publicado na web em 22072014

A facile one-step synthesis of 1H-benzoxazine-24-diones from heterocyclic anhydrides and TMSA was described This paper determines their antimicrobial activity against nine human bacterial pathogens by the broth microdilution method antioxidant activity by DPPHbull inactivation and a ferric-reducing power assay and toxicity by a brine shrimp Artemia salina assay The 1H-benzoxazine-24-dione yields were in the range of 57 to 98 The novel compound 1H-pyrazino[23-][13]oxazine-24-dione 4c showed the highest antioxidant capacity (DPPH 354 and FRAP 0063 micromol TEsmicromol)

Keywords 1H-benzoxazine-24-dione antimicrobial activity antioxidant activity toxicity

INTRODUCTION

Currently microbial resistance to first-line antibiotic agents is a public health concern and new drugs are required to treat infected patients Several heterocyclic structures have shown antibacterial activity including benzoxazine-24-diones1 Benzoxazine-24-diones are potential pharmacophores because of their registered activities potent inhibitor of hepatitis C virus2 butyrylcholinesterase inhibi-tor3 antiallergic4 antitumor5 antipsychotic6 antileishmanial7 and antimycobacterial8 among others The syntheses of benzoxazine-24--diones from anthranilic acid derivatives9 isatin10 allenamides11 and carbamoylbenzoic acid12 have been reported Rao et al13 reported the synthesis of isatoic anhydride from phthalimide and sodium hy-pochlorite in a basic one-pot solution This is the only methodology used to produce isatoic anhydride on a large scale However if the temperature is not controlled during the course of the reaction the yield is significantly reduced In addition large effluents of wastewa-ter are produced In general these processes involve several reaction steps and employ expensive noncommercial or dangerous reagents thus a better process must be designed

Viewing the process from a different perspective there is an increasing interest in compounds with high antioxidant activities which could counteract the oxidative stress associated with diseases14 Antioxidant activity screening is commonly done by in vitro assays as in the ABTSbull+15 ferric-reducing1617 and DPPH1819 methods

Recently we have reported the synthesis of heterocyclic com-pounds20-24 with antiparasitary25 and antioxidant2627 activities In the following sections an easy one-step synthesis of 1H-benzoxazine-24-diones from heterocyclic anhydride with TMSA is presented and their toxicity antimicrobial activities and antioxidant activities are reported

EXPERIMENTAL

Chemistry

All reagents were purchased in the highest quality available and were used without further purification The solvents used in column chromatography were obtained from commercial suppliers and used without distillation Nuclear Magnetic Resonance of 1H (200 MHz) and 13C (50 MHz) spectra were recorded on a Varian Mercury 200 MHz Spectrometer in DMSO-d6 with TMS as an internal standard Chemical ionization mass spectra were obtained with a Varian Titan 4000 ion trap GC-MS and the intensities were reported as a percentage relative to the base peak after the corresponding mz value HR-MS was recorded on an ESIAPCI-TOF Bruker model MicroTOF-II-FocusTM at the Universidad Autoacutenoma Metropolitana Campus Iztapalapa Infrared spectra were recorded on a Cary 660 series FTIR-ATR spectrophotometer Melting points were obtained on a Stuart apparatus model SMP30 the reported value is the average of three separate experiments

General procedure for the synthesis of benzoxazine-24-diones

The heterocyclic anhydride in THF (10 mM) and trimethylsyli-lazide (TMSA 105 equiv) were stirred in a Schlenk bulb for 17 h at 53 ordmC then temperature was increased to reflux and maintained for 2 h The resulting solution was concentrated under vacuum pressure until a solid was formed The solid was washed with diethyl ether (5 x 4 mL) to obtain 1H-benzoxazine-24-diones in high purity

1H-31-benzoxazine-24-quinone (4a) (For full characterization see lit)2829 CAS number 118-48-9 yield 85 white solid Rf 058 (pe-troleum etherEtOAc 11 vv) 1H-NMR (200 MHz DMSO-d6) δ 1174 (br s 1H) 791 (dd J1=807 J2=11 Hz 1H) 774 (td J1=779 J2=128 Hz 1H) 725 (m 2H) 13C-NMR (50 MHz DMSO-d6) δ 1599 1471 1414 1369 1289 1235 1153 CG-MS mz 164 [M+H]+

Research ArticleA Novel One-Pot and One-Step Microwave-AssistedCyclization-Methylation Reaction of AminoAlcohols and Acetylated Derivatives with DimethylCarbonate and TBAC

Adriaacuten Ochoa-Teraacuten1 Leticia Guerrero2 and Ignacio A Rivero1

1 Centro de Graduados e Investigacion en Quımica del Instituto Tecnologico de Tijuana Boulevard Alberto LimonPadilla SN 22510 Tijuana BC Mexico

2 Area de Ciencias Basicas e Ingenierıas Universidad Autonoma de Nayarit Cd de la Cultura AmadoNervo SN 63190 Tepic Nay Mexico

Correspondence should be addressed to Leticia Guerrero lguerreruanedumx

Received 12 April 2014 Revised 19 August 2014 Accepted 20 August 2014 Published 14 October 2014

