Chiral lanthanide(III) complexes of sulphur-nitrogen-oxygen ligand derived from aminothiourea and sodium D-camphor-β-sulfonate

Six new chiral lanthanide complexes derived from sodium D-camphor-beta -sulfonate and aminothiourea with Ln = La3+, Pr3+, Nd3+, Sm3+, Eu3+ and Gd3+ of the type LnL(3) have been synthesized and characterized on the bases of their elemental analysis, molar conductance. IR. XPS. CD, electronic spectra, magnetic moments and thermal analysis methods. It was found that NaL acts as an SNO tridentate ligand. The visible spectra of Pr-III and Sm-III show characteristic f-f transitions and the nephelauxetic parameter (beta), the bonding parameter (b(1,2)) and covalency parameter (delta) of these transitions has been evaluated. These data indicate the weak involvement of the 4f orbitals in complex formation. A nine-coordinated model has been proposed for these complexes. (C) 2001 Elsevier Science B.V. All rights reserved.