A Heterometallo‐Supramolecular Polymer with CuI and FeII Ions Introduced Alternately

Abstract A new heterometallo‐supramolecular polymer with alternating Cu I and Fe II ions (polyCuFe) was synthesized by simple 0.5:0.5:1 complexation of Cu I and Fe II salts with an unsymmetrical ditopic ligand ( L1 ) bearing phenanthroline and terpyridine moieties as the metal coordination sites. Selective complexation was confirmed by UV/Vis spectroscopic titration experiments, and the alternate alignment of the two metal ions in polyCuFe was supported by ESI‐MS data. Cyclic voltammetry of a polyCuFe film showed two reversible redox waves at 0.29 and 0.78 V vs. Ag/Ag + based on the redox of Cu I /Cu II and Fe II /Fe III , respectively. Each oxidation state was successfully observed by acquisition of XPS spectra. A solid‐state display device was fabricated using the polymer film and a gel electrolyte. The device showed multi‐colour electrochromic behaviour by changing an applied potential, based on the different redox potentials of the two metal ions.