Academic Editor Antal Tungler

A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-13-oxazolidin-2-ones fromamino alcohols catalyzed by a ionic liquid was developed This novel one-pot and one-step cyclization-methylation reactionrepresents an easier and faster method than any other reported protocols that can be used to obtain the desired products in goodyields and high purity Applyingmicrowave irradiation at 130∘C in the presence of TBAC dimethyl carbonate acts simultaneously ascarbonylating andmethylating agent and surprisingly promotes an in situ basic trans esterificationwhen aN-acetylated amino alco-hol is used as starting material Furthermore dimethyl carbonate worked better than diethyl carbonate in performing this reaction

1 Introduction

In general amino alcohols are readily available by reductionof an 120572-aminoacid and are important precursors in thesynthesis of 13-oxazolidin-2-ones [1ndash6] Phenylalanine-derived aminoalcohols phenylglycine and valine amongothers are used for the preparation of commerciallyimportant 13-oxazolidin-2-one chiral auxiliaries In thiscontext a large number of reagents have been used in thepresence of amino alcohols to synthesize 13-oxazolidin-2-ones Early methods are focused to employ phosgene inreactions with amino alcohols [7ndash9] Other early effortstoward the synthesis of 13-oxazolidin-2-ones consist inthe fusion of urea with the amino alcohols above theirmelting points [10ndash12] Cyclization with tosyl chloride can beachieved with N-methylated Boc amino alcohol derivatives[13] More recently with the decreasing use of phosgenean efficient synthesis of 13-oxazolidin-2-ones from diethylcarbonate (DEC) has become prevalent [3 14 15]

In general the preparation of 4-substituted-N-alkyloxa-zolidin-2-ones is achieved through a two steps sequence thatis the carbonylation of 12-amino alcohols or N-acetylatedamino alcohols with phosgene or triphosgene followed bythe N-alkylation of the resulting 13-oxazolidin-2-one withan alkyl halide (R2X) or a basic deacetylation and alkylation(Scheme 1)

These procedures are not ecofriendly due to risks asso-ciated with toxic and corrosive reagents such as phos-gene and carcinogenic alkyl halides A safer easier andecofriendly alternative can be conceived with the use ofnontoxic dimethyl carbonate (DMC) There are only a fewexamples where dimethyl carbonate simultaneously actsas carbonylating and alkylating agent Among them thecase of oximes with an 120572ndashCH

2group for the synthesis

of 3-methyl-45-disubstituted-4-oxazolin-2-ones [16] Morerecently the preparation of N-methylbenzoxazol-2-onesfrom o-aminophenol and dimethyl carbonate with catalytic

Research ArticleSynthesis and Antioxidant Evaluation ofEnantiomerically Pure Bis-(123-triazolylmethyl)aminoEsters from Modified 120572-Amino Acids

Juan I Sarmiento-Saacutenchez1 Adriaacuten Ochoa-Teraacuten2 and Ignacio A Rivero2

1 Facultad de Ingenierıa Universidad Autonoma de Sinaloa Boulevard de las Americas SN 80040 Culiacan SIN Mexico2 Centro de Graduados e Investigacion del Instituto Tecnologico de Tijuana Boulevard Alberto Limon Padilla SNApdo Postal 1166 22500 Tijuana BC Mexico

Correspondence should be addressed to Juan I Sarmiento-Sanchez jsarmientouasedumx

Received 3 June 2014 Accepted 5 August 2014 Published 15 October 2014

Academic Editor Santiago Garcia-Granda

Copyright copy 2014 Juan I Sarmiento-Sanchez et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

The efforts for synthesis of enantiomerically pure bis-(123-triazolylmethyl)amino esters 6 are reported in good yields from an insitu generated 120572-azidomethyl ketone Optimum experimental conditions were established for preparation of 120572-halomethyl ketones10 and 120572-NN-dipropargylamino esters 11 all derived from 120572-amino acids The starting materials reacted under conventional clickchemistry conditions revealing a specific reactivity of bromomethyl ketones over chloromethyl ketonesThe antioxidant activity ofcompounds6was assayed byDPPHmethodThe compound6cwith an IC

50of 7557plusmn 174 120583gmLminus1 was themost active Technically

this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics dependingon the nature of the modified 120572-amino acids employed in the synthesis

1 Introduction

Click chemistry has been defined as an efficient and an almostperfect method (very selective with high yields and widescope) for the synthesis of new and diverse compounds basedin a carbon-heteroatom bond formation This reaction hasbeen particularly useful for coupling two molecules azidesand alkynes to get 123-triazole compounds [1] Howeverit was only after the discovery of copper catalysis thatits applications began to be studied [2] Click chemistrymeets the requirements of an innovative functionalizationstrategy for biomolecules because it is efficient selective andwithout side reactions Rostovtsev et al [3] and Tornoslashe et al[4] have reported that 14-disubstituted 123-triazoles arespecifically prepared from azides and terminal alkynes undercopper(I) catalysis to give 14-substituted products with highregioselectivity The regioisomeric 15-disubstituted triazolesare available from azides and terminal alkynes by the use ofeither magnesium acetylides or ruthenium catalysts [1 5 6]123-Triazole compounds have attracted attention because

they exhibit a broad variety of biological activities For exam-ple compounds such as 1 are active against Mycobacteriumtuberculosis [7] other compounds act as anticancer 2 [8]antifungal 3 [9] or antitumor agents 4 [10] Scheme 1 Somebiomedical applications have been described for examplethe labelling of biomolecules [11] In addition 123-triazoleshave been used in the coupling of modified 120572-amino acidsin oligopeptide synthesis [4 12ndash17] Furthermore this classof modified oligopeptides 5 showed activity as inhibitors ofcysteine protease CPB28ΔCTE in Leishmania mexicana [18]and antiviral activity against HIV-1 gp120 [19 20]

