A Switchable Molecular Rotator: Neutron Spectroscopy Study on a Polymeric Spin-Crossover Compound

• Published in: Journal of the American Chemical Society 2012-03, Vol.134 (11), p.5083-5089
• Main Authors: Rodríguez-Velamazán, J. Alberto, González, Miguel A, Real, José A, Castro, Miguel, Muñoz, M. Carmen, Gaspar, Ana B, Ohtani, Ryo, Ohba, Masaaki, Yoneda, Ko, Hijikata, Yuh, Yanai, Nobuhiro, Mizuno, Motohiro, Ando, Hideo, Kitagawa, Susumu
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja206228n

A quasielastic neutron scattering and solid-state 2H NMR spectroscopy study of the polymeric spin-crossover compound {Fe(pyrazine)[Pt(CN)4]} shows that the switching of the rotation of a molecular fragmentthe pyrazine ligandoccurs in association with the change of spin state. The rotation switching was examined on a wide time scale (10–13–10–3 s) by both techniques, which clearly demonstrated the combination between molecular rotation and spin-crossover transition under external stimuli (temperature and chemical). The pyrazine rings are seen to perform a 4-fold jump motion about the coordinating nitrogen axis in the high-spin state. In the low-spin state, however, the motion is suppressed, while when the system incorporates benzene guest molecules, the movements of the system are even more restricted.