Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xvii, 217 p. : ill. Includes abstract. Includes bibliographical references.

Thesis (Ph.D.) - University of St Andrews, November 2008. / Restricted until 24th November 2009, during which time access is available with the consent of the Head of School.

Photochemical properties of sulphonated phthalocyanine complexes of aluminium, zinc, tin and silicon, and octa-carboxyphthalocyanine complexes of aluminium and zinc have been investigated. These water-soluble metallophthalocyanine (MPc) complexes, especially the sulphonated aluminium and zinc phthalocyanines, were found to be good photosensitisers for the transformation of the toxic mono-, tri- and penta-chlorophenols in aqueous solutions. The efficiency of MPc sensitiser towards photo-transformation of chlorophenols depends on its effectiveness to generate singlet oxygen as well as its photostability. Octa-substituted thiol-derivatised phthalocyanine complexes of cobalt, iron and zinc were synthesized and their spectral and electrochemical properties investigated. The photochemical properties ofthe zinc phthalocyanine complexes in non-aqueous solutions were comparable to those in literature. Ultrathin films of the octasubstituted thiol-derivatised phthalocyanine complexes of cobalt, iron and zinc were, for the first time, immobilized onto gold electrodes using the self-assembling technique. Surface electrochemistry indicates that the ultrathin films are surface-confined self-assembled monolayer (SAM) species. Gold electrodes modified with the redox-active SAMs of cobalt and iron phthalocyanine complexes proved to be potential electrochemical sensors for the detection of thiols (L-cysteine, homocysteine and penicillamine) and thiocyanate in aqueous solutions (pH 4). The limits of detection for the thiols and thiocyanate were in the range of ∼ 10⁻⁷ and 10⁻⁶ mol dm⁻³, respectively. The modification process was reproducible and the modified electrodes showed good stability and, if stored in pH 4 buffer solutions, could be used for the analysis of thiols and thiocyanate for about a month without the need for recalibration. Etching of gold marred electrochemical detection of cyanide with the MPc-SAM-modified gold electrodes. Interestingly, however, kinetic and equilibria studies revealed strong interaction of octabutylthiophthalocyaninatoiron (II), FeOBTPc, with cyanide in both DMF and DMSO solutions.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1981 / Includes bibliographical references. / by Ze'ev Shaked. / Ph. D. / Ph.D. Massachusetts Institute of Technology, Department of Chemistry

Isotopic and spectrophotometric assays show that micromolar concentrations of heavy metal ions (particularly Ag⁺ and Hg²⁺) stimulate ATPase activity but inhibit Ca²⁺ uptake in isolated SR vesicles. Both effects are caused by increased Ca²⁺ permeability of the membrane, apparently the result of activation of the Ca²⁺ release system of the vesicles due to heavy metal binding to a critical sulfhydryl group associated with the Ca²⁺ release channels. CU²⁺catalyzed co-oxidation of this sulfhydryl with exogenous cysteine to form a mixed disulfide also results in activation of the Ca²⁺ release system. The rate and extent of Cu²⁺/cysteine-induced release is maximal at physiological pH and is inhibited by local anaesthetics and Mg²⁺, suggesting that the redox state of this sulfhydryl may play a role in activation of the Ca²⁺ release system of intact muscle. Modification of the SR with the proteolytic enzyme trypsin also increases the Ca²⁺ permeability of the SR, and enhances the rate of Ca²⁺ release activated by cAMP, doxorubicin, Hg²⁺, and Cu²⁺/cysteine. The rates of release activated by all reagents are stimulated by a factor of five after five minutes exposure to trypsin. Hg²⁺- and Cu²⁺/cysteine-activated release are not stimulated further, while cAMP- and doxorubicin-activated release continue to increase up to maximum of 20-fold stimulation after 15 minutes exposure to trypsin. Inhibitors of the Ca²⁺ release system such as Mg²⁺ and ruthenium red still inhibit release from proteolytically modified SR, and the binding affinities of activators and inhibitors to their sites are not significantly altered by proteolysis; only the rates of Ca²⁺ transport are affected. The most probable mechanisms of tryptic stimulation of Ca²⁺ release are (1) removal of a regulatory protein or subunit of the Ca²⁺ release system, making more channels available for transport; (2) increasing the single channel unitary conductance; (3) increasing the open time of activated channels. The biphasic character of proteolytic stimulation of cAMP- and doxorubicin-activated release (as opposed to monophasic stimulation of Hg²⁺- and Cu²⁺/cysteine-activated release} suggests that more than one of the above parameters are involved in tryptic stimulation of the Ca²⁺ release system.

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The g-proteobacterium Shewanella oneidensis MR-1 reduces a wide range of terminal electron acceptors, including solid Fe(III) oxides. Pathways for Fe(III) oxide reduction by S. oneidensis include non-reductive (organic ligand-promoted) solubilization reactions, and either direct enzymatic, or indirect electron shuttling pathways. Results of the present study expand the spectrum of electron acceptors reduced by S. oneidensis to include the naturally occurring disulfide compounds cystine, oxidized glutathione, dithiodiglycolate, dithoidiproponiate and cystamine. Subsequent electron shuttling experiments demonstrated that S. oneidensis employs the reduced (thiol) form of the disulfide compounds (cysteine, reduced glutathione, mercaptoacetate, mercaptopropionate, and 2-nitro-5-thiobenzoate, cystamine) as electron shuttles to transfer electrons to extracellular Fe(III) oxides. The results of the present study indicate that microbial disulfide reduction may represent an important electron-shuttling pathway for electron transfer to Fe(III) oxides in anaerobic marine and freshwater environments.