XANES STUDIES OF COBALT COMPLEXES WITH AMINO-ACIDS

XANES studies at the K-absorption edges of four biologically important cobalt (II) complexes have been carried out. The complexes are : glyc inate, alanate, valinate and glutamate of cobalt(II). The study reveal s the following trend in the ionicities : valinate > glycinate > gluta mate > alanate. The results from the present study have been correlate d with the results from IR studies and magnetic studies. The IR functi onal group frequencies of > C=O group have been found to have the same order as the order of chemical shifts of K-absorption edges. The tren d in the variation of the magnetic moments has been found to be simila r to the trend of changes in the chemical shifts. The present study su pports octahedral structure for the complexes. Also the complexes have been found to have the same symmetry group O-h.