HYPERSENSITIVITY IN COMPLEXES OF Nd(III) AND Ho(III) WITH DIBASIC AND POLYBASIC LIGANDS

Abstract

Abstract The hypersensitive transitions 4 I 9/2 → 4 G 5/2' 2 G 7/2 in Nd(III) and 5 I 6' 5 G 6' 5 F 1 in Ho(III) have been studied for fanthanide complexes in aqueous solution with dibasic and polybasic ligands as well as for some mixed ligand complexes. For the dibasic ligands, a linear relation is observed between the oscillator strength of the hypersensitive transition and the sum of the ligand pKa values. With ligands which contain both N and O coordination sites, the correlation holds when only the basicity of the O sites is considered.