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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Electronic transitions of transition metal monoboride and monoxides

Wang, Na, 王娜 January 2014 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
62

Molecular structures and physicochemical properties of some chiral andhelical transition metal complexes with polypyridines and tetradentateanionic ligands

何國強, Ho, Kwok-keung, Paul. January 1996 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
63

MAGNETIC PROPERTIES AND MOESSBAUER SPECTRA OF TRANSITION-METAL COMPLEXES

Wesolowski, Wayne E. January 1971 (has links)
No description available.
64

An investigation of novel reactivity and bonding in rare earth metal complexes

Johnson, Kevin Ross David January 2012 (has links)
The synthesis, structure and reactivity of organolanthanide complexes supported by a family of novel bis(phosphinimine)carbazole and bis(phosphinimine)pyrrole pincer ligands is presented. Through the systematic development of the ligand frameworks, rare earth metal species with unique structure and reactivity were encountered. A variety of complexes that exhibited unusual bonding modes were prepared and characterized by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. Modulation of the ligand frameworks allowed for rational manipulation of the steric and electronic environment imparted to the metal. Incorporation of a variety of N-aryl rings (mesityl, phenyl, para-isopropylphenyl and 2-pyrimidine) and PR2 moieties (PPh2, PO2C2H4 and PMe2) into the ligand design led to rare earth complexes that revealed diverse reaction behaviour. In particular, C–H bond activation, sigmatropic alkyl migration and ring opening insertion reactivity were observed. Kinetic and deuterium labeling studies are discussed with respect to the unique reaction mechanisms encountered during the study of these highly reactive organometallic rare earth complexes. / xxvi, 247 leaves : ill. (some col.) ; 29 cm + 1 CD-ROM
65

Transition metal complexes of ethanolamine

Howard, Walter Jack 12 1900 (has links)
No description available.
66

Preparation and characterization of thioaurite cluster compounds

Schaaff, T. Gregory 08 1900 (has links)
No description available.
67

Synthesis and thermal decomposition of [CM(CO)CH₂S(Ph)CH₂CH=CH₂] BF₄, M=Fe, Ru

Bruno, Deborah Suzanne 12 1900 (has links)
No description available.
68

The solid state polymerization of alkali metal acrylates /

Saviotti, Paolo. January 1975 (has links)
No description available.
69

Unidirectional solidification of rare earth oxide-metal composites.

Stendera, James Windsor January 1974 (has links)
No description available.
70

Theoretical studies on cluster compounds

Lin, Zhenyang January 1989 (has links)
This Thesis describes some theoretical studies on ligated and bare clusters. Chapter 1 gives a review of the two theoretical models, Tensor Surface Harmonic Theory (TSH) and Jellium Model, accounting for the electronic structures of ligated and bare clusters. The Polyhedral Skeletal Electron Pair Theory (PSEPT), which correlates the structures and electron counts (total number of valence electrons) of main group and transition metal ligated clusters, is briefly described. A structural jellium model is developed in Chapter 2 which accounts for the electronic structures of clusters using a crystal-field perturbation. The zero-order potential we derive is of central-field form, depends on the geometry of the cluster, and has a well-defined relationship to the full nuclear-electron potential. Qualitative arguments suggest that this potential produces different energy level orderings for clusters with a nucleus with large positive charge at the centre of the cluster, enabling the spherical jellium model to be applied to alkali metal clusters seeded with magnesium and zinc. Analysis of the effects of the non-spherical perturbation on the spherical jellium shell structures leads to the conclusion that for a cluster with a closed shell electronic structure a high symmetry arrangement which is approximately or precisely close packed will be preferred. It also provides a basis for rationalising those structures, which have been predicted using ab initio calculations, of clusters with incomplete shell electronic configurations In Chapter 3, the geometric conclusions derived in the structural jellium model are developed in more detail. Alkali metal clusters with closed shell electronic configurations according to the jellium model adopt geometries of high symmetry and based on the T<sub>d</sub> , O<sub>h</sub> and I<sub>h</sub> point groups. For high nuclearity clusters alternative high symmetry structures can occur and those which are either the most close packed or spherical are predicted to be the most stable. When the jellium closed shell "magic numbers" coincides with one of these high symmetry structures then the cluster will be particularly stable. The group theoretical consequences of the Tensor Surface Harmonic Theory are developed in Chapter 4 for[ML<sub>2</sub>]<sub>n</sub>, [ML<sub>4</sub>]<sub>n</sub> and [ML<sub>5</sub>]<sub>n</sub> clusters where either the xz and yz or x<sup>2</sup>-y<sup>2</sup> and xy components to L<sup>π</sup><sub>d</sub> and L<sup>δ</sup><sub>d</sub> do not contribute equally to the bonding. The closed shell requirements for such clusters are defined and the orbital symmetry constraints pertaining to the interconversion of conformers of these clusters are described. In Chapter 5 Stone's Tensor Surface Harmonic methodology is applied to high nuclearity transition metal carbonyl cluster compounds with 13-44 metal atoms. Two limiting bonding situations are identified and represented in terms of general electron counting rules. If the radial bonding effects predominate the clusters are characterised by 12n<sub>s</sub>+Δ<sub>i</sub> valence electrons, where Δ<sub>i</sub> is the characteristic electron count of the interstitial moiety. If radial and tangential bonding effects are important then the total number of valence electrons is 12n<sub>s</sub>+2(s<sub>s</sub>+s<sub>i</sub>-l), where s<sub>s</sub> and s<sub>i</sub> are the number of skeletal bonding molecular orbitals associated with surface (s<sub>s</sub>) and interstitial (s<sub>i</sub>) moieties. Chapter 6 develops a new theoretical framework to account for the bonding in the high nuclearity ligated clusters with columnar topologies. The wave functions of columnar metal clusters can be expressed as an expansion based on the particle on the cylinder problem. This bonding analysis is applied to clusters containing columns of triangles and squares. In Chapter 7 the origin of non-bonding orbitals in molecular compounds is reviewed and analysed using general quantum mechanical considerations. A combination of the pairing theorem and a group theoretical analysis leads to a definition of the number of the non-bonding molecular orbitals in co-ordination, polyene and cluster compounds. The non-bonding molecular orbitals have been generated by defining the nodal characteristics of the relevant orbitals and evaluating the solutions under the appropriate boundary conditions. The stereochemical role of nonbonding molecular orbitals in co-ordination compounds is also discussed.

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