SlideShare a Scribd company logo

Defense

•Download as PPT, PDF•
•
K
Kothanda Rama Pichaandi
1 of 74
08-18-08 Kothanda Rama Pichaandi Chemistry Department, Tulane University, New Orleans Defense Seminar Synthesis of Strained Ring Compounds: Precursors to Disilyne via Molecular Beam Method
Introduction Multiple bonded (Me)2Si O Si Si Me Me Me Me Si C Me Me Me Me CH3Si+ CH3Si - CH3Si (C2H5)3Si Low valent  Organosilicon reactive intermediates involves one or more silicon atoms that are either multiply bonded or low valent in nature.  Many of them are transient in nature and can be observable only at very low temperature under condensed matrix conditions. Si Si MeMe Si Ph Ph Si Bu Bu t t
Microlitho graphy Applications of Organosilicon Reactive Intermediates Semiconductors Aerospace Industries Stereo selective synthesis Me O Ph O O Si Bu Bu AgOTs O O O Ph Me Si Bu Bu 6 electro cyclization Ph COOHHO MeIreland-Claison rearrangement Hydrolysis (1) (2) (3) t tt t
Synthesis of a series of Bis(siliranes): Precursors to Disilyne via Molecular Beam Method ------------------------------------------------------------------------------ ----------------------------------------------------------------------------- The Thermal and Photochemical Decomposition of 2,2,3,3-Tetramethyl-1,1-bis(dimethylphenylsilyl) Silirane Manuscript under preparation for Organometallics Project I Project II Project III Content of the Talk Manuscript under preparation for Organometallics Synthesis, Electrochemistry and Spectroelectrochemistry of a Silicon (IV) Phthalocyanine Chloride Submitted to Inorganica Chemica Acta
Synthesis of a Series of Bis(siliranes): Precursors to Disilyne via Molecular Beam Method
HC CH C E = Si, Ge, Sn, PbE E RR H2C CH2 E E R R R R Why Multiple Bonded Compounds of Heavier Elements are Reactive Si Ge Sn Pb C
HC CH E = Si, Ge, Sn, PbE E RR H2C CH2 E E R R R R  Pauli repulsion from the inner shell electrons.  Mismatch in Orbital size and s electrons become increasingly lone pair in character. Why Multiple Bonded Compounds of Heavier Elements are Reactive
hυ  Stable disilene Stable Multiple Bonded Silicon Compounds KC8 / THF  Stable disilyne Mes = Me Me Me Si SiMe3 Mes SiMe3 Mes Si Si Mes Mes Mes Mes Si Si Si Si (Me3Si)2HC (Me3Si)2HC CH(SiMe3)2 CH(SiMe3)2 i Pr i PrSiSi (Me3Si)2HC (Me3Si)2HC i Pr Br Br Br Sekiguchi, A.; Kinjo, R.; Ichinohe, M. Science 2004, 305, 1755. West, R.; Fink, M. J.; Michl, J. Science 1981, 214, 1343
Si Si HH 10 20 30 40 0 kcalmol-1 Si SiH H 42.3 20.4 Si Si H H 11.8 Si Si H H H SiSi H 10.8 Obstacles in the Synthesis of Simple Disilynes  Existence of more stable isomers and small energy barriers for conversions H SiSi H * 14.9 12.7 H SiSi H *  High reactivity 3.1 1.9 Colegrovet, B. T.; SchaeferIII, H. F. J. Am. Chem. Soc 1991, 113, 1557.
ablation laser pulse rotating rod inert gas reactive intermediate 118 nm laser pulse TOF Mass Spectrometer reflectron microchannel plate Can We Generate and Observe the Simple Disilynes MOLECULAR BEAM METHOD Animation with permission from Dunkan’ group, University of Georgia, Athens
Ando et al., J. Am. Chem. Soc., 1997, 119, 3629 Why We Have Chosen Bis(silirane)  Evidence for disilyne from bis(silirane) Si Si Me Me Me Me Me Me Me Me R R Si Si R R Si SiR R SiMe3 Me3Si Me3Si SiMe3 SiMe3Me3Si ΔΔ
Ge Ge Ge Mes Mes Mes Mes Mes Mes Ge Ge Mes Mes Mes Mes + Ge Mes Mes Ge Si Ge Mes Mes Mes Mes Mes Mes Ge Ge Mes Mes Mes Mes Si Mes Mes + Ge Si Mes Mes Mes Mes Ge Mes Mes +  2+1 type fragmentation by laser ablation method Fink et al. Organometallics 2002, 21, 2438. Mes = Me Me Me Why We Have Chosen Bis(silirane)
Stable Bis(silirane): The Target Ando et al., J. Am. Chem. Soc., 1997, 119, 3629. 2000, 122, 3775. SiSi Me Me Me Me Me Me Me Me Me Me SiSi Me Me Me Me Me Ph Ph Me Me Me SiSi Me Me Me Me Me Me Me Me Me MeMe Me Me Me
Synthetic Approach to the tert-Butyl Substituted Bis(silirane) Si CH H CH Me Me Me Me Cl Si Si Me Me Me Me Me Me tert-butylLi Si CH CH Me Me H Me Me Me Me Me Br2 Si CH CH Me Me Br Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me ether CH2Cl2 KC8 /THF 80% 90% 83% Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me NBS / CCl4 AIBN Mg* / THF 37% 23% 2.47 Å 1.94 Å Orthorhombic C2221
Bromination of Disilane – a Synthetic Challenge Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me Me Br Me Me Me BrMe MeBr Me Br Me NBS / CCl4 AIBNhv / 1 H NMR(d8THF) 1H NMR(d8THF)  HPLC separation gave near pure compound Thermally unstable at room temp. 13 C NMR (THF-d8)Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr BrHC CH2Br Side Products Separated in HPLC Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr Me CH2
Proposed Route to the Impurities Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr Me CH2 Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me CH Me Br Me Me Me Me MeBr Me Br Me NBS / CCl4 AIBNhv / Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br Me Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr BrHC CH2Br -HBr Br
Disordered Crystal Structure Si-Si = 2.658 Å Rhombohedral Space group R C3 3 Superimposed along the Si-Si axis DFT Optimized Structure Si-Si = 2.801 Å Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br Me Si Si Me Me Me Me Me Me C Me Me C Me Me C Me Me C Me Me Me Me Me Me Si-Si = 2.69 Å Wiberg et al Angew.Chem.Int.Ed.Engl. 1986, 25, 79.
Distinct NMR Behavior of tert-Butyl Substituted Bis(silirane) Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me Mg* / THF (B) (B) (A) (B) (B) 1 H NMR (C6D6) (A) (B)
Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me Mg* / THF (B) (B) (A) (B) (B) (C) (C) (B) (B) (B) (B) (C) (C) (C) (A) 13 C{1 H} NMR (C6D6) Distinct NMR Behavior of tert-Butyl Substituted Bis(silirane)
1 H NMR (C6D6) (B) 1 H NMR (C6D6) (D) (F) (F) SiSi Me Me Me Me Me Me Me Me Me Me (D) (F) Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (A) Comparison of NMR Behavior
13 C{1 H) NMR (C6D6) C B B C B B C A Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (C) (C) SiSi Me Me Me Me Me Me Me Me Me Me (D) (E) (F) (F) (D) (E) (F)(F) Comparison of NMR Behavior
Question About the Structure of the Molecule Bis(silirane) Disilacyclohexane Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br MeSi Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me Me Me Me Me
DFT Calculation Supports Experimental 29 Si NMR Value - 62.86 +36.21 Spectroscopic Evidence for the Bis(silirane) Structure -60.7Experimental
