Su Sheng-Qun, Wu Shu-Qi, Hagihala Masato, Miao Ping, Tan Zhijian, Torii Shuki, Kamiyama Takashi, Xiao Tongtong, Wang Zhenxing, Ouyang Zhongwen, Miyazaki Yuji, Nakano Motohiro, Nakanishi Takumi, Li Jun-Qiu, Kanegawa Shinji, Sato Osamu
Institute for Materials Chemistry and Engineering & Integrated Research Consortium on Chemical Sciences (IRCCS), Kyushu University, Fukuoka, 819-0395, Japan.
Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tokai, Ibaraki, 319-1106, Japan.
Nat Commun. 2021 May 12;12(1):2738. doi: 10.1038/s41467-021-23057-4.
Water reorientation is essential in a wide range of chemical and biological processes. However, the effects of such reorientation through rotation around the metal-oxygen bond on the chemical and physical properties of the resulting complex are usually ignored. Most studies focus on the donor property of water as a recognized σ donor-type ligand rather than a participant in the π interaction. Although a theoretical approach to study water-rotation effects on the functionality of a complex has recently been conducted, it has not been experimentally demonstrated. In this study, we determine that the magnetic anisotropy of a Co(II) complex can be effectively controlled by the slight rotation of coordinating water ligands, which is achieved by a two-step structural phase transition. When the water molecule is rotated by 21.2 ± 0.2° around the Co-O bond, the directional magnetic susceptibility of the single crystal changes by approximately 30% along the a-axis due to the rotation of the magnetic anisotropy axis through the modification of the π interaction between cobalt(II) and the water ligand. The theoretical calculations further support the hypothesis that the reorientation of water molecules is a key factor contributing to the magnetic anisotropy transition of this complex.
水分子的重新取向在广泛的化学和生物过程中至关重要。然而，通过围绕金属 - 氧键旋转而产生的这种重新取向对所得配合物的化学和物理性质的影响通常被忽略。大多数研究集中在水作为公认的σ供体型配体的供体性质上，而不是作为π相互作用的参与者。尽管最近已经进行了研究水旋转对配合物功能影响的理论方法，但尚未通过实验证明。在本研究中，我们确定Co(II)配合物的磁各向异性可以通过配位水配体的轻微旋转有效控制，这是通过两步结构相变实现的。当水分子围绕Co - O键旋转21.2±0.2°时，由于通过改变钴(II)与水配体之间的π相互作用使磁各向异性轴旋转，单晶的定向磁化率沿a轴变化约30%。理论计算进一步支持了水分子的重新取向是导致该配合物磁各向异性转变的关键因素这一假设。
