Thesis (Ph. D.)--University of Adelaide, 1985. / Includes bibliographical references (leaves 262-284).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

by So Wan-hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1980. / Bibliography: leaves 82-85.

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Bibliography: leaves 262-284 / v, 284 leaves : ill ; 31 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, 1985

Thesis (PH. D.)--University of Nebraska, 1940. / eContent provider-neutral record in process. Description based on print version record. "Literature cited": p. 18-19, 35.

Thesis (PH. D.)--University of Nebraska, 1940. / eContent provider-neutral record in process. Description based on print version record. "Literature cited": p. 18-19, 35.

The main aim of this project was to develop new reagents capable of exchanging selenium for oxygen under mild conditions, to obtain new carboselenaldehyde (1) and selone (2) compounds. Phenylphosphonoselenoic dichloride (3) was prepared as a solution in xylene. It was reacted with (1,2-dithiol-3-ylidene)carbaldehydes and indolizine-3-carbaldehydes to afford 1,6aλ4-dithia-6-selena-pentalenes (5) and indolizine-3-carboselenaldehydes (6), respectively. The indolizine-3-carbaldehydes had previously been prepared from the corresponding indolizines, in turn prepared from the appropriate pyridinium bromide salts. CHSe(5)(6)Phenylphosphonoselenoic dichloride (3) was also reacted with several other carbonyl compounds. Reactions with N,N.-dimethyl- fonnamide, 5-phenyl-3H-1,2-dithiol-3-one, 2,6-dimethyl-4H.-pyran-4-one, 4-hydroxypyridine, 1-methylpyrrolidin-2-one, hexeihydro-2H-azepin-2-one, and 2,4,6-cycloheptatrien-1-one met with varied success, and only N,N-dimethylselenoformamide (7), 5-phenyl-3H-1,2-dithiole-3-selone (8), and 2,6-dimethy1-4H-pyraxi-4-selone (9) were obtained.(8)(9)The presence of a stabilising substituent was therefore required, and was introduced as a tungsten pentacarboiyl species. Pentacarbon-yl(indolizine-3-carboselenaldehyde-Se) tungsten(0) (10) and penta-carbonyl(2,4,6-cycloheptatriene-1-selone-Se)tungsten(0) (11) were obtained from the reaction of the corresponding oarboryl compounds with phenylphosphonoselenoic dichloride (3) in the presence of tetra- ethylanunonium iodopentacarbonyltungstate(0).The reagent (4) was prepared from the reaction of chlorodlphenyl- phosphine and tetramethylammonium selenocyanate, and was reacted in situ with indolizine-3-carbaldehydes to produce not only indolizine-3-carboselenaldehydes (6), but also compounds which were proposed on the strength of spectral and analytical evidence as being members of the novel 3-(indolizin-3-yl)-2,5-dihydro-2-selenoformyl-1,2,4-selena- diazole-5-selone (12) system.

Selenonium cations are electron deficient species in which the central selenium atom is bonded to three carbon chains (aryl or alkyl). Trimethylselenonium iodide was synthesized by reaction of methyllithium with metallic selenium to produce methylselenolithium which was, in turn, reacted with the appropriate alkylbromide. The selenide thus formed was further methylated at the selenium atom with methyl iodide in methanol in the presence of sodium tetraphenylborate. After several recrystallizations the selenonium analytes were characterized by AAS, FT-IR, $ sp1$H-NMR, $ sp{13}$C-NMR, FAB-MS and LAMMA spectroscopic techniques and used as standards for analytical methods development. / The analysis was performed by high performance liquid chromatography with atomic absorption detection. The chromatography on a cynopropyl silica bonded phase was optimized for mobile phase composition by response surface analysis. The resulting surface response plots permitted a differentiation between the mechanisms of action of two mobile phase modifiers: triethylamine and trimethylsulfonium iodide. The improvement in chromatographic efficiency resulted in two to three fold decrease in the limit of detection. An extraction procedure with liquefied phenol was evaluated for the determination, by HPLC-AAS, of traces of selenonium cations in biological samples. The advantages and shortcomings of the HPLC-THG-AAS approach are discussed.

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