The cycloaddition of azides and alkynes is typicallycarried out in refluxing toluene but labile molecules maynot be stable under these conditions Also although organicazides are generally safe compounds those of low molecularweight can be unstable and therefore difficult to handleThis is especially true for small molecules with several azidefunctionalities which would be of much interest for thegeneration of polymeric structures Thus a methodologythat avoids isolation of organic azides as intermediates is

LECopyright copy 2014 by American Scientific Publishers

Printed in the United States of America

Science of Advanced MaterialsVol 6 pp 1ndash8 2014

(wwwaspbscomsam)

Size-Dependent Enhanced Energy Transfer fromTryptophan to CdSeMercaptopropionic AcidQuantum Dots A New Fluorescence ResonanceEnergy Transfer NanosensorA Tirado-Guiacutezar1 G Pina-Luis1lowast F Paraguay-Delgado2 and D Ramiacuterez-Herrera1

1Centro de Graduados e Investigacioacuten Instituto Tecnoloacutegico de Tijuana AP 1166 Tijuana 22500 BC Meacutexico2Centro de Investigacioacuten en Materiales Avanzados S C Departamento de Fiacutesica de Materiales Av Miguel de Cervantes120 Complejo Industrial Chihuahua CP 31109 Chihuahua Chih Meacutexico

ABSTRACT

We report here the interaction of mercaptopropionic acid (MPA)-capped CdSe quantum dots (QDs) of differentsizes with tryptophan in aqueous solution Two populations of QDs emitting at 578 and 596 nm were testedin two concentration ranges CdSeMPA QDs efficiently quenched the photoluminescence (PL) of tryptophanin a size-dependent manner The results revealed that the binding constant (KA) and the number of bindingsites (n) were higher for larger QDs and the values of logKA were proportional to n The PL of QDs wasgradually enhanced with increasing amount of tryptophan indicating a fluorescence resonance energy transfer(FRET) from tryptophan to QDs The Foumlrster radius and donorndashacceptor distances were estimated from theexperimental measurements of energy transfer efficiency A more effective process occurred in the larger-sizedQD acceptors Under the optimized conditions QDs596 showed a linear increase of PL in the presence oftryptophan in the concentration range of 0 to 9times10minus7 M (R= 0995) and a detection limit of 54times10minus7 M Nointerference from coexisting amino acids such as tyrosine phenylalanine and glycine was found High selectivityand sensitivity and a fast response time make CdSeMPA QDs a suitable nanosensor for the quantitativedetermination of tryptophan

KEYWORDS CdSe QDs Nanoparticle Size Energy Transfer Tryptophan Detection

1 INTRODUCTIONQuantum dots (QDs) have attracted considerable attentionin recent years for their applications in chemistry physicsand biology1 As a result of quantum confinement suchnanoparticles have optical and electronic properties thatcan be adjustable through their size2 Compared to conven-tional organic fluorophores QDs have narrow and sym-metric emission bands and high photochemical stability34

The modification of QDs with biomolecules has beenwidely used in biological field for various applicationssuch as cell and tissue labeling5 for bioimaging6 and drugdelivery7 In contrast to the large number of reports on theuse of QDs as fluorescent labeling for biomolecules theapplications of QDs as a new class of nanomaterials inchemical sensing are still in the early stages Some studies

lowastAuthor to whom correspondence should be addressedEmails gpinaluistectijuanamx gpinaluisyahoocomReceived xx Xxxx xxxxAccepted xx Xxxx xxxx

based on the chemical sensing of small molecules and ionsusing QDs have been reported8ndash14

Foumlrster resonance energy transfer (FRET) is a processwhereby a donor (D) transfers energy to an acceptor(A) via a through-space-dipolendashdipole interaction FREToccurs over distances of 1ndash10 nm when there is apprecia-ble overlap between the emission spectrum of the donorand the absorption spectrum of the acceptor Analyticalmethods based on FRET have high sensitivity and arevery easy to perform FRET-based methods are very use-ful in detecting ligand-receptor binding by measuring theenhancement in fluorescence intensity of the acceptor QDshave been used in FRET systems both as donors15ndash19 andas well as energy acceptors20ndash24

Amino acids are biomolecules of great relevance asthey involve in several functions in the living organismTryptophan is one of the most important amino acids forhuman nutrition and is also involved in neurotransmissionprocesses as a serotonin and melatonin precursor2627 Asthe distribution transport and toxicity of QD are closely

