Effect of water-acetone solvent on the stability of copper(II) and nickel(II) nicotinamide complexes

Author: Isaeva V.   Gesse Zh.   Sharnin V.  

Publisher: MAIK Nauka/Interperiodica

ISSN: 1070-3284

Source: Russian Journal of Coordination Chemistry, Vol.32, Iss.5, 2006-05, pp. : 325-328

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Abstract

Complexation of nicotinamide with Cu2+ and Ni2+ ions in a water-acetone solvent is studied. The equilibrium constants of these reactions are determined by potentiometric titration at the ionic strength 0.25 mol/l NaClO4 and 298 K in the interval of mixed solvent compositions from 0 to 0.45 molar fraction of acetone. The Cu(II) complex with nicotinamide becomes stronger in a water-acetone mixture. The dependence of the stability constant of the Ni(II) complex with nicotinamide on the concentration of the organic component in the solution has extremum with a minimum at 0.1–0.2 molar fraction of acetone. The effect of a change in the solvate state of the reactants on the stability of the complexes is discussed.