Complexes of uranium and thorium tetrahalides with oxygen-donor ligands

Abstract

Thorium and uranium tetrachloride from complexes with dimethyl sulphoxide (DMSO), ThCl₄,5DMSO and UCl₄, 3DMSO, respectively, and with hexamethylphosphoramide (HMPA), MCl₄,2HMPA (M = Th and U). The dimethyl sulphoxide complexes undergo thermal vacuum decomposition to give ThOCl₂ and U₃O₈, respectively, whereas the HMPA complexes sublime above 200°. The corresponding tetrabromides form the complexes MBr₄,6DMSO (M = Th and U), ThBr₄,3HMPA, and UBr₄, 2HMPA. Vaccum thermal decomposition of UBr₄,6DMSO leads to the formation of UO₂Br₂DMSO at 140–170°, and finally a mixture of U₃O₈ and UO₂Br₂; ThBr₄,6DMSO decomposes directly to ThOBr₂. Thermal decomposition of ThBr₄,3HMPA yields ThBr₄,2HMPA above 150°, which, like UBr₄,2HMPA, sublimes above 250°. Some chemical properties, infrared spectra, and magnetic susceptibilities are reported.