This project investigates the photochemistry of sulfoximines and sulfondiimines, which are capable of releasing two different reactive intermediates upon irradiation with light. The goal of this research is to establish general principles that govern the sequence of photorelease of reactive intermediates by sulfoximines and sulfondiimines. Sulfoximines are one of the few classes of compounds that are capable of undergoing dual-release photochemistry, and this project is expected to establish which properties regulate the sequence of release. By providing a basis to control the sequence of photorelease, this project is expected to facilitate the development of dual-release photochemistry for uses in biochemical assays and phototherapies.

The generation of two different reactive intermediates from a single chromophore is a rare occurrence in photochemistry. One of the few examples is the release of nitrenes and atomic oxygen from dibenzothiophene sulfoximines upon irradiation with light. The scarcity of systems capable of undergoing dual-release photochemistry means there is no conceptual framework to predict which properties will control the sequence of release. Thus, the overall objective of this project is to establish the general principles that govern dual-release photochemistry by investigating the photochemistry of thiophene-based sulfoximines. Specifically, the effect of modulating the bond dissociation energies and the excited state properties on the sequence of release will be interrogated with computational and spectroscopic methods. The second important objective of this proposal is to test the generality of the proposed framework by examining if the principles observed for sulfoximines can predict the sequence of release for sulfondiimines. The intriguing potential of dual-release photochemistry arises from the proximity that two reactive intermediates can be produced, which is expected to allow two transient intermediates to combine to form new intermediates that are inaccessible by any other means.

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