A Synthetic Approach to the Optimization of Silicon-Rosindolizine SWIR Fluorophores

Author

• Timothy Lewis, University of MississippiFollow

Date of Award

Spring 5-14-2023

Document Type

Undergraduate Thesis

Department

Chemistry and Biochemistry

First Advisor

Jared H. Delcamp

Second Advisor

Nathan I. Hammer

Third Advisor

Daniell A. Mattern

Relational Format

Dissertation/Thesis

Abstract

Fluorophores emitting within the near-infrared (700 – 1000 nm) or shortwave-infrared (1000 – 1700 nm) regions of the electromagnetic spectrum are of particular interest for their potential to supplement or even outright replace commonly used biological imaging techniques, such as magnetic resonance imaging and computed tomography scanning. Various characteristics make these molecules particularly appealing to researchers, such as their ease of synthetic tunability, generally low toxicity, and high solubility in biological media in comparison to other NIR- and SWIR-emissive fluorophores. Different molecular skeletons have been examined for use as the core of these imaging agents, such as squaraine, cyanine, and xanthene-based systems. In this work, a modified silicon-xanthene core was substituted with different indolizine donors and silicon-alkyl groups in order to determine their effect on relevant photophysical properties and fluorophore stability for use as in vivo biological imaging agents. Properties of the fluorophores including absorption and emission wavelength, magnitude of Stokes shift, fluorescence quantum yield, and molecular brightness were all studied herein. The results demonstrate that each dye was emissive well within the NIR-IIb (1300 – 1700 nm) window and showed appreciable molecular brightness for SWIR fluorophores. The 2-ethylhexyl silicon substituent and xylyl-based core were both observed to increase the stability of the fluorophores to aqueous decomposition relative to the other dye derivatives examined.

Recommended Citation

Lewis, Timothy, "A Synthetic Approach to the Optimization of Silicon-Rosindolizine SWIR Fluorophores" (2023). Honors Theses. 2913.
https://egrove.olemiss.edu/hon_thesis/2913

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