Discovering Compatible Environments for Dye Molecules: From the Spectroscopic Evaluation of Ionic Aggregates to the Enhancement of Singlet Oxygen

Date
2014-04-30
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Abstract
The specific light absorbing capabilities of molecules has been taken advantage of numerous times in scientific literature, as interesting photophysical and photochemical phenomena can be easily recognized and characterized through optical spectroscopy. Consequently, small light absorbing molecules have shown to be valuable tools in the field of self-organization and aggregation as often these processes results in specific spectral signatures of these molecules. Cyanine dyes have been used predominantly in this regard as their photophysical properties are heavily influenced based on their environmental surroundings. This basic principle is the foundation for this work, where small cationic cyanine dyes are utilized to understand what drives the organization of molecules into aggregate structures. Herein, we present evidence that aggregation of multiple cyanine dyes can be encouraged by the addition of both simple and complex electrolytes, a phenomenon not fully investigated in the literature thus far. Specifically, the aggregation of cationic cyanine dyes seems to be a direct reflection of the molecular structure of the dye itself in addition to its ability to form a contact ion pair with a counter ion. The formation of a contact ion pair is pivotal in the aggregation process, and is a result of similarity between both the dye and the counter ion water affinity. Additionally, our work aimed at pushing the limits of soluble aggregates to form organic nanoparticles, which were found to maintain the redox ability of their ionic counterparts. From here we crossed into the field of metallic nanoparticles and where the light absorbing properties and subsequent photochemistry of a dye, Rose Bengal, was altered by covalently linking it to a core-shell nanoparticle. These experiments lead to the proof-of-principle that the singlet oxygen production of Rose Bengal could be enhanced in aqueous solution when in close proximity to a metal nanoparticle.
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Keywords
Chemistry--Physical
Citation
Mooi, S. M. (2014). Discovering Compatible Environments for Dye Molecules: From the Spectroscopic Evaluation of Ionic Aggregates to the Enhancement of Singlet Oxygen (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25717