Structural and Spectral Features of Complex Salts Composed of [Ni(dmit)2]− and Four- or Six-Coordination Nickel(II) Complexes of Alkyl-Substituted Cyclam

Abstract

Abstract Slow inter-diffusion of (NBu4)[Ni(dmit)2] (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) and a metal complexes ligated with alkyl-substituted cyclam, [Ni(NMe2-dcyclam)](ClO4)2 (I), [Ni(NMe2-ax-dcyclam)](ClO4)2 (II), and [Ni(NMe4-dcyclam)]Cl2 (III), (NMe2-dcyclam = (1RS,4RS,5RS,8SR,11SR,12SR)-1,5,8,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane, NMe2-ax-dcyclam = (1RS,4RS,5SR,8SR,11SR,12RS)-1,5,8,12–tetramethyl-1,4,8,11-tetraazacyclotetradecane, NMe4-dcyclam = (1RS,4RS,5RS,8SR,11SR,12SR)-1,4,5,8,11,12-hexamethyl-1,4,8,11-tetraazacyclotetradecane), yielded black crystals of [Ni(NMe2-dcyclam)(CH3CN)2][Ni(dmit)2]2 (1), [Ni(NMe2-ax-dcyclam)][Ni(dmit)2]2 (2), and [Ni(NMe4-dcyclam)][Ni(dmit)2]2 (3), respectively. In these complex salts, the cationic complex I adopted an octahedral six-coordination geometry with two molecules of acetonitrile occupying the trans coordination sites (structure A), while those of complexes II and III adopted a square-planar four-coordination geometry (structure B). The Ni–Ni distances between cation and anion in structure B were shorter than those of structure A. In the IR spectra, ν(C=S) of structure B was observed 10 cm−1 higher than that of structure A, and only in compound 2, ν(C=C) was split at 1346 and 1323 cm−1. Electric conductivities of compounds 1–3 were about 10−6 S cm−1 at room temperature behaving as semiconductors.