EXAFS studies of some Copper(II) mixed-ligand complexes

X-ray K-absorption spectroscopic studies have been carried out on copper (H) mixed-ligand complexes with glutamic acid and aspartic acid as the primary ligands, where as water, pyridine, imidazole and benz-imidazole have been used as secondary ligands. Chemical shifts obtained from the X-ray absorption data have indicated that the glutamic acid complexes are more ionic as compared to their corresponding aspartic acid complexes having similar secondary ligands. Further, we have estimated the average metal-ligand bond distances from the fine structure data. For the different complexes studied under the present investigation, the studies reveal that the bonding parameter alpha(1) decreases with the increase in the percentage covalency of the metal-ligand bond. Thus, the bonding parameter alpha(1) may be used for the estimation of percentage covalency of the metal-ligand bond in other similar complexes.