Large Magnetic Anisotropy in Linear CoII Complexes - Ab Initio Investigation of the Roles of Ligand Field, Structural Distortion, and Conformational Dynamics.

Autor: Roy Chowdhury, Sabyasachi, Mishra, Sabyashachi
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Zdroj: European Journal of Inorganic Chemistry; Jan2017, Vol. 2017 Issue 3, p659-668, 10p
Abstrakt: Linear or near-linear bicoordinate mononuclear CoII complexes are studied as potential single-molecule magnets owing to the strong spin-orbit coupling constant of CoII and its low coordination number, which results in the retention of the unquenched metal-orbital angular momentum. The spin-orbit-coupled unquenched orbital angular momentum of the metal center produces strong magnetic anisotropy through ligand-field interactions. The role of the ligand environment, structural distortions, and conformational changes on the magnetic anisotropy of CoII complexes are investigated through ab initio electronic-structure calculations. The zero-field splitting parameters, g tensors, and transition-magnetic-moment matrix elements among the Kramers pairs are evaluated to obtain the effective anisotropy barriers ( Ueff) and the mechanism for the relaxation of magnetization in a series of CoII complexes, for which the estimated values of Ueff range between 394 and 974 cm-1 and include the largest effective anisotropy barriers reported for transition-metal complexes. The calculations reveal that the ligand-field strength, structural distortion, and conformational changes not only affect the magnetic anisotropy barrier but also significantly alter the mechanism of relaxation of the magnetic moments. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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