Theoretical Design of High-spin Organic Molecules with Heterocycles as Ferromagnetic Coupling Units  

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508-511,共4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 ) ,FokYingTungEducationFoundation( No.710 13) and Foundation of Northeast Normal University( No.1114 34)

摘　　要：Novel stable high spin molecules possessing three different arranged fashions are designed with - · N-N< as a spin-containing(SC) fragment, phenylene as an end group and various aromatic molecules, such as benzene(1), 2,6-pyridine(2), 3,5-pyridine(3), pyridazine(4), 4,6-pyrimidine(5), 2,6-pyrimidine(6), pyrazine(7) and triazine(8), as a ferromagnetic coupling(FC) unit. The effects of the different coupling units on the spin multiplicities of the ground states and their stabilities were investigated by means of AM1-CI approach. It has been found that the spin densities on the two atoms of the SC fragment are different from delocalization results in the specific stability of - · N-N<. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC(-N-) increases. It is shown that the heterocycles as the coupling units have influence on the stabilities of the high-spin ground states. That the heteroatom lying in m -phenyl can improve ferromagnetic coupling, while the heteroatom lying in o -phenyl or p -phenyl is not in favor of the ferromagnetic coupling.Novel stable high spin molecules possessing three different arranged fashions are designed with - · N-N< as a spin-containing(SC) fragment, phenylene as an end group and various aromatic molecules, such as benzene(1), 2,6-pyridine(2), 3,5-pyridine(3), pyridazine(4), 4,6-pyrimidine(5), 2,6-pyrimidine(6), pyrazine(7) and triazine(8), as a ferromagnetic coupling(FC) unit. The effects of the different coupling units on the spin multiplicities of the ground states and their stabilities were investigated by means of AM1-CI approach. It has been found that the spin densities on the two atoms of the SC fragment are different from delocalization results in the specific stability of - · N-N<. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC(-N-) increases. It is shown that the heterocycles as the coupling units have influence on the stabilities of the high-spin ground states. That the heteroatom lying in m -phenyl can improve ferromagnetic coupling, while the heteroatom lying in o -phenyl or p -phenyl is not in favor of the ferromagnetic coupling.

关 键 词：HETEROCYCLE Coupling unit BIRADICAL HIGH-SPIN AM1-CI B3LYP 

分 类 号：O626[理学—有机化学]