Electrochemical studies of some nickel(ll) complexes of the type [Ni(N - N - S)(CN)] and [Ni2(N - N - S)2-µ-(CN)] (CIPO4): Generation of nickel (I) species

Abstract

The electron transfer behaviour of Ni(II) complexes [NiL(CN)](L= L¹-L³) and [Ni₂L<img src="http://www.niscair.res.in/jinfo/equation36.gif" alt="" border="0" />-<em>µ</em>-(CN)](CIO₄) (where HL¹ = methyl 2-[(2'-aminoethyl)amino]cyclopent-l-enedithiocarboxylate, HL² = methyl 2-[(2'-dimethylaminoethyl)amino]cyclopent-l-enedithiocarboxylate, HL³ =methyl 2-[(2'-diethylaminoethyl)amino]cyclopent-l-enedithiocarboxylate) has been investigated by cyclic voltammetric measurements in acetonitrile. In the potential range of 0 to - 2 V all the mononuclear complexes undergo metalcentred quasi-reversible one-electron reduction and the E_1/2 values (ca. - 1.57 V vs SCE) remain almost unchanged with the variation of L. For the dinuclear complex two-step one-electron transfer occurs and the corresponding redox potentials are - 0.96 and - 1.61 V (vs SCE). The conproportionation constant for the mixed-valence species has been estimated to be 10¹¹.