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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
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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.
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The gold color
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2- Phenomenological Description of Single Walled Carbon nanotubes
(SWNT)
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SWNT are conceptuallyconsidered as rolled-up graphite sheet even it does not related to the real fabrication way.
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Schematic description
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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.
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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
4- THEORETICAL CALCULATIONS
CONFINED TiO2 SPECIES into CNTnoted
molecule@CNT
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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
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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
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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
Before Confinement After
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T/P- (TiO2)2@(12,0
T/P transforms in Trans
Before Confinement After
Separated Dimers
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Parallele position (P)
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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
Before Confinement After
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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.
Before Confinement After
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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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