Spectral studies of neodymium complexes containing tetramethylurea (TMU) as ligand

Abstract

Spectral studies of the neodymium complexes of formula [Nd(TMU) 6](ClO 4) 3, [Nd(CF 3SO 3)(TMU) 5](CF 3SO 3) 2, [Nd(NCS) 3(TMU) 4], [Nd(NO 3) 3(TMU) 3], [NdCl 3(TMU) 3] and [Nd(TMU) 3(H 2O) 6]Br 3 were made. The spectra of the compounds were recorded in the regions of 4G 5 2 , 2G 7 2 ← 4I 9 2 (I) and 2P 1 2 ← 4I 9 2 (H) transitions in the solid state, at room temperature and at 77 K and also in acetonitrile solutions. For the cubic perchlorate and hexafluorophosphate complexes the crystal-field parameters ( B k q ) were calculated by the equivalent operator method. The nephelauxetic ( \\ ̄ gb), covalent ( b 1 2 ) and Sinha (δ) parameters were determined for all the compounds. The oscillator strengths, in acetonitrile, for the hypersensitive (I) bands were also calculated and related to the basicity of the anions.