Phosphine oxide and suiphoxide complexes of thorium(IV) and uranium(IV) halogenoacetates

Abstract

Complexes of thorium(IV) and uranium(IV) carboxylates with phosphine oxides and sulphoxides of the types M(O₂CR)₄·nL [n= 4, M = Th or U, L = Me₂SO (dmso), R = CF₃ and L = PMe₃O (tmpo), R = CCl₃ or CHCl₂;M = U,L = tmpo,R = CF₃; n= 3, M = Th, L = tmpo,R = CF₃ and L = PPh₃O (tppo) or dmso, R = CCl₃; M = U, L = tppo, R = CF₃ and L = dmso or Ph₂SO (dpso), R = CCl₃; n= 2, M = Th, L = tppo, R = CF₃ or CHCl₂ and L = dpso, R = CF₃ or CCl₃; M = U, L = dpso, R = CF₃ and L = tppo, R = CCl₃ or CHCl₂; n= 1, M = Th or U, L = dmso, R = CHCl₂] have been prepared. The i.r. and u.v.–visible spectra [uranium(IV) complexes only] of these compounds are reported and the effects of steric crowding on the possible bonding arrangements of the carboxylate groups in the complexes are discussed in terms of a cone angle approach to steric crowding about the central metal ions.