COMPLEXATION AND ELECTRONIC SPECTRA OF NEODYMIUM(III)-AMINO ACID-1,10-PHENANTHROLINE SYSTEMS IN AQUEOUS SOLUTION

摘要

Complexation of neodymium(III)-glutamate(glu)-phenanthro, neodymium(III)-aspartate(asp)-phenanthroline(phen) ternary systems and the corresponding binary systems in aqueous solution are discussed at various values of pH. Based on change regularity of hypersensitive transition intensities, the neodymium(III)-aspartate-phenanthroline ternary complex has a general formula of Nd(asp)(3)phen, but the composition of the complex of Nd(III) with glutamate and phenanthroline is complicated and has not been determined. The electronic spectra of these complexes were studied, Slater-Condon parameters F-ks and the Lande parameter xi(4f) were obtained. The rms deviation between calculated and observed energy levels is less than 43 cm(-1). Bonding in these complexes are also investigated and bonding parameters calculated. The results show that Nd(III) and amino acids form complexes by ionic linkage with carboxylic oxygens, but with some weak covalency. Besides, the degrees of covalency in ternary complexes are larger than those in binary complexes. [References: 21]