Thoriurn(IV) Complexes with Bidentate Schiff Base Ligands

Abstract

Department of Chemistry, Utkal University, Vani Vihar, Bhubaneswar-751 004. Thorium( V) forms a number of complexes with the bidentate Schlff base ligands (donor set NO) derived by the condensation of salicylaldebyde with p-toluidine, p-anisidine and p-phenetidine. It Is observed that the neutral Schiff bases and not their anions are coordinated to central Thorium(IV) atom. The complexes have the general formulae ThL₂X₄ (X=CI, I, NO₃) or ThL₃X₄ (X= NCS), where L represents the bidentate Schiff base. All except the iodo complexes are very stable at room temperature. The iodo complexes decompose slowly giving off iodine vapours. The chloro and iodo complexes are 8-coordinated, the thiocyanato complexes contain N-bonded isothiocyanates and are 10-coordinated, whereas the nitrato complexes involve the nitrate groups in bidentate coordination through two oxygen atoms, thus providing examples of 12-coordinated species. All the complexes are diamagnetic. The TGA and DTA data of some of the complexes are presented, and the stoichiometry of decomposition processes determined, In all cases, ThLX₄, ThX₄, ThOX₂ and ThO₂ (X=CI, NCS) are formed as Intermediate compounds.