Ab Initio Calculations Show Why m-Phenylene Is Not Always a Ferromagnetic Coupler

	Ab Initio Calculations Show Why m-Phenylene Is Not Always a Ferromagnetic Coupler
	Shu Fang; Ming-Shi Lee; David A. Hrovat; Weston Thatcher Borden
	1995
发表期刊	Journal of the American Chemical Society
期号	117 页码:6727-6731
摘要	In agreement with the experimental results of the groups of Rassat and Iwamura on respectively m-phenylene bis(tert-butyl nitroxides) 2 and 3, ab initio calculations on m-benzoquinodimethane (la) and m-phenylene bis(nitroxide) (la) find that near dihedral angles of 4 = 90" between the benzene ring and the radical-bearing groups, the singlet falls below the triplet in energy. The change in m-phenylene from a ferromagnetic coupler at angles around 4 = 0" to an antiferromagnetic coupler around 4 = 90" is found to be largely due to selective destabilization of the antisymmetric (A) combination of the singly-occupied orbitals on each of the radical centers by a u orbital of this symmetry on the m-phenylene coupler. The asymmetry about 4 = 90" in the singlet-triplet energy difference that is calculated for Id is shown to be due to additional interactions of the oxygens of the singly-occupied nitroxyl orbitals with p-n AOs of the benzene ring.
关键词	Ab Initio Calculations M-phenylene Ferromagnetic Coupler
学科领域	其他
收录类别	其他
语种	英语
文献类型	期刊论文
条目标识符	http://ir.las.ac.cn/handle/12502/1099
专题	中国科学院成都文献情报中心_情报研究部
推荐引用方式 GB/T 7714	Shu Fang,Ming-Shi Lee,David A. Hrovat,et al. Ab Initio Calculations Show Why m-Phenylene Is Not Always a Ferromagnetic Coupler[J]. Journal of the American Chemical Society,1995(117):6727-6731.
APA	Shu Fang,Ming-Shi Lee,David A. Hrovat,&Weston Thatcher Borden.(1995).Ab Initio Calculations Show Why m-Phenylene Is Not Always a Ferromagnetic Coupler.Journal of the American Chemical Society(117),6727-6731.
MLA	Shu Fang,et al."Ab Initio Calculations Show Why m-Phenylene Is Not Always a Ferromagnetic Coupler".Journal of the American Chemical Society .117(1995):6727-6731.

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