No description available.

<p> The products and mechanism of the photolytic rearrangement of the equilibrium mixture of triphenylmethylcyclopentadienes have been studied. Direct irradiation of the equilibrium mixture of triphenylmethylcyclopentadienes yields 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene. Photolysis with a triplet sensitizer yields dimeric products in addition to 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene. Thermolytic isomerization of 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene is reported. The predominant isomer in the equilibrium mixture of triphenylmethylcyclopentadiene has been established as 2-triphenylmethylcyclopentadiene.</p> / Thesis / Master of Science (MSc)

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

Fluorescent labeling of biological materials using small organic dyes is widely employed in the life sciences and have been used in a variety of applications that include diagnostics and imaging. Quantum dots have the potential to overcome problems encountered by organic molecules and have been exploited for applications in biological imaging and in single particle tracking studies. The dithiolane ring can be exploited to attach a diversity of organic compounds to CdSe–ZnS core–shell nanoparticles. The introduction of spectroscopic labels as trans-azobenzene chromophores offers the opportunity to quantify the average number of dithiolane anchoring groups attached to each quantum dot. The transition from monomeric ligands with a single dithiolane anchor to polymeric ligands with multiple dithiolane anchoring groups can be exploited to raise the number of chromophoric labels adsorbed on each quantum dot. Systems showing FRET have been developed on the basis of supramolecular association of BODIPY based dyes or quantum dots as donors and organic chromophores as acceptors. Amino - terminated dyes and quantum dots associate with the chromophores through an ammonium moiety on addition of acid, thereby bringing them closer. Addition of base increases back the fluorescence intensity of the donor completely because of the dissociation. However a similar system with quantum dots as donor, show a very small restoration of fluorescence possibly due to non-specific interaction. In the next project, introduction of spectroscopic labels, in the form of BODIPY dye within the ligands offered the opportunity to quantify the average number of dithiolane anchoring groups attached to each quantum dot. Both fluorescence resonance energy transfer and electron transfer mechanisms are responsible for the quenching of quantum dot fluorescence and unfortunately does not make the system suitable for pH sensing. In the final project, BODIPY-oxazine based fluorophore – photochrome dyad has been assembled by a connecting triazole ring, such that the emission of the former can be modulated by the electronic and structural changes caused by the photoinduced transformations of the later. Further experiments need to be conducted on the fluorophore – photochrome dyads to switch the luminescence of the former with optical inputs.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Neal Zondlo, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

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Thesis (Ph. D.)--University of Hong Kong, 1988.

Thesis (Ph.D.)--McMaster University (Canada), 1993. / Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6168. Adviser: R. F. Childs.

Thesis (Ph. D.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.