摘要
利用—·N—S—为自旋中心 (SC) ,苯为端基 (EG) ,苯、吡啶、哒嗪、嘧啶、吡嗪、三嗪为耦合单元 (FC) ,设计三种不同排列方式的新型稳定高自旋分子 .由于自旋密度在杂环 (FC)和—·N—S— (SC)组成的体系中自由基双中心的部分离域 ,导致—·N—S—自由基的特殊稳定性 .三种不同的排列方式中 ,其三重态的稳定性随主要SC (—N— )原子间距离的增大而降低 .从三个系统八个体系三重态的稳定性来看 ,FC上的杂原子位于取代基的间位能提高体系的铁磁耦合作用 。
Novel stable high spin molecules possessing three differently arranged fashions are designed using -.N-S- as spin-containing (SC) fragment, phenylene as end groups and various aromatic, such as benzene (1), 2,6-pyridine (2), 3,5-pyridine (3), pyridazine (4), 4,6-pyrimidine (5), 2,6-pyrimidine (6), pyrazine (7), triazine (8) as, a ferromagnetic coupling (FC) unit. The effect of the different coupling units on the spin multiplicities of the ground states and their stabilities was. investigated by means of AM1-CI approach. It is found that the spin densities on the two atoms of the SC are different from delocalization results in the specific stability of -.N-S-. In these molecules, the stabilities of the triplet states decrease when the distance between the atom of central SC (-N-) increases. It is shown that nitrogen-containing aromatic rings as coupling unit influence the stabilities of high-spin ground states.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2003年第6期808-811,共4页
Acta Chimica Sinica
基金
国家自然科学基金 (Nos.2 980 4 0 0 2
2 0 2 740 0 6)
霍英东青年教师基金 (No.71 0 1 3)资助项目