SiSi Me Me Me Me Me Me Me Me Me Me SiSi Me Me Me Me Me Me Me Me Ph Ph Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me 29 Si{1 H} NMR Comparison -60.7 -82.8 -82.1
Si Si SiMe3 SiMe3 Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me3Si SiMe3 Me Me Me Me Me Me 140 0 C Si Si SiMe3 SiMe3 Me Me Me Me Me Me Me Me Me Me OO2 Chemical Evidence for the Bis(silirane) Structure Si Si Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me
Si Si Me Me Me Me Me Me Me Me Ph Ph Si Me Me Me Me Si Ph Ph Si Si Me Me Me Ph Ph Si Si Ph Ph Me Me Me Me Me Similarity with Ando’s Results Ando et al J.Am.Chem.Soc.1997, 119, 3629.
Evidence from Sekiguchi’s Report Sekiguchi etal. J.Am.Chem.Soc. 2007, 129, (25), 7766. Si Si R R 2-butene Si Si R RC C H Me Me H Si Si R RH Me Me H Si Si R H Me Me H R Si Si R H Me Me H R Si C R H Si C HMe Me R Si Si H H MeMe RR 0 (kcal/mol) 23.2 10.7 13.4 13.0 21.6 - 14.8 + 12.5 2.7 8.6 R = Sii Pr[CH(SiMe3)2]2
Si Si SiMe3 SiMe3 Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me3Si SiMe3 Me Me Me Me Me Me 140 0 C Si Si SiMe3 SiMe3 Me Me Me Me Me Me Me Me Me Me OO2 Si Si Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me Me Me Me X Chemical Evidence for the Bis(silirane) Structure
1 H NMR (C6D6) (B) 1 H NMR (C6D6) (D) (F) (F) SiSi Me Me Me Me Me Me Me Me Me Me (D) (F) Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (A) Can We Justify the NMR Behavior ?
0 20 40 60 80 100 120 140 160 180 0 5 10 15 20 25 30 Phenyl Methyl tert-butyl PotentialEnergy(Kcal/mol) Dihedral angle(C-Si-Si-C)(deg) Energy Profile of Rotational Conformers
Laser Ablation of Bis(silirane) Animation with permission from Dunkan’ group, University of Georgia, Athens Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me
Preliminary Laser Ablation Results Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me + 150 200 250 300 0.066 0.064 0.062 0.060 0.058 intensity mass 254 170 Reasoning Dissolved oxygen
Si Si Si Si Br Br Br Br Br Si Si Monoclinic P21/nP21/c C2/c Crystal Structures P21/c Si Si
Conclusion  Synthesized the air, moisture, thermally stable tert-butyl substituted bis(silirane)  Confirmed the bis(silirane) structure by NMR spectroscopy and thermolysis reaction with bis(trimethylsilylacetylene)  Rotational barrier of 30 kcal/mol justified the conformational rigidity in solution  Preliminary Laser ablation experiments suggested the formation of the disilyne and the cyclic disilene.  Established crystal structures for various intermediates.
The Thermal and Photochemical Decomposition of 2,2,3,3-Tetramethyl-1,1-bis(dimethylphenylsilyl) Silirane Kothanda Rama Pichaandi, Joel T Mague, Mark J Fink. Chemistry Department, Tulane University, New Orleans, LA 70118, USA. Manuscript Under Preparation for Organometallics
Classification of Silylenes  Transient silylenes  Stable silylenes  Have very short life time at room temperature  Can be observable only at very low temperature Si Ph Ph Si Me Me Si Bu Bu t t N Si N Bu Bu N Si N Bu Bu N Si N Np Np Si Me3Si SiMe3 Me3Si SiMe3 N-Heterocyclic silylenes 2,2,5,5-tetrakis(trimethylsilyl) silacyclopentane-1,1-diyl t t t t West. et.al., Acc. Chem. Res. 2000, 33, (10), 704. Kira et.al. J. Am. Chem. Soc. 1999, 121, (41), 9722.
Seiferth et.al., J.Am.Chem.Soc 1975, 97, 7162. Kira et.al., J. Chem. Soc., Dalton Trans., 2002, 1539. Precursors for Transient Silylenes  Strained ring molecules Si Me Me Me Me Me Me MeMe Me Me + Si Me Me ΔΔ hυ Si Me Me Me Me Me Me Si SiMe3 SiMe3 Me Me Si Si Si BuMe2Si SiMe2 t Bu SiMe2 t BuBuMe2Si SiMe2 t Bu SiMe2 t Bu t t 2+1 Type Fragmentation
Si Ph Ph SiMe3 SiMe3 hv Si2Me6 + SiPh2 Precursors for Transient Silylenes Ando et.al. J. Am. Chem. Soc. 1978, 100, 3613. Fragmentation due to the aromatic chromophore  Polysilanes Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Ph Ph SiMe3 SiMe3 Si H Sii Pr3Pr3Si Pr3Si i i Branched Cyclic
Ando et.al. J. Am. Chem. Soc. 1999, 121, 3651 Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Si SiSi Si Me Me Me Me Me Me Me Me Me MeMe2Si + hv Fragmentation due to the σ - σ* transitions  Polysilanes Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Ph Ph SiMe3 SiMe3 Si H Sii Pr3Pr3Si Pr3Si i i Branched Cyclic Precursors for Transient Silylenes
Molecule with Two Independent Substructures for Silylene Generation Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Me Me Me Me Si Si Si Me Me Ph Me Me Ph + Si Si Me Ph Me Me Ph Me + Me Me Me Me hυ hυ
Synthetic Strategy for the Silirane Si CH Me Me CH Me Me ClCl Me Si Me Ph Cl Me Si Me Ph Li Me Si Me Ph Si CH CH Me Me Me Me Si Ph Me Me Me Si Me Ph Si Me Me Me Me Si Ph Me Me Br Br Si Si Si Me Me Ph Me Me Ph Me Me Me Me Li / THF THF NBS/CCl4 Mg* / THF AIBN 62% 42%80% Air, moisture sensitive. Unstable at room temperature.
Crystal Structure 2.381 1.886 2.389 1.928 Monoclinic P21/C Me Si Me Ph Si Me Me Me Me Si Ph Me Me Br Br
1 H NMR (C6D6) Si Si Si Me Me Ph Me Me Ph Me Me Me Me Confirmation of Silirane Structure
13 C NMR (C6D6) Si Si Si Me Me Ph Me Me Ph Me Me Me Me Confirmation of Silirane Structure
29 Si{1 H} NMR (C6D6) Theo: -110.4, -22.1 -123.9 -13.9 Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Sii Pr3Pr3Sii MeMe -149.6 Gaspar et.al.; Organometallics, 1999, 18, 3921 Confirmation of Silirane Structure
Decomposition Pathway of Silirane Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Me Me Me Me Si Si Si Me Me Ph Me Me Ph + Si Si Me Ph Me Me Ph Me + Me Me Me Me Xhυ or ∆ hυ or ∆
Trapping Reactions Si SiMe2Ph SiMe2PhMe Me Si SiMe2Ph SiMe2Phhv or Me3SiOMe Et3SiH Si SiMe2Ph SiMe2Ph Me3Si MeO Me Me Me Me Me Me SiMe3Me3Si Si SiMe2Ph SiMe2Ph Me3Si Me3Si - 80% ( ) 90% ( ) Si SiMe2Ph SiMe2Ph Et3Si H 80% (hv) 80% ( ) hυ Decompose
T T b a a b P P P P P P After 5.5 h photolysis Pure Before photolysis Confirmation of Formation of the Trimethylmethoxysilane Adduct by 29 Si{1 H} NMR Si SiMe2Ph SiMe2Ph Me3Si MeO P P P Si SiMe2Ph SiMe2Ph Me Me Me Me b a T – MeOSiMe3
After 5.5 h photolysis Pure Before photolysis T T c a or b c e e a or b d d Confirmation of Formation of the Bis(trimethylsilylacetylene) Adduct by 29 Si{1 H} NMR Si SiMe2Ph SiMe2Ph Me3Si Me3Si a or b c a or b Si SiMe2Ph SiMe2Ph Me Me Me Me d e T = SiMe3Me3Si
c 1.10 – 0.4 = 0.70 ∼ 0.71 TME After 5.5 h photolysis MeOSiMe3 Si SiMe2Ph SiMe2PhMe Me Me Me Me Me Me Me MeOSiMe3 Si SiMe2Ph SiMe2PhMe Me Me Me Calculation of Quantitative Formation of Silylene by 1 H NMR Before photolysis Si SiMe2Ph SiMe2Ph Me3Si MeO + Si SiMe2Ph SiMe2PhMe Me Si SiMe2Ph SiMe2Ph hv orMe Me Me Me Me Me +
