Synthesis, characterization and electrochemical investigations of mixed-ligand copper(II)-organic supramolecular frameworks.

Two mixed-ligand copper(II)-organic coordination compounds with 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me 2 bpy) as a primary ligand while aliphatic malonate (Hmal) and aromatic 2-hydroxynicotinate (2-OHNA) as secondary ligands, were synthesized. These complexes are formulated as: [Cu(Hmal)(5,5′-Me 2 bpy)(H 2 O)](ClO 4 ) 1 and [Cu 2 (2-OHNA) 2 (5,5′-Me 2 bpy) 2 (NO 3 )](NO 3 ) 2. These two complexes were structurally characterized by single crystal X-ray diffraction analysis. Characterization was further supported by powder X-ray diffraction analysis, elemental analyses, FT-IR, FAB-MASS and TGA, DSC studies. Cyclic voltammetric and UV-visible spectral studies of these two complexes have also been done. The electrochemical studies of complex 1 in DMSO and DMF have shown that this complex undergoes quasi-reversible diffusion-controlled one-electron transfer reaction without any chemical complication while complex 2 in DMSO undergoes quasi-reversible diffusion-controlled one electron transfer reaction, following EC mechanism. The electrochemical behaviour of complex 2 in DMF is complicated probably due to presence of more than one species in solution phase. [ABSTRACT FROM AUTHOR]