Gjergji Sini | CY Cergy Paris Université (original) (raw)
Papers by Gjergji Sini
Tetrahedron, 2000
The different chemioselectivity observed experimentally during the silylation of the title specie... more The different chemioselectivity observed experimentally during the silylation of the title species was investigated by means of theoretical methods. The influence of the solvent on the optimized geometries and relative energies of different reaction intermediate species was studied by applying the continuum model at the DFT/6-31+ G∗//DFT/6-31+G∗ level. Two groups of neutral reaction intermediates were considered: dianion–bislithium intermediates in the case of crotonic acid and monoanion–lithium intermediates in the case of its silyl ester. It was found in both cases that in the gas phase the negative charge is better stabilized when delocalized over the entire molecular skeleton, while in solution the solute–solvent interactions are more important when the charge is localized over the oxygen atoms. For the dianion–bislithium intermediates, the intramolecular interactions are more important and the chain-delocalized charge intermediate remains the most stable one, even in solution. This is not the case for the monoanion–lithium intermediates because the solvent effect inverts the gas phase stability order. The differences observed experimentally in solution are thus explained by the differences in the stability order of these reaction intermediate species.
Organometallics, 2001
CH 3 ) 3 Si-CtC-CtC-Si(OCH 2 CH 2 ) 3 N‚2CHCl 3 (3‚2CHCl 3 ) was analyzed crystallographically. E... more CH 3 ) 3 Si-CtC-CtC-Si(OCH 2 CH 2 ) 3 N‚2CHCl 3 (3‚2CHCl 3 ) was analyzed crystallographically. Each chloroform molecule interacts with diacetylene 3 through one C-H‚‚‚O contact and one C-H‚‚‚π contact. Based on distances and angles, these interactions are found to be weaker than those encountered in compounds containing only C-H‚‚‚O interactions or C-H‚‚‚π interactions. A comparison between the infrared, 13 C, and 29 Si NMR data of 3 obtained in CHCl 3 or CDCl 3 solutions with data obtained in the solid state for the unsolvated material gives further evidence that the chloroform molecules are only weakly bonded to the diacetylenic silatrane. Density functional theory (DFT) calculations have been carried out at the B3LYP level that confirm these findings. Figure 4. Optimized structures (DFT at the B3LYP level) of 6‚CHCl 3 and 7‚CHCl 3 . Distances are in angstroms and angles in degrees. The dissociation energy (E d ) of chloroform is in kcal mol -1 .
The Journal of Physical Chemistry C, 2015
Journal of the Chemical Society, Perkin Transactions 2, 1992
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
Nature communications, 2016
Establishing fundamental relationships between strain and work function (WF) in organic semicondu... more Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ∼0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of ...
J Am Chem Soc, 1992
ABSTRACT The bonding mechanism in a variety of electron-pair bonds is studied by means of an ab i... more ABSTRACT The bonding mechanism in a variety of electron-pair bonds is studied by means of an ab initio valence bond method specifically designed for a rigorous separation of the covalent Heitler-London and the ionic contributions to the bond energy. While a number of bonds (H-H, H3C-H, H3Si-H, Li-Li, Na-F) are found to correspond to the traditional covalent (Heitler-London) or ionic pictures, some other bonds, even homopolar ones (H2N-NH2, HO-OH, F-F), have an unbound or weakly bound covalent component. These latter bonds do not owe their stability to the low energy of either the covalent or the ionic components, but rather to a very large resonance energy (53-79 kcal/mol) between these valence bond structures and as such are named "charge-shift bonds". Two general observations about electron-pair bonds are shown to be indirect marks of charge-shift bonding. These are Sanderson's "lone-pair bond weakening effect" and the finding of negative standard electron deformation densities in the bonding region. The stabilization brought by charge-shift bonding is shown to derive from the decrease of the electronic kinetic energy at the bonding region. Its magnitude correlates with the compactness of the valence orbitals involved in the bond and is reinforced by the presence of lone pairs adjacent to these orbitals. Larger and larger resonance energies are predicted as the bonded atoms change from left to right and from bottom to top of the Periodic Table. Other trends and features of charge-shift bonds are discussed.
Organometallics, 1994
Page 1. Volume 13, Number 4, April 1994 Communications 0 Copyright 1904 American Chemical Sociew ... more Page 1. Volume 13, Number 4, April 1994 Communications 0 Copyright 1904 American Chemical Sociew Why Is @-Me Elimination Only Observed in do Early Transition Metal Complexes? An Organometallic Hyperconjugation ...
Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized... more Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors show relatively high V oc thanks to good energy level matching between them and the associated D102 indoline dye. However, they yield relatively low J sc and FF compared to Spiro-OMeTAD based control devices, which is due to an order of magnitude lower conductivity with respect to Spiro-OMeTAD. Maximum solar-to-electrical energy conversion efficiencies of 1.2% under standard illumination condition was obtained. Stability tests of unsealed devices in air under continuous illumination have been performed and devices based on new compounds have kept up to 80% of their initial efficiency.
J. Mater. Chem. A, 2015
A hybrid surface exhibiting a fast and reversible switch between hydrophobic and hydrophilic stat... more A hybrid surface exhibiting a fast and reversible switch between hydrophobic and hydrophilic states was prepared by spin-coating a porous TiO 2 layer by a mixture of TiO 2 nanoparticles with 11-(4-phenylazo) phenoxy undecanoic acid (denoted as the AzoC11 acid). The nanocomposite film corresponding to the 10% AzoC11 acid/TiO 2 mass fraction exhibited both a very important and fast variation of the contact angle (by more than 120 ), along with an excellent reversibility. The wettability switching is explained by the trans / cis / trans isomerization of the AzoC11 acid under light irradiation or heating. Upon trans / cis isomerization, optical absorption bands were found to exhibit drastic evolution, the origin of which is discussed in detail by means of a time-dependent density functional theory (TDDFT) study. Subsequent to these isomerization processes, various mechanisms explaining the wettability variations were investigated by comparing the results obtained by DFT calculations, wetting measurements for different surface ratios of the AzoC11 acid under UV irradiation, and by analyzing the molecular structure and molecular surfaces of trans and cis-isomers of the AzoC11 acid. † Electronic supplementary information (ESI) available: Theoretical absorption spectra of trans-and cis-AzoC11 acid in THF, absorption onset on the UV-vis spectra of AzoC11 acid solution, theoretical estimation of molecular-areas, expression of surface ratio, values of the wetting study, comparison of contact angle variations versus the irradiation conditions. See
Inorganica Chimica Acta
Ab initio (B3LYP) calculations show that PD·HReH4(PH3)3 (PD = Proton donor) interactions follow ... more Ab initio (B3LYP) calculations show that PD·HReH4(PH3)3 (PD = Proton donor) interactions follow the order PD = pyrrole > NH3 > HCCH > C2H4 > CH3H ∼ 0 and decrease with the pKa of the PD. For equivalent pKa's, NH interacts more strongly than CH. However, intermolecular hydrogen-bonding of the MH·HC type is too weak to be detected experimentally in FTIR or UV-vis studies between ReH5(PPh3)3 and PhCCH, C6F5H or PhCHCl2.
RSC Adv., 2015
Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized... more Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors show relatively high V oc thanks to good energy level matching between them and the associated D102 indoline dye. However, they yield relatively low J sc and FF compared to Spiro-OMeTAD based control devices, which is due to an order of magnitude lower conductivity with respect to Spiro-OMeTAD. Maximum solar-to-electrical energy conversion efficiencies of 1.2% under standard illumination condition was obtained. Stability tests of unsealed devices in air under continuous illumination have been performed and devices based on new compounds have kept up to 80% of their initial efficiency.
The Journal of Physical Chemistry, 1990
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
ChemNanoMat, 2015
Three 3,6-di(4-methoxyphenyl)amino N-alkylated carbazoles were synthesized, characterized and inc... more Three 3,6-di(4-methoxyphenyl)amino N-alkylated carbazoles were synthesized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors showed relative high V oc thanks to good energy level matching between them and D102 dye. However, they yield relatively low J sc and FF compared to spiro-OMeTAD-based control devices, which is due to an order of magnitude lower mobility and conductivity with respect to spiro-OMeTAD. Maximum PCEs for Nethyl and N-hexyl 3,6-di(4-methoxyphenyl)amino carbazoles (2 a, 2 b) are 1.6 %, and 1.8 % respectively, whereas spiro-OMeTAD devices gave 4.4 %. Stability tests in air under continuous illumination have been reported.
... Chem., Int. Ed. 34 (1995) 2507: (b) BP Panel, J. WesL W. Yao. JC Lee Jr., E. Peris. TF Koetzl... more ... Chem., Int. Ed. 34 (1995) 2507: (b) BP Panel, J. WesL W. Yao. JC Lee Jr., E. Peris. TF Koetzle, GPA Yap, LB. Fortin, JS Ricci, G. Sini, A. Albinati, O. Eisenstein. ... MJ Frish. J. Chem, Phys. 98 (1994) 11623. 1131 J, Chatt. J. Coffey, J. Chem Soc,, Sect. A 11963) 1969. References. ...