Conclusion  Synthesized a Silirane with two independent substructures for silylene generation.  Photolysis as well as thermolysis of silirane generated a bissilyl substituted silylene and not the cyclic one.  Silylene was intercepted with trapping agents such as triethylsilane, trimethylmethoxysilane and bis(trimethylsilylacetylene).  Quantitative formation of silylene was confirmed by NMR experiments.
Synthesis, Electrochemistry and Spectroelectrochemistry of a Silicon (IV) Phthalocyanine Chloride Kothanda Rama Pichaandi, Heiko Jacobsen, and Mark J. Fink Department of Chemistry, Tulane University, New Orleans, LA 70118 Manuscript submitted to Inorganic Chemica Acta N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Cl
Phthalocyanine Polymers: Introduction
Polymers with direct Si-Si bond expected to possess better electronic properties due to σ delocalization in the polysilane backbone Phthalocyanine Polymers with Direct Si-Si Bond: a Novel Idea
Earlier Reports of Cofacial Dimers Kobayashi et.al. Chem. Eur. J 2002, 8, 1474 Hanack et.al. Angew. Chem. Int. Ed. 2002, 41, 3239 N N N N N N N NIn t Bu t Bu t Bu t Bu N N N N N N N NIn t Bu t Bu t Bu t Bu N N Me Me Me Me N N Me Me Me Me N N N N N N N NIn t Bu t Bu t Bu t Bu Cl Mg, TMEDA, THF n BuO NH NH NH n BuO N N N N N N N NSi n BuO n BuO On Bu On Bu On Bu On Bun BuO n BuO Si2Cl6, quinoline N N N N N N N NSi n BuO n BuO On Bu On Bu On Bu On Bun BuO n BuO ClCl  Accompanied with Impurities  Polymers from this is difficult
N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Cl Can We Synthesize the Dimer by Wurtz Coupling Reaction ? N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3CH3 n Bun Bu Polymers hυ
Cl Cl n Bu n Bu Br n Bu n BuBr n Bu n Bu NC NCn Bu NH NH NH N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3Cl n Bu RMgCl/ether Ni(dppe)Cl2 (cat.) Br2, CH2Cl2 Fe (cat.) CuCN, DMF NH3, CH3OH CH3SiCl3, quinoline 180°C Synthesis of Monomeric Silicon Phthalocyanine 77% 71% 66%98% 46% Highly air, moisture and light sensitive dark green powder Lieberman etal., Inorg. Chem. 2001, 40, 932 a c b s a b c 1 HNMR (CDCl3)
Attempts towards the Dimeric Phthalocyanine Uncharacterizable products  Green color solution dark reddish violet color then back to green color N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3Cl KC8, THF  Trials :Molar ratio of 1:1, 1:2, 1:3 (SiPc: KC8)  Dimethoxyethane as solvent  Other reducing agents like Na and tert-butyl Li gave the same results N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3HO +
Si Cl CH3 Si Cl CH3 Si CH3 KC 8 - Cl Si CH3 Si CH3 THF Can We Explain the Failure of Wurtz Coupling Reaction which can Lead to an Alternative Route.  Stability of the anion radical and ability of cleavage of Cl- ion ?  Redox process at the central metal atom or on the phthalocyanine ring ?  Cyclic voltametry  Spectroelectrochemistry  DFT Calculations Experiments to address these questions + Impurities Si Cl CH3 Si Cl CH3 Si CH3 Si OH CH3 KC 8 - Cl O2 Si CH3 Si CH3 X X THF
Cyclic Voltametry  Two one-electron reductions and two one electron oxidations within the limit of solvent.  I, II reductions and I oxidations are reversible 2 1 0 -1 -2 -1.2x10 -5 -8.0x10 -6 -4.0x10 -6 0.0 4.0x10 -6 8.0x10 -6 CURRENT(A) VOLTAGE(V) -1.62 -1.44 -1.08 0.55 0.67 1.32 1.41 -0.99
300 350 400 450 500 550 600 650 700 750 800 850 900 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) 895,870,850,744,594,454 Spectroelectrochemistry Isosbestic points: 723,640,398,340,288 696,665,375, 352 REDUCTION I (-1200mV)
300 350 400 450 500 550 600 650 700 750 800 850 900 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction I (-1200 mV) Reverse 14% reduction in Q-band intensity Initial Reverse After reduction
300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction II (-1700 mV) 744,594,454 Isosbestic points: 720,401 696,665,375, 375, 352
300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction II (-1700 mV) Reverse 55% reduction in Q-band intensity Initial Reverse After reduction
400 500 600 700 800 0.0 0.1 0.2 0.3 0.4 0.5 absorbance wavelength(nm) Oxidation I (850 mV) 594, 566 Isosbestic points: 723,617,398,350 696,665,624, 375
300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Oxidation II (1450 mV)
300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Oxidation II (1450 mV) Reverse Initial Reverse After oxidation
DFT Calculations to Explain the Spectroelectrochemistry HOMO LUMO LUMO +1 Unconjucated p orbitals of central carbon atoms
CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transitionorbital contributions 152  153 152  154 152  154 153  155 152  154 152  154 300 350 400 450 500 550 600 650 700 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) Sn(Pc)Cl2 651nm 696
CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transition orbital contributions 152  153 152  154 152  154 153  155 152  154 152  154 300 350 400 450 500 550 600 650 700 750 800 850 900 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) 594
CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transition orbital contributions 152  153 152  154 152  154 153  155 152  153 152  154 400 500 600 700 800 0.0 0.1 0.2 0.3 0.4 0.5 absorbance wavelength(nm)
Alternative Approach to the Dimer N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3CH3 n Bun Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Br N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3HSiBr Si Si KC8 THF KC8 / THF
Conclusion  Attempt made to synthesize the dimer with Si-Si bond through Wurtz coupling reaction.  CV, Spectroelectrochemistry answered the two questions. i) Stability of anion ii) Redox process takes place in the phthalocyanine ring  Alternative approach to the dimer can be using bromomethyl siliconphthalocyanine instead of its chloro analog.
Acknowledgement Dr. Mark J. Fink (Advisor) Collaborators Dr. Joel T. Mague Crystallography Dr. Mark Sulkes Laser experiments Dr. Heiko Jacobsen DFT calculation Dr. Russell H. Schmehl Spectroelectrochemistry expts Dr. James Bollinger Cyclic Voltametry Committee members Dr. Alexander L Burin Dr. Russell H. Schmehl Dr. Mark Sulkes My group members Faculty Members Staffs of Chemistry Dept My Tulane Friends My Family Members NSF Dr. Peter Gaspar

