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Theoretical Design of High‐spin Organic Molecules with —·N—N— as a Spin‐containing Fragment and Heterocycles as an End Group
Author(s) -
Chu DeQing,
Wang LiMin,
Zhang JingPing,
Wang RongShun
Publication year - 2006
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200690308
Subject(s) - chemistry , pyridazine , pyrazine , pyridine , molecule , crystallography , delocalized electron , pyrimidine , triazine , spin (aerodynamics) , stereochemistry , computational chemistry , medicinal chemistry , organic chemistry , engineering , aerospace engineering
Novel stable high spin molecules possessing three different arranged fashions are designed with –·N–N< as a spin‐containing (SC) fragment, various aromatic, such as benzene ( 1 ), pyridine ( 2 ), pyridazine ( 3 ), pyrimidine ( 4 ), pyrazine ( 5 ), triazine ( 6 ) as end groups (EG) and phenyl as a ferromagnetic coupling (FC) unit. The effects of a different end groups 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 resulting 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. The orders of the stability of triplet states for 1a n , 1b n , 1c n [They are isomers in which SC is connected with FC in different way ( 1a n , N 1 NNN 1 ; 1b n , N 1 N N 1 N; 1c n , NN 1 N 1 N) and six heterocycles are EG] show that the stability of triplet states with heterocycles as end groups is higher than that with phenyl as end groups, and in the order:triazine (EG)>pyrimidine, pyrazine>pyridine, pyridazine.