Macroscopic Polarization Change via Electron Transfer in a Valence Tautomeric Cobalt Complex

• Published in: Nature communications Vol. 11; no. 1; p. 1992
• Main Authors: Wu, Shu-Qi, Liu, Meijiao, Gao, Kaige, Kanegawa, Shinji, Horie, Yusuke, Aoyama, Genki, Okajima, Hajime, Sakamoto, Akira, Baker, Michael L., Huzan, Myron S., Bencok, Peter, Abe, Tsukasa, Shiota, Yoshihito, Yoshizawa, Kazunari, Xu, Wenhuang, Kou, Hui-Zhong, Sato, Osamu
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.04.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/125; 639/638/263/915; 639/638/298/917; Chemistry; Cobalt; Cobalt compounds; Cooling; Dipole moments; Electron transfer; Electrons; Humanities and Social Sciences; Induced polarization; Infrared spectroscopy; Ligands; Light; Metastable state; multidisciplinary; Polarization; Pyroelectricity; Science; Science (multidisciplinary); Single crystals; Solvents; Switching; Tautomerism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-15988-1

Polarization change induced by directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, we investigate electronic pyroelectricity in the crystal of a mononuclear complex, [Co(phendiox)( rac -cth)](ClO 4 )·0.5EtOH ( 1 ·0.5EtOH, H 2 phendiox = 9, 10-dihydroxyphenanthrene, rac -cth = racemic 5, 5, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane), which undergoes a two-step valence tautomerism (VT). Correspondingly, pyroelectric current exhibits double peaks in the same temperature domain with the polarization change consistent with the change in dipole moments during the VT process. Time-resolved Infrared (IR) spectroscopy shows that the photo-induced metastable state can be generated within 150 ps at 190 K. Such state can be trapped for tens of minutes at 7 K, showing that photo-induced polarization change can be realized in this system. These results directly demonstrate that a change in the molecular dipole moments induced by intramolecular electron transfer can introduce a macroscopic polarization change in VT compounds. Polarization change from directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, the authors provide a proof-of-concept of electronic pyroelectricity induced by intramolecular electron transfer in the single crystal of a valence tautomeric compound.