FLUO 1

“Organometallic” chemistry of iodine(III) fluorides

S. DiMagno, sdimagno1@unl.edu. Department of Chemistry, University of Nebraska, Lincoln, NE, United States Fluoride is a uniquely hard ligand that is known to stabilize high oxidation states of transition metal ions. Here we show that fluoride ion also has a similar effect upon diaryliodonium(III) species and discuss how treating iodine(III) as a transition metal can lead to control of inner-sphere redox events, ligand promoted exchange reactions, and disproportionation. Control of these processes is key to developing successful fluorination protocols using iodonium fluorides.

FLUO 2

Reductive elimination chemistry under the “electrophilic” fluorination conditions

A. Vigalok, avigal@post.tau.ac.il, A. W. Kaspi, A. Yahav-Levi, and I. Goldberg. School of Chemistry, Tel Aviv University, Tel Aviv, Israel The synthesis of organofluorine compounds via the “electrophilic” fluorination of C-H bonds in the presence of Pd(II) catalysts has recently received a great deal of attention. Yet, mechanistic understandings of the reactivity of organometallic Pd(II) complexes and their Pt(II) analogs toward the “electrophilic” fluorination reagents are still lacking. In our presentation, we will describe an unusual reactivity of Pd(II) and Pt(II) complexes which takes place upon their reaction with XeF2, as well as N-F bond-containing reagents. Competing pathways leading to C-C, C-I or C-F bond formation will be presented.

FLUO 3

Silver catalysis for carbon fluorine bond formation

T. Ritter, ritter@chemistry.harvard.edu. Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, United States Transition metal-mediated fluorinations of aryl nucleophiles is presented. Reactions include Pd- and Ag-mediated fluorination of arylboronic acids, arylstannanes, and arylsilanes.

FLUO 4

Effect of metal cluster on perfluoroalkylation of metallic nitride fullerenes

O. V. Boltalina1, ovbolt@lamar.colostate.edu, N. B. Shustova1, I. V. Kuvychko1, S. H. Strauss1, A. A. Popov2, Y. S. Chen4, M. M. Mackey3, C. E. Coumbe3, J. P.

Phillips3, and S. Stevenson3. 1Departement of Chemistry, Colorado State University, Fort Collins, CO, United States, 2Department of Chemistry, Moscow State University, Moscow, Russian Federation, 3Department of Chemistry, University of Southern Mississippi, Hattiesburg, MS, United States, 4ChemMetCARS Beam Line, Advanced Photon Source, Argonne, IL, United States In this work, we prepared a series of perfluoroalkylated metallic nitride fullerenes by using synthetic methods described earlier and newly developed techniques. A series of pure compounds with various Rf’s and different substitution degree was isolated, their structures were determined by 19F NMR spectroscopy combined with quantum-chemical calculations at the DFT level of theory, and for some derivatives - by X-ray crystallography. We have determined that the most stable addition patterns for trifluoromethylated derivatives involve formation of long ribbons or loops of edge-sharing m- and p-C6(CF3)2 hexagons, which has been known as a fundamental addition-pattern principle for hollow higher fullerenes. However, significant differences in the structural features were also discovered which are caused by the presence of the metallic cluster inside the carbon cage. These new features will be discussed in detail.

FLUO 5

Organometallic aspects of metal-catalyzed trifluoromethylation of organic halides

D. Vicic, vicic@hawaii.edu. Department of Chemistry, University of Hawaii, Honolulu, HI, United States At the time of this abstract submission, there were no reports of catalytic trifluoromethylation of organic bromides or chlorides. To aid in the development of a catalytic process, a number of nickel and copper trifluoromethyl complexes have been prepared to help elucidate the fundamental organometallic aspects of metal-catalyzed trifluoromethylation reactions. In this report, we present a thorough study of the steric and electronic effects of the trifluoromethyl ligand, strategies to render catalytic reactions possible, and novel transformations from well-defined metal trifluoromethyl complexes.

FLUO 6

Electrophilic trifluoromethylation reactions using hypervalent iodine reagents

A. Togni, togni@inorg.chem.ethz.ch. Department of Chemistry, Swiss Federal Institute of Technology, ETH Zurich, Zurich, ZH, Switzerland 1-Trifluoromethyl-1,2-benziodoxol-3(1H)-one is accessible in a two-step synthesis from 2-iodobenzoic acid and is a representative of a new class of reagents for the electrophilic trifluoromethylation of a variety of substrates. Thus,

thiols, for example, are smoothly converted at low temperature to the corresponding trifluoromethyl ether typically in quantitative yield. Primary phosphines may be sequentially mono- and bis(trifluoromethylated) and sulfonic acids react to give trifluoromethyl sulfonates. Primary and secondary alcohols form the corresponding ethers but require the activation of the reagent by zink bis(triflimide). Most recently, we found that nitriles undergo N-trifluoromethylation in a Ritter-type reaction in the presence of a suited nucleophile. The lecture will give an overview about these reactions from a preparative point of view and will discuss mechanistic aspects for selected transformations.

FLUO 7

Insight into the mechanism of electrophilic trifluoromethylation by CF3-bearing 1,2-benziodoxoles

J. M. Welch, jwelch@inorg.chem.ethz.ch, and A. Togni. Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, ETH Zurich, Zurich, Switzerland The mechanism of the reaction of sulfonic acids with the electrophilic trifluoromethylating reagents 1-trifluoromethyl-1,2-benziodoxol-3-(1H)-one (1) and 1-trifluoromethyl-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (2) has been carefully analyzed using rate and competition studies. The reagents show related, but distinctly different behavior towards sulfonic acids. Relative rates of reaction of sulfonic acids toward 1 and 2 as well as several other related hypervalent iodine based electrophilic trifluoromethylating reagents have also been determined, showing 1 to be most reactive toward sulfonic acids. In addition, initial mechanistic investigations, on the basis of competition studies, have also been carried out on the reaction of 1 and 2 with thiols showing 2 to be significantly (approximately 14 times) more reactive toward thiols. The results of these studies suggest completely different mechanisms of action of 1 and 2 toward hard (oxygen) and soft (sulfur) nucleophiles and demonstrate the differences in reactivites of 1 and 2 toward different substrates.

