Since thiophene very often yields compounds that are analogous to benzene derivatives in general physiological properties, it was decided to attempt to prepare the nitro and amino derivatives of 1,1,1-trichloro-2,2-bis-(2-thienyl)-ethane (V) as well as the nitro and amino derivatives of 2,2,3-trichloro-1,1-bis-(2-thienyl)-butane (VI).

Abstract Two novel conjugated polymers (PTP-SiO) and (PTP-P-SiO) with alternating N-containing heterocycles and siloxane (-Si-O-) units were synthesized using the Heck reaction. The incorporation of siloxane units in the polymers improves their thermal stability and processability. The polymers can be dissolved in organic solvent and exhibited good thermal stability with 5¢H weight loss temperature above 370¢J under nitrogen atmosphere. The photoluminescence (PL) spectra of PTP-SiO and PTP-P-SiO in solution show maximum peaks at 491 and 520 nm respectively. The heterocycles in the two polymers contain N- atoms, which can coordinate with transition or lanthanides metal ions to form complexes. The absorption spectra show peaks at around 275~290 nm and 320~330 nm, which are attributed to £k-£k* and n-£k* transitions, respectively. On the other hand, the emission spectra consist of peaks at around 408~420 nm and 491~520 nm. These two emission peaks belong to £k-£k* and n-£k* transitions of the ligands, respectively. With pyridazine ( heterocycle with ¡VN=N- group) ring, PTP-P-SiO shows more significant variation upon coordination with metals ions as compared to PTP-SiO. These variations of optical property offer a possibility for application in chemosensors for detection of metal ions.

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Graduate

In view of the increasing importance of thiophene derivatives as chemotherapeutic agents, it was considered of interest to apply the Reformatsky reaction to the synthesis of compounds containing the thiophene nucleus with the thought that these might serve as intermediates for further syntheses.

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bstract Cancer has been the first lethal factor in Taiwan, and hepatitis B is also a serious problem in our country. We have identified that the extracts of Taiwanese Schisandraceous plants, including Schizandra arisanensis, Kadsura matsudai and K. japonica, have inhibitory effect on type B hepatitis surface antigen (HBsAg) and e-antigen (HBeAg). Besides, we also find that the extracts of Echinops grijsii can inhibit the growth of human cancer cell line, KB and Hela. To purify active compounds by using column chromatography and high-performance liquid chromatography, we have furnished fifty-eight compounds from above Schisandraceous plants, including thirty-seven C18 lignans composed of [6.8.6]-dibenzocyclooctadiene skeleton, nine C19 homolignans, four triterpenes, three steroids and five cyclic-aromatic compounds. In the case of Echinops grijsii, we got thirteen major compounds containing eight thiophenes, four triterpenes, and a sterol. Structural elucidation of the novel homolignan and ten lignans are based on the spectral and chemical analyses, mainly by using two-dimensional nuclear magnetic resonance (NMR) of 1H and 13C nucleus. From the anti-HBsAg and anti-HBeAg assay, we found that four of new C18 lignans and one known (+)-gomisin K3 (33) lignan exhibited the significant inhibitory effects on surface antigen of hepatitis B virus. Moreover, to modify the known lignans, kadsurarin with different halogens and functional group having nitrogen atom, as well as (+)-gomisin K3 with several kinds of phenyl compounds and sulfur functional groups are processed. The preliminary structures and bioactivity relationships (SAR) studies demonstrated that (+)-gomisin K3 with sulfuric functional group could decrease cytotoxicity and increase inhibitory effect on surface antigen and e-antigen of hepatitis B virus. In the part of studying synthesis by using inactive 5¡¦-(but-3-en-1-ynyl)-2,2¡¦ -bithiophene (1) from Echinops grijsii, the yne-ene moiety of its structure was hydrolyzed into carbonyl group and then was attached a serious of various carbon number of hydroxy groups. Besides the above experiment, £\-trithienyl (1) was served as a substrate and made it into unsaturated carbonyl group, which then was linked with a series of hydroxy groups. Cytotoxicity datum showed that the derivatives of bi-thiophene have better anticancer activity than derivatives of tri-thiophene. And the assay results also exhibited that the bi-thiophene derivatives with hydroxy group with less than three carbon numbers have better inhibitory activity against cancer cells.

In block-selective solvent, the rod-coil block copolymers can form various micellar structures. With block copolymers that contain a conjugated polymer block, the conformation of the conjugated polymer can be reflected by spectral changes in the solution. Therefore, it is of interest to study the relationship between the spectral changes and the nature of the conjugated polymer. The fundamental physical properties of poly(3-hexyl thiophene) (P3HT) were studied. Five P3HT samples with different molecular weights were used. We have determined the relationship between physical and spectral properties of this polymer and its molecular weight. In particular, we have found that the refractive index increments, the maximum absorbance wavelength, extinction coefficients, and the emission wavelengths, increase with molecular weight. Diblock copolymers of poly(3-hexyl thiophene)-block-poly(2-hydroxyethyl methacrylate) (P3HT-b-PHEMA) were also studied. The morphological and spectral changes of these block copolymers were studied at various stages of micelle formation in block selective solvents. The relationship between the volume fraction of the P3HT block and their physical and spectral properties were also discussed. / Thesis (Master, Chemistry) -- Queen's University, 2010-03-31 11:30:44.539