Epsilon Open Archive

Abstract

The thesis summarizes and discusses the results from coordination chemistry studies of solvated d10 metal and copper(II) ions, and mercury(II) halide complexes in the strong electron-pair donor solvents liquid and aqueous ammonia, trialkyl phosphite, triphenyl phosphite and trialkylphosphine. The main techniques used are EXAFS, metal NMR and vibrational spectroscopy, and crystallography. Four crystal structures containing ammonia solvated metal ions have been determined. Questions addressed concern whether any changes in the preferential coordination numbers and geometries occur when these metal ions are transferred from aqueous ammonia to liquid ammonia solution, or to phosphorous donor solvents. Liquid ammonia and trialkyl phosphites are found to possess similar electron-pair donor properties, DS=56 for both, while trialkylphosphines are known to be even stronger electron-pair donors. The studies reveal that the ammonia-solvated d10 metal ions obtain very different configurations in liquid ammonia, with gold(I) being linear, copper(I) and silver(I) trigonal, zinc(II) and mercury(II) tetrahedral, and cadmium(II), indium(III) and thallium(III) octahedral. The ammonia-solvated copper(I) and silver(I) ions are linear in aqueous ammonia solution because of the lower ammonia activity, as the third ammine complexes are very weak in aqueous systems. In the phosphorous donor solvents surveyed, the copper(I) ion is tetrahedral while the silver(I) ion is tetrahedral or trigonal and the gold(I) ion is trigonal or linear. The ammonia solvated copper(II) ion has a Jahn-Teller distorted octahedral configuration in liquid ammonia solution and solid [Cu(NH3)6](ClO4)2, as determined by EXAFS. In liquid ammonia, mercury(II) chloride and mercury(II) bromide are completely dissociated, whereas the ammonia solvated mercury(II) iodide, [HgI2(NH3)2], complex has a near tetrahedral configuration. In tri-n-butylphosphine, mercury(II) iodide is completely dissociated, forming a linear solvate complex in a melt at elevated temperature.