FLUO 8

Fluorine substitution on arenes: Thermodynamic and kinetic consequences on C-H activation and direct arylation from a computational perspective

J. Guihaumé1, E. Clot1, R. N. Perutz2, and O. Eisenstein1, odile.eisenstein@univ-montp2.fr. 1Institut Charles Gerhardt CNRS 5253, Université Montpellier 2, Montpellier, Hérault, France, 2Chemistry, University of York, York, Yorkshire, United Kingdom The presence of fluoro substituents on arenes has been shown to influence significantly the reactivity of arenes in catalytic cross coupling reactions. Earlier computational work notably by Fagnou et al and Maseras et al has shown that C-

H acidity is an important parameter in direct arylation and that C-H activation is controlled by the number and position of fluorine on the arenes. We present a computational study of the full pathway of direct arylation by Pd(II) acetate complexes, showing how fluoro substituent modifies the energy barriers and thermodynamic of the whole multi-step (C-H activation, C-C coupling) reaction.

FLUO 9

Ligand-assisted aromatic C-F bond activation

S. A. Macgregor, s.a.macgregor@hw.ac.uk, and J. A. Panetier. Department of Chemistry, Heriot-Watt Unversity, Edinburgh, Midlothian, United Kingdom Ligand–assisted C-F activation involves the concerted addition of a C-F bond over a metal-ligand moiety. Previously, we showed this can occur with e--rich phosphine complexes to yield metallophosphoranes. We now extend this concept to other metal-ligand combinations. DFT calculations on the reactions of polyfluoroaromatics with [Rh(PMe3)3(SiR3)] and [Rh(PMe3)3(BR2)] show ligand-assistance with direct elimination of fluoro-silanes and -boranes is competitive with conventional oxidative addition/reductive elimination. In the latter case, ‘boryl-assistance’ explains the selective activation of pentafluoropyridine at the 2-position.

FLUO 10

Toward “green” routes to fluorocarbons: New chemistry of iron- and nickel organofluorometallacycles

R. T. Baker1, rbaker@uottawa.ca, S. H. Ahn1, A. Farhat1, S. L. Granville1, N. M. Hunter1, W. Pell1, I. Korobkov1, M. Harmjanz2, D. E. Morris4, B. L. Scott3, S. Z. Knottenbelt5, M. L. Kirk5, and S. I. Gorelsky1. 1Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, ON,

Canada, 2Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, United States, 3Materials Physics Applications Division, Los Alamos National Laboratory, Los Alamos, NM, United States, 4Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, United States, 5Department of Chemistry and Biochemistry, University of New Mexico, Albuquerque, NM, United States Efficient, metal-catalyzed C-C bond–forming transformations of polyfluoroalkenes are still uncommon, with most examples limited to vinylorganofluorine compounds, CH2=CHRF.[1] In an extensive follow-up on our earlier discovery of effective Ni phosphite complex-catalyzed hydrodimerization of polyfluoroalkenes,[2] we are investigating the synthesis and chemical reactivity of Fe and Ni organofluorometallacycles derived from the oxidative coupling of fluoroalkenes. Ni metallacycles supported by diimine and diamine ligands, for example, readily undergo oxidation to trivalent and tetravalent complexes,[3] including a series of mixed-valent dinuclear cations, {[Ni(κ2-C4F8)(N-N)(μ-X)]2}+ (X = halide, azide). Analysis of structural, electrochemical, and spectroscopic (EPR, IR, UV/VIS) properties using DFT will be discussed along with prospects for developing additional catalyzed reactions of hydrofluoroalkenes.

[1] Recent examples for C-C bond coupling: Akkerman, F. A.; Kickbusch, R.; Lentz, D. Chem. Asian J. 2008, 3, 719; for RF –X additions: Huang, X.-T.; Chen, Q.-Y. J. Org. Chem. 2001, 66, 4651. [2] Baker, R. T. et al. US patent 5,670,679, 1996 (to DuPont). [3] Harmjanz, M.; Gorelsky, S. I.; Morris, D. E.; Scott, B. L.; Baker, R. T.; Knottenbelt, S. Z.; Kirk, M. L., submitted for publication, 2009.

FLUO 11

Planned and surprising results in organometallic fluorine chemistry

D. Lentz, lentz@chemie.fu-berlin.de, F. A. Akkerman, C. Ehm, R. Kickbusch, M. F. Kuhnel, and M. Roemer. Anorganische Chemie, Institut fur Chemie und Biochemie - Freie Universitat Berlin, Berlin, Germany In order to study the chemistry of 1,1,4,4-tetraflurobutatriene1 effective synthetic methods for the synthesis of fluorinated 1,3-butadienes based on C-C coupling reactions of C2 building has been developed.2 1,1,4,4-tetraflurobutatriene reacts with Vaska’s complex forming the expected a triene complex3 and with various dienes yielding the products of the Diels-Alder reaction. However, a rather unexpected complex shown in Fig. 1 (left) was isolated on reaction with Fe2(CO)9.