The Journal of Physical Chemistry, 1989
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
Advanced Functional Materials, 2014
Journal of the Chemical Society, Chemical Communications, 1989
ABSTRACT
Tetrahedron, 2000
The different chemioselectivity observed experimentally during the silylation of the title specie... more The different chemioselectivity observed experimentally during the silylation of the title species was investigated by means of theoretical methods. The influence of the solvent on the optimized geometries and relative energies of different reaction intermediate species was studied by applying the continuum model at the DFT/6-31+ G∗//DFT/6-31+G∗ level. Two groups of neutral reaction intermediates were considered: dianion–bislithium intermediates in the case of crotonic acid and monoanion–lithium intermediates in the case of its silyl ester. It was found in both cases that in the gas phase the negative charge is better stabilized when delocalized over the entire molecular skeleton, while in solution the solute–solvent interactions are more important when the charge is localized over the oxygen atoms. For the dianion–bislithium intermediates, the intramolecular interactions are more important and the chain-delocalized charge intermediate remains the most stable one, even in solution. This is not the case for the monoanion–lithium intermediates because the solvent effect inverts the gas phase stability order. The differences observed experimentally in solution are thus explained by the differences in the stability order of these reaction intermediate species.
Organometallics, 2001
CH 3 ) 3 Si-CtC-CtC-Si(OCH 2 CH 2 ) 3 N‚2CHCl 3 (3‚2CHCl 3 ) was analyzed crystallographically. E... more CH 3 ) 3 Si-CtC-CtC-Si(OCH 2 CH 2 ) 3 N‚2CHCl 3 (3‚2CHCl 3 ) was analyzed crystallographically. Each chloroform molecule interacts with diacetylene 3 through one C-H‚‚‚O contact and one C-H‚‚‚π contact. Based on distances and angles, these interactions are found to be weaker than those encountered in compounds containing only C-H‚‚‚O interactions or C-H‚‚‚π interactions. A comparison between the infrared, 13 C, and 29 Si NMR data of 3 obtained in CHCl 3 or CDCl 3 solutions with data obtained in the solid state for the unsolvated material gives further evidence that the chloroform molecules are only weakly bonded to the diacetylenic silatrane. Density functional theory (DFT) calculations have been carried out at the B3LYP level that confirm these findings. Figure 4. Optimized structures (DFT at the B3LYP level) of 6‚CHCl 3 and 7‚CHCl 3 . Distances are in angstroms and angles in degrees. The dissociation energy (E d ) of chloroform is in kcal mol -1 .
The Journal of Physical Chemistry C, 2015
Journal of the Chemical Society, Perkin Transactions 2, 1992
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
Nature communications, 2016
Establishing fundamental relationships between strain and work function (WF) in organic semicondu... more Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ∼0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of ...
J Am Chem Soc, 1992
ABSTRACT The bonding mechanism in a variety of electron-pair bonds is studied by means of an ab i... more ABSTRACT The bonding mechanism in a variety of electron-pair bonds is studied by means of an ab initio valence bond method specifically designed for a rigorous separation of the covalent Heitler-London and the ionic contributions to the bond energy. While a number of bonds (H-H, H3C-H, H3Si-H, Li-Li, Na-F) are found to correspond to the traditional covalent (Heitler-London) or ionic pictures, some other bonds, even homopolar ones (H2N-NH2, HO-OH, F-F), have an unbound or weakly bound covalent component. These latter bonds do not owe their stability to the low energy of either the covalent or the ionic components, but rather to a very large resonance energy (53-79 kcal/mol) between these valence bond structures and as such are named "charge-shift bonds". Two general observations about electron-pair bonds are shown to be indirect marks of charge-shift bonding. These are Sanderson's "lone-pair bond weakening effect" and the finding of negative standard electron deformation densities in the bonding region. The stabilization brought by charge-shift bonding is shown to derive from the decrease of the electronic kinetic energy at the bonding region. Its magnitude correlates with the compactness of the valence orbitals involved in the bond and is reinforced by the presence of lone pairs adjacent to these orbitals. Larger and larger resonance energies are predicted as the bonded atoms change from left to right and from bottom to top of the Periodic Table. Other trends and features of charge-shift bonds are discussed.
Organometallics, 1994
Page 1. Volume 13, Number 4, April 1994 Communications 0 Copyright 1904 American Chemical Sociew ... more Page 1. Volume 13, Number 4, April 1994 Communications 0 Copyright 1904 American Chemical Sociew Why Is @-Me Elimination Only Observed in do Early Transition Metal Complexes? An Organometallic Hyperconjugation ...
Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized... more Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors show relatively high V oc thanks to good energy level matching between them and the associated D102 indoline dye. However, they yield relatively low J sc and FF compared to Spiro-OMeTAD based control devices, which is due to an order of magnitude lower conductivity with respect to Spiro-OMeTAD. Maximum solar-to-electrical energy conversion efficiencies of 1.2% under standard illumination condition was obtained. Stability tests of unsealed devices in air under continuous illumination have been performed and devices based on new compounds have kept up to 80% of their initial efficiency.
