Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Kerry A. Kinney. Vita. Includes bibliographical references. Also available from UMI.

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Thesis (Ph.D.)--New Jersey Institute of Technology, Dept. of Chemical Engineering, Chemistry and Environmental Science, 1994. / Includes bibliographical references (leaves 167-174). Also available via the World Wide Web.

Co(NO)(NO₂)₂L₂ complexes (L = PPh₃, PMePh₂, PMe₂Ph, PMe₃, PEt₃, PEt₂Ph, PEtPh₂, PPrPh₂, PBu₃ and 1/2DPPPr) were prepared from the reactions of Co(NO)X₂L₂ (X = Cl, Br) with sodium nitrite in methanol freshly distilled from magnesium methoxide. The complexes were characterized by elemental analysis, 15-N labeling, infrared and NMR spectroscopy. The crystal structure of Co(NO)(NO₂)₂(PMePh₂)₂ was determined by X-ray diffraction. The cobalt atom has tetragonal pyramidal geometry. The nitrosyl group in the axial position is strongly bent. The NO₂ ligands have two different ligating geometries: one is bound to cobalt through the nitrogen atom and the other is bidentate forming an asymmetric four membered ring. The phosphine ligands are equivalent and trans to each other. Multinuclear NMR spectroscopy (¹H, ³¹P, ¹⁵N and ¹⁴N) was used to determine the solution structure of Co(NO)(NO₂ )₂L₂ complexes, to study mono and bisnitrosyls of cobalt, to establish some correlations between NMR parameters and structural characteristics of these complexes and to follow their reactions in solution. Reactions of Co(NO)(NO₂)₂L₂ with CO, NO and RCOX were observed to produce Co(NO)₂XL complexes. Since the structure may be indicative of electronic requirements at the metal center as well as the reactivity of the compounds, The crystal structures of Co(NO)₂Cl(PPh₃) and Co(NO)₂(ONO)(PPh₃) were also determined. In these complexes the cobalt atoms have pseudotetrahedral geometry. The CoNO angles are in the range considered to be linear. They are geniculated in an "atracto" conformation. Co(NO)(NO₂)₂L₂ and Co(NO)₂(ONO)L complexes react with oxygen in the solid state or in solution to form Co(NO₃)₂(OL)₂ complexes. When the reactions with O₂ were carried out in the presence of an excess of olefins, the formation of nitrates is inhibited Co(NO₂)₂(OL)₂ and olefin oxides are formed instead. The crystal structures of Co(NO₃)₂(OPMePh₂)₂ and Co(NO₂)₂(OPMePh₂)₂ were determined by X-ray diffraction. In these complexes, the NO₃ and NO₂ groups are bidentate. They are arranged in a cis configuration around the cobalt atom.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Complexes of the type MX(η²-NO₃)(CO)₂(PPh₃)₂, (M = Mo, X = Cl, Br; M = W, X = Br) were prepared from the reactions of MX₂(CO)₂(PPh₃)₂ with ammonium nitrate in acetone. The complexes were characterized by elemental analyses, ¹⁵N labelling, infrared and NMR spectroscopy. The nitrate ligand is bidentate and the complexes are seven-coordinate. Novel nitrite complexes of molybdenum and tungsten of the type M(NO₂)₂(PPh₃)₂ were prepared. The compounds were characterized by elemental analyses, ¹⁵N labelling, infrared and multinuclear NMR spectroscopy. Both NO₂ ligands are chelating and the two NO₂, PPh₃ and CO ligands are equivalent. Molybdenum dinitrosyl complexes were synthesized by the reduction of nitrate ions. The crystal structure of cis-dinitrosyl-cis-dichloro-trans-bis-(triphenylphosphine)molybdenum(II) was determined by x-ray diffraction. Both the nitrosyl groups are linear. Mo(NO)₂Cl₂(OPPh₃)₂ and Mo(NO)₂Cl(NO₃)(OPPh₃)₂ were synthesized by the reaction of MoCl(η²-NO₃)(CO)₂(PPh₃)₂ with NO in acetone/toluene mixture. The nitrosyl ligands are linear and the phosphineoxide ligands are cis to each other. The dinitrite complex Rh(NO)(NO₂)₂(PPh₃)₂ of the series Rh(NO)X₂(PPh₃)₂ (X - monodentate anions) was prepared as a direct derivative of Rh(NO)Cl₂(PPh₃)₂ by its reaction with sodium nitrite. The complex is square pyramidal with an apical nitrosyl ligand. The two NO₂ groups are present as the nitro and the nitrito group. Rh(NO)(NO₂)₂(PPh₃) reacted with oxygen and formed Rh(NO₃)₃(PPh₃)₂. The reaction of Rh(NO)(NO₂)₂(PPh₃)₂ with CO in acetonitrile produced Rh(CO)(NO₂)(PPh₃)₂. The complex Rh(CO)(NO₂)(PPh₃)₂ is square planar with the phosphine ligands in the trans positions.

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Suc Chiu Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 57-60). / Abstracts in English and Chinese. / TITLE PAGE --- p.i / THESIS COMMUTE --- p.ii / ABSTRACT (English) --- p.iii / ABSTRACT (Chinese) --- p.iv / ACKNOWLEDGMENTS --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.ix / Chapter CHAPTER ONE --- General introduction and methodology / Chapter 1.1 --- General introduction --- p.1 / Chapter 1.2 --- Approximation in ab initio calculation --- p.4 / Chapter 1.2.1 --- Born-Oppenheimer approximation --- p.5 / Chapter 1.2.2 --- Density function theory (DFT) --- p.6 / Chapter 1.2.3 --- Periodic supercell approach for solid reaction --- p.8 / Chapter 1.2.4 --- Pseudopotential approximation --- p.11 / Chapter CHAPTER TWO --- "Adsorption of N02 molecules on zigzag (6,0) and (8,0) single-walled carbon nanotubes (SWNTs)" / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Computational details --- p.17 / Chapter 2.3 --- Resultsand discussion --- p.19 / Chapter 2.3.1 --- "Adsorption of a single N02 on (6,0) SWNT" --- p.19 / Chapter 2.3.2 --- "Adsorption of a second N02 on (6,0) SWNT" --- p.22 / Chapter 2.3.3 --- "Comparison of NO2 adsorptions on (8,0) SWNT with different cutoff energies" --- p.25 / Chapter 2.3.4 --- "Adsorption of more N02 on a (8,0) SWNT" --- p.28 / Chapter 2.4 --- Summary --- p.34 / Chapter CHAPTER THREE --- Diameter dependence for the adsorption of N02 molecules on zigzag single-walled carbon nanotubes (SWNTs) (n=6~12) / Chapter 3.1 --- Introduction --- p.35 / Chapter 3.2 --- Computational method --- p.37 / Chapter 3.3 --- Results and discussion --- p.38 / Chapter 3.3.1 --- Adsorption of a single N02 on SWNT --- p.38 / Chapter 3.3.2 --- Adsorption of a second on N02 SWNT --- p.40 / Chapter 3.3.3 --- Electronic structures of SWNTs after NO2 adsorption --- p.42 / Chapter 3.4 --- Summary --- p.55 / References --- p.57

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