Ionic liquids as new reaction media and catalysts have been experimentally and theoretically recognized and accepted. They are environmentally friendly or ‘‘greener’’ alternatives to organic solvents because they have very low vapor pressure and are non-explosive and thermally stable over a wide temperature range. They can be employed as solvents for a number of chemical processes, such as separation, reactions, two-phase catalysis, extractions and polymerizations. One of the new applications of ionic liquids is in the synthesis of organic compounds including amides. Carboxamide ligands have been part of the growing research in the field of coordination chemistry of transition metal complexes. We have developed a new method for the synthesis of these amides using ionic liquids as the reaction media. H 2 enzo (1) has been prepared under optimum conditions. The Ni(II), Cu(II), Zn(II) and Co(III) complexes of enzo 2- , with the formula: (2) [Ni(enzo)] (3) [Cu(enzo)] (4) [Zn(enzo)] (5) [N(n-Bu) 4 ][Co(enzo)(CN) 2 ] (6) [N(n-Bu) 4 ][Co(enzo)(N 3 ) 2 ] (7) [N(n-Bu) 4 ][Co(enzo)(SCN) 2 ] have also been synthesized and characteraized by UV-Vis, FT-IR, 1 H-NMR and elemental analysis. The structure of [Zn(enzo)] (4) (distorted square pyramidal) and [N(n-Bu) 4 ][Co(enzo)(CN) 2 ] (5) (distorted octahedral) were determined by X-ray crystallography. The di-anionicenzo 2- acts as a tetradentate ligand and occupies the equatorial positions through pyridine and amide nitrogen atoms. In complex (4), the oxygen atom of amide carbonyl group from adjacent ligand, coordinates to the axial position of the metal ion and leads to the formation a polymeric structure for this complex. In complex (5), with a distorted octahedral structure, two cyanide ligands occupy the axial situations. The electrochemical behavior of the ligand and its complexes are investigated. Photophysical property of the ligand has been studied and its changes in the presence of metal ions have been determined. The optimized structure, absorption spectrum, molecular orbitals that involved in electronic transitions of the ligand and its fluorescence have been calculated by computational methods. Finally, the antibacterial activity of the synthesized compounds has also been investigated.
