The polarizability（α） and second hyperpolarizability（γ） were systemically investigated for singlet diradical complex involving X（X=B,Al,Ga） atom.The results show that both the α and γ can be effectively tune...The polarizability（α） and second hyperpolarizability（γ） were systemically investigated for singlet diradical complex involving X（X=B,Al,Ga） atom.The results show that both the α and γ can be effectively tuned by varying the distance R（between compound A and a water molecule） and acceptor atom X.The lone pair of electrons from the O atom of the water molecule entered into the vacant p orbital of atom X,which increased the diradical character and led to the increase of the α and γ values.Furthermore,the polarizable continuum model（PCM） was used to test the effects of H2O and CCl4 solvents on the α and γ values.Both the α and γ values of the studied diradical complex 1a（1b,1c） in H2O and CCl4 were uniformly enhanced.And the solvent effects of H2O on either α or γ were larger than those of CCl4.展开更多
This paper presents a Density Functional or Time Dependent Density Functional （DFT/TDDFT） study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers： bis（iso...This paper presents a Density Functional or Time Dependent Density Functional （DFT/TDDFT） study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers： bis（isothiocyanato-S）（2,2^1-bipyridyl） platinum（II） （[Pt（SCN）2（bpy）]）, （isothiocyanato-S）（thiocyanato-N）-（2,2^1-bipy- ridyl） platinum（II） （[Pt（SCN）（NCS）（bpy）]）, and bis（thiocyanato-N）（2,2^1）-bipyridyl）platinum（II） （[Pt（NCS）2（bpy）]）, in which different coordination ligands based on the N- and S-coordination of the thiocyanato ligands control the luminescent color. The electronic structures were studied using the B3LYP functional. Optimized geometries Were compared to the experimentally observed structures. TDDFT calculation was carded out to investigate the excited singlet and triplet states. Calculations have been performed both in vacuo and in solvents, using a polarized continuum model （PCM） to account for solute-solvent interactions. Inclusion of the solvent led to a significant energy change, and as a consequence, the computed spectrum calculated in the presence of the solvent was in good agree- ment with the experimental determinations. The first two absorptions were found to originate from mixed plati- num-SCN （or NSC） to bipyridyl-n＊ transitions rather than pure metal-to-ligand-charge-transfer （MLCT） transitions, whereas the higher-energy bands arose from intraligand n→π＊ transitions. The stretching frequencies of C≡N have been calculated both in the ground and excited states, which are relative to the charge transition during the excitation. In addition, different sizes of basis sets were also discussed in this paper.展开更多
Theoretical calculations were carried out to predict the aqueous-phase acidities of a series of drug 1-phenyl-4-propylpiperazine and its derivatives. The performances of the density functional theory（DFT） methods B3...Theoretical calculations were carried out to predict the aqueous-phase acidities of a series of drug 1-phenyl-4-propylpiperazine and its derivatives. The performances of the density functional theory（DFT） methods B3LYP and B3P86, solvation models[the polarized continuum model（PCM） and the conductor-like polarized conti- nuum model（CPCM）], and the basis set effect were tested. A comparison between the theoretical and experimental pKa values for para-substituted 1-phenyl-4-propylpiperazines reveals that the accuracy of B3LYP is better than that of B3P86, and the basis set 6-31＋＋G（d,p） and the CPCM model are suitable for calculating pKa values of the substituted 1-phenyl-4-propylpiperazine. For the investigated compounds, a reasonable agreement between the experimental and calculated oKo values was also observed.展开更多
基金Supported by the National Natural Science Foundation of China(No.20873017)the Natural Science Foundation of Jilin Province,China(No.20101154)
文摘The polarizability（α） and second hyperpolarizability（γ） were systemically investigated for singlet diradical complex involving X（X=B,Al,Ga） atom.The results show that both the α and γ can be effectively tuned by varying the distance R（between compound A and a water molecule） and acceptor atom X.The lone pair of electrons from the O atom of the water molecule entered into the vacant p orbital of atom X,which increased the diradical character and led to the increase of the α and γ values.Furthermore,the polarizable continuum model（PCM） was used to test the effects of H2O and CCl4 solvents on the α and γ values.Both the α and γ values of the studied diradical complex 1a（1b,1c） in H2O and CCl4 were uniformly enhanced.And the solvent effects of H2O on either α or γ were larger than those of CCl4.
基金Project supported by the National Natural Science Foundation of China （N0s. 20273023, 10647104）.
文摘This paper presents a Density Functional or Time Dependent Density Functional （DFT/TDDFT） study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers： bis（isothiocyanato-S）（2,2^1-bipyridyl） platinum（II） （[Pt（SCN）2（bpy）]）, （isothiocyanato-S）（thiocyanato-N）-（2,2^1-bipy- ridyl） platinum（II） （[Pt（SCN）（NCS）（bpy）]）, and bis（thiocyanato-N）（2,2^1）-bipyridyl）platinum（II） （[Pt（NCS）2（bpy）]）, in which different coordination ligands based on the N- and S-coordination of the thiocyanato ligands control the luminescent color. The electronic structures were studied using the B3LYP functional. Optimized geometries Were compared to the experimentally observed structures. TDDFT calculation was carded out to investigate the excited singlet and triplet states. Calculations have been performed both in vacuo and in solvents, using a polarized continuum model （PCM） to account for solute-solvent interactions. Inclusion of the solvent led to a significant energy change, and as a consequence, the computed spectrum calculated in the presence of the solvent was in good agree- ment with the experimental determinations. The first two absorptions were found to originate from mixed plati- num-SCN （or NSC） to bipyridyl-n＊ transitions rather than pure metal-to-ligand-charge-transfer （MLCT） transitions, whereas the higher-energy bands arose from intraligand n→π＊ transitions. The stretching frequencies of C≡N have been calculated both in the ground and excited states, which are relative to the charge transition during the excitation. In addition, different sizes of basis sets were also discussed in this paper.
基金Supported by the National Natural Science Foundation of China（Nos.21173151, J1103315） and the National Basic Research Program of China（No.2011CB201202）.
文摘Theoretical calculations were carried out to predict the aqueous-phase acidities of a series of drug 1-phenyl-4-propylpiperazine and its derivatives. The performances of the density functional theory（DFT） methods B3LYP and B3P86, solvation models[the polarized continuum model（PCM） and the conductor-like polarized conti- nuum model（CPCM）], and the basis set effect were tested. A comparison between the theoretical and experimental pKa values for para-substituted 1-phenyl-4-propylpiperazines reveals that the accuracy of B3LYP is better than that of B3P86, and the basis set 6-31＋＋G（d,p） and the CPCM model are suitable for calculating pKa values of the substituted 1-phenyl-4-propylpiperazine. For the investigated compounds, a reasonable agreement between the experimental and calculated oKo values was also observed.
