Identifier

etd-06172013-105703

Degree

Doctor of Philosophy (PhD)

Department

Chemistry

Document Type

Dissertation

Abstract

Materials incorporating fluorescent π-electron conjugated molecular species for sensing and imaging are advantageous over other detection or identification methods such as colorimetric reporters. Fluorescent materials offer easy recognition of binding events due to the highly sensitive nature of fluorescence techniques down to the single molecule level. The properties of fluorescent molecules allow for rapid attenuation of observable readout due to the facile transport of excited state energy via both inter- and intramolecular pathways. This dissertation primarily focused on the development and study of a general platform for ratiometric fluorescent chemosensing using surface-immobilized oligomers, as well as in depth explorations of the unique properties of the chemosensors utilizing this platform. It encompasses bichromophoric fluorescent energy transfer cassettes consisting of a mono-disperse conjugated oligomer and a red-shifted energy transfer acceptor that is specifically reactive on the presence of a chosen analyte. Molecular organization of these cassettes into a surface- immobilized monolayer lends excellent and advantageous properties to the devices for sensing purposes primarily due to enhanced efficiency of intermolecular energy transfer within the monolayer. Several intriguing properties of this class of sensing devices are described, as well as how these properties, such as the effect of exciton delocalization and spatial control of energy transfer efficiency can be harnessed to generate practical chemosensing films that undergo significant emission wavelength (color) shift upon analyte exposure. The fundamental properties of this strategy toward ratiometric fluorescent chemosensing are described as applied to the measurements of acidity (pH) and fluoride ion concentration as practical examples. A smaller project that is part of this dissertation involves the synthesis of a semi- napthofluorescein fluorescent dye with a reactive handle for bioconjugation. This new dye exhibits an unusually large Stokes shift due to its broad absorption spectrum, and also shows highly bathochromically-shifted emission. The properties of this dye compound were studied and fully characterized and included as a chapter of this dissertation.

Date

2013

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Nesterov, Evgueni

DOI

10.31390/gradschool_dissertations.228

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