Synthesis, Crystal Structure and Stability Studies of Dithiocarbamate Complexes of Some Transition Elements (M=Co, Ni, Pd)

Abstract

Single-crystal x-ray structure determinations have been recorded at 295 K for the dithiocarbamate metal compounds [Co(Et2dtc)3], [Co(nPr2dtc)3], [Pd(iPr2dtc)2] and [Pd(Et2dtc)2]. The stability constants(K) in EtOH of dialkyldithiocarbamate metal complexes [M(R2dtc)n] (M=Co, Ni, Pd. R=Me, Et, iPr, nPr. n=2, 3. dtc=dithiocarbamate) are determined by UV-vis data. The stability of the metal complexes increases in the order: Co<Ni<Pd. The effects of alkyl groups on the stability of [M(R2dtc)2] (M=Ni and Pd) increase in the order: Me<Et<nPr<iPr, and [Co(R2dtc)3] decrease in the order: Et>iPr>nPr>Me. The results obtained from this study confirm that the stability due to alkyl groups may be partly attributed to changes in the residual positive charge and also partly to steric hindrance of branched alkyl-groups. The comparison between the solid and solution states shows that the [M(R2dtc)2] (M=Pd, Ni) complexes have similar changes in M-S distance and stability with change in alkyl group. [M(iPr2dtc)2] has the shortest M-S distance and the highest stability in solution. Keywords: Transition MetalStability ConstantsX-ray StructureDithiocarbamate