Oxovanadium(IV) and amino acids—VIII. l-histidine derivatives and related ligands: A spectroscopic study

Abstract The coordination structures of various species in aqueous solutions of oxo-vanadium(IV) + derivatives of l -histidine ( 1 ) and related ligands (3-methyl- l -histidine, 1-methyl- l -histidine, l -histidine methyl ester, l -histidinol, Nα- acetyl- l -histidine and histamine) have been studied by investigating the pH dependence of the circular dichroism, isotropic absorption and electron spin resonance spectra, and are compared with the structures of the corresponding complexes of l -histidine. Comparison of the spectroscopic results for all systems studied indicates coordination geometries.