The palladium catalyzed C-C coupling reactions have been expanded to the synthesis of trifluorovinyl substituted derivatives of ferrocene4 and cymantrene. The synthesis of 1,1-bis(trifluorovinyl)ferrocene failed for a long time due to the high reactivity of this compound yielding ansa ferrocenes on contact with silica (Fig. 1 right). The hydrometallation reaction of fluorinated allenes has been studied in detail, yielding substituted vinyl complexes.5 With Schwarz’ reagent no stable hydrometallation product could be isolated on reaction with tetrafluoroallene. Trifluoroallene and 1,3-difluoroallene could be isolated.

FLUO 12

Trifluorovinylcopper: Useful synthon for the preparation of oxygen and nitrogen heterocycles and fluorinated polycyclic aromatic hydrocarbons

D. J. Burton, donald-burton@uiowa.edu. Department of Chemistry, Universitry of Iowa, Iowa City, IA, United States Trifluorovinylcopper is readily prepared from trifluorovinylzinc or cadmium reagents. Subsequent syn addition of the vinylcopper reagent stereospecifically provides the dienylcopper reagent, which can be readily converted to a functionalized derivative that can be elaborated to fluorinated α-pyrans, 4-quinolizones, and fluorinated naphthalenes, phenanthrenes and anthracenes. Representative examples of these applications will be discussed.

FLUO 13

Synthesis and reactivity of perfluorinated tetracyclones: Toward new fluoromaterials

P. A. Deck1, pdeck@vt.edu, J. P. Evans1, B. S. Hickory1, S. Sen1, C. S. Carfagna1, C. Slebodnick1, K. W. Felling2, and W. G. Hollis3. 1Department of Chemistry, Virginia Tech, Blacksburg, VA, United States, 2Department of Chemistry, University of Central Arkansas, Conway, AR, United States, 3Department of Chemistry, Roanoke College, Salem, VA, United States

We established several years ago that perfluoroaromatic substituents may be attached to cyclopentadienes using nucleophilic aromatic substitution reactions. This method is sufficiently general to allow access to a wide range of highly fluorinated species. In a previous incarnation, we used these techniques to afford metallocene and other organometallic species (Coord. Chem. Rev. 2006, 250, 1032). However more recently we learned that many of our fluoroarylated cyclopentadienes undergo further oxidation, under catalytic conditions, to afford corresponding cyclopentadienones with gratifying efficiency. Reactions of these unusual ketones with alkynes, via [4+2] cycloaddition and concomitant CO extrusion, affords highly fluorinated polyarenes. This paper describes our efforts to develop these synthetic methods as a common platform for new fluoromaterials including well-defined, nanoscopic species having fluorous surfaces, and highly stable, aromatic fluoropolymers.

FLUO 14

Award Address (ACS Award for Creative Work in Fluorine Chemistry Sponsored by Honeywell). Fluorine as a ligand substituent in organometallic chemistry

R. P. Hughes, rph@dartmouth.edu. Department of Chemistry, Dartmouth College, Hanover, NH, United States The structural and chemical effects of fluorine as a substutuent on carbon ligands in organometallic compounds will be discussed.

FLUO 15

Fluorinated pincer chemistry: Synthesis and reactivity of new iridium(I) pincer dehydrogenation and decarbonylation catalysts

D. M. Roddick, dmr@uwyo.edu, J. J. Adams, and N. Arulsamy. Department of Chemistry, University of Wyoming, Laramie, WY, United States Dehydrohalogenation of (RfPCP)Ir(H)Cl(L) systems affords a series of unusual four- and five-coordinate Ir(I) pincer complexes, (RfPCP)Ir(L)x (x = 1 or 2; L = CO, alkene, (C2F5)2PMe, C6H5CN). These compounds function as both alkane dehydrogenation and aldehyde decarbonylation catalysts, with activities that are distinctly different from corresponding non-fluorinated donor PCP systems.

FLUO 16

Adventures with fluorinated ligands in multiple-bond metathesis reactions

M. J. A. Johnson1,2, mjjohnson@anl.gov, M. L. Macnaughtan1, S. R. Caskey1, and J. W. Kampf1. 1Department of Chemistry, University of Michigan, Ann Arbor,

MI, United States, 2Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, United States Some beneficial as well as deleterious effects of fluoride and fluorinated ligands on the longevity, activity and selectivity of well-defined transition metal catalysts for multiple-bond metathesis reactions are outlined. Processes that involve migration or elimination reactions of fluoride are highlighted.

FLUO 17

N-Heterocyclic carbenes: Versatile ligands in inorganic fluorine chemistry

E. G. Hope, egh1@le.ac.uk, D. A. Harding, and G. A. Solan. Department of Chemistry, University of Leicester, Leicester, United Kingdom Investigations of the unique ligand properties of N-heterocyclic carbenes in coordination chemistry and catalysis have recently been extended to the first NHC-transition metal fluoride complexes. Here, we describe our synthetic and structural investigations of ruthenium, osmium, rhodium and iridium NHC-fluoride complexes, formed via either ligand substitution reactions or oxidative fluorination of low-valent metal NHC metal complexes. In specific examples subsequent ligand-centred C-H bond activation processes allow the formation of metallacyclic products.

