Electric dipole intensity parameters for a series of structurally related Nd(Ill) complexes and oscillator strengths of multiplet to multiplet electronic transitions

Abstract

The absorption spectral intensity data for multiplet to multiplet electronic transitions in a series of structurally related Nd(III) complexes of the type, Nd(diket)₃(N)₂ (where diket is 1-phenyl-1,3butanedione (benzoylacetone, bzac), 1,3-diphenyl-1,3-propanedione (dibenzoylmethane, dbm) and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butenedione (theonyltrifluoro acetone, ttfa) and (N)2 stands for two molecules of unidentate nitrogen ligands: pyridine, 2-chloro-, 2-bromo-, 2-acetyl, 3-acetyl-, 4-acetylpyridine or one mole of bidentate 2,2'-bipyridine or <i>o</i>-phenanthroline) have been recorded in methanol, DMF, acetonitrile and isopropanol. The ligands differ only in the nature and position of substituent while the complexes have identical chromophore NdO₆N₂. The variation of oscillator strengths of different 4<i>f</i>-4<i>f</i> transitions and computed values of electric dipole intensity, Judd-Ofelt parameters (Tl) suggest specific correlations between the relative intensities, ligand structure and nature of Nd(III)-ligand interaction. These complexes have been found to be monomeric in isopropanol, cryoscopically and ebullioscopically, suggesting that all the Nd(III) complexes most probably involve an octa-coordination.