Free and Encapsulated (TiO 2 ) 2 Dimers into Carbon Nanotubes Presented by Prof. TANGOUR Bahoueddine University of Tunis-El Manar, Tunisia S. Dargouthi,

Free and Encapsulated (TiO2)2 Dimers into Carbon Nanotubes

Presented byProf. TANGOUR Bahoueddine

University of Tunis-El Manar, Tunisia

S. Dargouthi, S. Boughdiri, B. Tangour

ICMCC2015 JUNE 15-16 TORONTO - CANADA

1- Introduction toNanotechnology

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Nanotechnologies are concerned with: Controlledproduction, design, characterization and application of structures, devices, and systemspresenting size and shape at the nanometer scale and exhibiting at least one novel/superior characteristic or property.


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The nanometer scale

Humanhair fragment and a network of single-walled carbon nanotubes.


The gold color

ICMCC2015 JUNE 15-16 TORONTO - CANADA 5

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2- Phenomenological Description of Single Walled Carbon nanotubes

(SWNT)


SWNT are conceptuallyconsidered as rolled-up graphite sheet even it does not related to the real fabrication way.

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Schematic description



Different types of Carbon SWNT

ChiralΘ ≠ 0 and 30° (n,m) type

Semi-conductor Gap = [2-4] eV

Achiral θ=30°Armchair (n,n)type

Semi-metallic Gap = [0,2 - 1,4] eV

Achiral θ=0°Zigzag (n,0) typeMetallic

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3- Confined molecules inside carbon nanotubes


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fullerenes encapsulated into CNT C60@CNT

Nanotubes offer a unique opportunity for investigation of physical and chemical processes in confined systems


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Release of carboplatin from CNT.


Representative HRTEM pictures were shown after incubation of CNT-Carboplatin A) 30min B) 24h in cell culture medium at 37°C.

Nanomedicine April 2008, Vol. 3, No. 2, Pages 175-182

http://www.futuremedicine.com/loi/nnm

4- THEORETICAL CALCULATIONS

CONFINED TiO2 SPECIES into CNTnoted

molecule@CNT


Calculation details

DFT B3LYP calculations

Different basis sets

6-311G and 6-311G (d).

Hundreds of atoms

Thousands of basis functions

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TiO2


RTi-O (Å)=1.629 (exp. =1.704)O-Ti-O (°)=111.4 (exp.=113.0)

TiO2 molecule is only detected into noble gas matrix at very low temperature of some Kelvin.

CNTs with different diameters

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TiO2@CNT


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Different Confinement interactions

Chemical Interactions

Physical Interactions

Without confinement effect

Energy Variation (in arbitrary units)

CNT Diameter in Á


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TiO2@CNT (8,0) D=6.267 Å

Stabilisation of the molecule by roughly 50 kcal/mol


RTi-O (Å)=1.612 (1.629 in free molecule)O-Ti-O (°)=94.6 (111.4 in free molecule )

Confinement of TiO2 molecule will help its manipulation at room temperature


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3 possible Dimers (TiO2)2Trans DIMER (T)

Cis DIMER (C)

Tetrahedron/ Pyramidal DIMER (T/P)

Optimized Structures


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Stabily Comparison

CONFINED DIMERS


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T- (TiO2)2@(12,0

Few and non signifiant changes

Before Confinement After


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C- (TiO2)2@(12,0

Few and non signifiant changes



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T/P- (TiO2)2@(12,0

T/P transforms in Trans


Separated Dimers

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Parallele position (P)


Transitory specie


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Orthogonal position (O)

Transitory specie


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Confined (P) Dimer

(P) Transforms in (O) and stays in iteraction

with CNT’s edge



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Confined (O) DimerThe dimer keeps his structure when confined so

Stabilizing of the transitory species (TiO2)2 by encapsulation intocarbon nanotubes.



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Stabilisation by confinement

Dargouthi Sarra a, Boughdiri Salima and Tangour Bahoueddine, 2015Acta Chimica Slovenica, 61, in press

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THANK YOU FOR YOUR ATTENTION


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Free and Encapsulated (TiO 2 ) 2 Dimers into Carbon Nanotubes Presented by Prof. TANGOUR Bahoueddine University of Tunis-El Manar, Tunisia S. Dargouthi,