Preparation and Electrochromic Properties of Co(Ⅱ)–Bis-2,2':6',2"-terpyridine Metallo-supramolecular Polymer

Abstract

A metallo-supramolecular polymer CoL was prepared by coordination of Co(Ⅱ) ions to ligand L: 1,4-bis(2,2':6',2-terpyridine-4-yl)benzene. Electrochemical and electrochromic properties of the polymer film were analyzed in acetonitrile with 0.1 M tetra-n-butylammonium perchlorate as an electrolyte. The polymer film exhibited excellent electrochromic property with absolutely reversible color change between orange and pale yellow by the redox reaction of Co ions. Its optical contrast was 13% at 524 nm with bleaching time of 2.8s and darkening time of 24s. The coloration efficiency of the polymer film was 20.7 cm2/C. After 300 switching cycles, the optical contrast only decline 2%. The long-term redox switching study confirmed the high stability of the polymer to the test environment.