The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6-31G(d,p)and 6-311++G(d,p)basis set by Gaussian program.The results from natural bond orbital(NBO)analysis have been ...The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6-31G(d,p)and 6-311++G(d,p)basis set by Gaussian program.The results from natural bond orbital(NBO)analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule.The electron density based local reactivity descriptors such as Fukui functions were calculated.The dipole moment(μ)and polarizability(α),anisotropy polarizability(Δα)and first order hyperpolarizability(βtot)of the molecule have been reported.Thermodynamic properties of the title compound were calculated at different temperatures.展开更多
A novel metal-organic coordination polymer [Co（m-BDC）（Medpq）·2H2O]n（m-H2BDC = benzene-1,3-dicarboxyalic acid,Medpq = 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline） has been hydrothermally synthesized and st...A novel metal-organic coordination polymer [Co（m-BDC）（Medpq）·2H2O]n（m-H2BDC = benzene-1,3-dicarboxyalic acid,Medpq = 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline） has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.The title compound crystallizes in monoclinic,space group C2/c with a = 19.986（4）,b = 15.789（3）,c = 16.292（3）（A°）,β = 126.54（3）°,V = 4130.3（14）（A°）^3,C23H18N4O6Co,Mr = 505.34,Dc = 1.625 g·cm^-3,Z = 8,μ = 0.883 mm^-1,F（000） = 2072,the final R = 0.0772 and wR = 0.1428.The crystal structure of complex 1 is an infinite zigzag-like chain of hexacoordinate Co^3＋ ions,in which the Co^3＋ ions are bridged in two coordination modes by m-BDC^2＋ ligands and decorated by Medpq ligands,showing a slightly distorted octahedral geometry.Additionally,the compound shows strong fluorescence in the solid state at room temperature.Natural bond orbital（NBO） analysis is performed by using the NBO method built in Gaussian 03 Program.The calculation results show a covalent interaction between the coordinated atoms and Co^3＋ ions.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
Analyses of chemical bonding and geometric structures in species with chalcogen elements EThF_2(E=O,S,Se,Te) are performed by the density functional theory. Kohn–Sham molecular orbitals and Th–E bond lengths of thes...Analyses of chemical bonding and geometric structures in species with chalcogen elements EThF_2(E=O,S,Se,Te) are performed by the density functional theory. Kohn–Sham molecular orbitals and Th–E bond lengths of these species both indicate multiple bond character for the terminal chalcogen complexes. This is also confirmed by natural bond orbital analyses using the oneelectron density matrix generated by relativistic density functional calculations. Theoretical analyses indicate that electron donation from E to Th increases down the chalcogen group(O<S<Se<Te). These molecules can serve as examples of multiple bonding between actinide elements and selenium or tellurium.展开更多
Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of o-hydroxybenzoic acid were carried out at the B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that of the c...Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of o-hydroxybenzoic acid were carried out at the B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that of the crystal. The calculated results show that the total energy of the dimer is much lower than the sum energies of the two monomers, and the average strength of the double hydrogen bonds is about 38.37 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses were performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and ?GT, the change of Gibbs free energy for the aggregation from monomer to the dimmer, is 26.47 kJ/mol at 298.15 K and 0.1 MPa, implying the spontaneous process of forming the dimer. The correlation graphics of S0m, H0m and temperatures is depicted.展开更多
The optimized geometries and vibration frequencies of luteolin,methanol and luteolin-（CH3OH）n complexes have been investigated by density functional theory using B3LYP method.Four stable luteolin-CH3OH complexes,six...The optimized geometries and vibration frequencies of luteolin,methanol and luteolin-（CH3OH）n complexes have been investigated by density functional theory using B3LYP method.Four stable luteolin-CH3OH complexes,six stable luteolin-（CH3OH）2 complexes and four stable luteolin-（CH3OH）3 complexes have been obtained.The theories of atoms in molecules（AIM） and natural bond orbital（NBO） have been used to analyze the hydrogen bonds of these compounds,and their interaction energies corrected by basis set superposition error are between-8.046 and-76.124 kJ/mol.The calculation results indicate strong hydrogen bonding interactions in the luteolin-（CH3OH）n complexes.Then the nuclear magnetic resonance（NMR） and electronic absorption spectrum of luteolin have been calculated,and the results are in agreement with the experimental data.展开更多
Theoretical study of several O-nitrosyl carboxylate compounds have been performed using quantum computational ab initio RHF and density functional B3LYP and B3PW91 methods with 6-31G^(**) basis set.Geometries obtained...Theoretical study of several O-nitrosyl carboxylate compounds have been performed using quantum computational ab initio RHF and density functional B3LYP and B3PW91 methods with 6-31G^(**) basis set.Geometries obtained from DFT calculations were used to perform the natural bond orbital(NBO)analysis.It is noted that weakness in the O_(3)-N_(2) bond is due to nO_(1)→σO_(3)-N_(2) delocalization and is responsible for the longer O_(3)-N_(2) bond lengths in O-nitrosyl carboxylate compounds.It is also noted that decreased occupancy of the localized σO_(3)-N_(2) orbital in the idealized Lewis structure,or increased occupancy of σO_(3)-N_(2) of the non-Lewis orbital,and their subsequent impact on molecular stability and geometry(bond lengths)are related with the resulting p character of the corresponding sulfur natural hybrid orbital(NHO)of σ_(O_(3)-N_(2)) bond orbital.In addition,the charge transfer energy decreases with the increase of the Hammett constants of subsitutent groups.展开更多
文摘The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6-31G(d,p)and 6-311++G(d,p)basis set by Gaussian program.The results from natural bond orbital(NBO)analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule.The electron density based local reactivity descriptors such as Fukui functions were calculated.The dipole moment(μ)and polarizability(α),anisotropy polarizability(Δα)and first order hyperpolarizability(βtot)of the molecule have been reported.Thermodynamic properties of the title compound were calculated at different temperatures.
