Non-covalent interactions involving aromatic rings are responsible for a wide array of phenomena in chemistry and biology. An interesting, yet underexplored non-covalent interaction is the arene-perfluoroarene interaction. Aromatic and perfluoroaromatic compounds have opposite quadrupoles and this electrostatic complementarity results in their stacking interaction. Theoretical studies of arene-perfluoroarene interactions in the gas phase indicate high binding energies. Furthermore, these interactions have been utilized in solid-state chemistry, supramolecular chemistry, DNA/protein stabilization, and bioconjugation. Despite their ubiquitous applications and growing interests, the strengths of arene-perfluoroarene interactions in aqueous solution have not been studied theoretically or experimentally. Here, we designed a systematic and quantitative study of these interactions with both experimental data and computational modeling. Prior to the experimental work, we computationally studied the nature of arene-perfluoroarene interactions and built initial theoretical models. Then by synthesizing a small library of model compounds, we quantified these interactions in various media and further validated the trends in several physical organic phenomena such as the effects of fluorination, solvent, and ring size. Lastly, using this large set of experimentally determined data, we performed a thorough computational benchmark study to determine the most accurate and efficient DFT method for modeling arene-perfluoroarene interactions. From this comprehensive experimental and computational study, it was observed that fluorination, extension of the π systems, and enhancement of solvent polarity greatly stabilizes the stacking energy up to 16-fold and the highest Ka is achieve in H2O. By interplaying computation and experiment synergistically, we promote the fundamental understanding and reliable modeling, and thus, rational design of arene-perfluoroarene interactions in various biological applications.

Investigating arene-perfluoroarene interactions in solution using computation and experiment

ACS Fall 2020 Virtual Meeting

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