OXOVANADIUM(IV) AND AMINO-ACIDS .8. L-HISTIDINE DERIVATIVES AND RELATED LIGANDS - A SPECTROSCOPIC STUDY

The coordination structures of various species in aqueous solutions of oxovanadium(IV) + derivatives of L-histidine (1) and related ligands (3-methyl-L-histidine, 1-methyI-L-histidine, L-histidine methyl ester, L-histidinol, N alpha-acetyl-L-histidine and histamine) have been stu died by investigating the pH dependence of the circular dichroism, iso tropic absorption and electron spin resonance spectra. and are compare d with the structures of the corresponding complexes of L-histidine. C omparison of the spectroscopic results for all systems studied indicat es coordination geometries.