Sci Adv Mater 2014 Vol 6 No 3 1947-293520146001008 doi101166sam20141742 1

Journal of Luminescence 134 (2013) 729ndash738

Contents lists available at SciVerse ScienceDirect

Journal of Luminescence

0022-23

n Corr

journal homepage wwwelseviercomlocatejlumin

New dual emission fluorescent sensor for pH and Pb(II) basedon bis(napfthalimide) derivative

Georgina Pina-Luis an Marisela Martınez-Quiroz a Adrian Ochoa-Teran a Hisila Santacruz-Ortega bEduardo Mendez-Valenzuela a

a Centro de Graduados e Investigacion en Quımica Instituto Tecnologico de Tijuana AP 1166 Tijuana 22500 BC Mexicob Departamento de investigacion en Polımeros y Materiales Universidad de Sonora Hermosillo Sonora 83000 Mexico

a r t i c l e i n f o

Article history

Received 8 December 2011

Received in revised form

2 July 2012

Accepted 16 July 2012Available online 13 September 2012

Keywords

Dual emission

pH sensor

Pb sensor

Excimer

Bis(naphtalimides)

13$ - see front matter amp 2012 Elsevier BV A

xdoiorg101016jjlumin201207002

esponding author Tel thorn52 664 6233772 fa

ail addresses gpinaluisyahoocom gpinaluis

a b s t r a c t

This paper describes a novel dual emission bis-18-naphthalimide sensor for selective determination of

pH and Pb2thorn ions The influence of the variability in the backbone that links the two fluorophores

(naphthalimides) as a function of pH and metal ions was studied by UVndashvisible and fluorescence

spectroscopy Compounds 1(andashd) with different length alkyl linkers (CH2)n (nfrac141 2 4 and 6) showed no

excimer formation in aqueous solution Fluorescence emission of these derivatives varied in a narrow

range of pH (5ndash8) and was only slightly influenced by the addition of metal ions in CH3CN solutions

However derivative 1e with amino-containing spacer (CH2ndashNHndashCH2) showed excimer emission in

aqueous solution a wide response to pH (25ndash95) and fluorescence enhancement with selective

behavior towards metal ions The pH sensor based in derivative 1e has a sufficient selectivity for

practical pH monitoring in the presence of Lithorn Nathorn Kthorn Csthorn Ca2thorn Mg2thorn Ba2thorn Cu2thorn Pb2thorn Ni2thorn

Zn2thorn and Cd2thorn The coordination chemistry of these complexes was studied by UVndashVis fluorescence

and 1H NMR This chemosensor displayed high selectivity fluorescence enhancement toward Pb2thorn ions

in the presence of the metals ions mentioned in CH3CN solutions Competitive assays show that a 1-fold

of metal cations in each case compared with Pb2thorn ions results in less than 75 fluorescence intensity

changes Linear calibration up to 1105 M for Pb(II) ions (Rfrac1409968) was obtained and detection

limit resulted of 50108 M

1 Introduction

The determination of pH has a great interest in different areassuch as environmental monitoring clinical analysis control andmonitoring of biochemical reactions industrial processes devel-opment of new pharmaceutical products and scientific researches[1ndash7] Although the measurement of pH based on electrochemicalmethod is well established and known it has disadvantages andlimitations for example the signal can be influenced by electro-magnetic fields and aggressive analytes (alkaline solutions orF ions) which can destroy the glass surface of the electrode The pHsensors based in optical measurements offer very promisingalternatives that eliminate these drawbacks They are versatileeasy to miniaturize inexpensive and can be used for remotesensing In particular the fluorescence method is sensitiveselective and provides the possibility of fluorescence imagingmeasurement

ll rights reserved

x thorn52 664 6234043

tectijuanamx (G Pina-Luis)

On the other hand heavy metals represent an environmentalconcern due to their harmful effects on human health In particularlead produces a wide variety of health effects such as mentalretardation cardiac and neurologic diseases even when present inlow concentration The determination of lead by analytical methodssuch as flame or plasma techniques can lead to a low precision andsensitivity due to the effects of high back-ground and chemicalinterferences Thus the fluorimetric methods are an alternative thatcan provide good selectivity sensitivity and low cost Despite theseadvantages most fluorimetric methods for determination of heavymetals are based on a fluorescence quenching which is not the bestalternative so there is a great interest in developing fluorescentsensor that give rises an increase in the analytical signal

The measurement of fluorescence can be affected by fluctuationsin excitation source photobleaching of the fluorophore reagentdetector drifts and background fluorescence These effects can beavoided using ratiometric measurements [8ndash11] The method isbased on fluorescence intensity measurement of a sensitive indica-tor at two different wavelengths that prevents most of the systema-tic errors associated with this type of measurement The number ofspecial fluorophores sensitive to pH or metal ions with dualexcitation or emission wavelengths is limited An approach for

Journal of Environmental Protection 2013 4 270-279 doi104236jep201343032 Published Online March 2013 (httpwwwscirporgjournaljep)

Evaluation of the Physicochemical Behavior of Waste Water Treatment Polyelectrolytes with Metal Ions

