published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 1981.

No description available.

The compounds reported here were prepared for the purpose of determining the effects of active groups on the pyridine ring, and to determine the effects of substituted methyl groups on the nucleus. These compounds are to be tested for tuberculostatic activity.

This study explores the synthesis and reduction of some n-phenacylpyridines and is an investigation of various derivatives.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains viii, 88 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 81-88).

No description available.

Research described herein seeks to study the reactivity of CpRu(P-P)H with pyridinium and azetidinium cations. For the former, we wish to determine if a previously established methodology for the regioselective reduction of a particular pyridinium cation may be extended to other pyridinium cations and if the methodology may be improved with the introduction of a pendant amine in the diphosphine. Our studies have shown that this methodology could not be extended to pyridinium cations having substituents on the pyridinium ring. For the latter, we seek to establish the reactivity of CpRu(P-P)H with azetidinium cations and compare these results to what the Norton Group has previously established in studies concerning aziridinium cations. Our studies have shown that opening of azetidinium is about six orders of magnitude slower compared to the opening of aziridinium.

Chloride, bromide, pyridinium and quinolinium homologues of 4-(N- hexadecylpyridinium-4-ylmethylidene-amino)-2,6-dichlorophenolate have been investigated in solution, Langmuir and Langmuir-Blodgett films. Techniques including spectroscopy, surface potential measurement, quartz crystal microbalance, surface plasmon resonance, atomic force microscopy, reectometry and X-ray diffraction have been used to characterise these molecular systems. In solution, solvatochroism was observed and Benisi-Hildebrand analysis revealed dimeric aggregation. Langmuir monolayers were compressed at the air/water interface and chromophore rotation was observed by surface potential measurement. Langmuir- Blodgett monolayers showed lm-thickness dependence on the deposition-pressure. Monolayer thicknesses between 6-24Ä were measured using SPR and molecular areas between 40-l25Ä2 were measured using a quartz crystal microbalance. Both the molecular/s/area)and monolayer thicknesses were deposition-pressure dependent. The high tilt phases were visually distinguishable from the low tilt phases using atomic force microscopy, The compounds showed phase behaviour that was predominantly alike for the bromide and chloride homologues but different for the pyridinium and quinolinum homologues. Multilayer Y-type films of the merocyanine dyes were analysed using reectometry and deposition-pressure dependent thicknesses were found. Alternate layer structures of NLO-active hemicyanine amphiphiles were used to achieve homogeneous. orientation ordering using active and inactive spacer layers. Ordering was achieved but the optical efficiency was reduced by high proportions of inactive material and interlayer dipole formation. Double chained hemicyanine molecules were used to form Z-type structures and subsequent layers were found to significantly interdigitate. Different chain lengths were found to interdigitate by the length of the shortest chain. Gas detection experiments were undertaken on the quinolinium, dichloro merocyanine using three optical geometries. The absorption method showed slow switching and poor sensitivity. The Kretschmann SPR geometry showed high sensitivity and rapid switching. The grating SPR geometry showed rapid switching but was less sensitive than the ATR method. Protonation of the monolayers was investigated using hydrochloric acid gas, acetic acid vapour and stearic acid immobilised within the lm.

In the first part of this thesis, the synthesis, characterization and investigation of ortho-phenyleneethynylenes containing heterocycles, are presented. These compounds display changes in absorption and emission spectra varying with their functionalization and size. These compounds also have the ability to coordinate with metals. The synthesis of coordination compounds and their crystallographic data are reported. The synthesis and characterization of tetraethynyl thiophene compounds containing pyridines are also presented. These compounds exhibit differences in absorption and emission spectra upon exposure to various metal salts. The final topic to be discussed is the synthesis and characterization of diphenyl amine polymers. These polymers could in principle be used in NLO applications or light emitting devices.