Copper(II) Complexes of N, N′‐Bis‐βCarbamoylethyl) Ethylenediamine in Aqueous Solution

The interactions of the ligand N, N ‐bis‐(β‐carbamoylethyl)‐ethylenediamine (BCEN) with copper (II) in aqueous solution have been investigated by potentiometric and spectrophotometric techniques. The two protonation constants of the ligand at 25° in 0.2 M NaNO3are 105‐51and 105‐44 The quantitative equilibrium studies of the stepwise reactions which precede the formation of CuBCEN2+ and the Cu‐O to Cu‐N bond rearrangements at the two amide sites are described in detail. Electronic spectra of the copper (II) chelates formed are measured and discussed.