Recommended

Ic981126o
Ic981126oIc981126o
Ic981126oinscore
 
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Luciana Pirone
 
Size control of Nanoparticles
Size control of NanoparticlesSize control of Nanoparticles
Size control of NanoparticlesOscar1Miranda2
 
UQ364438_OA
UQ364438_OAUQ364438_OA
UQ364438_OAWayne Tan
 
Carbonate removal from coastal sediments for the determination of organic c a...
Carbonate removal from coastal sediments for the determination of organic c a...Carbonate removal from coastal sediments for the determination of organic c a...
Carbonate removal from coastal sediments for the determination of organic c a...Mahbubul Hassan
 
Schiff base
Schiff baseSchiff base
Schiff baseTDMNS College T.Kalikulam
 
PresentationS
PresentationSPresentationS
PresentationSSulaimon Hamed
 
سعد النصراوي
سعد النصراويسعد النصراوي
سعد النصراويAli Abdul Razaq
 

Recommended

Ic981126o
Ic981126oIc981126o
Ic981126oinscore
 
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Luciana Pirone
 
Size control of Nanoparticles
Size control of NanoparticlesSize control of Nanoparticles
Size control of NanoparticlesOscar1Miranda2
 
UQ364438_OA
UQ364438_OAUQ364438_OA
UQ364438_OAWayne Tan
 
Carbonate removal from coastal sediments for the determination of organic c a...
Carbonate removal from coastal sediments for the determination of organic c a...Carbonate removal from coastal sediments for the determination of organic c a...
Carbonate removal from coastal sediments for the determination of organic c a...Mahbubul Hassan
 
Schiff base
Schiff baseSchiff base
Schiff baseTDMNS College T.Kalikulam
 
PresentationS
PresentationSPresentationS
PresentationSSulaimon Hamed
 
سعد النصراوي
سعد النصراويسعد النصراوي
سعد النصراويAli Abdul Razaq
 
aziz presentation (1)
aziz presentation (1)aziz presentation (1)
aziz presentation (1)aziz ahmad
 
Spectroscopic characterization and biological activity
Spectroscopic characterization and biological activitySpectroscopic characterization and biological activity
Spectroscopic characterization and biological activityMahmoud Abdulla
 
Assemblies of aziridinemethanols
Assemblies of aziridinemethanolsAssemblies of aziridinemethanols
Assemblies of aziridinemethanolsPeter ten Holte
 
CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007Zara_Mohammed
 
Graphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical ApplicationsGraphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical ApplicationsDr. Sitansu Sekhar Nanda
 
Pet and pet ct study guide
Pet and pet ct study guidePet and pet ct study guide
Pet and pet ct study guideSpringer
 
北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014Hajime Ito
 
Important selected model question for neet
Important selected model question for neetImportant selected model question for neet
Important selected model question for neetMudassarHusain1
 
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...Alexander Decker
 
A05620107
A05620107A05620107
A05620107iosrphr_editor
 
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Alexander Decker
 
Science model papers
Science model papersScience model papers
Science model papersMervinSiriwardana
 
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...Al Baha University
 
Rita's Paper 1
Rita's Paper 1Rita's Paper 1
Rita's Paper 1Ya (Rita) Zhang
 
Questions for you
Questions for youQuestions for you
Questions for youRoshen Reji Idiculla
 
Binuclear cu(ii), ni(ii) and co(ii)
Binuclear cu(ii), ni(ii) and co(ii)Binuclear cu(ii), ni(ii) and co(ii)
Binuclear cu(ii), ni(ii) and co(ii)TDMNS College T.Kalikulam
 
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's ClassesIIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's ClassesSOURAV DAS
 
Gate 1994 Chemistry
Gate 1994 ChemistryGate 1994 Chemistry
Gate 1994 ChemistryPRERAK
 
Polymers
PolymersPolymers
PolymersRana zia ur Rehman
 
Basic organic chemistry
Basic organic chemistryBasic organic chemistry
Basic organic chemistryMD. SHOHIDUL ISLAM
 
polymer
polymerpolymer
polymerAmit kumar
 
Presentation on crystallinity in polymers
Presentation on crystallinity in polymersPresentation on crystallinity in polymers
Presentation on crystallinity in polymersRahamat Ullah Joy
 

More Related Content

What's hot

aziz presentation (1)
aziz presentation (1)aziz presentation (1)
aziz presentation (1)aziz ahmad
 
Spectroscopic characterization and biological activity
Spectroscopic characterization and biological activitySpectroscopic characterization and biological activity
Spectroscopic characterization and biological activityMahmoud Abdulla
 
Assemblies of aziridinemethanols
Assemblies of aziridinemethanolsAssemblies of aziridinemethanols
Assemblies of aziridinemethanolsPeter ten Holte
 
CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007Zara_Mohammed
 
Graphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical ApplicationsGraphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical ApplicationsDr. Sitansu Sekhar Nanda
 
Pet and pet ct study guide
Pet and pet ct study guidePet and pet ct study guide
Pet and pet ct study guideSpringer
 
北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014Hajime Ito
 
Important selected model question for neet
Important selected model question for neetImportant selected model question for neet
Important selected model question for neetMudassarHusain1
 
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...Alexander Decker
 
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Alexander Decker
 
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...Al Baha University
 
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's ClassesIIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's ClassesSOURAV DAS
 
Gate 1994 Chemistry
Gate 1994 ChemistryGate 1994 Chemistry
Gate 1994 ChemistryPRERAK
 

What's hot (18)

aziz presentation (1)
aziz presentation (1)aziz presentation (1)
aziz presentation (1)
 
Spectroscopic characterization and biological activity
Spectroscopic characterization and biological activitySpectroscopic characterization and biological activity
Spectroscopic characterization and biological activity
 
Assemblies of aziridinemethanols
Assemblies of aziridinemethanolsAssemblies of aziridinemethanols
Assemblies of aziridinemethanols
 
CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007CAPE Chemistry Unit 2 Paper 1 2007
CAPE Chemistry Unit 2 Paper 1 2007
 
Graphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical ApplicationsGraphene Based Material for Biomedical Applications
Graphene Based Material for Biomedical Applications
 
Pet and pet ct study guide
Pet and pet ct study guidePet and pet ct study guide
Pet and pet ct study guide
 
北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014北大有機元素化学雑誌会M1岩本2014
北大有機元素化学雑誌会M1岩本2014
 
Important selected model question for neet
Important selected model question for neetImportant selected model question for neet
Important selected model question for neet
 
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
Coordination modes of a new ligand derived from pyrazoline with cr(iii), mn(i...
 
A05620107
A05620107A05620107
A05620107
 
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
Synthesis and characterization of complexes of schiff base [1, 2 diphenyl -...
 
Science model papers
Science model papersScience model papers
Science model papers
 
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Al...
 