FLUO 18

Reactivity of homoleptic late transition metal complexes with fluorinated alkoxide ligands

L. H. Doerrer, doerrer@bu.edu, J. S. Lum, and S. A. Cantalupo. Department of Chemistry, Boston University, Boston, MA, United States Our group has prepared homoleptic compounds of late first row transition metal complexes including four-coordinate, divalent compounds of the form [M(ORF)4]2- where ORF = perfluoro-t-butoxide and M=Co, Ni, as well as three-

coordinate, divalent compounds of the form [M(ORF)3]- in which M = Fe, Co, Cu, and Zn. More recently we have prepared the two-coordinate, monovalent derivative [Cu(ORF)2]- and the related derivative [Cu(OCPh(CF3)2)2]-. They have been characterized with X-ray crystallography, UV-vis spectroscopy, solution magnetic susceptibility, and cyclic voltammetry. Some reactivity studies of these interesting new compounds will be presented including that of Cu(I) with O2 and O-atom transfer agents. Preliminary data demonstrating C-H activation will be shown and discussed in the context of Cu-N systems.

FLUO 19

Highly fluorinated ligands and counter ions in coinage metal alkene chemistry

R. Dias, dias@uta.edu. Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, United States Copper, silver, and gold play an important role in a number of industrial and academic laboratory scale processes and biochemical reactions involving alkenes. However, isolation of thermally molecules with coinage metal ion-alkene bonds is challenging due to their reactivity and/or labile nature. We describe the successful synthesis and structural characterization of a number of Cu(I), Ag(I), and Au(I) complexes involving ethylene or other alkenes using highly fluorinated tris(pyrazolyl)borate ligands or weakly coordinating counter ions.

FLUO 20

Perfluoropentaphenylborole: A potent Lewis acid for small molecule activation

W. Piers, wpiers@ucalgary.ca, C. Fan, and M. Parvez. Department of Chemistry, University of Calgary, Calgary, Alberta, Canada Recently, we described the synthesis of the new perfluoroaryl boron-based Lewis acid, perfluoropentaphenylborole. The Lewis acidity of the boron center is boosted both by the presence of fluorinated aryl groups and the antiaromaticity of the borole core. The synthesis and properties of this compound will briefly be discussed, followed by a survey of its reactivity. In particular, its reactivity with various alkynes, its ability to strongly bind weak Lewis bases like carbon monoxide and alkyl halides, and its activation of dihydrogen will be presented.

FLUO 21

Synthesis, structure, and chemistry of the ammonia adducts of the pentafluorophenylboranes, H3N·B(C6F5)nH(3-n): Hydrogen bonds, triple bonds, and agostic interactions

S. J. Lancaster, S.Lancaster@uea.ac.uk, A.-M. Fuller, and D. L. Hughes. Department of Chemistry, University of East Anglia, Norwich, United Kingdom Facile and efficient syntheses of mono- and bis-(pentafluorophenyl)borane and their ammonia adducts will be presented and the solid state structures compared to those of ammonia tris(pentafluorophenyl)borane and ammonia borane. The utility of ammonia tris(pentafluorophenyl)borane in the construction of hydrogen-bonded networks has been demonstrated.1 The deprotonation of the adducts H3N·B(C6F5)nH(3-n) and preparation of amidoborate complexes of the group 4 metals will be described. Amongst the highlights of which will be the remarkable solid state structure of bis(cyclopentadienyl)hafniumdi(amidobis(pentafluorophenyl)borate), in which the amidoborate ligands are engaged in hydrogen bonding to internal and external donors and an agostic interaction to hafnium.

The first examples of octahedral group 4 complexes of the amidoborate ligand family and the particular difficulties encountered will be discussed. A convenient synthesis of a tris(pentafluorophenyl)borane protected titanium-nitrogen triple bonded complex has been developed.2 The potential and limitations of this system for the future development of molecular nitrido titanium chemistry will be explored.

Fuller, A.; Mountford, A. J.; Coles, S. J.; Horton, P. N.; Hughes, D. L.; Hursthouse, M. B.; Male, L.; Lancaster, S. J. Dalton Trans. 2008, 6381.

Fuller, A.; Clegg, W.; Harrington, R. W.; Hughes, D. L.; Lancaster, S. J. Chem. Commun. 2008, 5776.

FLUO 22

Solid-phase synthesis of functionalized fluoroarenes and trifluoromethylarenes

M. S. Wiehn, matthias.wiehn@ioc.uka.de, and S. Bräse. Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany Fluorine-containing drugs played a major role over the last decade, especially in pharmaceutical and crop sciences. Many studies have shown that metabolism and pharmacokinetics can advantageously be altered by introducing fluorine atoms. With the advent of solid phase chemistry as an innovative tool for combinatorial chemistry, ample methods of synthesizing small molecular entities suitable for screening are now available. Herein, we report the first methods for the traceless solid-phase synthesis of functionalized fluoroarenes and trifluoromethylarenes by novel fluorinating cleavage strategies.

FLUO 23

Combinatorial solid-phase synthesis of gem-difluoro compound libraries

M. S. Wiehn, matthias.wiehn@ioc.uka.de, and S. Bräse. Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany The solid phase synthesis of three compound biaryl libraries containing difluoromethyl units featuring a fluorinating cleavage strategy from a dithiane linker is presented. The average reaction yield per step was up to 96% in a synthetic sequence over five to six steps. Key features were Suzuki coupling reactions, transesterification with potassium cyanide and amidation reaction with trimethyl aluminium on solid supports.

FLUO 24

Pentafluorophenylcopper: From luminescent complexes to weakly coordinating borate polyelectrolytes

F. Jaekle, fjaekle@andromeda.rutgers.edu, A. Doshi, and K. Venkatasubbaiah. Department of Chemistry, Rutgers University - Newark, Newark, NJ, United States Our recent studies on the properties and applications of pentafluorophenyl copper will be discussed. Pentafluorophenyl copper forms highly unsual supramolecular structures in the presence of sigma- or pi-donor ligands. Intriguing photophysical properties result, including thermochromic behavior and strong luminescence in the solid state. At the same time, pentafluorophenyl copper also serves as a convenient base-free aryl transfer reagent for the preparation of perfluoroarylboranes and perfluoroarylborate polyelectrolytes. Their self-assembly behavior in solution will be described.