Eduardo A Loacutepez Maldonado1 Mercedes T Oropeza Guzmaacuten12 Georgina Pina-Luis1 Adriaacuten Ochoa-Teraacuten1

1Graduate and Research Center of the Technical Institute of Tijuana Tijuana Meacutexico 2Centre for Research and Technological De-velopment in Electrochemistry Tijuana Meacutexico Email ochoatectijuanamx Received November 25th 2012 revised January 3rd 2013 accepted February 2nd 2013

ABSTRACT

In this paper is describing the physicochemical behavior of polyelectrolytes (PEs) used in waste water treatment with mono- di- and trivalent metal ions as K+ Mg2+ Zn2+ Fe3+ Sn2+ Cd2+ Pb2+ Cu2+ Ni2+ Al3+ and Cr3+ A coagulant polyelectrolyte Poly(vinyl sulfate) potassium salt (PVSK) and a commercial available Flocculant Trident 2756 were used as models for the study The colloidal titration UV-Vis spectroscopy technique was successfully implemented in order to evaluate the complexation of PEs with Toluidine Blue O (OTB) and the ability of different metal ions to dis-place the OTB from the PE-OTB complex and form the PE-metal ion complex From the experiments was concluded that PVSK has a high affinity for Al3+ and Mg2+ while the Flocculant has the highest affinity for Sn2+ followed by Zn2+ and Mg2+ The absorbance profiles of polyelectrolyte-OTB complex (Absorbance vs MetalPE) were used to calculate association constants On the other hand the mass balance of OTB and its absorbance profiles were used to calculate the association constants of polyelectrolyte-metal ion complexes Thus metal ions with the highest affinities have the highest association constant Metal ions with the highest affinities present the highest values of association constant Keywords Polyelectrolytes Metal Ions Colloidal Titration UV-Vis Spectroscopy O-Toluidine Wastewater

Treatment

1 Introduction

Polyelectrolyte chains have atoms or groups of atoms which have the ability to chelate or exchange sities with metal ions [1] The most common coordinating atoms present in a polymer chain either central or side chain are nitrogen oxygen phosphorus and sulfur [2] For those polymers in which the polymer-metal ion interaction involves an ion exchange process the most common are the quaternary ammonium with chloride sulphate and hydroxyl counterions [3] Polyelectrolyte-metal ion interaction could be electrostatic or may include the formation of coordinated bonds The type of interaction depends on the chemical nature (ionization potential and electronic affinity) of the functional groups The vari- ables that affect the PE-metal ion interaction are classi- fied into two groups intrinsic and extrinsic to the polymer [4] The former group includes the polymer structure in terms of composition and geometry which affects the flexibility of the chains in solution branches of the chain chemical nature of the functional groups and their dis-

tribution at the polymer chain etc The second group includes the charge and type of the metal ion pH ionic strength temperature and dielectric constant of the medium [56] The knowledge of association phenomena of metal ions with charged macromolecules is essential for understanding of their physicochemical behavior in environmental biological systems and in waste water treatment by coagulation-flocculation [7-9]

Polyelectrolytes are used in coagulation-flocculation processes mainly to remove suspended particles turbidity and color However due to their chemical nature polyelectrolytes also interact with oppositely charged species as metal ions that are present in the wastewater For example the treatment of waste water from semiconductor fabrication industry with high suspended solids content of heavy metals where the objective is to remove suspended solids as well as heavy metals content Therefore it is important to study the physicochemical behavior of polyelectrolytes with different metal ions present in the waste water with the aim of determining the affinity and capacity of removal of each metal with polyelectrolytes in order to determinated the optimal Corresponding author

Copyright copy 2013 SciRes JEP

Adsorption of Phenol and Chlorophenol Mixtures on Silicalite-1 Determined by GC-MS Method 125

Adsorption of Phenol and Chlorophenol Mixtures on Silicalite-1 Determined by GC-MS MethodZareth Ortiz-Arzate14 Thelma S Jimeacutenez-Bravo1 Norma A Saacutenchez-Flores2 Graciela Pacheco-Malagoacuten2

Silvia Bulbulian2 and Ignacio A Rivero13

1 Instituto Nacional de Investigaciones Nucleares Departamento de Quiacutemica Meacutexico DF Meacutexico2 Centro de Ciencias Aplicadas y Desarrollo Tecnoloacutegico Universidad Nacional Autoacutenoma de Meacutexico Av Universidad 3000

Col Universidad Nacional Autoacutenoma de Meacutexico Ciudad Universitaria AP 70-186 Delegacioacuten Coyoacaacuten CP 04510 Meacutexico D F Meacutexico

3 Centro de Graduados e Investigacioacuten en Quiacutemica del Instituto Tecnoloacutegico de Tijuana Apartado Postal 1166 Tijuana B C 22000 Meacutexico iriverotectijuanamx