Rita's Paper 1
Rita's Paper 1Rita's Paper 1
Rita's Paper 1
 
Questions for you
Questions for youQuestions for you
Questions for you
 
Binuclear cu(ii), ni(ii) and co(ii)
Binuclear cu(ii), ni(ii) and co(ii)Binuclear cu(ii), ni(ii) and co(ii)
Binuclear cu(ii), ni(ii) and co(ii)
 
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's ClassesIIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
IIT JAM Biotechnology ( bt ) 2022 Question Paper | Sourav Sir's Classes
 
Gate 1994 Chemistry
Gate 1994 ChemistryGate 1994 Chemistry
Gate 1994 Chemistry
 

Viewers also liked

Presentation on crystallinity in polymers
Presentation on crystallinity in polymersPresentation on crystallinity in polymers
Presentation on crystallinity in polymersRahamat Ullah Joy
 
Polymer science: preparation and uses of polymers
Polymer science: preparation and uses of polymersPolymer science: preparation and uses of polymers
Polymer science: preparation and uses of polymersVARSHAAWASAR
 
Polymers and their properties
Polymers and their propertiesPolymers and their properties
Polymers and their propertiesripestone_ho
 

Viewers also liked (10)

Polymers
PolymersPolymers
Polymers
 
Basic organic chemistry
Basic organic chemistryBasic organic chemistry
Basic organic chemistry
 
polymer
polymerpolymer
polymer
 
Presentation on crystallinity in polymers
Presentation on crystallinity in polymersPresentation on crystallinity in polymers
Presentation on crystallinity in polymers
 
Organic chemistry
Organic chemistryOrganic chemistry
Organic chemistry
 
Polymer
Polymer Polymer
Polymer
 
Polymer
PolymerPolymer
Polymer
 
Polymer science: preparation and uses of polymers
Polymer science: preparation and uses of polymersPolymer science: preparation and uses of polymers
Polymer science: preparation and uses of polymers
 
Polymer ppt
Polymer pptPolymer ppt
Polymer ppt
 
Polymers and their properties
Polymers and their propertiesPolymers and their properties
Polymers and their properties
 

Similar to Defense

Energia r.p.h.chang
Energia r.p.h.changEnergia r.p.h.chang
Energia r.p.h.changCesar Diaz
 
RSC ADV Prashant 6th paper (1)
RSC ADV Prashant 6th paper (1)RSC ADV Prashant 6th paper (1)
RSC ADV Prashant 6th paper (1)Prashant Sharma
 
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...Yuriko Takahashi
 
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...Owen Summerscales
 
3rd Gen. OLED -- TADF
3rd Gen. OLED -- TADF3rd Gen. OLED -- TADF
3rd Gen. OLED -- TADFChris Huang
 
Bchir JACS 2005
Bchir JACS 2005Bchir JACS 2005
Bchir JACS 2005Omar Bchir
 
The (2, 3) witting rearrangement
The (2, 3) witting rearrangementThe (2, 3) witting rearrangement
The (2, 3) witting rearrangementrajenderkarnekanti
 
plasmonic sensors
plasmonic sensorsplasmonic sensors
plasmonic sensorsSimithaS2
 
Fullerenes-An explorative study.pptx
Fullerenes-An explorative study.pptxFullerenes-An explorative study.pptx
Fullerenes-An explorative study.pptxZeeshan Nazir
 
Chirality and its biological role (English language) - www.wespeakscience.com
Chirality and its biological role (English language) - www.wespeakscience.comChirality and its biological role (English language) - www.wespeakscience.com
Chirality and its biological role (English language) - www.wespeakscience.comZeqir Kryeziu
 
Synlett 2014_25_2649-53
Synlett 2014_25_2649-53Synlett 2014_25_2649-53
Synlett 2014_25_2649-53Subrata Ghosh
 
supercapacitor application for future generation
supercapacitor application for future generationsupercapacitor application for future generation
supercapacitor application for future generationsushantalenka2
 
Catalytic Antibodies_JACS 1987 Powell et. al.
Catalytic Antibodies_JACS 1987 Powell et. al.Catalytic Antibodies_JACS 1987 Powell et. al.
Catalytic Antibodies_JACS 1987 Powell et. al.Michael Powell
 
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...Stephan Irle
 
Long Period Polytype Boundaries Mat Res Bull
Long Period Polytype Boundaries Mat Res BullLong Period Polytype Boundaries Mat Res Bull
Long Period Polytype Boundaries Mat Res BullDr Jim Kelly
 
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...Grupo de Pesquisa em Nanoneurobiofisica
 

Similar to Defense (20)

Energia r.p.h.chang
Energia r.p.h.changEnergia r.p.h.chang
Energia r.p.h.chang
 
RSC ADV Prashant 6th paper (1)
RSC ADV Prashant 6th paper (1)RSC ADV Prashant 6th paper (1)
RSC ADV Prashant 6th paper (1)
 
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...
I. Novel, One-Pot Reactions towards Molecular Alkaline Earth Species, II. Exp...
 
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...
Reductive Cyclotrimerization of Carbon Monoxide to the Deltate Dianion by an ...
 
3rd Gen. OLED -- TADF
3rd Gen. OLED -- TADF3rd Gen. OLED -- TADF
3rd Gen. OLED -- TADF
 
2017 imms roli
2017 imms roli2017 imms roli
2017 imms roli
 
Bchir JACS 2005
Bchir JACS 2005Bchir JACS 2005
Bchir JACS 2005
 
PhD Presentation
PhD PresentationPhD Presentation
PhD Presentation
 
The (2, 3) witting rearrangement
The (2, 3) witting rearrangementThe (2, 3) witting rearrangement
The (2, 3) witting rearrangement
 
plasmonic sensors
plasmonic sensorsplasmonic sensors
plasmonic sensors
 
Fullerenes-An explorative study.pptx
Fullerenes-An explorative study.pptxFullerenes-An explorative study.pptx
Fullerenes-An explorative study.pptx
 
Chirality and its biological role (English language) - www.wespeakscience.com
Chirality and its biological role (English language) - www.wespeakscience.comChirality and its biological role (English language) - www.wespeakscience.com
Chirality and its biological role (English language) - www.wespeakscience.com
 
Synlett 2014_25_2649-53
Synlett 2014_25_2649-53Synlett 2014_25_2649-53
Synlett 2014_25_2649-53
 
Geometrical Isomerism in Olefins
Geometrical Isomerism in OlefinsGeometrical Isomerism in Olefins
Geometrical Isomerism in Olefins
 
supercapacitor application for future generation
supercapacitor application for future generationsupercapacitor application for future generation
supercapacitor application for future generation
 
Catalytic Antibodies_JACS 1987 Powell et. al.
Catalytic Antibodies_JACS 1987 Powell et. al.Catalytic Antibodies_JACS 1987 Powell et. al.
Catalytic Antibodies_JACS 1987 Powell et. al.
 
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...
SWCNT Growth from Chiral and Achiral Carbon Nanorings: Prediction of Chiralit...
 
Long Period Polytype Boundaries Mat Res Bull
Long Period Polytype Boundaries Mat Res BullLong Period Polytype Boundaries Mat Res Bull
Long Period Polytype Boundaries Mat Res Bull
 
POSTER
POSTERPOSTER
POSTER
 
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...
Self assembled hybrid films of phosphotungstic acid and aminoalkoxysilane sur...
 

