<scp>Fine‐Tuning</scp> of Structural Distortion and Magnetic Anisotropy by Organosulfonates in Octahedral Cobalt(<scp>II</scp>) Complexes
Dong Shao, Fangxue Xu, Lei Yin, Hongqing Li, Yu‐Chen Sun, Zhongwen Ouyang, Zhenxing Wang, Yi‐Quan Zhang, Xin‐Yi Wang
Abstract
Comprehensive Summary Precise modulation of the magnetic anisotropy of metal ions remains highly important for the development of high–performance single‐molecule magnets (SMMs). We herein reported the synthetic, structural, spectral, magnetic, and computational studies on four mononuclear Co II complexes in a distorted octahedral environment. The change of the organosulfonate anions triggers significant modification of the distorted octahedral CoN 6 coordination sphere, which enables us to tackle the influence of the structural distortion on the magnetic anisotropy in these complexes. Magnetic measurements revealed that the four complexes possess easy–plane magnetic anisotropy with large and positive zero‐field splitting parameters, which decrease with the increasing distortion of the pseudo–octahedral Co II coordination geometry. This correlation was further confirmed by high–frequency/–field EPR (HF–EPR) spectra and theoretical calculations. Dynamic magnetic susceptibility measurements indicate that these complexes both exhibit slow magnetic relaxation under an external dc field, indicating the field‐induced single‐ion magnets (SIMs) of the four complexes. These results indicate that structural distortion plays an important role in the magnetic anisotropy of Co II complexes and should be carefully considered in the design of molecular complexes with high magnetic anisotropy.