4 Universidad Autoacutenoma del Estado de Meacutexico Toluca Meacutexico

Received October 4 2012 accepted April 22 2013

J Mex Chem Soc 2013 57(2) 125-131copy 2013 Sociedad Quiacutemica de Meacutexico

ISSN 1870-249XArticle

Abstract A method is presented in which gas chromatography cou-pled with mass spectrometry (GC-MS) allows quantitative simultane-ous detection of mixtures of phenol (Ph) 2-chlorophenol (2-CPh) 3-cholorphenol (3-CPh) and 4-cholorophenol (4-CPh) in aqueous mixtures after being adsorbed on silicalita-1 utilizing selected-ion monitoring (SIM) and full-scan modes mass selective detection GC-MS with SIM at mz = 64 and mz = 128 showed good detection selectivity for mixtures of Ph 2-CPh and 3-CPh (M1) and 2-CPh and 4-CPh (M2) Silicalita-1 was obtained from an amorphous organo-alu-mino-silicic gel from rice husk an abundant and low cost agricultural waste residue that is readily available in large quantities This product was used as a sorbent for solid phase extraction of organic analytes from aqueous solutions The adsorption of the three chlorophenol isomers ortho- meta- and para- by silicalite-1 has been studied independently showing that meta- and para-chlorophenol isomers are adsorbed more than ortho-chlorophenol However the adsorption behavior of mixtures of these isomers was not reported In this work it was found that when the ortho-isomer is mixed either with meta-or para-chlorophenol considerable differences were observed in the adsorption process in the studied mixture the ortho-isomer was ad-sorbed more than the meta-and para-chlorophenolKey words Silicalite-1 rice husk GC-MS ortho-chlorophenol me-ta-chlorophenol para-chlorophenol

Resumen En este trabajo se presenta un meacutetodo cromatograacutefico aco-plado a la espectrometriacutea de masas (GC-MS) que permite la deteccioacuten simultaacutenea de fenol(Ph) 2-clorofenol (2-CPh) 3-clorofenol (3-CPh) y 4-clorofenol (4-CPh) en mezclas acuosas despueacutes de ser adsorbidas sobre silicalita-1 utilizando iones previamente seleccionados (SIM) y el espectro completo de iones Los iones en SIM de mz = 64 y 128 mostraron una buena deteccioacuten y selectividad para mezclas de Ph 2-CPh y 3CPh (M1) y 2-CPh y 4-Cph (M2) La silicalita-1 se obtuvo a partir de un gel oacutergano-alumino-siliacutecico amorfo proveniente de caacutescara de arroz material abundante y de bajo costo dado que proviene de residuos agriacutecolas disponible faacutecilmente en grandes cantidades Este producto se utilizoacute como un sorbente en la extraccioacuten en fase soacutelida de analitos orgaacutenicos a partir de soluciones acuosas La adsorcioacuten de los tres isoacutemeros de clorofenol orto meta y para por la silicalita-1 ha sido estudiada de forma independiente mostrando que los isoacutemeros meta y para clorofenol se adsorben maacutes que el orto-clorofenol Sin embargo el comportamiento de adsorcioacuten de mezclas de estos isoacuteme-ros no se ha reportado En este trabajo se ha encontrado que cuando el isoacutemero orto se encuentra en mezcla con el meta o para-clorofenol presentan diferencias considerables como se observoacute en el proceso de adsorcioacuten en la mezcla estudiada el isoacutemero orto se adsorbe maacutes que el meta y para-clorofenolPalabras clave Silicalita-1 caacutescara de arroz CG-EM orto-clorofe-nol meta-clorofenol para-clorofenol

Introduction

Phenols and related compounds are toxic to humans and aquatic life Chlorophenols are formed as metabolites of agricultural pesticides in pulp bleaching processes and as byproducts of the chlorination of drinking waters (NMx-AA-050-1981) [1] The adsorption technique is one of the alternative treatment processes currently being considered to achieve required levels in the removal of phenols The adsorption of phenols by differ-ent adsorbents has been investigated to identify the relationship between adsorption capacity and adsorbent characteristics such as surface area and pore size distribution for separation applica-tions in the drinking water concentration range [2]

Activated carbon as one of the active adsorbents has been extensively used in the process due to its predominant pro-portion of micropores Alternative adsorbents studied include

naturally occurring materials such as biosorbentes [6] clays zeolites and resins [7]

Silicalite-1 (SLC-1) which has a similar structure to ZSM-5 is a molecular sieve that was first synthesized in early 1970s [8] It was obtained from rice husk through a calcinations pro-cess under specific conditions that allow retention of organic matter [9 10] This material is a zeolite with a high content of silica [11 12] SLC-1 is hydrophobic and can remove organic molecules in liquid or gaseous samples It is a polymorph of silica with an unusual crystal structure It has a tetrahedral geometry of mostly 5-membered rings of silicon-oxygen tetra-hedra This spatial distribution has interesting channels with a diameter of 6 Aring that are defined by rings of 10 oxygen atoms [8]

The high hydrophobicity of SLC-1 allows it to capture aromatic components of highly toxic simple structures among

Selective Reduction of Phenylacetylene with AlMgO Particles usedas an Alternative Water-Reactive Generator of Hydrogen