Defense

  • 1. 08-18-08 Kothanda Rama Pichaandi Chemistry Department, Tulane University, New Orleans Defense Seminar Synthesis of Strained Ring Compounds: Precursors to Disilyne via Molecular Beam Method
  • 2. Introduction Multiple bonded (Me)2Si O Si Si Me Me Me Me Si C Me Me Me Me CH3Si+ CH3Si - CH3Si (C2H5)3Si Low valent  Organosilicon reactive intermediates involves one or more silicon atoms that are either multiply bonded or low valent in nature.  Many of them are transient in nature and can be observable only at very low temperature under condensed matrix conditions. Si Si MeMe Si Ph Ph Si Bu Bu t t
  • 3. Microlitho graphy Applications of Organosilicon Reactive Intermediates Semiconductors Aerospace Industries Stereo selective synthesis Me O Ph O O Si Bu Bu AgOTs O O O Ph Me Si Bu Bu 6 electro cyclization Ph COOHHO MeIreland-Claison rearrangement Hydrolysis (1) (2) (3) t tt t
  • 4. Synthesis of a series of Bis(siliranes): Precursors to Disilyne via Molecular Beam Method ------------------------------------------------------------------------------ ----------------------------------------------------------------------------- The Thermal and Photochemical Decomposition of 2,2,3,3-Tetramethyl-1,1-bis(dimethylphenylsilyl) Silirane Manuscript under preparation for Organometallics Project I Project II Project III Content of the Talk Manuscript under preparation for Organometallics Synthesis, Electrochemistry and Spectroelectrochemistry of a Silicon (IV) Phthalocyanine Chloride Submitted to Inorganica Chemica Acta
  • 5. Synthesis of a Series of Bis(siliranes): Precursors to Disilyne via Molecular Beam Method
  • 6. HC CH C E = Si, Ge, Sn, PbE E RR H2C CH2 E E R R R R Why Multiple Bonded Compounds of Heavier Elements are Reactive Si Ge Sn Pb C
  • 7. HC CH E = Si, Ge, Sn, PbE E RR H2C CH2 E E R R R R  Pauli repulsion from the inner shell electrons.  Mismatch in Orbital size and s electrons become increasingly lone pair in character. Why Multiple Bonded Compounds of Heavier Elements are Reactive
  • 8. hυ  Stable disilene Stable Multiple Bonded Silicon Compounds KC8 / THF  Stable disilyne Mes = Me Me Me Si SiMe3 Mes SiMe3 Mes Si Si Mes Mes Mes Mes Si Si Si Si (Me3Si)2HC (Me3Si)2HC CH(SiMe3)2 CH(SiMe3)2 i Pr i PrSiSi (Me3Si)2HC (Me3Si)2HC i Pr Br Br Br Sekiguchi, A.; Kinjo, R.; Ichinohe, M. Science 2004, 305, 1755. West, R.; Fink, M. J.; Michl, J. Science 1981, 214, 1343
  • 9. Si Si HH 10 20 30 40 0 kcalmol-1 Si SiH H 42.3 20.4 Si Si H H 11.8 Si Si H H H SiSi H 10.8 Obstacles in the Synthesis of Simple Disilynes  Existence of more stable isomers and small energy barriers for conversions H SiSi H * 14.9 12.7 H SiSi H *  High reactivity 3.1 1.9 Colegrovet, B. T.; SchaeferIII, H. F. J. Am. Chem. Soc 1991, 113, 1557.
  • 10. ablation laser pulse rotating rod inert gas reactive intermediate 118 nm laser pulse TOF Mass Spectrometer reflectron microchannel plate Can We Generate and Observe the Simple Disilynes MOLECULAR BEAM METHOD Animation with permission from Dunkan’ group, University of Georgia, Athens
  • 11. Ando et al., J. Am. Chem. Soc., 1997, 119, 3629 Why We Have Chosen Bis(silirane)  Evidence for disilyne from bis(silirane) Si Si Me Me Me Me Me Me Me Me R R Si Si R R Si SiR R SiMe3 Me3Si Me3Si SiMe3 SiMe3Me3Si ΔΔ
  • 12. Ge Ge Ge Mes Mes Mes Mes Mes Mes Ge Ge Mes Mes Mes Mes + Ge Mes Mes Ge Si Ge Mes Mes Mes Mes Mes Mes Ge Ge Mes Mes Mes Mes Si Mes Mes + Ge Si Mes Mes Mes Mes Ge Mes Mes +  2+1 type fragmentation by laser ablation method Fink et al. Organometallics 2002, 21, 2438. Mes = Me Me Me Why We Have Chosen Bis(silirane)
  • 13. Stable Bis(silirane): The Target Ando et al., J. Am. Chem. Soc., 1997, 119, 3629. 2000, 122, 3775. SiSi Me Me Me Me Me Me Me Me Me Me SiSi Me Me Me Me Me Ph Ph Me Me Me SiSi Me Me Me Me Me Me Me Me Me MeMe Me Me Me
  • 14. Synthetic Approach to the tert-Butyl Substituted Bis(silirane) Si CH H CH Me Me Me Me Cl Si Si Me Me Me Me Me Me tert-butylLi Si CH CH Me Me H Me Me Me Me Me Br2 Si CH CH Me Me Br Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me ether CH2Cl2 KC8 /THF 80% 90% 83% Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me NBS / CCl4 AIBN Mg* / THF 37% 23% 2.47 Å 1.94 Å Orthorhombic C2221
  • 15. Bromination of Disilane – a Synthetic Challenge Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me Me Br Me Me Me BrMe MeBr Me Br Me NBS / CCl4 AIBNhv / 1 H NMR(d8THF) 1H NMR(d8THF)  HPLC separation gave near pure compound Thermally unstable at room temp. 13 C NMR (THF-d8)Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr BrHC CH2Br Side Products Separated in HPLC Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr Me CH2
  • 16. Proposed Route to the Impurities Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr Me CH2 Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me CH Me Me CH Me Me CH Me Me CH Me Me CH Me Br Me Me Me Me MeBr Me Br Me NBS / CCl4 AIBNhv / Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br Me Si Si Me Me Me Me Me Me Me Me Br CH Me MeMe MeBr BrHC CH2Br -HBr Br
  • 17. Disordered Crystal Structure Si-Si = 2.658 Å Rhombohedral Space group R C3 3 Superimposed along the Si-Si axis DFT Optimized Structure Si-Si = 2.801 Å Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br Me Si Si Me Me Me Me Me Me C Me Me C Me Me C Me Me C Me Me Me Me Me Me Si-Si = 2.69 Å Wiberg et al Angew.Chem.Int.Ed.Engl. 1986, 25, 79.
  • 18. Distinct NMR Behavior of tert-Butyl Substituted Bis(silirane) Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me Mg* / THF (B) (B) (A) (B) (B) 1 H NMR (C6D6) (A) (B)
  • 19. Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me Br Me Me Me BrMe MeBr Me Br Me Mg* / THF (B) (B) (A) (B) (B) (C) (C) (B) (B) (B) (B) (C) (C) (C) (A) 13 C{1 H} NMR (C6D6) Distinct NMR Behavior of tert-Butyl Substituted Bis(silirane)
  • 20. 1 H NMR (C6D6) (B) 1 H NMR (C6D6) (D) (F) (F) SiSi Me Me Me Me Me Me Me Me Me Me (D) (F) Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (A) Comparison of NMR Behavior
  • 21. 13 C{1 H) NMR (C6D6) C B B C B B C A Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (C) (C) SiSi Me Me Me Me Me Me Me Me Me Me (D) (E) (F) (F) (D) (E) (F)(F) Comparison of NMR Behavior
  • 22. Question About the Structure of the Molecule Bis(silirane) Disilacyclohexane Si Si Me Me Me Me Me Me Me Br Me Me Me BrMe MeBr Me Br MeSi Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me Me Me Me Me
