Copper(II) complexes of N,N′-bis(2-carbamoylethyl)ethylenediamine in methanol–water

Abstract

The interactions of the N,N′-bis(2-carbamoylethyl)ethylenediamine (bcen) with copper(II) in 50 wt.% methanol–water have been investigated by a potentiometric technique. The two protonation constants of the ligand at 25.0 ± 0.1 °C and 0.10 mol dm^–3 NaClO₄ are 10^8.50 and 10^5.05 dm³ mol^–1. The formation of [Cu(bcen)]²⁺ and the Cu–O to Cu–N bond rearrangements at the two amide sites of this complex have been studied quantitatively under the same conditions. Solvent effects on the protonation constants of the ligand and on the equilibrium constants of these reactions are discussed.