FLUO 25

Frustrated Lewis pairs in small molecule activation and reactivity

D. W. Stephan, dstephan@chem.utoronto.ca, P. Chase, M. A. Dureen, R. Neu, E. Otten, and M. Ullrich. Department of Chemistry, University of Toronto, Toronto, Ontario, Canada Frustrated Lewis Pairs (FLPs) are combinations of donor and acceptors where steric demands preclude the formation of a classical Lewis acid-base adducts. Such combinations provide the opportunity for the unquenched Lewis acidity and basicity to act on a third molecule. In cases where a threshold combined Lewis acidity and basicity is met, FLPs are shown to activate a variety of small molecules including H2, alkenes, alkynes, CO2, N2O and SO2.

FLUO 26

Cationic bidentate Lewis acids for the complexation of fluoride anions

Y. Kim, H. Zhao, and F. P. Gabbai, francois@tamu.edu. Department of Chemistry, Texas A&M University, United States This lecture will focus on the chemistry of cationic main group Lewis acids whose anion affinity is increased by Coulombic and/or cooperative effects. In addition to describing the synthesis and properties of these novel main group cations, we will also demonstrate their use for the complexation of fluoride anions. Example of such compounds include the sulfonium fluorosilane [1-Ant2FSi-2-Me2S-(C6H4)]+ ([1]+) which has been synthesized as a triflate salt by alkylation of 1-Ant2FSi-2-MeS-(C6H4) with MeOTf. This cationic fluorosilane complexes fluoride to afford the corresponding zwitterionic difluorosilicate complex 1-Ant2F2Si-2-Me2S-(C6H4) (1-F) with a binding constant of 7 (±1) × 106 M-1 in CHCl3. Structural and computational results indicate that the high fluorophilicity of [1]+ arises from

both Coulombic and cooperative effects which lead to formation of a Si-F→S interaction with a F→S distance of 2.741(3) Å. These results, which are supported by a NBO analysis, indicate that proximal 3rd row onium ions can serve to enhance the fluoride affinity of main group Lewis acids via cooperative effects.

FLUO 27

Syntheses, thermal stabilities, and structures of metal salts of the superweak anion B12F12

2-

S. H. Strauss1, steven.strauss@colostate.edu, D. V. Peryshkov1, and A. A. Popov2. 1Department of Chemistry, Colorado State University, Fort Collins, CO, United States, 2Chemistry Department, Moscow State University, Moscow, Russian Federation The thermal and chemical stability of the superweak anion B12F12

2- allowed the generation of reactive metal cations in the solid state by thermal desolvation of M(solv)xB12F12 salts. Their reactivity was tested by CO binding to some of the desolvated salts MxB12F12 to form nonclassical cationic carbonyls. The thermal stabilities of various salts of B12F12

2- (up to 500+ °C) will be discussed and compared with that homologous salts of other weakly coordinated anions, which decompose at much lower temperatures. X-ray structures of a wide range of metal salts of B12F12

2-, including K2(H2O)2B12F12, K2(H2O)4B12F12, K2(CH3CN)2B12F12, Cs2(CH3CN)B12F12, Cs2(H2O)B12F12, Ni(H2O)6B12F12, Co(CH3CN)6B12F12, Ag2(CH3CN)8B12F12, Ag2(CH3CN)5B12F12, Ag2(CH3CN)4B12F12, and others will be presented. Details of (i) the packing of B12F12

2- anions in the lattice and (ii) hydrogen bonding between F atoms of B12F12

2- and coordinated solvent molecules will be discussed in light of the possible use of the partially or completely-desolvated reactive salts of B12F12

2- for small-molecule catalysis.

FLUO 28

Self-aggregation tendency of salts bearing fluorinated counterions and long alkylic chains in aromatic and aliphatic low polar solvents

L. Rocchigiani, G. Ciancaleoni, S. Crocchianti, A. Laganà, C. Zuccaccia, D. Zuccaccia, and A. Macchioni, alceo@unipg.it. Department of Chemistry, University of Perugia, Perugia, Italy The results of 1H- and 19F-diffusion and 19F,1H-HOESY NMR studies on the self-aggregation tendency of zirconocenium salts ([Zr][X]) with alkylic chains (miming the growth of a polymeryl chain) of variable length1 and di-long chain quaternary ammonium salts ([(C18H37)2Me2N][X]) with different X- counterions are reported. It is shown that the tendency to self-aggregate of [Zr][X] results enhanced enormously in cyclohexane (with respect to that in benzene) to the point that the percentage of ion quadruples is noticeable even at the concentration level used

in the olefin polymerizations. The effect of X- on the tendency of [(C18H37)2Me2N][X] to form both ion quadruples and higher aggregates is quantified by applying several models of indefinite aggregation. Mathematical fitting of their appropriate formulations allows realistic thermodynamic parameters of the self-aggregation processes to be evaluated.

