Session: Undergraduate Research Posters: Computational Chemistry:

Different mirror images of chiral compounds can produce different pharmacological effects in biological systems. Enantiomers may have immensely different biological effects including toxicity. Because of this, it is important to detect and control the chiral purity of pharmaceutical compounds. Current chiral sensing methods involve chromatographic techniques that require expensive instrumentation. Chiral supramolecular sensors are a cheaper alternative but most often lack the sensitivity that is required. The Stephenson Organic Research Group at Loyola University is currently working to develop a novel, easy-to-use, chiral sensor capable of reducing screening time and cost by synthesizing, resolving, and testing asymmetric xanthene derivatives. Their primary goal is to form a series of highly sensitive xanthene-based sensors that will function as a platform for chiral sensors. Due to the high quantum yield of xanthene dyes such as rhodamine and fluorescein, these xanthene-based sensors are expected to have a greater sensitivity and higher fluorescent output than is observed for molecular sensors that currently exist. The Computational Chemistry Group at Mississippi College was approached to collaborate on this research to help focus the experimental studies. Computational methods are used to determine how different analytes affect the stability of the zwitterion/analyte complex. Through these computational methods it is hoped that the method of stabilization and systematic reason for variations in stability can be determined. Relative energies are computed for all pertinent diastereomeric complexes using density functional theory (DFT). The functionals employed are B3LYP, M06-2X, and ωB97XD. The basis sets employed are Dunning and coworkers’ correlation consistent basis sets: cc-pVDZ and cc-pVTZ.

Clifton Stephenson

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