J. Mater. Chem. A, 2015
A hybrid surface exhibiting a fast and reversible switch between hydrophobic and hydrophilic stat... more A hybrid surface exhibiting a fast and reversible switch between hydrophobic and hydrophilic states was prepared by spin-coating a porous TiO 2 layer by a mixture of TiO 2 nanoparticles with 11-(4-phenylazo) phenoxy undecanoic acid (denoted as the AzoC11 acid). The nanocomposite film corresponding to the 10% AzoC11 acid/TiO 2 mass fraction exhibited both a very important and fast variation of the contact angle (by more than 120 ), along with an excellent reversibility. The wettability switching is explained by the trans / cis / trans isomerization of the AzoC11 acid under light irradiation or heating. Upon trans / cis isomerization, optical absorption bands were found to exhibit drastic evolution, the origin of which is discussed in detail by means of a time-dependent density functional theory (TDDFT) study. Subsequent to these isomerization processes, various mechanisms explaining the wettability variations were investigated by comparing the results obtained by DFT calculations, wetting measurements for different surface ratios of the AzoC11 acid under UV irradiation, and by analyzing the molecular structure and molecular surfaces of trans and cis-isomers of the AzoC11 acid. † Electronic supplementary information (ESI) available: Theoretical absorption spectra of trans-and cis-AzoC11 acid in THF, absorption onset on the UV-vis spectra of AzoC11 acid solution, theoretical estimation of molecular-areas, expression of surface ratio, values of the wetting study, comparison of contact angle variations versus the irradiation conditions. See
Inorganica Chimica Acta
Ab initio (B3LYP) calculations show that PD·HReH4(PH3)3 (PD = Proton donor) interactions follow ... more Ab initio (B3LYP) calculations show that PD·HReH4(PH3)3 (PD = Proton donor) interactions follow the order PD = pyrrole > NH3 > HCCH > C2H4 > CH3H ∼ 0 and decrease with the pKa of the PD. For equivalent pKa's, NH interacts more strongly than CH. However, intermolecular hydrogen-bonding of the MH·HC type is too weak to be detected experimentally in FTIR or UV-vis studies between ReH5(PPh3)3 and PhCCH, C6F5H or PhCHCl2.
RSC Adv., 2015
Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized... more Three tris(thienylphenyl)amine-based molecular glass hole transporting materials were synthetized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors show relatively high V oc thanks to good energy level matching between them and the associated D102 indoline dye. However, they yield relatively low J sc and FF compared to Spiro-OMeTAD based control devices, which is due to an order of magnitude lower conductivity with respect to Spiro-OMeTAD. Maximum solar-to-electrical energy conversion efficiencies of 1.2% under standard illumination condition was obtained. Stability tests of unsealed devices in air under continuous illumination have been performed and devices based on new compounds have kept up to 80% of their initial efficiency.
The Journal of Physical Chemistry, 1990
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
ChemNanoMat, 2015
Three 3,6-di(4-methoxyphenyl)amino N-alkylated carbazoles were synthesized, characterized and inc... more Three 3,6-di(4-methoxyphenyl)amino N-alkylated carbazoles were synthesized, characterized and incorporated in solid state dye-sensitized solar cells. Devices using these compounds as solid hole conductors showed relative high V oc thanks to good energy level matching between them and D102 dye. However, they yield relatively low J sc and FF compared to spiro-OMeTAD-based control devices, which is due to an order of magnitude lower mobility and conductivity with respect to spiro-OMeTAD. Maximum PCEs for Nethyl and N-hexyl 3,6-di(4-methoxyphenyl)amino carbazoles (2 a, 2 b) are 1.6 %, and 1.8 % respectively, whereas spiro-OMeTAD devices gave 4.4 %. Stability tests in air under continuous illumination have been reported.
... Chem., Int. Ed. 34 (1995) 2507: (b) BP Panel, J. WesL W. Yao. JC Lee Jr., E. Peris. TF Koetzl... more ... Chem., Int. Ed. 34 (1995) 2507: (b) BP Panel, J. WesL W. Yao. JC Lee Jr., E. Peris. TF Koetzle, GPA Yap, LB. Fortin, JS Ricci, G. Sini, A. Albinati, O. Eisenstein. ... MJ Frish. J. Chem, Phys. 98 (1994) 11623. 1131 J, Chatt. J. Coffey, J. Chem Soc,, Sect. A 11963) 1969. References. ...
The Journal of Physical Chemistry, 1989
quantitative diabatic curves of VB type, for thermal as well as photochemical reactions.
Advanced Functional Materials, 2014
Journal of the Chemical Society, Chemical Communications, 1989
ABSTRACT