Synthesis of diaryl dithiocarbamate complexes of zinc and their uses as single source precursors for nanoscale ZnS

Abstract

Diaryldithiocarbamate complexes, [Zn(S2CNAr2)2], have been prepared with a view to comparing their structures, reactivity and thermally-promoted degradation with respect to the well-studied dialkyl-derivatives. In the solid-state both [Zn{S2CN(p-tol)2}2] and [Zn{S2CN(p-anisyl)2}2] are monomeric with a distorted tetrahedral Zn(II) centre, but somewhat unexpectedly, the bulkier naphthyl-derivative [Zn{S2CN(2-nap)2}2]2 forms dimeric pairs with five-coordinate Zn(II) centres. Preliminary reactivity studies on [Zn{S2CN(p-tol)2}2] suggests that it binds amines and cyclic amines in a similar fashion to the dialkyl complexes and can achieve six-coordination as shown in the molecular structure of [Zn{S2CN(p-tol)2}2(2,2′-bipy)]. The thermal decomposition of [Zn{S2CN(p-tol)2}2] was studied in oleylamine solution by both heat-up and hot-injection methods. Nanorods of ZnS were produced in both cases with average dimensions of 17 × 2.1 nm and 11 × 3.5 nm respectively, being significantly shorter than those produced from [Zn(S2CNiBu2)2] under similar conditions. This is tentatively attributed to the differing rates of amine-exchange between diaryl- and dialkyl dithiocarbamate (DTC) complexes and/or their differing rates of DTC loss following amine-exchange. The solid-state decomposition of [Zn{S2CN(p-tol)2}2] has also been studied at 450 °C under argon affording irregular and large (10–300 µm) sheet-like particles of wurtzite.