1. Rocchigiani, L.; Zuccaccia, C.; Zuccaccia, D.; Macchioni, A. Chem. Eur. J., 2008, 14, 6589.

FLUO 29

Ion pairing via NMR spectroscopy: General trends

P. S. Pregosin, pregosin@inorg.chem.ethz.ch. Laboratory of Inorganic Chemistry, ETHZ, Honggerberg, Zurich, Switzerland PGSE diffusion and 1H, 19F HOESY NMR characteristics for a wide variety of a) cationic transition metal complexes b) inorganic salts, c) organic salts (e.g., brucinium derivatives), and d) the aryl carbocations (p-R-C6H4)2CH+, or (p-CH3O-C6H4)xCPh3-x

+, will be presented. The solvent dependence suggests strong ion pairing in CDCl3, intermediate ion pairing in CD2Cl2 and little ion pairing in [D6]acetone for all of these various salts. The 1H, 19F HOESY NMR spectra frequently reveal a specific approach of the anion with respect to the cation. These studies, together with solid-state and DFT calculations support the experimental NMR results and represent the first example of a more general approach to understanding the factors which affect ion pairing.

FLUO 30

Activation of carbon-fluorine bonds by zirconium complexes

W. D. Jones1, jones@chem.rochester.edu, B. M. Kraft1, E. Clot2, and O. Eisenstein2. 1Department of Chemistry, University of Rochester, Rochester, NY, United States, 2Institut Charles Gerhardt, Université Montpellier 2, Montpellier, CNRS 5253, France Pentamethylcyclopentadienylzirconiumdihydride has been found to react with a variety of fluorocarbons, including aliphatics and aromatics. The zirconium hydride dimer [Cp*2ZrH]2 reacts with perfluoroolefins (e.g. perfluoropropene) by way of insertion/beta-fluorine elimination pathways to give the corresponding hydrocarbons. Reactions with cyclic-perfluoroolefins, however, reveal a different pathway for C-F activation. The distribution of regioisomers is inconsistent with insertion/beta-F-elimination but consistent with a 4-centered concerted H/F exchange. Details of these reactions, and DFT calculations on the system providing support for the new pathway, will be discussed.

FLUO 31

C-F-Activation using NHC stabilized nickel complexes

U. Radius, u.radius@uni-wuerzburg.de. Department of Inorganic Chemistry, University of Würzburg, Würzburg, Germany The presentation covers the synthesis and reactivity of complexes of the type [Ni2(R2Im)4(COD)] (R2Im = 1,3-Di(organyl)imidazole-2-ylidene). These compounds transfer the complex fragments [Ni(R2Im)2] in stoichiometric and catalytic reactions under mild conditions. Focus of the seminar will be on the use of these complexes in carbon fluorine activation reactions and the use of these processes in catalytic reactions.

Molecular structure of [Ni2(iPr2Im)4(COD)].

Catalytic C-F activation of perfluorotoluene.

References:

T. Schaub, U. Radius, Efficient C-F- and C-C-Activation by a Novel N-Heterocyclic Carbene-Nickel(0) Complex, Chem. Eur. J. 2005, 11, 5024-5030. T. Schaub, M. Backes, U. T. Schaub, M. Backes, U. Radius, Catalytic C-C-Bond

Formation accomplished by Selective C-F-Activation of Perfluorinated Arenes, J. Am. Chem. Soc. 2006, 128, 15964-15965. T. Schaub, A. Steffen, T. Braun, U. Radius, C-F Bond Activation of fluorinated Arenes using NHC stabilized Nickel (0) Complexes: Selectivity and Mechanistic Investigations, J. Am. Chem. Soc.2008, 130, 9304 - 9317.

FLUO 32

Catalytic transformations of polyfluoroarenes

J. Love, jenlove@chem.ubc.ca. Department of Chemistry, University of British Columbia, Vancouver, BC, Canada We have developed a strategy for the preparation of functionalized fluoroaromatics that have potential as building blocks for pharmaceuticals and materials. This approach requires activation and functionalization of strong aryl C-F bonds. We have discovered that several group 10 metal complexes are capable of catalyzing the cross-coupling of a range of polyfluoroarenes. High selectivity for C-F cleavage is achieved, even when more reactive bonds are present (e.g., C-Br). Both C-C and C-O bonds can be formed in high yields, providing a convenient route to functionalized fluoroaromatics. Studies of reaction scope and limitations, as well as mechanistic and kinetic analyses, will be presented.

FLUO 33

Carbon-fluorine bond activation with main group compounds

O. V. Ozerov1, ozerov@chem.tamu.edu, W. Gu1, C. Douvris2, B. M. Foxman2, and C.-H. Chen2. 1Department of Chemistry, Texas A&M University, College Station, TX, United States, 2Department of Chemistry, Brandeis University, Waltham, MA, United States Activation of carbon-fluorine bonds attracts attention both because of the fundamental challenge of this difficult target and because of the environmental impact of the polyfluorinated organics. We have developed methods for conversion of aliphatic C-F bonds to C-H and C-C bonds using silicon- and aluminum-based catalyst. The crucial cleavage of the C-F bond is presumed to occur via abstraction of fluoride by highly fluorophilic silylium or alumenium

cations. The key to unlocking the remarkable reactivity of these cationic Lewis acids is the use of halogenated carboranes – robust weakly coordinating anions. This presentation will describe the features of the main-group catalyzed process, attempt an analysis of the mechanism, and delineate the synthetic advances towards making this process more economical and accessible.

