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

Planar divalent nickel dithiocarbamates Ni-(dtc)2 (dtc- =dithiocarbama to anions) show interesting reactivity patterns in their reactions wit h Lewis bases. These complexes form mixed ligand complexes with PR3 ea sily. But, simple hard nitrogen bases do not displace all the nickel d ithiocarbamates. A chelating base like en displaces the dithiocarbamat e 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 o ut from the solution. Chemical analysis of the crystals showed a 1:2 r atio of Ni to S and the absence of dtc-ion. The possibility Of S2O32- being the counter anion was tested. Even though infrared spectrum coul d not confirm the S2O32- anion, the final confirmation came form the X -ray analysis of the authentic crystals. This is a rare occasion of me tal ion catalyzed oxidation of S2- to S2O32- ions.