Two copper(II) complexes with the general formula of [Cu(L)(H2O)](ClO4)2, 1, and [Cu(L)2](ClO4)2, 2, where L =3-((pyridin-2-ylmethyl)amino)propanamide were synthesized and characterized by elemental analyses, IR, UV-Vis spectroscopy techniques and molar conductance measurements. The crystal structures of the complexes were identified by single crystal X-ray diffraction analyses. The tridentate ligand L acts as an N2O-donor through the nitrogen atoms of pyridine and amine moieties as well the oxygen atom of amide group. The copper(II) ions in both complexes have distorted octahedron structures so that, the Cu(II) ion in 1 is coordinated by an aqua ligand and a tridentate ligand defining the basal plane, and by two oxygen atoms of the perchlorate ions occupying the axial positions. However, two ligands L coordinated to copper(II) ion in 2 ,where four nitrogen atoms of pyridine and amine groups occupied the equatorial position and two oxygen atoms of the amide moieties exist in the apexes. The chromotropism (halo-, solvato- and ionochromism) of both complexes were studied using visible absorption spectroscopy. The complexes are found to be soluble in water and organic solvents and displayed reversible halochromism due to the flexible and sensitive nature of the amide group with changing pH values. The solvatochromism property is due to structural change followed by solvation of the vacant sites of the complexes. The complexes demonstrated obvious ionochromism and exhibited high-sensitive and selective towards CN- and N3- anions in presence of other halide and pseudo-halide ions.