Anna Kozina bull Jose L Iturbe bull Ignacio A Rivero

Received 14 December 2012 Accepted 29 April 2013

Springer Science+Business Media New York 2013

Abstract A new inorganic material was used to produce

hydrogen in situ by contact with water for reduction of

unsaturated hydrocarbons Phenylacetylene reduction into

styrene and ethylbenzene was chosen as a model reduction

reaction We show that a fine control over the reaction

yield and selectivity can be obtained by controlling the

hydrogen release and such parameters of the synthesis as

the temperature water content and the speed of stirring

We found that the largest amount of water at 80 C and

vigorous stirring result in the highest yield and selectivity

of the reaction An alternative way of reaction control is

suggested as compared to a conventional way of a catalyst

inhibition The new possibility of the reaction control may

be of a wide interest for the laboratory synthesis for a good

number of hydrogenation reactions

Keywords Hydrogenation AlMgO particles Hydrogen source Phenylacetylene

1 Introduction

The hydrogenation (reduction) of unsaturated organic

compounds is a widely used chemical reaction for many

industrial applications in such as petro- food and health

industry The hydrogenation of alkynes is an important

industrial process to obtain alkenes and alkanes The

interest in reduction of phenylacetylene (PA) has its origin

in the reaction products styrene (ST) and ethylbenzene

(EB) Styrene is an extremely important monomer in

numerous polymerization reactions therefore its produc-

tion from phenylacetylene is important both from scientific

and industrial standpoints However the styrene production

is not a trivial task since the hydrogenation reaction

(Eq 1) usually does not stop on the first stage and results in

a mixture of styrene with ethylbenzene or even proceeds

completely to ethylbenzene alone

Ph--CCHPh--C=CH2Ph--CH2CH3 eth1THORN

To obtain styrene as a main product the reaction must be

thoroughly controlled by tuning the reaction conditions

Therefore PA partial reduction is a convenient model to

evaluate the process design performance of catalyst or to

optimize reaction conditions There are two main

conditions to be fulfilled in any typical hydrogenation

reaction (i) the presence of a catalyst (usually platinum

group metals) and (ii) the hydrogen source Also there are

at least two ways to carry out the hydrogenation first

hydrogen may be added to the reaction in a gaseous form as

a batch (from a balloon under atmospheric pressure or a

built hydrogen source under high pressure andor

temperature) or a dilute steam of reactant mixed with

hydrogen is made to flow above or through the catalyst

(flow hydrogenation) [1] Thus there are mainly two ways

to gain control over the process ratemdashby decreasing the

A Kozina J L Iturbe I A Rivero

Departamento de Quımica Instituto Nacional de Investigaciones

Nucleares 52750 Ocoyoacac Estado de Mexico Mexico

e-mail annakozinafisicaunammx

Present AddressA Kozina

Instituto de Fısica Universidad Autonoma Nacional de Mexico

CU 04510 Mexico DF Mexico

Present AddressI A Rivero (amp)

Centro de Graduados e Investigacion en Quımica Instituto

Tecnologico de Tijuana 22000 Tijuana Mexico

e-mail iriverotectijuanamx

Catal Lett

DOI 101007s10562-013-1019-1

Authors personal copy

LGAC-QOFS-Prod_Articulos_RESUMEN

1) 2017 Microchim Acta 1841-9

2) 2017 Chem Eng Journal 307 981-988

3) 2017Sensor And acuatorB Chem 244 922-927

4) 2017 SuprmolChem 1277585

8) 2016 Mendelev Commun 26 69-71 A Ochoa Teran

9) 2016 J Mater Sci D Aguilar Garcia

10) 2016 Sensor Actuat B-Chem 233 459-468 L M de la Rosa Romo

Flavone functionalized magnetic nanoparticles A new fluorescent sensor for Cu2+ ions with nanomolar detection limit

