The use of sulfoxide ligands for transition metal catalyzed transformations has recently been brought to the forefront in organic chemistry. The synthesis of a series of tri- and disulfoxides will be presented, and their applications investigated. Their use in rhodium catalyzed 1,4-additions of phenylboronic acid to 2-cyclohexen-1-one result in enantioselectivities up to 80%. The incorporation of β-amino acid residues into polypeptides has resulted in new foldamers whose structures and enhanced stability provide interesting opportunities for new biological applications. A novel strategy for an iterative peptide synthesis involving β-amino acids will be proposed. Lastly, a hydroamidation-type strategy for the construction of β3-amino acids, or more specifically of β-(N-acylamino)acrylates, will be presented as preliminary work towards the goal of dipeptide synthesis.

Despite the great abundance of C–H bonds in readily available starting materials, their use in synthesis of functionalized molecules has been hampered by the high bond strengths, rendering them inert to common organic reagents. However, recent progress in the field has addressed this issue, enabling selective C–H bond functionalizations to be performed using catalytic transition metal mediated processes. Herein, the use of sulfonyl chlorides as versatile reagents for C–H bond functionalizations is reported. Using chelation assistance, the regioselective conversion of C–H bonds to either C–S, C–Cl or C–C bonds was achieved. The methodology development, substrate scope determination and mechanistic investigations will be discussed.

The use of sulfoxide ligands for transition metal catalyzed transformations has recently been brought to the forefront in organic chemistry. The synthesis of a series of tri- and disulfoxides will be presented, and their applications investigated. Their use in rhodium catalyzed 1,4-additions of phenylboronic acid to 2-cyclohexen-1-one result in enantioselectivities up to 80%. The incorporation of β-amino acid residues into polypeptides has resulted in new foldamers whose structures and enhanced stability provide interesting opportunities for new biological applications. A novel strategy for an iterative peptide synthesis involving β-amino acids will be proposed. Lastly, a hydroamidation-type strategy for the construction of β3-amino acids, or more specifically of β-(N-acylamino)acrylates, will be presented as preliminary work towards the goal of dipeptide synthesis.

Studies of gas-phase ionic clusters have become an integral component in understanding microsolvation and catalysis by transition metal cations. Further interest in this field is due to the possibility of bridging the gap between the condensed and gas phases by developing our understanding of clusters and the possibility that small clusters can have unique chemical and catalytic properties. Most gas phase studies have focused on singly charged ions. Electrospray allows for the production of multiply charged ions solvated by a few solvent molecules. Understanding smaller reactive species such as metal centered clusters with well-defined, gas phase conditions also allows for detailed comparison between theory and experiments. In these studies the main focus is to understand bond activation by transition metal cations and solvation of transition metal dications. The gas phase ions of interest are studied using an electrospray-ionization or laser-ablation dual time-of-flight mass spectrometer and are characterized using photofragment spectroscopy in the visible and ultraviolet regions of the spectrum. Photofragment spectroscopy is a powerful method that can be used in gas phase studies to gather a wealth of information on the ions' bond strengths, spectroscopic constants, and dissociation kinetics and dynamics. The study of TiO + (CO 2 ) spectroscopy (Chapter 3) was a result of study of CO 2 bond activation by Ti + that went on to provide a wealth of information on the spectroscopy and dissociation kinetics of this molecule. An electronic transition of the TiO + chromophore was observed, 2 Π[arrow left] 2 Δ, revealing new information about the excited state and the effect of TiO + electronic state on the metal- CO 2 ligand interaction. The photodissociation spectrum of this molecule is well resolved and shows progressions in the covalent Ti-O stretch and metal-ligand stretch and rock. The lifetime of electronically excited TiO + (CO 2 ) was measured, and depends strongly on vibrational energy. Calculations on TiO + and TiO + (CO 2 ) were combined with experimental results on TiO + (CO 2 ) to predict spectroscopic transitions of TiO + , an astrophysically interesting molecule. The photodissociation dynamics of M 2+ (CH 3 CN)n(H 2 O)m where M = Co and Ni, (Chapter 4) is important in understanding the gas phase microsolvation of metal dications. The coordination number and type of solvent affect the dissociation pathways. M 2+ (CH 3 CN)n (n>2) primarily lose a solvent molecule. Electron transfer is a minor channel for n=3 and is the only channel observed for n=2. Mixed clusters M 2+ (CH 3 CN)n(H 2 O)m preferentially lose water. Loss of acetonitrile is a minor channel, as is proton transfer. Water is the proton donor. Replacing acetonitrile with water increases the proton transfer channel. Nickel and cobalt complexes show similar dissociation dynamics, with proton transfer more likely for nickel complexes. Methane activation by transition metal catalysts is industrially important as it can be used to produce gasoline from natural gas. We studied the products and intermediates of the reaction of laser-ablated platinum atoms with methane (Chapter 5). Photoionization efficiency curves were measured for PtCH 2 and the [H-Pt-CH 3 ] insertion intermediate using tunable vacuum ultraviolet light. The resulting ionization energies were combined with bond strengths for the cations to derive bond strengths for the neutrals. These were used to construct a potential energy surface for methane activation by platinum atoms.

Includes bibliographical references. / 249 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1991

Typescript (photocopy) / viii, 283 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1980

Title on spine: Transition metal complexes / 173 leaves : ill., tables, graphs ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1979) from the Dept. of Physical and Inorganic Chemistry, University of Adelaide

Typescript (photocopy) / 2 microfiche in end pocket / 190 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1984

1 v. (various pagings) : ill., plates ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1973) from the Dept. of Physical and Inorganic Chemistry, University of Adelaide

This thesis presents a number of largely independent forays into developing an understanding of the unique chemistry of transition metal clusters. The first chapter of this thesis represents an initial foray into mapping the chemical reactivity of transition metal clusters - a monumental task that will doubtless continue for some time. The small slice undertaken in this work investigates the reactivity with CO of a series of the smallest possible metal clusters; 4d (Nb - Ag) homonuclear metal trimers. In Chapter 2, two known transition metal clusters were studied using CASSCF (MCSCF) and MRCI methods, only to find that DFT methods provided more accurate Ionisation Potentials (IPs). Thus Chapter 3 was devoted to optimising a density functional to predict IPs. As clusters get larger, the number of possible structures grows rapidly too large for human intuition to handle, thus Chapter 4 is devoted to the use of an automated stochastic algorithm, “Kick”, for structure elucidation. Chapter 5 improves on this algorithm, by permitting chemically sensible molecular fragments to be defined and used. Chapter 6 then comes full circle and uses the new Kick algorithm to investigate the reaction of CO with a series of mono-substituted niobium tetramers (i.e. Nb₃X). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1350246 / Thesis (Ph.D.) - University of Adelaide, School of Chemistry and Physics, 2009