Metal ion complex formation in non-aqueous solvents: Formation constants of Cu(II) and Yb(III) isobutyrate and α-hydroxyisobutyrate

Abstract

Formation constants of Cu(II) and Yb(III) complexes with isobutyrate and α-hydroxyisobutyrate have been determined in water, ethanol, ethylene glycol, dimethylsulfoxide, 40 per cent dimethylsulfoxide-water, and formamide. Conditions imposed were 25°C and 0·10 M ionic strength. The order of complex stabilities in the different solvents is ethanol > DMSO > ethylene glycol > 40 per cent DMSO-H 2O≈ formamide > H 2O. The complex stabilities are discussed in terms of the solvating power and dielectric constant of the medium.