Synthesis, characterization, and conducting properties of heterobimetallic salts of cyanoiminomethanedithiolate ligand

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, cdc(2-) = cyanoiminomethanedithiolate (C2N2S22-)) have been synthesized by reacting a solution of K-2[M'(cdc)(2)] with [M(bpy)(3)]X-2 (X = Cl- and SO42-) in equimolar ratio. These complexes have been characterized by elemental analysis, solution conductance, and magnetic susceptibility measurements, IR, H-1 and C-13 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 v(C N) frequency in I-2-doped products of these complexes as compared to the parent complexes clearly reveals interaction of the C N aroup of the ligand cdc(2-) resulting in decrease in v(C N) bond order and in turn partial reduction of I-2 The I-2-doped products of the majority of the complexes show enhanced room-temperature conductivity and exhibit semiconducting behavior.