This thesis describes an investigation of the coordination chemistry of l-cyanoguanidine (cnge), l-carbamoylguanidine (clge) and l-amidino-O-ethylurea (aOeu). Various copper(II) complexes of these analogous molecules were synthesised and characterised using mainly X-ray crystallographic and spectroscopic (infrared and UV-visible) techniques. Only bis (cnge) complexes were observed for copper(II) ions. The monodentate cnge ligands coordinated the copper(II) via their nitrile nitrogen atoms which were located in trans equatorial positions of the copper(II) ions's tetragonally distorted octahedral coordination sphere. Comparison of the infrared spectra of the complexes with that of cnge indicated that the spectra were highly diagnostic of coordination to the copper(II) ion. Clge exhibited amphoteric properties; the neutral, anionic and cationic derivatives formed complexes with the copper(II) ion. Whereas the former pair gave bis chelate complexes, the latter derivatives acted merely as a cation and was remote from the copper(II) ion's coordination sphere. Complexation of the neutral molecule resulted in a proton transfer from a terminal amine group to a central nitrogen atom permitting chelation via an imine nitrogen atom and a carbonyl oxygen atom to give a square planar CUN2O2 chromophore. The structural ramifications of this tautomeric shift were near identical to those observed upon cation formation which occurred by protonation of the central nitrogen atom of the uncoordinated neutral molecule. Unequivocal structural data could not be obtained for the complex of the anionic derivative. Spectroscopic analysis indicated, however, that chelation occurred via two imine nitrogen atoms to give a square planar CuN4 chromophore. Ethanolysis of cnge was effected in the presence of copper(II) ions and ethanol producing complexes of aOeu with a metal:ligand ratio of 1:1 or 1:2. In both complexes the ligand(s) chelated the copper(II) ion via two imine nitrogen atoms. The former complex, a dimer, exhibited a square pyramidal CUN2X3 chromophore (X=Cl,Br) whilst the latter complex was a bis chelate with a square planar CUN4 chromophore. Monitoring the Uv-visible and infrared spectra of ethanol solutions containing copper(II) chloride and cnge, indicated the presence of a plethora of reactions. However, it was concluded that initially mono and/or bis(cnge)copper(II) complexes, of low stability, were present in equilibrium with the reactants. Subsequently, ethanolysis of coordinated cnge occurred producing mono(aOeu)copper(II) complexes. Series first order kinetics approximated to those of the ethanolysis reaction. The ethanolysis process was then repeated to give the final product a bis(cnge)copper(II) complex.

The rates of reaction of the constituents of sodium-potassium alloy with water have been determined in the temperature range 20 - 600C. They fall into two categories; the first is applicable to the instant the alloy meets the water, and the second applies to reaction of the metal through a bubble of hydrogen. The rates are widely different for these two stages, yet the activation energies are similar, being 38.3 and 33.0 KJ/mole respectively for sodium, and 24.5 and 27.3 KJ/mole respectively for potassium. The rate of reaction of sodium alone at 30 C, has also been determined. The behaviour of liquid metals when injected into water has been studied by high speed photography. Such jets disintegrate, after a short distance of travel, into small globules, each contained within a hydrogen gas bubble. These globules then travel upwards through water and consequently react much more slowly. The reaction rate may be reduced by the addition of small concentrations of mineral acids to the water, due to the, formation of salts at the metal-water interface which are less soluble than sodium hydroxide. Strong solutions of acid however, increase the rate of reaction. The addition of hydroxide ions as NH4OH has little effect on the rates. The metals undergo secondary reaction in that the hydrogen which is initially formed subsequently reacts with the metal to produce hydrides. These are eventually hydrolysed. The most probable reaction intermediate in the solution phase of the reaction is the solvated electron, e - (sq)' which has been detected photographically due to its absorption of light in the visible region of the spectrum. Overall reaction mechanisms for both reaction in solution and reactions at the metal surface have been proposed.

