A Direct Hydrogen-1 and Phosphorus-31 Nuclear Magnetic Resonance Cation Solvation Study of Al(ClO(4))(3), Ga(ClO(4))(3), In(ClO(4))(3), UO(2)(ClO(4))(2), and UO(2)(NO(3))(2) in Water-Acetone-Dimethylsulfoxide and Water-Acetone-Hexamethylphosphoramide Mixtures

A competitive solvation study of Al(ClO(4))(3), Ga(ClO(4))(3), In(ClO(4))(3), UO(2)(ClO(4))(2), and UO(2)(NO(3))(2) in water-acetone-dimethylsulfoxide (DMSO) and water-acetone-hexamethylphosphoramide (HMPT) mixtures has been carried out by direct H(1) and p(31) nuclear magnetic resonance (NMR) techniques. At low temperature, proton and ligand exchange are slow enough in these systems to permit the observation of signals for bulk and coordinated molecules of water and the organic bases (DMSO and HMPT). Both DMSO and HMPT compete effectively with water for coordination sites in the Al(3+), Ga(3+), and In(3+) systems, with steric effects dominating the HMPT results. Both Al(3+) and In(3+) are able to bind a maximum of two to three HMPT molecules, for example. In contrast, UO(2+) is solvated selectively by the organic molecules to the allowed maximum of 4 molecules per cation. H(1) and P(31) NMR spectral results support