Anisotropic Change in the Magnetic Susceptibility of a Dynamic Single Crystal of a Cobalt(II) Complex. Issue 3 (9th December 2016)

• Record Type: Journal Article
• Authors: Yao, Zi‐Shuo; Wu, Shu‐Qi; Kitagawa, Yasutaka; Su, Sheng‐Qun; Huang, You‐Gui; Li, Guo‐Ling; Ni, Zhong‐Hai; Nojiri, Hiroyuki; Shiota, Yoshihito; Yoshizawa, Kazunari; Kang, Soonchul; Kanegawa, Shinji; Sato, Osamu
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 3(2017)
• Page Start: 717
• Page End: 721
• Publication Date: 2016-12-09
• Subjects: cobalt -- magnetic switching -- phase transitions -- shape change -- symmetry breaking; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201606165
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Atypically anisotropic and large changes in magnetic susceptibility, along with a change in crystalline shape, were observed in a Co II complex at near room temperature. This was achieved by combining oxalate molecules, acting as rotor, and a Co II ion with unquenched orbital angular momentum. A thermally controlled 90° rotation of the oxalate counter anion triggered a symmetry‐breaking ferroelastic phase transition, accompanied by contraction–expansion behavior (ca. 4.5 %) along the long axis of a rod‐like single crystal. The molecular rotation induced a minute variation in the coordination geometry around the Co II ion, resulting in an abrupt decrease and a remarkable increase in magnetic susceptibility along the direction perpendicular and parallel to the long axis of the crystal, respectively. Theoretical calculations suggested that such an unusual anisotropic change in magnetic susceptibility was due to a substantial reorientation of magnetic anisotropy induced by slight disruption in the ideal D 3 coordination environment of the complex cation. Abstract : Magnetic switching : A cobalt(II) complex displays atypically anisotropic and large changes in magnetic susceptibility along with a change in crystalline shape at near room temperature. The change is in response to a thermally controlled 90° rotation of the oxalate counter anion during a symmetry‐breaking ferroelastic phase transition.