  • 23. DFT Calculation Supports Experimental 29 Si NMR Value - 62.86 +36.21 Spectroscopic Evidence for the Bis(silirane) Structure -60.7Experimental
  • 24. SiSi Me Me Me Me Me Me Me Me Me Me SiSi Me Me Me Me Me Me Me Me Ph Ph Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me 29 Si{1 H} NMR Comparison -60.7 -82.8 -82.1
  • 25. Si Si SiMe3 SiMe3 Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me3Si SiMe3 Me Me Me Me Me Me 140 0 C Si Si SiMe3 SiMe3 Me Me Me Me Me Me Me Me Me Me OO2 Chemical Evidence for the Bis(silirane) Structure Si Si Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me
  • 26. Si Si Me Me Me Me Me Me Me Me Ph Ph Si Me Me Me Me Si Ph Ph Si Si Me Me Me Ph Ph Si Si Ph Ph Me Me Me Me Me Similarity with Ando’s Results Ando et al J.Am.Chem.Soc.1997, 119, 3629.
  • 27. Evidence from Sekiguchi’s Report Sekiguchi etal. J.Am.Chem.Soc. 2007, 129, (25), 7766. Si Si R R 2-butene Si Si R RC C H Me Me H Si Si R RH Me Me H Si Si R H Me Me H R Si Si R H Me Me H R Si C R H Si C HMe Me R Si Si H H MeMe RR 0 (kcal/mol) 23.2 10.7 13.4 13.0 21.6 - 14.8 + 12.5 2.7 8.6 R = Sii Pr[CH(SiMe3)2]2
  • 28. Si Si SiMe3 SiMe3 Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Me3Si SiMe3 Me Me Me Me Me Me 140 0 C Si Si SiMe3 SiMe3 Me Me Me Me Me Me Me Me Me Me OO2 Si Si Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me Me Me Me Me X Chemical Evidence for the Bis(silirane) Structure
  • 29. 1 H NMR (C6D6) (B) 1 H NMR (C6D6) (D) (F) (F) SiSi Me Me Me Me Me Me Me Me Me Me (D) (F) Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me (B) (B) (A) (B) (B) (A) Can We Justify the NMR Behavior ?
  • 30. 0 20 40 60 80 100 120 140 160 180 0 5 10 15 20 25 30 Phenyl Methyl tert-butyl PotentialEnergy(Kcal/mol) Dihedral angle(C-Si-Si-C)(deg) Energy Profile of Rotational Conformers
  • 31. Laser Ablation of Bis(silirane) Animation with permission from Dunkan’ group, University of Georgia, Athens Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me
  • 32. Preliminary Laser Ablation Results Si Si Me Me Me Me Me Me Me Me Me Me Me MeMe Me Si Si Me Me Me Me Me Me Si Si Me Me Me Me Me Me Me Me Me Me + 150 200 250 300 0.066 0.064 0.062 0.060 0.058 intensity mass 254 170 Reasoning Dissolved oxygen
  • 34. Conclusion  Synthesized the air, moisture, thermally stable tert-butyl substituted bis(silirane)  Confirmed the bis(silirane) structure by NMR spectroscopy and thermolysis reaction with bis(trimethylsilylacetylene)  Rotational barrier of 30 kcal/mol justified the conformational rigidity in solution  Preliminary Laser ablation experiments suggested the formation of the disilyne and the cyclic disilene.  Established crystal structures for various intermediates.
  • 35. The Thermal and Photochemical Decomposition of 2,2,3,3-Tetramethyl-1,1-bis(dimethylphenylsilyl) Silirane Kothanda Rama Pichaandi, Joel T Mague, Mark J Fink. Chemistry Department, Tulane University, New Orleans, LA 70118, USA. Manuscript Under Preparation for Organometallics
  • 36. Classification of Silylenes  Transient silylenes  Stable silylenes  Have very short life time at room temperature  Can be observable only at very low temperature Si Ph Ph Si Me Me Si Bu Bu t t N Si N Bu Bu N Si N Bu Bu N Si N Np Np Si Me3Si SiMe3 Me3Si SiMe3 N-Heterocyclic silylenes 2,2,5,5-tetrakis(trimethylsilyl) silacyclopentane-1,1-diyl t t t t West. et.al., Acc. Chem. Res. 2000, 33, (10), 704. Kira et.al. J. Am. Chem. Soc. 1999, 121, (41), 9722.
  • 37. Seiferth et.al., J.Am.Chem.Soc 1975, 97, 7162. Kira et.al., J. Chem. Soc., Dalton Trans., 2002, 1539. Precursors for Transient Silylenes  Strained ring molecules Si Me Me Me Me Me Me MeMe Me Me + Si Me Me ΔΔ hυ Si Me Me Me Me Me Me Si SiMe3 SiMe3 Me Me Si Si Si BuMe2Si SiMe2 t Bu SiMe2 t BuBuMe2Si SiMe2 t Bu SiMe2 t Bu t t 2+1 Type Fragmentation
  • 38. Si Ph Ph SiMe3 SiMe3 hv Si2Me6 + SiPh2 Precursors for Transient Silylenes Ando et.al. J. Am. Chem. Soc. 1978, 100, 3613. Fragmentation due to the aromatic chromophore  Polysilanes Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Ph Ph SiMe3 SiMe3 Si H Sii Pr3Pr3Si Pr3Si i i Branched Cyclic
  • 39. Ando et.al. J. Am. Chem. Soc. 1999, 121, 3651 Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Si SiSi Si Me Me Me Me Me Me Me Me Me MeMe2Si + hv Fragmentation due to the σ - σ* transitions  Polysilanes Si Si Si Si Si Si MeMe Me Me Me Me Me Me Me Me Me Me Si Ph Ph SiMe3 SiMe3 Si H Sii Pr3Pr3Si Pr3Si i i Branched Cyclic Precursors for Transient Silylenes
  • 40. Molecule with Two Independent Substructures for Silylene Generation Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Me Me Me Me Si Si Si Me Me Ph Me Me Ph + Si Si Me Ph Me Me Ph Me + Me Me Me Me hυ hυ
  • 41. Synthetic Strategy for the Silirane Si CH Me Me CH Me Me ClCl Me Si Me Ph Cl Me Si Me Ph Li Me Si Me Ph Si CH CH Me Me Me Me Si Ph Me Me Me Si Me Ph Si Me Me Me Me Si Ph Me Me Br Br Si Si Si Me Me Ph Me Me Ph Me Me Me Me Li / THF THF NBS/CCl4 Mg* / THF AIBN 62% 42%80% Air, moisture sensitive. Unstable at room temperature.
  • 43. 1 H NMR (C6D6) Si Si Si Me Me Ph Me Me Ph Me Me Me Me Confirmation of Silirane Structure
  • 44. 13 C NMR (C6D6) Si Si Si Me Me Ph Me Me Ph Me Me Me Me Confirmation of Silirane Structure
  • 45. 29 Si{1 H} NMR (C6D6) Theo: -110.4, -22.1 -123.9 -13.9 Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Sii Pr3Pr3Sii MeMe -149.6 Gaspar et.al.; Organometallics, 1999, 18, 3921 Confirmation of Silirane Structure
  • 46. Decomposition Pathway of Silirane Si Si Si Me Me Ph Me Me Ph Me Me Me Me Si Me Me Me Me Si Si Si Me Me Ph Me Me Ph + Si Si Me Ph Me Me Ph Me + Me Me Me Me Xhυ or ∆ hυ or ∆
  • 48. T T b a a b P P P P P P After 5.5 h photolysis Pure Before photolysis Confirmation of Formation of the Trimethylmethoxysilane Adduct by 29 Si{1 H} NMR Si SiMe2Ph SiMe2Ph Me3Si MeO P P P Si SiMe2Ph SiMe2Ph Me Me Me Me b a T – MeOSiMe3
  • 49. After 5.5 h photolysis Pure Before photolysis T T c a or b c e e a or b d d Confirmation of Formation of the Bis(trimethylsilylacetylene) Adduct by 29 Si{1 H} NMR Si SiMe2Ph SiMe2Ph Me3Si Me3Si a or b c a or b Si SiMe2Ph SiMe2Ph Me Me Me Me d e T = SiMe3Me3Si
  • 50. c 1.10 – 0.4 = 0.70 ∼ 0.71 TME After 5.5 h photolysis MeOSiMe3 Si SiMe2Ph SiMe2PhMe Me Me Me Me Me Me Me MeOSiMe3 Si SiMe2Ph SiMe2PhMe Me Me Me Calculation of Quantitative Formation of Silylene by 1 H NMR Before photolysis Si SiMe2Ph SiMe2Ph Me3Si MeO + Si SiMe2Ph SiMe2PhMe Me Si SiMe2Ph SiMe2Ph hv orMe Me Me Me Me Me +
