Synthesis, crystal structure and electrochemical properties of [NBu4][Ni(mdt)2]: a potential precursor for new materials (mdt = 1,3-dithiole-4,5-dithiolate)

Abstract

Reaction of methylenedithio-1,3-dithiol-2-one with sodium methanolate resulted in the anionic ligand mdt^2– (mdt = 1,3-dithiole-4,5-dithiolate) which has been co-ordinated to nickel. The salt [NBu₄][Ni(mdt)₂] was successfully crystallised and its crystal structure showed that the Ni(mdt)₂ unit is significantly distorted from planarity. Electrochemical studies showed that [NBu₄][Ni(mdt)₂] can be further oxidised in two steps via the neutral [Ni(mdt)₂] complex to a partially oxidised positively charged complex. The neutral complex has also been successfully synthesized by oxidation with TCNQ. The redox potential of the oxidation from the neutral to the partially oxidised positive Ni(mdt)₂ complex is relatively low, +0.60 V, making this compound a promising precursor for the preparation of conducting materials, based on derived cation radical salts.