PRODUCTION OF THIOSULFATE ANION FROM THE REACTION OF BIS(DIALKYLDITHIOCARBAMATO)NICKEL(II) COMPLEXES WITH ETHYLENEDIAMINE

Planar divalent nickel dithiocarbamates Ni-(dtc)2 (dtc- =dithiocarbamato anions) show interesting reactivity patterns in their reactions with Lewis bases. These complexes form mixed ligand complexes with PR3 easily. But, simple hard nitrogen bases do not displace all the nickel dithiocarbamates. A chelating base like en displaces the dithiocarbamate anion completely from the complexes and formed pink colored solution in an aqueous medium. The chromophore was identified to be [Ni(en)3]2+ and the counter anion was dtc-. On ageing, pink crystals separated out from the solution. Chemical analysis of the crystals showed a 1:2 ratio of Ni to S and the absence of dtc-ion. The possibility Of S2O32- being the counter anion was tested. Even though infrared spectrum could not confirm the S2O32- anion, the final confirmation came form the X-ray analysis of the authentic crystals. This is a rare occasion of metal ion catalyzed oxidation of S2- to S2O32- ions.