Some urea and phosphine oxide complexes of thorium(IV) and uranium(IV) trihalogenoacetates

Abstract

Complexes of thorium(IV) and uranium(IV) trifluoro- and trichloro-acetates of the types M(O₂CR)₄·nL [n= 4, M = Th or U, L = CO(NHMe)₂, R = CCl₃ and M = Th, L = CO(NHMe)₂, R = CF₃; n= 3, M = Th or U, L = PMePh₂O or PMe₂PhO, R = CF₃ or CCl₃ and M = U, L = CO(NHMe)₂, R = CF₃; n= 2.5, M = Th or U, L = CO(NMe₂)₂, R = CCl₃; n= 2, M = Th or U, L = CO(NMe₂)₂ R = CF₃] 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.