Theoretical design of high-spin biradical molecules with heterocycles as coupling unit  

作　　者：王立敏 储德清 张景萍 王荣顺 

机构地区：[1]Faculty of Material and Chemical EngineeringTianjin Polytechnic University,Tianjin 300160,China [2]Faculty of ChemistryNortheast Normal University, Changchun 130024,China [3]Faculty of ChemistryNortheast Normal University,Changchun 130024,China

出　　处：《中国有色金属学会会刊：英文版》2006年第B02期715-718,共4页Transactions of Nonferrous Metals Society of China

基　　金：Projects(29804002, 20274006) supported by the National Natural Science Foundation of China Projects(029307, 029302) supported by Tianjin Polytechnic University, China

摘　　要：Computational studies of a class of potentially stable high-spin biradicals that two-atom-three-electron spin centers SC units connected by heterocycles FC and phenyl EG were described. The geometry and character of the spin exchange interaction were obtained by means of UB3LYP/6-31G*. The results show that the molecules possessing three different arranged fashions are designed with -·N-S as SC fragment, pyridine as FC and phenyl as EG, the spin densities on the two atoms of the SC fragment are different from the delocalization results in the specific stability of-·N-S. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC (-N-) increases. Molecules with -·N-S as SC fragment, pyridine, pyrazine and triazine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with pyridine as FC is the highest, and that for the molecule with pyrazine as FC is the lowest. Molecules with -·N-S, -·N-O and -·N-NH as SC fragment, pyridine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with -·N-S as SC is the highest, that for the molecule with -·N-NH as SC is the lowest.Computational studies of a class of potentially stable high-spin biradicals that two-atom-three-electron spin centers SC units connected by heterocycles FC and phenyl EG were described. The geometry and character of the spin exchange interaction were obtained by means of UB3LYP/6-31G＊. The results show that the molecules possessing three different arranged fashions are designed with -·N-S as SC fragment, pyridine as FC and phenyl as EG, the spin densities on the two atoms of the SC fragment are different from the delocalization results in the specific stability of -·N-S. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC （-N-） increases. Molecules with -·N-S as SC fragment, pyridine, pyrazine and triazine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with pyridine as FC is the highest, and that for the molecule with pyrazine as FC is the lowest. Molecules with -·N-S, -·N-O and -·N-NH as SC fragment, pyridine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with -·N-S as SC is the highest, that for the molecule with -·N-NH as SC is the lowest.

关 键 词：杂环化合物 铁磁耦合单元 高自旋双游离基分子 理论设计 

分 类 号：O621.25[理学—有机化学]