1 Introduction

2 Experimental

21 Materials and apparatus

22 Synthesis of SiO2-coated magnetite nanoparticles

23 Amino-functionalization with AEAPS

24 Morin functionalization

25 Fluorescence titrations with Cu2+ ions

3 Results and discussion

31 Synthesis of magnetic fluorescent nanoparticles

32 Nanoparticle characterization

321 TEM characterization

322 FTIR characterization

323 VSM studies

324 TGA characterization

325 Zeta potential

33 Fluorescence detection of Cu2+ ions

34 Selectivity and interference study

35 Analytical performance of the nanosensor

4 NR not reported Conclusions

Acknowledgments

Appendix A Supplementary data

References

Biographies

11) 2016 Supramol Chem M Martinez Quiroz

12) 2016 Anal Lett L E Solis Delgado

13) 2016 Supramol Chem M A Landey J E Garcia

14) 2016 J Electochem Soc 165 4337 M I Salazar Gastelum

15) 2016 I A Rivero

18) 2015 Int J Electrochem Sci 10 6743-6753 I Monreal

19) 2015 Mater Express 5 33 A Tirado Guizar

20) 2015 MRS Commun 5 63-69 A Tirado Guizar


Introduction

Experimental

Synthesis method

Characterization

Results and discussion

Morphology and elemental analysis

XRD studies

Raman spectral study

Fluorescence analysis

Conclusions

Supplementary materials

Acknowledgments

References

2013 J Mex Chem Soc 57 54-60 D Madrigal R Somanathan

2014 Tetrahedron Asymmetr 25 997-1001 J A Romero A Navarrate F A Servin

Oxygenndashchlorine interactions in the transition s

1 Introduction


3 Conclusion

4 Experimental section

41 General procedure for the preparation of the monosulfona-mides

411 N-((1R2R)-2-Aminocyclohexyl)-35-dichloro-2-hydroxy-benzenesulfonamide 2

412 N-((1R2R)-2-Aminocyclohexyl)-23-dichlorobenzenesulf-onamide 3a

413 N-((1R2R)-2-Aminocyclohexyl)-24-dichlorobenzenesulf-onamide 3b

414 N-((1R2R)-2-Aminocyclohexyl)-25-dichlorobenzenesulf-onamide 3c

415 N-((1R2R)-2-Aminocyclohexyl)-26-dichlorobenzenesulf-onamide 3d

416 N-((1R2R)-2-Aminocyclohexyl)-25-dibromobenzenesulf-onamide 3e

42 Procedure for the addition of acetone to tra

Acknowledgments

References

2015 Digest J of Nanomat and Biostruc 10 161-167 D Madrigal Peralta

2015 Tetrahedron Lett 56 2355-2358 F A Servin J A Romero

Synthesis of C2-symmetric 12-diamine-functionalized organocatalysts mimicking enzymes in enantioselective Michael addition reactions

Introduction


Conclusions

Acknowledgments

References and notes

21) 2014 The Sci World Journal M A Landey Alvarez E Alcazar Zavala

22) 2014 Int J Mol Sci 15 5277-5291 E Hernandez Guevara S Ramirez Zatarain

1 Introduction

2 Results and Discussion

21 Chemical Synthesis

22 Antimicrobial Susceptibility Analysis

23Toxicity Test

3 Experimental Section

31 Biochemical and Molecular Identification of Methicillin Resistant S aureus (MRSA) Isolates


33 Toxicity Test


4 Conclusions

Acknowledgments

Author Contributions

Conflicts of Interest

References

23) 2014 J of Chemistry E A Lopez Maldonado

24) 2014 J Hazard Mater 279 1-10 E A Lopez Maldonado

Coagulationndashflocculation mechanisms in wastewater treatment plants through zeta potential measurements

1 Introduction

2 Materials and methods

21 Reagents

22 Methods

221 Wastewater sampling in the assembling semiconductor industry

222 Preparation of wastewater dispersions

223 Nonstoichiometric polyelectrolyte complexes (NIPECs) preparation

224 Colloid titration

225 Chemical precipitation

226 Micro-Jar tests

227 Analytical techniques

228 Scanning electron microscopic (SEM) images and energy-dispersive X-ray spectroscopy (EDS) microanalysis

229 Speciation

3 Results and discussions

31 Characterization of wastewater from electroplating process in a semiconductor industry

32 Determination of the isoelectric point for the electroplating wastewater


34 Process coagulationndashflocculation (single flocculation A)

35 Process coagulationndashflocculation (single flocculation B)

36 Process coagulationndashflocculation (single flocculation C)

37 Process coagulationndashflocculation (dual flocculation D)

4 Conclusions

Acknowledgements

References

25) 2014 Quim Nova 37 1297-1301 A Ochoa Teran

26) 2014 The Sci World Journal L Guerrero

27) 2014 The Sci World J A Ochoa Teran

28) 2014 Sci Adv Materials 6 1-8 A Tirado Guizar

29) 2013 J Lumin 134 729-738 M Martinez-Quiroz E Mendez Valenzuela

New dual emission fluorescent sensor for pH and Pb(II) based on bis(napfthalimide) derivative

Introduction

Experimental

Synthesis

General procedure for the preparation of compounds 1(a-d)

N-propyl-18-naphthalimide 2

Bis(N-propyl-18-naphthalimidyl) (1a)

Bis(N-butyl-18-naphthalimidyl) (1b)

Bis(N-hexyl-18-naphthalimidyl) (1c)

Bis(N-octyl-18-naphthalimidyl) (1d)

Bis(N-ethyl-18-naphthalimidyl)amine (1e)


Fluorescence characteristics

Dependence of pH on the fluorescent intensity of the dyes

Measuring range

The effect of ionic strength

Interference study of pH sensor

Influence of metal cations on the fluorescence intensity of the bis-18-naphthahlmide (1a-e)

UV-visible study

Interference study of lead sensor

1H NMR study

Conclusions

Acknowledgment

References

30) 2013 J Environm Protec 4 270-279 E A Lopez Maldonado

31) 2013 J Mex Chem Soc 57 125-131 I A Rivero

32) 2013 Catal Lett I A Rivero

Selective Reduction of Phenylacetylene with AlMgO Particles used as an Alternative Water-Reactive Generator of Hydrogen

Abstract

Introduction

Experimental

Synthesis and Characterization of AlMgO material

Reaction Scheme

Results

Material Characterization

Influence of Reaction Conditions on Product Outcome

Discussion

Conclusions

Acknowledgments

References