Synthesis and properties of a trinuclear copper(II) complex of a ligand with phthalocyanine and Schiff-base coordination sites

A trinuclear copper(II) phthalocyanine complex was synthesized by chelate coordination of the peripherally introduced Schiff-base nitrogen and phenoxide oxygen on the Cu(pc) core to a copper(II) ion. The magnetic, spectral and electrochemical properties were compared with those of the precursor mononuclear Cu(pc) complex with the NO chelate coordination site and a mononuclear Schiffbase copper(II) complex corresponding to the central bis-chelated unit of the title trinuclear complex. A stronger aggregating nature of the trinuclear complex compared with the precursor mononuclear Cu(pc) complex was confirmed by the spectral change of the Q band feature coming from the coordination to the copper(II) ion in dichloromethane. Two successive pc-ring reduction waves were not observed for the trinuclear complex in dichloromethane containing TBP(PF6), alternatively showing an irreversible wave in the reduction side. The central bis-chelated copper(II) ion was considered to play an important role for the redox behavior of the trinuclear complex.