Solution studies of tris(2-benzylaminoethyl)amine complexes of zinc(II) and copper(II): The catalytic hydrolysis of toxic organophosphate

Solution studies of the tetradentate ligand tris(2-benzylaminoethyl)amine, BzTren with both zinc(II) and copper(II) salts were investigated in aqueous methanol (33% v/v) by means of ¹H NMR, potentiometric, and UV-visible titrations as well as cyclic voltammetry. Subsequently, their zinc(II) and copper(II) complexes BzTren-M(OH₂)]²⁺ 1 and 2 (M²⁺ = Zn²⁺ and Cu²⁺) were synthesized and fully characterized by using FT-IR spectroscopy, elemental analysis, and thermal analysis. Complexes 1 and 2 are investigated kinetically for the catalytic hydrolysis of the toxic organophosphate parathion at 50 °C in aqueous methanol (33%, v/v). The kinetic results indicate that copper(II) complex 2 is more active than zinc(II) complex 1, presumably a reflection of the effective electron-withdrawing as well as the greatest electrophilicity of copper(II) ion.