Effect of configuration and conformation on the spin multiplicity in xylylene type biradicals
作者： Wang Lixiang , Wang Rongshun , Zhang Hong Zhang Jingping , Wang Limin
关键词: Ferromagnetism 、 Antiferromagnetism 、 Photochemistry 、 Energy level splitting 、 Crystallography 、 Ring (chemistry) 、 Ground state 、 Xylylene 、 Molecule 、 Magnetism 、 Chemistry
摘要: The singlet-triplet splitting energy gap ? E S -T = - T is calculated for the ortho-, meta-, and para-xylylenes their heteroatomic analogous by means of AM1-CI approach. It shown that when radical centers R˙(R˙=H 2 C˙—,H N˙ + — or HN˙—) are twisted sufficiently far out conjugation with benzene ring, tends to zero negative, i.e. para-phenylenes turn into weak ferromagnetic antiferromagnetic coupling unit, while they strong (meta-isomers) (ortho-, para-isomers) units under planar conformation. suggested serious conformation not recommended candidate design novel high-spin molecules stable ground states ortho- para-phenylene unit.
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