Dimethyl sulphoxide complexes of the actinide tetrachlorides

Abstract

The actinide tetrachlorides form three series of complexes with dimethyl sulphoxide (DMSO), MCl₄,7DMSO (M = U, Np, and Pu), MCl₄,5DMSO (M = Th—Np inclusive), and MCl₄,3DMSO (M = Th—Pu inclusive). The preparation of the three series of complexes and the stability trends within each series are discussed and some chemical and physical properties and infrared spectra are reported. Unlike the others, the protactinium(IV) compounds are unstable at room temperature. By preparing two of the uranium tetrachloride complexes with [²H₆]dimethyl sulphoxide it has been possible to make an unambiguous assignment of the SO vibrational frequency.