The crystal structures and electrochemical studies of two naphthalenic Schiff base copper(II) complexes

The Schiff base ligands, 2-hydroxy-N-cyclohexyl-l-naphthaldimine (I), and 3-hydroxy-N-cyclohexyl-2-naphthaldimine (II), and their corresponding Cu^II complexes (1–2) respectively were synthesized and characterized. The crystal and molecular structures of bis-{(cyclohexyl)(2-oxo-1H-naphth-1-ylidene)-methyl]aminato}copper(II) (1) and bis-{(cyclohexyl)(3-oxo-2H-naphth-2-ylidene)-methyl]aminato} copper(II) (2), were determined. The X-ray diffraction study shows that the geometry around the metal atom for (1), is stepped square planar with a step of 1.063 Å while for (2), the geometry around the metal atom for square planar with an angle between the coordination planes O(1)---Cu---N(1) and O(1a)---Cu---N(1a) of 39.9°. Electrochemical studies show a dependence of the Cu^II/Cu^I potentials on the ligand structure.