Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory  

作　　者：WANG Xue,SUN Gang,SUN ShiLing,LIU ChunGuang,QIU YongQing & FU Qiang Institute of Functional Material Chemistry,Faculty of Chemistry,Northeast Normal University,Changchun 130024,China 

出　　处：《Science China Chemistry》2010年第8期1746-1753,共8页中国科学（化学英文版）

基　　金：supported by the Application Foundation of Science and Technology Office of Jilin Province,China (20080901) and the Ministry of Education of China

摘　　要：Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculation were adopted to study the structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine (TTPPzH2 and TTPPzMg) using B3LYP method with the 6-31G(d) basis set.A comparison of the geometrical structures,atomic charges,molecular orbitals,UV-vis spectra and infrared (IR) spectra among tetrathieno[2,3-b]porphyrazine (TTPPzH2),phthalocyanine (H2Pc) and porphyrazine (H2Pz) compounds was performed.The substituent effect of the thiophene heterocycle for electron-donating on the structures and properties of these compounds has been discussed.Compared with other atoms,the charge distribution of Cβ atoms adjacent to the sulfur atom is significantly influenced by the thiophene heterocycle substituents.The enlargement of the HOMO-LUMO gaps from H2Pc and MgPc to TTPPzH2 and TTPPzMg is at the origin of the observed blue shift of the Q band when moving from H2Pc to TTPPzH2 compounds.Special emphasis has been devoted to the strongest B bands for TTPPzH2 compounds which show red shift due to the large destabilization of the lower lying occupied orbitals compared with the corresponding B bands of H2Pc compounds.With the assistance of animated pictures produced on the basis of the normal coordinates,the significant peaks and vibration modes in the IR spectra of all the compounds were assigned and analyzed.Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculation were adopted to study the structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine (TTPPzH2 and TTPPzMg) using B3LYP method with the 6-31G(d) basis set.A comparison of the geometrical structures,atomic charges,molecular orbitals,UV-vis spectra and infrared (IR) spectra among tetrathieno[2,3-b]porphyrazine (TTPPzH2),phthalocyanine (H2Pc) and porphyrazine (H2Pz) compounds was performed.The substituent effect of the thiophene heterocycle for electron-donating on the structures and properties of these compounds has been discussed.Compared with other atoms,the charge distribution of Cβ atoms adjacent to the sulfur atom is significantly influenced by the thiophene heterocycle substituents.The enlargement of the HOMO-LUMO gaps from H2Pc and MgPc to TTPPzH2 and TTPPzMg is at the origin of the observed blue shift of the Q band when moving from H2Pc to TTPPzH2 compounds.Special emphasis has been devoted to the strongest B bands for TTPPzH2 compounds which show red shift due to the large destabilization of the lower lying occupied orbitals compared with the corresponding B bands of H2Pc compounds.With the assistance of animated pictures produced on the basis of the normal coordinates,the significant peaks and vibration modes in the IR spectra of all the compounds were assigned and analyzed.

关 键 词：tetrathieno[2 3-b]porphyrazine DFT method molecular structure UV-VIS SPECTRA IR SPECTRA 

分 类 号：O621.13[理学—有机化学]