Polarographic study on nickel (II) complex with 2-mercaptoethanol

In the presence of 2-mercaptoethanol (2ME), the diffusion limited nickel wa ve in ammoniac buffer solutions splits in two kinetically controlled waves due to the formation of a Ni-2ME complex in chemical equilibrium with the N i-amminic complexes. The composition of this complex has been determined ex clusively from the polarographic data no catalytic phenomenon being evidenc ed. The complex contains as ligands two 2ME, one NH3 and one H2O molecule: Ni(C2H6OS)(2)(NH3)(H2O)(2+). The following chemical reaction: Ni(C2H6OS)(2)(NH3)(H2O)(2+) + NH3 +3 H2O reversible arrow Ni(NH3)(2)(H2O)(4 )(2+) + 2 C2H6OS is superimposed on the electrochemical one, causing the kinetic nature of t he limiting currents. A similar complex is produced in the Co-2ME system, w here the catalytic cobalt prewave is produced in addition.