Date of Award
Doctor of Philosophy (PhD)
Professor G.J. Schrobilgen
Xenon tetroxide was stabilized in SO2 ClF, BrF5 , and HF solvents rendering its 129 Xe and 17 O NMR spectroscopic characterization possible. The high symmetry about xenon in XeO4 allowed for the observation of the first 131 Xe resonance of chemically bonded xenon. Spin-lattice relaxation time measurements for 129 Xe and 131 Xe showed that the spin-rotation and the quadrupolar relaxation, respectively, are the predominent mechanisms of relaxation in XeO4 . The investigation of the 129 Xe NMR spectrum of [Na]4 [XeO6 ] in solution and solid state corrected the previously reported, erroneous value. Xenon tetroxide was shown to act as a Lewis acid towards CH3 CN solvent and fluoride ions yielding XeO4 (CH3 CN) and XeO4 F2 2- , respectively. The XeO4 (CH3 CN) adduct was characterized by 129 Xe NMR and Raman spectroscopy and contains the first example of a Xe(VIII)-N bond. The XeO4 F 22- anion was shown to exist as a mixture of its cis - and trans -isomers based on Raman spectroscopy. For the first time, XeO3 F2 was prepared in SO2 ClF, BrF5 , and HF solvents and characterized by 19 F and 129 Xe NMR spectroscopy. The novel XeO3 F 3- anion was prepared in low concentrations in SO2 ClF and BrF5 solvents and was identified by 19 F and 129 Xe NMR spectroscopy and shown to have a facial trioxo configuration. In the present work, the OsO4 F- anion was prepared and characterized by X-ray crystallography and vibrational spectroscopy as its N(CH3 )4+ salt. The OsO4 F 22- anion had been prepared in admixture with the OsO4 F- anion and was characterized by vibrational spectroscopy showing its cis -difluoro arrangement. The OsO 4 F- anion was shown to be identical to the anion that had been previously reported and charactized by vibrational and EXAFS spectroscopy and erroneously assigned as the cis -OsO 4 F22- anion. The Lewis acidbase reaction between OsO3 F2 and fluoride ions and CH3 CN yielded the OsO3 F3- anion and the OsO3 F2 (CH3 CN) adduct, respectively. The unambiguous identification of the OsO3 F3- anion as the exclusive, facial trioxo isomer was accomplished by determining the crystal structure of [N(CH3 )4 ][OsO3 F 3 ] and by vibrational spectroscopic characterization of the N(CH 3 )4+ and NO+ salts. The OsO 3 F2 (CH3 CN) adduct, however, exists as a mixture of its fac - and mer -isomers in solution and in the solid state based on 19 F and 15 N NMR and Raman spectroscopy. The Os(VIII) oxide fluoride, OsO3 F2 , acts as a Lewis base towards strong acids like AsF5 and SbF5 in HF solvent yielding [OsO3 F][AsF6 ], [OsO3 F][HF] 2 [AsF6 ], [Os2 O6 F3 ][AsF 6 ], [OsO3 F][HF][SbF6 ], and [OsO3 F][HF] 2 [SbF6 ], which were characterized by Raman spectroscopy. (Abstract shortened by UMI.)
Gerken, Michael, "Syntheses and characterization of xenon oxide and oxide fluorides of xenon(VIII), osmium(VIII), iodine(VII), and xenon(II)" (2000). Open Access Dissertations and Theses. Paper 2644.