Thesis (Ph.D.)--Brown University, 2005. / Vita. Thesis advisor: Christoph G. Rose-Petruck. Includes bibliographical references (leaves 95-107). Also available online.

Thesis (M. Sc.)--University of Canterbury, 2005. / Typescript (photocopy). On t.p. "n+" is superscript. "April 2005." Includes bibliographical references (leaves 135-137). Also available via the World Wide Web.

The work described in this thesis concerns the synthesis of actinide complexes and their reactivity towards small unsaturated molecules. Complexes bearing tetraphenoxide, borohydride and boroxide ligands have been evaluated. Additionally, work towards the synthesis of heterobimetallic uranium transition metal complexes and their applications in catalysis is discussed. Chapter one reviews important organoactinide complexes reported in the literature which effect chemical transformations on small unsaturated substrates. Actinide complexes supported by aryloxide or borohydride ligands are reviewed, along with actinide complexes in which metal p-arene interactions are present. Chapter two reports the synthesis and characterisation of a set of tetraphenol ligands, in addition to a number of attempted synthetic routes to tetraphenol ligands with alternate substitution. The chemistry of those tetradentate aryloxide ligands is introduced with bimetallic uranium(IV) and thorium(IV) complexes using different An(IV) and U(III) precursors. Chapter three reports the synthesis and characterisation of monometallic uranium and thorium complexes using a tetraphenol ligand. The varying chemistry between the two similar An(IV) ions, where the uranium complexes exist as a mixture of oligomers and the thorium complexes remain as well defined mononuclear complexes, is discussed within. A range of base adducts of mononuclear actinide complexes are reported, including a thorium trimethylsilylazide complex, a rare example of a metal organoazide. Chapter four describes the synthesis of homoleptic boroxide and heteroleptic borohydride complexes of uranium(III). The reactivities of these complexes with small unsaturated molecules are assessed, including the reaction of a low coordinate uranium(III) boroxide complex towards CO2 to provide a dinuclear uranium carbonate bridged complex. Chapter five introduces work towards heterobimetallic uranium transition metal complexes carried out in the Arnold group. The application of these complexes towards ring opening polymerisation chemistry is discussed in addition to investigations into the incorporation of transition metals into uranium(IV) complexes. Chapter Six presents the detailed experimental methods used to carry out this research.

Les molécules-aimants sont une classe d’objets aux propriétés très singulières, et dont les applications envisagées, certes sans doute lointaines, sont multiples. Dans le cadre du stockage de l’information, la principale propriété de ces molécules est le blocage de leur aimantation qui leur confère les propriétés de mémoire au niveau de la molécule unique. Théoriquement l’existence d’une aimantation spontanée au niveau d’une molécule de spin S ne peut exister que s’il y a une levée de dégénérescence à champ nul (ZFS) qui sépare les états de spin ±mS. Dans ce contexte, les molécules-aimants peuvent être divisées en deux classes : (i) les complexes mononucléaires dont la majorité comprennent, en général, des ions paramagnétiques présentant une forte anisotropie axiale qui à leurs tours sont responsables de la relaxation lente de l’aimantation dans le système, et (ii) les complexes polynucléaires, où les ions métalliques (métaux de transition et/ou lanthanides) communiquent entre eux par une interaction d’échange J ou par interaction dipolaire. Ce type de complexes peut à son tour diviser en deux parties : HomoBinucléaires et HétéroBinucléaires. Différents complexes de Co (II) et de Ni (II) sont synthétisés et étudiés chimiquement et magnétiquement avec ce type de ligand qui est capable d’accepter deux métaux dans deux sites de coordination liés par des différents ligands pontants (Cl-, Br-, NO3-, N3-, imidazole, etc..). Les mesures de susceptibilité magnétique de certains complexes montrent une interaction antiferromagnétique avec une anisotropie axiale de type Ising (D < 0) et autre de type planaire (D > 0). Cela est dû de la nature des ions métalliques et les géométries des complexes pentacoordinés (bipyramide trigonale et pyramide à base carrée). / For molecular magnetic materials to be used in applications, they must retain their magnetization at reasonable temperatures, which can be achieved with high-energy barriers for magnetization reversal and slow relaxation of the magnetization. In the field of Single-Molecule Magnets (SMMs), over the last decade, the main focus has shifted from large spin complexes to highly anisotropic systems which have displayed high energy barriers.1 Here, we used a cryptand ligand that forces a trigonal bipyramidal arrangement to obtain a large (in absolute value) negative zero field splitting parameter D.2 In order to use these molecules as models for entangled quantum bits (qbits), the cryptand ligand was chosen to have two coordination sites allowing the design of chemically stable binuclear complexes with tunable antiferromagnetic coupling. We prepared pentacoordinate complexes of Co(II) and Ni(II) with different bridging ligands (Cl-, Br-, NO3-, N3-, Im-, etc.). Magnetic measurements indicated an Ising type anisotropy and weak antiferromagnetic coupling as expected from the nature of the bridging ligands (N3- and Im-) and the trigonal bipyramidal geometry around the metal ions.

Xenopus Laevis has provided, during the last ten years, the basis of a growing body of physiological enquiries initiated by Jolly's research on reflex action. Its viability in the laboratory and amenability to operative procedure in particular, make it a peculiarly suitable object for investigation. It is regrettable therefore, that existing literature on the anatomy of Xenopus has been directed to elucidating those characteristics which are of especial interest to the Systematists and Morphologists rather than detailed information of a type which is essential to operative procedure. There is in particular no extant account of the endocrine system of Xenopus, although it is evident from superficial inspection that the suprarenal complex differs from that of the more familar Anura. The present enquiry concerns the Thyroid Gland, Pituitary and Epiphyseal Complexes with some observations concerning the possible occurrence of chromophil cells in the kidney of Xenopus laevis. The data have been placed on record specifically and constitution of these organs in physiological operations.

The first stable “free” N-heterocyclic carbene (NHC) was isolated in 1991, since then many classes of NHCs were synthesized and isolated. N-heterocyclic carbene ligands have become a common ligand in the synthesis of metal complexes, due to their strong σ-donation with poor πeptor ability. Among all the NHC metal complexes, Hollis group was interested in exploring -NHC pincer complexes. In 2005, Hollis and co-workers synthesized and isolated first achiral -NHC zirconium pincer amido complex and studied its catalytic ability to perform intramolecular hydroamination of aminoalkenes. Later, Hollis group designed and developed new NHCs with a saturated chiral backbone, and used these new ligands to generate a new series of metal complexes. This dissertation is focused on the design, synthesis and characterization of several chiral bi-dentate NHC ligands with varying substituents on the backbone. These NHC ligands were used to synthesize several chiral mono, bis and tris amido -NHC zirconium pincer complexes. Further, transmetallation to cobalt complexes were achieved. Intramolecular hydroamination was measured for several chiral bis and tris amido -NHC pincer zirconium catalysts. Variants of these catalytic systems were generated with differing steric hinderance and electronic structure. The enantioselectivity of these novel new molecules were studied.

no / Several Ru-arene and Ir–Cp* complexes have been prepared incorporating (N,N), (N,O) and (O,O) coordinating bidentate ligands and have been found to be active against both HT-29 and MCF-7 cell lines. By incorporating a biologically active ligand into a metal complex the anti-cancer activity is increased.

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published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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