We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of d...We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.展开更多
The molecular structure, the Natural Bond orbital (NBO) and the Time Dependent-DFT of both isomers cis or γ-Cl and trans or δ-Cl of RuCl2(L)2, where L stands respectively for 2-phenylazopyridine (Azpy), 2,4-dimethyl...The molecular structure, the Natural Bond orbital (NBO) and the Time Dependent-DFT of both isomers cis or γ-Cl and trans or δ-Cl of RuCl2(L)2, where L stands respectively for 2-phenylazopyridine (Azpy), 2,4-dimethyl-6-[phenylazo]pyridine (Dazpy), 2-[(3,5-dimethylphenyl)azopyridine] (Mazpy) and 2-pyridylazonaphtol (Nazpy) were calculated with DFT method at B3LYP/LANL2DZ level. The prediction of the frontier orbitals (Highest Occupied Molecular Orbital or HOMO and Lowest Unoccupied Molecular Orbital or LUMO) shows that the most active complexes suitable for electronic reactions are admitted to be the trans isomers. Moreover, δ-RuCl2 (Azpy)2 is discovered to react more actively as photo-sensitizer since its energy gap is the minimum. Besides, electronic structures of all complexes through NBO calculation indicate that Ru-N bonds are made of delocalization of occupancies from lone pair orbital of N atoms to the ruthenium. Moreover, Ru was assumed to have almost the same charge regardless the structure of the azopyridine ligands in the complex indicating that the ligands provide only a steric effect that is responsible for the ruthenium’s selectivity. Concerning the transition state, NBO analysis also highlights that the transition LP(Ru) π*(N1-N2) does correspond to t2g?π*(L). This transition is assumed to correspond to Metal to Ligand Charge Transfer (MLCT) that is responsible for the photo-sensitiveness of the metallic complex. Besides, TDDFT calculation of complexes showed that δ-RuCl2(Nazpy)2 displays the largest band during the absorption. For that reason, it is admitted to be the best photosensitizer due to a large system of conjugation provided by Nazpy ligand.展开更多
The optimized geometric structure and photophysical properties of 6-Amino-2-methylpyridine-3-carbonitrile dye have been studied by using Density Functional Theory (DFT). The lowest singlet excited state geometry optim...The optimized geometric structure and photophysical properties of 6-Amino-2-methylpyridine-3-carbonitrile dye have been studied by using Density Functional Theory (DFT). The lowest singlet excited state geometry optimized using Time-Dependent Density Functional Theory (TD-DFT). On the basis of ground and excited state geometries, the absorption spectra have been calculated using the DFT and TD-DFT method in gas phase and acetonitrile medium. To understand the Non-Linear Optical properties of 6-Amino-2-methylpyridine-3-carbonitrile dye, we computed dipole moment (μ), electronic polarizability (α), and first hyperpolarizability (β0) and second order hyperpolarizability (γ) using B3LYP density functional theory method in conjunction with 6-311++G(d) basis set.展开更多
We report a donor-acceptor(D-A)type non-luminescent neutral radical,tris-2,4,6-trichlorophenylmethyl-N,N-dimethyl-9H-carbazol-3-amine(TTM-Cz-DMA).The results of cyclic voltammetry and quantum chemistry calculation con...We report a donor-acceptor(D-A)type non-luminescent neutral radical,tris-2,4,6-trichlorophenylmethyl-N,N-dimethyl-9H-carbazol-3-amine(TTM-Cz-DMA).The results of cyclic voltammetry and quantum chemistry calculation confirm TTM-Cz-DMA has the non-Aufbau electronic structure,which means the singly occupied molecular orbital(SOMO)lies below the highest doubly occupied molecular orbital(HOMO).The non-Aufbau electronic structure changes to the Aufbau electronic structure after protonation and exhibits proton-responsive turn-on fluorescence,which is totally reversible by deprotonation.The dihedral angle between donor and acceptor moieties of TTM-Cz-DMA in excited state reduces from 88°to 62°after protonation,causing the turn-on fluorescence.Our results offer a viewing angle to understand the luminescence of radicals and provide a possible application of proton detection.展开更多
文摘We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.
文摘The molecular structure, the Natural Bond orbital (NBO) and the Time Dependent-DFT of both isomers cis or γ-Cl and trans or δ-Cl of RuCl2(L)2, where L stands respectively for 2-phenylazopyridine (Azpy), 2,4-dimethyl-6-[phenylazo]pyridine (Dazpy), 2-[(3,5-dimethylphenyl)azopyridine] (Mazpy) and 2-pyridylazonaphtol (Nazpy) were calculated with DFT method at B3LYP/LANL2DZ level. The prediction of the frontier orbitals (Highest Occupied Molecular Orbital or HOMO and Lowest Unoccupied Molecular Orbital or LUMO) shows that the most active complexes suitable for electronic reactions are admitted to be the trans isomers. Moreover, δ-RuCl2 (Azpy)2 is discovered to react more actively as photo-sensitizer since its energy gap is the minimum. Besides, electronic structures of all complexes through NBO calculation indicate that Ru-N bonds are made of delocalization of occupancies from lone pair orbital of N atoms to the ruthenium. Moreover, Ru was assumed to have almost the same charge regardless the structure of the azopyridine ligands in the complex indicating that the ligands provide only a steric effect that is responsible for the ruthenium’s selectivity. Concerning the transition state, NBO analysis also highlights that the transition LP(Ru) π*(N1-N2) does correspond to t2g?π*(L). This transition is assumed to correspond to Metal to Ligand Charge Transfer (MLCT) that is responsible for the photo-sensitiveness of the metallic complex. Besides, TDDFT calculation of complexes showed that δ-RuCl2(Nazpy)2 displays the largest band during the absorption. For that reason, it is admitted to be the best photosensitizer due to a large system of conjugation provided by Nazpy ligand.
文摘The optimized geometric structure and photophysical properties of 6-Amino-2-methylpyridine-3-carbonitrile dye have been studied by using Density Functional Theory (DFT). The lowest singlet excited state geometry optimized using Time-Dependent Density Functional Theory (TD-DFT). On the basis of ground and excited state geometries, the absorption spectra have been calculated using the DFT and TD-DFT method in gas phase and acetonitrile medium. To understand the Non-Linear Optical properties of 6-Amino-2-methylpyridine-3-carbonitrile dye, we computed dipole moment (μ), electronic polarizability (α), and first hyperpolarizability (β0) and second order hyperpolarizability (γ) using B3LYP density functional theory method in conjunction with 6-311++G(d) basis set.
基金This work was supported by the National Natural Science Foundation of China(Nos.51925303 and 91833304)the Programme for Jilin University Science and Technology Innovative Research Team(JLUSTIRT),China(No.2019TD-33).
文摘We report a donor-acceptor(D-A)type non-luminescent neutral radical,tris-2,4,6-trichlorophenylmethyl-N,N-dimethyl-9H-carbazol-3-amine(TTM-Cz-DMA).The results of cyclic voltammetry and quantum chemistry calculation confirm TTM-Cz-DMA has the non-Aufbau electronic structure,which means the singly occupied molecular orbital(SOMO)lies below the highest doubly occupied molecular orbital(HOMO).The non-Aufbau electronic structure changes to the Aufbau electronic structure after protonation and exhibits proton-responsive turn-on fluorescence,which is totally reversible by deprotonation.The dihedral angle between donor and acceptor moieties of TTM-Cz-DMA in excited state reduces from 88°to 62°after protonation,causing the turn-on fluorescence.Our results offer a viewing angle to understand the luminescence of radicals and provide a possible application of proton detection.