FLUO 34

C-F activation and derivatization of fluorinated alkenes in the coordination sphere of rhodium

T. Braun, thomas.braun@cms.hu-berlin.de, M. Teltewskoi, F. Wehmeier, and K. Altenhöner. Institut für Chemie, Humboldt University Berlin, Berlin, Germany One interesting tool for the derivatization of fluorinated molecules is based on the C-F activation of a carbon-fluorine bond at a transition metal center. The strategy often involves the selective removal of a fluorine atom from highly fluorinated precursors, followed by functionalization reactions in the coordination sphere of the metal.1 We will report on the C-F-activation and the stoichiometric or catalytic derivatization of fluorinated pyridines and alkenes at rhodium.2 Hexafluoropropene can be activated, and be selectively converted into 1,1,1-trifluoropropane in the presence of H2.3 Investigations on the reactivity of the fluoro complex [Rh(F)(PEt3)3], which is also produced, led to the development of a cyclic process for the formation of 1,1,1-trifluoropropane from perfluoropropene, HSiPh3 and H2.4 We also describe studies on the catalytic derivatization of hexafluoropropene to give silyl derivatives by transition metal mediated cleavage reactions of carbon-fluorine bonds.5 Finally, borylation reactions which are based on C-F activation steps will be discussed.6

(1) T. Braun, R. N. Perutz, Chem. Commun. 2002, 2749; W. D. Jones, Dalton Trans, 2003, 399; R. P. Hughes, Eur. J. Inorg. Chem., DOI: 10.1002/ejic.200900816. (2) T. Braun, D. Noveski, M. Ahijado, F. Wehmeier, Dalton Trans. 2007, 3820-3825. (3) T. Braun, D. Noveski, B. Neumann, H.-G. Stammler, Angew. Chem. Int. Ed. 2002, 41, 2745. (4) D. Noveski, T. Braun, M. Schulte, B. Neumann, H.-G. Stammler, Dalton Trans. 2003, 4075. (5) T. Braun, K. Altenhöner, F. Wehmeier, Angew. Chem. Int. Ed. 2007, 46, 5321. (6) T. Braun, M. Ahijado-Salomon, K. Altenhöner, M. Teltewskoi, S. Hinze, Angew. Chem.Int. Ed. 2009, 47, 1818.

FLUO 35

Carbon–fluorine bond activation in fluoroolefins promoted by adjacent metals

M. Cowie, martin.cowie@ualberta.ca, M. E. Slaney, J. Anderson, and R. McDonald. Chemistry, University of Alberta, Edmonton, Alberta, Canada

Reaction of the fluoroolefin-bridged complexes, [Ir2(CH3)(CO)2(μ-olefin)(dppm)2]+ (dppm = Ph2PCH2PPh2; olefin = F2C=CH2, F2C=CHF, F2C=CF2), with trimethylsilyl triflate or triflic acid at sub-ambient temperatures results in facile fluoride-ion abstraction of one of the geminal fluorines to give the corresponding fluorovinyl products. A second fluoride can also be removed to yield the corresponding vinylidene or fluorovinylidene species. With trifluoroethylene, fluoride abstraction can also be effected by water – although in this case the lone vicinal fluorine is removed to give an unusual coordination mode for the resulting 2,2-difluorovinyl group. Reaction of the fluorovinyl-containing complexes with hydrogen results in hydrogenolysis, converting tetrafluoroethylene to trifluoroethylene, which can in turn be converted to cis-difluoroethylene. Under similar conditions, 1,1-difluoroethylene is converted to fluoroethylene. Reaction of the cis-difluorovinyl-bridged complex, [Ir2(CH3)(OTf)(CO)2(μ-CF=CHF)(dppm)2]+, with CO yields two isomers of difluoropropene. Reaction of the 1-fluorovinyl analogue with water yields 2-fluoropropene. These and other results will be discussed.

FLUO 36

Catalytic dehalogenation of chlorinated and fluorinated ethylenes: Distinct mechanisms with triethylsilane and dihydrogen

A. A. Peterson, apeterson@csbsju.edu, and K. McNeill, kristopher.mcneill@env.ethz.ch. Department of Chemistry, University of Minnesota, Minneapolis, MN, United States The dehalogenation of chlorinated and fluorinated ethylenes was explored using (PR3)3RhCl and triethylsilane (Et3SiH) or dihydrogen (H2). Spectroscopic studies, in addition to substrate preference, indicate that rhodium hydride species are important intermediates. Kinetic parameters and product distribution for dehalogenation reactions were determined using NMR spectroscopy. Evidence for sequential halogen removal was obtained, and the rates of dehalogenation were found to increase with decreasing halogen content. It was also shown that this catalytic system has a preference for sp2-over sp3-hybridized carbon-halogen bonds. Dehalogenation using (PPh3)3RhCl and either H2 or Et3SiH support an insertion/β-halide elimination mechanism; however, the two systems display distinct differences. Based on these differences, the dominant pathway for Et3SiH is proposed to involve rhodium(I), while the H2 system is proposed to primarily involve rhodium(III).

FLUO 37

Sustainable fluorous chemistry

I. T. Horváth, istvan.t.horvath@cityu.edu.hk. Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, Hong Kong Special Administrative Region of China

The fluorous biphasic concept was based on the attachment of long perfluoroalkyl-groups to reagents and catalysts in appropriate number to achieve facile product separation [1]. While carbon and fluorine are readily available in Nature for large scale applications, the sustainability of fluorous chemistry has been limited by the persistency and toxicity of compounds containing long (>C6) perfluoroalkyl groups. While limiting the exposure could lower the risks, the use of shorter perfluoroalkyl groups could be a better solution because of lower toxicity and much shorter half-lives in humans. Therefore, the combination of shorter perfluoroalkyl groups could provide fluorous solubility and upon decomposition they could fall apart to less toxic compounds. However, the final solution to the persistency of fluorocarbons requires the development of a novel bioremediation technology, which could convert the fluorocarbons to carbon dioxide and fluorides.

[1] Horvath, I. T. and Rabai, J. Science, 1994, 266, 72-75.