  • 51. Conclusion  Synthesized a Silirane with two independent substructures for silylene generation.  Photolysis as well as thermolysis of silirane generated a bissilyl substituted silylene and not the cyclic one.  Silylene was intercepted with trapping agents such as triethylsilane, trimethylmethoxysilane and bis(trimethylsilylacetylene).  Quantitative formation of silylene was confirmed by NMR experiments.
  • 52. Synthesis, Electrochemistry and Spectroelectrochemistry of a Silicon (IV) Phthalocyanine Chloride Kothanda Rama Pichaandi, Heiko Jacobsen, and Mark J. Fink Department of Chemistry, Tulane University, New Orleans, LA 70118 Manuscript submitted to Inorganic Chemica Acta N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Cl
  • 54. Polymers with direct Si-Si bond expected to possess better electronic properties due to σ delocalization in the polysilane backbone Phthalocyanine Polymers with Direct Si-Si Bond: a Novel Idea
  • 55. Earlier Reports of Cofacial Dimers Kobayashi et.al. Chem. Eur. J 2002, 8, 1474 Hanack et.al. Angew. Chem. Int. Ed. 2002, 41, 3239 N N N N N N N NIn t Bu t Bu t Bu t Bu N N N N N N N NIn t Bu t Bu t Bu t Bu N N Me Me Me Me N N Me Me Me Me N N N N N N N NIn t Bu t Bu t Bu t Bu Cl Mg, TMEDA, THF n BuO NH NH NH n BuO N N N N N N N NSi n BuO n BuO On Bu On Bu On Bu On Bun BuO n BuO Si2Cl6, quinoline N N N N N N N NSi n BuO n BuO On Bu On Bu On Bu On Bun BuO n BuO ClCl  Accompanied with Impurities  Polymers from this is difficult
  • 56. N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Cl Can We Synthesize the Dimer by Wurtz Coupling Reaction ? N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3CH3 n Bun Bu Polymers hυ
  • 57. Cl Cl n Bu n Bu Br n Bu n BuBr n Bu n Bu NC NCn Bu NH NH NH N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3Cl n Bu RMgCl/ether Ni(dppe)Cl2 (cat.) Br2, CH2Cl2 Fe (cat.) CuCN, DMF NH3, CH3OH CH3SiCl3, quinoline 180°C Synthesis of Monomeric Silicon Phthalocyanine 77% 71% 66%98% 46% Highly air, moisture and light sensitive dark green powder Lieberman etal., Inorg. Chem. 2001, 40, 932 a c b s a b c 1 HNMR (CDCl3)
  • 58. Attempts towards the Dimeric Phthalocyanine Uncharacterizable products  Green color solution dark reddish violet color then back to green color N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3Cl KC8, THF  Trials :Molar ratio of 1:1, 1:2, 1:3 (SiPc: KC8)  Dimethoxyethane as solvent  Other reducing agents like Na and tert-butyl Li gave the same results N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bu n Bu n Bu CH3HO +
  • 59. Si Cl CH3 Si Cl CH3 Si CH3 KC 8 - Cl Si CH3 Si CH3 THF Can We Explain the Failure of Wurtz Coupling Reaction which can Lead to an Alternative Route.  Stability of the anion radical and ability of cleavage of Cl- ion ?  Redox process at the central metal atom or on the phthalocyanine ring ?  Cyclic voltametry  Spectroelectrochemistry  DFT Calculations Experiments to address these questions + Impurities Si Cl CH3 Si Cl CH3 Si CH3 Si OH CH3 KC 8 - Cl O2 Si CH3 Si CH3 X X THF
  • 60. Cyclic Voltametry  Two one-electron reductions and two one electron oxidations within the limit of solvent.  I, II reductions and I oxidations are reversible 2 1 0 -1 -2 -1.2x10 -5 -8.0x10 -6 -4.0x10 -6 0.0 4.0x10 -6 8.0x10 -6 CURRENT(A) VOLTAGE(V) -1.62 -1.44 -1.08 0.55 0.67 1.32 1.41 -0.99
  • 61. 300 350 400 450 500 550 600 650 700 750 800 850 900 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) 895,870,850,744,594,454 Spectroelectrochemistry Isosbestic points: 723,640,398,340,288 696,665,375, 352 REDUCTION I (-1200mV)
  • 62. 300 350 400 450 500 550 600 650 700 750 800 850 900 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction I (-1200 mV) Reverse 14% reduction in Q-band intensity Initial Reverse After reduction
  • 63. 300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction II (-1700 mV) 744,594,454 Isosbestic points: 720,401 696,665,375, 375, 352
  • 64. 300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Reduction II (-1700 mV) Reverse 55% reduction in Q-band intensity Initial Reverse After reduction
  • 65. 400 500 600 700 800 0.0 0.1 0.2 0.3 0.4 0.5 absorbance wavelength(nm) Oxidation I (850 mV) 594, 566 Isosbestic points: 723,617,398,350 696,665,624, 375
  • 66. 300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Oxidation II (1450 mV)
  • 67. 300 350 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Absorbance(x10-5/M-1cm-1) Wavelength(nm) Oxidation II (1450 mV) Reverse Initial Reverse After oxidation
  • 68. DFT Calculations to Explain the Spectroelectrochemistry HOMO LUMO LUMO +1 Unconjucated p orbitals of central carbon atoms
  • 69. CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transitionorbital contributions 152  153 152  154 152  154 153  155 152  154 152  154 300 350 400 450 500 550 600 650 700 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) Sn(Pc)Cl2 651nm 696
  • 70. CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transition orbital contributions 152  153 152  154 152  154 153  155 152  154 152  154 300 350 400 450 500 550 600 650 700 750 800 850 900 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Absorbance(x10-5/M-1cm-1) Wavelength(nm) 594
  • 71. CH3(SiPc)Cl [CH3(SiPc)Cl]- [CH3(SiPc)Cl]+ λ 658 596 714 Dominant transition orbital contributions 152  153 152  154 152  154 153  155 152  153 152  154 400 500 600 700 800 0.0 0.1 0.2 0.3 0.4 0.5 absorbance wavelength(nm)
  • 72. Alternative Approach to the Dimer N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3CH3 n Bun Bu N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3Br N N N N N N N NSi n Bu n Bu n Bu n Bu n Bu n Bun Bu n Bu CH3HSiBr Si Si KC8 THF KC8 / THF
  • 73. Conclusion  Attempt made to synthesize the dimer with Si-Si bond through Wurtz coupling reaction.  CV, Spectroelectrochemistry answered the two questions. i) Stability of anion ii) Redox process takes place in the phthalocyanine ring  Alternative approach to the dimer can be using bromomethyl siliconphthalocyanine instead of its chloro analog.
  • 74. Acknowledgement Dr. Mark J. Fink (Advisor) Collaborators Dr. Joel T. Mague Crystallography Dr. Mark Sulkes Laser experiments Dr. Heiko Jacobsen DFT calculation Dr. Russell H. Schmehl Spectroelectrochemistry expts Dr. James Bollinger Cyclic Voltametry Committee members Dr. Alexander L Burin Dr. Russell H. Schmehl Dr. Mark Sulkes My group members Faculty Members Staffs of Chemistry Dept My Tulane Friends My Family Members NSF Dr. Peter Gaspar