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. The application of ionic liquids as novel media may provide convenient solutions to both the solvent emission and catalyst reuse problem. One of the new applications of ionic liquids is in the synthesis of organic compounds including amides. Quinoline carboxamide ligands have been part of the growing research in the field of coordination chemistry of transition metal complexes. The solvent used in the (1) [Cu(qcq)(OAc)(H 2 O)], (2) [Cu(qcq)(NCS)], (3) [Cu(qcq)(ClO 4 )( H 2 O)], (4) [Cd(qcq)(OAc)(H 2 O)], (5) [Zn(qcq)(OAc)(H 2 O)], (6) [Co(qcq) 2 ] ClO 4 , (7) [Ni(qcq) 2 ].H 2 O Have also been synthesized and characteraized by UV-Vis, FT-IR, 1 H-NMR and elemental analysis. The structures of [Cu(qcq)(OAc)(H 2 O)], [Cd(qcq)(OAc)(H 2 O)], [Co(qcq) 2 ] ClO 4 were determined by X-ray crystallography and show distorted octahedral geometry around the central metal ions. The X-ray crystal structure of [Zn(qcq)(OAc)(H 2 O)] was also determined. This compound is a five coordinated complex with a distorted trigonal bipyramidal structure. The mono-anionic qcq - is coordinated via the amide N atom. The three N atoms of the carboxamide ligand are arranged in a meridional fashion around Cd and Cu. The other three positions are occupied by one oxygen atom from water and two oxygen atoms from the acetate ion which acts as a bidentate ligand. Acetate ion act as mono dentate ligand in Zn complex. Different modes of coordination of acetate ion in Zn and Cd complexes is revealed by X-ray crystallography and conform to the FT-IR data obtained from spectral studies. Another interesting aspect is the coordination of the deprotonated carboxamide ligand to Zn and Cd metal ions which are among the rare complexes reported for these two metals. We have successfully synthesized the N-bonded complexes of qcq - with Zn(II) and Cd(II).
