Synthesis, Characterization, and Conducting Properties of Heterobimetallic Salts of Cyanoiminomethanedithiolate Ligand

Abstract

Abstract Heterobimetallic ion-pair complexes of the type [M(bpy)3][M′(cdc)2] (M = Fe2+, Co2+, and Ni2+; M′ = Ni2+ and Cu2+; bpy = 2,2′-bipyridine, cdc2− = cyanoiminomethanedithiolate (C2N2S22−)) have been synthesized by reacting a solution of K2[M′(cdc)2] with [M(bpy)3]X2 (X = Cl− and SO42−) in equimolar ratio. These complexes have been characterized by elemental analysis, solution conductance, and magnetic susceptibility measurements, IR, 1H and 13C NMR, ESR, and UV–visible spectroscopies and pressed pellet conductivity technique. Three of these salts show behavior of semiconductors in the 295–443 K temperature range while the remaining are insulators. The lowering of the ν(C≡N) frequency in I2-doped products of these complexes as compared to the parent complexes clearly reveals interaction of the C≡N group of the ligand cdc2− resulting in decrease in ν(C≡N) bond order and in turn partial reduction of I2. The I2-doped products of the majority of the complexes show enhanced room-temperature conductivity and exhibit semiconducting behavior.