基金Supported by the Research Fund for the Doctoral Innovative Program of Jiangsu Province (No. CXLX11_0581)
文摘A novel metal-organic coordination polymer [Co（m-BDC）（Medpq）·2H2O]n（m-H2BDC = benzene-1,3-dicarboxyalic acid,Medpq = 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline） has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.The title compound crystallizes in monoclinic,space group C2/c with a = 19.986（4）,b = 15.789（3）,c = 16.292（3）（A°）,β = 126.54（3）°,V = 4130.3（14）（A°）^3,C23H18N4O6Co,Mr = 505.34,Dc = 1.625 g·cm^-3,Z = 8,μ = 0.883 mm^-1,F（000） = 2072,the final R = 0.0772 and wR = 0.1428.The crystal structure of complex 1 is an infinite zigzag-like chain of hexacoordinate Co^3＋ ions,in which the Co^3＋ ions are bridged in two coordination modes by m-BDC^2＋ ligands and decorated by Medpq ligands,showing a slightly distorted octahedral geometry.Additionally,the compound shows strong fluorescence in the solid state at room temperature.Natural bond orbital（NBO） analysis is performed by using the NBO method built in Gaussian 03 Program.The calculation results show a covalent interaction between the coordinated atoms and Co^3＋ ions.
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.
基金supported by ‘‘Strategic Priority Research Program’’of the Chinese Academy of Sciences(No.XDA02020000)the National Natural Science Foundation of China(Nos.21573273,21501189)the support from Hundred Talents Program(CAS)
文摘Analyses of chemical bonding and geometric structures in species with chalcogen elements EThF_2(E=O,S,Se,Te) are performed by the density functional theory. Kohn–Sham molecular orbitals and Th–E bond lengths of these species both indicate multiple bond character for the terminal chalcogen complexes. This is also confirmed by natural bond orbital analyses using the oneelectron density matrix generated by relativistic density functional calculations. Theoretical analyses indicate that electron donation from E to Th increases down the chalcogen group(O<S<Se<Te). These molecules can serve as examples of multiple bonding between actinide elements and selenium or tellurium.
基金This work was supported by the Natural Science Foundation of Shandong Province (No. Y2002B06)
文摘Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of o-hydroxybenzoic acid were carried out at the B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that of the crystal. The calculated results show that the total energy of the dimer is much lower than the sum energies of the two monomers, and the average strength of the double hydrogen bonds is about 38.37 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses were performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and ?GT, the change of Gibbs free energy for the aggregation from monomer to the dimmer, is 26.47 kJ/mol at 298.15 K and 0.1 MPa, implying the spontaneous process of forming the dimer. The correlation graphics of S0m, H0m and temperatures is depicted.
文摘The optimized geometries and vibration frequencies of luteolin,methanol and luteolin-（CH3OH）n complexes have been investigated by density functional theory using B3LYP method.Four stable luteolin-CH3OH complexes,six stable luteolin-（CH3OH）2 complexes and four stable luteolin-（CH3OH）3 complexes have been obtained.The theories of atoms in molecules（AIM） and natural bond orbital（NBO） have been used to analyze the hydrogen bonds of these compounds,and their interaction energies corrected by basis set superposition error are between-8.046 and-76.124 kJ/mol.The calculation results indicate strong hydrogen bonding interactions in the luteolin-（CH3OH）n complexes.Then the nuclear magnetic resonance（NMR） and electronic absorption spectrum of luteolin have been calculated,and the results are in agreement with the experimental data.
基金We gratefully thank the National Natural Science Foundation of China(Grant No.10774039)the grant from Development Program in Science and Technology of Henan Province(Grant No.102300410114)Foundation for University Key Teacher by the Ministry of Education of Henan Province,and Henan University of Science and Technology for Young Scholars(Grant No.2009QN0032)for their support of this work.
文摘Theoretical study of several O-nitrosyl carboxylate compounds have been performed using quantum computational ab initio RHF and density functional B3LYP and B3PW91 methods with 6-31G^(**) basis set.Geometries obtained from DFT calculations were used to perform the natural bond orbital(NBO)analysis.It is noted that weakness in the O_(3)-N_(2) bond is due to nO_(1)→σO_(3)-N_(2) delocalization and is responsible for the longer O_(3)-N_(2) bond lengths in O-nitrosyl carboxylate compounds.It is also noted that decreased occupancy of the localized σO_(3)-N_(2) orbital in the idealized Lewis structure,or increased occupancy of σO_(3)-N_(2) of the non-Lewis orbital,and their subsequent impact on molecular stability and geometry(bond lengths)are related with the resulting p character of the corresponding sulfur natural hybrid orbital(NHO)of σ_(O_(3)-N_(2)) bond orbital.In addition,the charge transfer energy decreases with the increase of the Hammett constants of subsitutent groups.
