Spectral Intensities and Bonding Parameters for some Praseodymium(III) and Neodymium(III) Complexes with Benzimidazoles

Chemical Laboratories. University of Rajasthan, Jaipur-802 004

Manuscript received 20 May 1986, revised 2 June 1988, accepted 11 June 1988

The electronic spectral intensity parameters (Judd-Ofelt; T_$\lambda$) calculated from absorption spectral data for the complexes of praseodymium(III) and neodymium(III) nitrates with benzimidazole and 2-methyl-, 2-ethyl- and 2-n-propyl-benzimidazoles are reported. The conductance of these derivatives in dimethylformamide suggests 1 : 1 electrolytic nature. The infrared spectral data indicate the presence of C_2v as well as D_2h-nitrate ions in the complexes. The correlation of the intensity of hypersensitive transitions with bonding (nephelauxetic ratio and degree of covalency) parameters are also reported.