Generation and Solution Reactivity of Nitroxyl (HNO)

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With this renewal award, the Organic and Macromolecular Chemistry Program continues its support of the work of Professor John Toscano of the Chemistry Department at Johns Hopkins University. The research will extend the PI's studies of reactive intermediates to research involving the generation and solution reactivity of nitroxyl (HNO). The research will address two main goals: (1) to develop a variety of new photochemical and thermal precursors to HNO and (2) to use these precursors (as well as existing ones) to elucidate the fundamental solution-phase chemistry of HNO. Photochemical precursors to HNO that will be examined include HNO-diene Diels-Alder adducts, hydroxynitrene (HON) precursors, and photosensitive O-substituted sulfohydroxamic acid derivatives. The project will involve the use of nanosecond time-resolved infrared (TRIR) spectroscopy, as well as more standard experimental and computational tools. The direct detection of HNO by TRIR spectroscopy in both aqueous and organic solvents will be attempted. The reactivity of HNO with various species of both fundamental and biological interest will also be examined by TRIR spectroscopy.The biochemistry of the nitroxyl system has recently received significant attention, especially as a potential alternative to current treatments of cardiac failure. Although unique biological responses have been attributed to nitroxyl, very little is known about the fundamental solution chemistry of this deceptively simple system. The mechanistic information concerning nitroxyl, which impacts upon the physiology of many organisms, will be extremely valuable to the biomedical community. This research will afford broad training for students who will acquire a wide range of skills. Undergraduate participation in the proposed research will be emphasized with students from Johns Hopkins University and nearby Towson University involved.