Thesis (Ph. D.)--California Institute of Technology, 1989. UM #89-15,396. / Advisor names found in the Acknowledgements pages of the thesis. Title from home page. Viewed 01/19/2010. Includes bibliographical references.

Doctor's dissertation at Upsala (Sweden) university.

Marburg, Universiẗat, Diss., 2001.

Graduate

A study is described of the kinetics of reactions in which the complexes trans-Ir (CO)X(PPh₃)₂, where X = Cl, Br and I, are used for the catalytic homogeneous hydrogenation of olefins, in particular maleic acid. The catalytic activity is poor in benzene solutions but is enhanced in coordinating solvents such as N, N'-dimethylacetamide. The kinetics were studied by measurements of hydrogen uptake, at various experimental conditions in which iridium, olefin and hydrogen concentrations were varied. The rate-law is complex showing between zero and first order in each of iridium, substrate and hydrogen concentrations. The dependence of rate on the halogen followed the order I>Br>Cl, and quite remarkably traces of oxygen in the system enhance the hydrogenation rate considerably. Supplementary spectrophotometry studies have elucidated some of the equilibria involved and the mechanisms proposed show the importance of a solvent assisted dissociation step in making available a coordination site on the transition metal complex. A detailed path for the catalytic hydrogenation is suggested. / Science, Faculty of / Chemistry, Department of / Graduate

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The oxidative addition of the N-H bond of both heterocyclic and acyclic amines and the O-H bond of phenols, water and carboxylic acids to iridium(I) trimethylphosphines complexes was studied and the reactivity of the resulting hydrido amido-, aryloxo- and carboxylato iridium(III) complexes was investigated. Oxidative addition of the N-H bond of pyrrole, indole, 3-methylindole, 7-azaindole, carbazole and aniline to [Ir(COD)(PMe₃)₃]CI (<b>1a</b>) (COD = 1,5-cyclooctadiene) produces merIr( NR₂)H(PMe₃)₃CI (<b>2a-f</b>) complexes. That these amines were bound to iridium through an Ir-N bond was established by ¹H, ³¹P and ¹³C NMR spectroscopy, IR spectroscopy, C-H analyses and single crystal x-ray diffraction. Similarly, oxidative addition of the O-H bond of phenol, p-cresol, 3,5-dimethylphenol, and water to [Ir(COD)(PMe₃)₃]CI (la) produces mer-Ir(OR)H(PMe₃)₃C1 (<b>5a-c and 6</b>) which were characterized by ¹H, ³¹P and ¹³C NMR spectroscopy, C H analyses and single crystal x-ray diffraction. A preliminary study of the reactivity of both the amido and aryloxo complexes suggests that because of the increased electron affinity of the heteroatoms involved (N or 0), there is high electron density at the heteroatoms in these complexes and therefore the M-N or M-O bond can heterolyze more easily than M-C bonds. This increased tendency of the M-N or M-O bond to heterolyze leads to decomposition reactions when attempts are made to open up a coordination site at the metal center by removing the chloride ligand. / Ph. D.

This thesis describes an investigation of the complex gamma-ray spectra accompanying the decay of iridium 192 and iridium 194. Precision energy measurements of twenty-one gamma-rays in Ir 192 and fourteen gamma-rays in Ir 194 have been made using the 50 cm. double focusing beta-ray spectrometer. In addition, the angular correlation function for the cascade gamma-rays of Ir 194 has been determined. A number of new radiations have been found In each spectrum and decay schemes are proposed for each nuclide. / Thesis / Master of Science (MS)

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