FLUO 38

Addition of pentafluorosulfanyl halides to enolates

J. T. Welch, jwelch@uamail.albany.edu, P. R. Savoie, and B. D. Wertz. Department of Chemistry, University at Albany, Albany, New York, United States To date utility of the pentafluorosulfanyl group in aliphatic chemistry has been limited by the necessity to synthesize the aliphatic pentafluorosulfanyl containing compounds by the addition of a pentafluorosulfanyl halide to a suitable olefinic precursor. The addition reaction is best effected under conditions favoring homolytic scission of the pentafluorosulfanyl – halogen bond. The preparation of α-pentafluorosulfanyl carbonyl compounds normally requires both the preparation of an enol acetate, most commonly under thermodynamic conditions, and the subsequent hydrolysis of the intermediate pentafluorosulfanyl halide adduct. Both of these steps render the process relatively inefficient and profoundly limit regio- and stereochemical control. Methods to effect the direct addition of pentafluorosulfanyl halides to a reactive enolate formed with either kinetic or thermodynamic control will be described.

FLUO 39

Fluorobicyclobutanes: Theoretical insights and synthetic approaches

D. M. Lemal, david.m.lemal@dartmouth.edu, and D. Sang. Department of Chemistry, Dartmouth College, Hanover, New Hampshire, United States Hybrid density functional calculations reveal that fluorine substitution has profound effects on the nature and behavior of bicyclo[1.1.0]butane. The calculations also provide insight into the underlying basis for these effects.

Computational results and their significance will be discussed together with synthetic approaches to highly fluorinated bicyclobutanes.

FLUO 40

Synthesis of trifluoromethylated heterocyclic compounds

V. Petrov1, viacheslav.a.petrov@usa.dupont.com, and W. Marshall2, Will.marshall@usa.dupont.com. 1CRD, DuPont Co., Wilmington, DE, United States, 2CCAS, DuPont Co., Wilmington, DE, United States Although thiophilic reactions are quite common for sulfur containing hydrocarbons, examples of the reaction involving cyclic sulfides are rare. This presentation will cover an interesting type of the reactions of polyfluorinated sulfur containing heterocyclic materials, involving attack of soft nucleophiles on the sulfur of heterocycle. Trifluoromethylated thietanes also can serve as starting materials for the synthesis of fluorinated dihydrofuranes. These compounds form in as the result of reductive ring expansion of thietanes under action of Al/PbCl2 system. The reaction of 1-trifluoromethyl- and 2,2-bis(trifluoromethyl)- oxiranes with sulfur containing nucleophiles, such as CS2 and ArN=C=S results in the formation of fluorinated 1,3-oxothiolanes. We also demonstrated that 2,2-bis(trifluoromethyl)-alkoxythietanes depending on reactionconditions can be converted into either 1,2- or 1,3- dithiolanes. The treatment of thietanes with certain phosphines leads to the formation of the corresponding 1,1-bis(trifluoromethyl)-2-alkoxycyclopropanes. The mechanism, scope and limitations of new reactions will be discussed.

FLUO 41

Fluoride formation in blends of hydrofluoroethers and isopropanol with various water concentrations

J. C. Birkbeck1, JBirkbec@pantex.com, H. C. Knachel3, C. D. Barklay2, D. P. Kramer2, W. E. Moddeman1, and J. M. Kehren4. 1Applied Technology Division, B&W Pantex Plant, Amerillo, TX, United States, 2Research Institute, University of Dayton, Dayton, OH, United States, 3Chemistry Department, University of Dayton, Dayton, OH, United States, 4Electronic Markets Division, 3M Corporation, Saint Paul, MN, United States A blend consisting of 95.5 wt% methyl nonafluorobutyl ether and 4.5 wt% IPA is relatively stable, but does degrade very, very slowly with the production of hydrogen fluoride. It was originally thought that water was involved in the degradation of the blend. The rate of fluoride formation in the blend was followed with water concentrations between 100 and 500 ppm. Fluoride was determined by specific ion electrode. Rate data were accumulated from samples aged at 6o, 26o, 36o and 46oC. The results showed the change in water concentration had no affect on the rate of fluoride produced. However, when the IPA concentration was

increased by a factor of four, an eight-fold increase in the rate of fluoride occurred.

FLUO 42

(E)-trimethyl(perfluoroprop-1-enyl)silane as a reagent to transfer perfluoroprop-1-enyl group to ketones and aldehydes catalyzed by CsF

V. A. Petrov, R. B. Larichev, roman.larichev@usa.dupont.com, and G. J. Grier. Central Research and Development, DuPont Company, Wilmington, DE, United States Analogous to trifluoromethyltrimethylsilane (Ruppert’s reagent) (E)-trimethyl(perfluoroprop-1-enyl)silane, prepared by deprotonation of (Z)-1,2,3,3,3-pentafluoroprop-1-ene at -78 C with LDA in presence of chlorotrimethylsilane, was shown to transfer the perfluoroprop-1-enyl group to a number of electrophiles containing carbonyl group in the presence of catalytic amount of fluoride anion. The pentafluoropropenyl group was transferred to formaldehyde when KF is used as a catalyst, while acetaldehyde, benzaldehyde, acetone, and trifluoroacetophenone with CsF as the catalyst resulting in stereoselective formation of TMS ethers of secondary and tertiary alcohols containing cis-CF3CF=CF- fragment in moderate to good yields. However, the catalytic action of CsF with hexafluoroacetone and formaldehyde, and tetrabutylammonium fluoride with trifluoroacetophenone afford a clean formation of a 5-membered cyclic product as a result of consecutive addition of two carbonyl groups to the fluorinated carbanion followed by attack of the generated alkoxy anion at the double bond with a loss of the fluoride, which completes the catalytic cycle. Thus, different products can be obtained depending on the source of the fluoride ion.