Trends in spectral parameters and nephelauxetic ratio values for some lanthanoid(III)-catechol complexes

Department of Chemistry, Dr. H. S. Gour University, Sagar-470 003, India

E-mail: rashmitiwari@epatra.com

Manuscript received 24 July 2001. revised 17 May 2002, accepted 27 August 2002

Electronic spectral studies of Pr^III, Ne^III and Er^III in complexation with catechol (cat) have been undertaken with a view to evaluate the oscillator strengths (ƒ_IO), Judd-Ofelt parameters (^{\( {\displaystyle \tau \,}\)_{\(\lambda \,\)}}), inter-electronic repulsion Racah parameters (δE^K) and nephelauxetic ratios (δE³/δE¹) in the pH range 4.0-6.0. The extent of covalency in metal-ligand interaction have been estimated. The oscillator strength values for some specific hypersensitive transistions were found to be significantly large.