When a polymeric biomaterial is employed within a living system an interface is created between the solid surface of the polymer and an aqueous environment. The processes that occur at this interface will determine if the biomaterial is accepted by the patient and often will determine if the specific function of the biomaterial can be achieved. Increasingly, novel biomaterials are expected to perform more sophisticated functions and, therefore, their surfaces must be designed to realize precise interfacial events, such as specific interactions with proteins and cells or controlled biodegradation. To design polymeric biomaterials with specific surface properties it is necessary to develop surface analytical techniques that can accurately characterize these properties. The work described in this thesis has aimed to investigate the potential contribution of the atomic force microscope (AFM) to this characterization. The advantages of utilizing AFM in the study of polymeric biomaterials lie in the ability of the instrument to visualize insulating surfaces at a high resolution within a variety of environments, including gaseous and liquid environments. Therefore, it is possible to image the nanoscopic organization of polymeric biomaterials within environmental conditions that are similar to the conditions encountered within living systems. Initial studies have concentrated on imaging the surface morphology of poly(ethylane oxide) (PEG) samples in air. These studies highlighted the high resolution capability of the AFM on untreated polymer samples. On sphemlitic samples, the AFM has visualized the lamellar organization of crystalline fibres. These lamellae had widths of between 10 and 30 nm and height variations of less than 15 nm. The ability of the AFM to resolve such structures, without the introduction of an etching or staining procedure required by transmission electron microscopy, relies on the sensitivity of the instrument to changes in the height of the topography. This sensitivity has been further utilized to image polymer strands with recorded widths of 8 nm. This width represents an overestimation of the true dimensions of the strand due to the finite size of the AFM probe apex and using the circular probe model it has been calculated that the strands have true widths of less than 0.8 nm, indicating that they are composed of one or two PEG molecules. Further studies on PEG have demonstrated the ability to control polymer surface morphology through changes in the temperature of thin film preparation and changes in the method of polymer solution deposition. The work on PEG surface morphology acts as the foundation for the remaining studies, which employ the AFM to study biodegradable polymers within aqueous environments. This in situ application of the AFM has recorded the changes in surface morphology that occur to poly(sebacic anhydride) (PSA) during surface erosion in alkaline conditions. These studies have visualized the preferential degradation of amorphous regions of sphemlites over the crystalline fibres for solution cast and melt-crystallized samples. It has been found that rapid cooling during the solidification of PSA increases the amount of amorphous material at the surface of samples. However, once this outer layer has been eroded the underlying material is dominated by crystalline fibres. In situ AFM studies have also demonstrated the pH dependence of the rate of PSA surface erosion. The AFM techniques developed to visualize the evolution of surface changes during PSA erosion have then been employed to investigate the degradation of immiscible blends of PSA and the polyester poly(DL-lactic acid) (PLA). PLA degrades at a slower rate than PSA and therefore, as these blends eroded the surface morphology became dominated by PLA, revealing the phase separation of the material. For solution cast samples on mica substrates it was found that at high PSA content the PSA formed a continuous network around islands of PLA. However, as the relative content of PLA increased the morphology reversed and the PLA formed the network around islands of PSA. The interest in studying biodegradable polymers is derived from their application in surface eroding drug delivery systems. Having demonstrated the potential of the AFM to visualize dynamic interfacial changes occurring to these polymeric biomaterials, the in situ studies were extended to investigate the release of a model protein drug from a degrading polymer film. The system under investigation was a poly(ortho ester) film containing particles of bovine serum albumin. The AFM visualized the initiation of dissolution of some protein particles within minutes of the exposure of the sample to a pH 6 environment. Other particles, however, displayed retarded dissolution behaviour and did not appear to dissolve until the sample had been exposed to the pH 6 environment for over 1 hour. To assist the interpretation of these studies computational methods of calculating changes in volume during polymer degradation and protein dissolution have been developed on the Genesis II system. In the final experiments of this thesis, the application of a novel combined atomic force microscopy/surface plasmon resonance instrument is described. This instrument allows the simultaneous acquisition of topographical data by the AFM and kinetic data by the surface plasmon resonance instrument (SPR). The instrument is first applied to a simple poly(ortho ester) system to demonstrate that the changes surface morphology and polymer film thickness can be simultaneously monitored. Then, the PSA/PLA blends were re-analysed. This analysis highlighted the synergistic information obtained by the combined AFM/SPR and revealed new data on the relationship between polymer phase separation and biodegradation kinetics. NB. This ethesis has been created by scanning the typescript original and may contain inaccuracies. In case of difficulty, please refer to the original text.

Thesis (Ph. D.)--Dept. of Pharmacology, University of Sydney, 1999. / Title from title screen. Interactive three dimensional molecular data and multiple colour images. Text presented in Hypertext Markup Language (.htm); images in standard formats (.jpg, .gif); molecules presented mostly as Cambridge Protein Data Bank format (.pdb); some molecules presented in alternative X. Mol cartesian co-ordinates format (.xyz); search facility in PERL script. Includes bibliographical references. A printed form was produced with limited features as a Faculty requirement; may also be issued in CD-ROM.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed July 22, 2008). PDF text: v, 167 p. : ill. (some col.) ; 5 Mb. UMI publication number: AAT 3291922. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008. / Committee Chair: C. David Sherrill; Committee Member: Jean-Luc Bredas; Committee Member: Mostafa El-Sayed; Committee Member: Peter J. Ludovice; Committee Member: Thomas Orlando.

Thesis (doctoral)--Technische Universiteit Delft, 1997. / Vita. Includes bibliographical references.

Thesis (doctoral)--Technische Universiteit Delft, 1997. / Vita. Includes bibliographical references.

Inaugural-Dissertation zur Erlangung der Doktorwürde einer hohen naturwissenschaftlich-mathematischen Fakultät der Ruprecht-Karls-Universität zu Heidelberg.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.