Synthesis of Zinc Dimethyldithiocarbamate by Reductive Disulfide Bond Cleavage of Tetramethylthiuram Disulfide in Presence of Zn^2+

The zinc(II) complex [Zn2(dmdtc)2(μ-dmdtc)2] has been synthesized directly from thiram ligand, containing a disulfide bond {dmdtc = N,N-dimethyldithiocarbamate; thiram = N,N-tetramethylthiuram disulfide}, and characterized by elemental analysis and spectroscopic methods. Surprisingly thiram, undergoes a reductive disulfide bond scission upon reaction with Zn^2+ in methanolic media to give the [Zn2(dmdtc)2(μ-dmdtc)2] complex. The crystal structure of Zn(II) complex has been determined by single crystal X-ray diffraction. Zinc is 4+1 coordinate, with four nearly identical tetrahedral bonds and a longer fifth bond being similar to some reported [Zn(dtc)2(L)] complexes. The crystal structure of this complex is built up of dimeric units, [Zn(dmdtc)(μ-dmdtc)2], so that each unit has two thiocarbamate groups, one wholly bound to a zinc atom as a bidentate ligand and the other in a bridging coordination mode between the two Zn(II) atoms. This structure clearly shows scission of the disulfide bond in the thiram ligand to give two dimethyldithiocarbamate ligands coordinated to the Zn(II) ion.