Studies on Effect of Conformation on Spin Multiplicity of m-Phenylene Type of Biradicals by Different Approaches  

作　　者：WANG Li-min ZHANG Jing-ping WANG Rong-shun 

机构地区：[1]Faculty of Chemistry,Northeast Normal University,Changchun 130024,P.R.China

出　　处：《Chemical Research in Chinese Universities》2003年第4期489-493,共5页高等学校化学研究(英文版)

基　　金：Supported by the National Natural Science Foundation of China( No.2 980 4 0 0 2,2 0 2 74 0 0 6 ) ,FokYing-TungEducationFoundation( No.710 13) and Foundation of Northeast Normal University( No.1114 34)

摘　　要：The effect of the conformation on the spin multiplicity of the ground state and the stability of the ground state were investigated for m-phenylene type of biradicals by means of comparative study with DFT, CASSCF and AM1-CI approaches. It was found that AM1-CI approach is reliable in dealing with the stability of the high-spin ground state with the change of conformation; DFT method can give the reasonable results of the spin density of the high-spin state. Furthermore, when one or two radical centers are twisted sufficiently out of the conjugation with the benzene ring, m-phenylene turns into weak ferromagnetic and weak antiferromagnetic coupling units, respectively.The effect of the conformation on the spin multiplicity of the ground state and the stability of the ground state were investigated for m-phenylene type of biradicals by means of comparative study with DFT, CASSCF and AM1-CI approaches. It was found that AM1-CI approach is reliable in dealing with the stability of the high-spin ground state with the change of conformation; DFT method can give the reasonable results of the spin density of the high-spin state. Furthermore, when one or two radical centers are twisted sufficiently out of the conjugation with the benzene ring, m-phenylene turns into weak ferromagnetic and weak antiferromagnetic coupling units, respectively.

关 键 词：m-Phenylene HIGH-SPIN CONFORMATION DFT CASSCF AM1-CI 

分 类 号：O625[理学—有机化学]