Synthesis, spectroscopic, photophysical and electrochemical properties of cyano-bridged copper(I)–ruthenium(II) complexes

Abstract

Complexes of the formula [(N–N)Cu(AsPh3)CN] (N–N=2,2′–bipyridine, 1,10–phenanthroline) have been synthesized. Ru(bpy)2Cl2.2H2O and [(η5–cp)Ru(PPh3)2Cl] react with [(N–N)Cu(AsPh3)CN] to give cyano-bridged compounds. IR spectral studies in the low frequency region (700–50 cm−1) and 4000–400 cm−1 region reveal cyano bridging in the complexes. Luminescence measurements suggest oxidation of metal centres (CuI–CuII and RuII–RuIII) on excitation at a charge transfer band. This has been substantiated with electrochemical studies of complexes which exhibit quasi-reversible reductions viz. RuIII⧹RuII and CuII⧹CuI. The deposition of metallic copper is also observed at a potential of −1.55 V. Based on these data, a mechanism for photo-redox reaction of complexes has been presented. The properties of these bimetallic complexes are compared with those of parent complexes.