Development of a hydrolysis-based small-molecule hydrogen selenide (H2Se) donor.

Selenium is essential to human physiology and has recently shown potential in the treatment of common pathophysiological conditions ranging from arsenic poisoning to cancer. Although the precise metabolic and chemical pathways of selenium incorporation into biomolecules remain somewhat unclear, many such pathways proceed through hydrogen selenide (H2Se/HSe-) formation. Despite this importance, well-characterized chemistry that enables H2Se release under controlled conditions remains lacking. Motivated by this need, we report here the development of a hydrolysis-based H2Se donor (TDN1042). Utilizing 31P and 77Se NMR experiments, we demonstrate the pH dependence of H2Se release and characterize observed reaction intermediates during the hydrolysis mechanism. Finally, we confirm H2Se release using electrophilic trapping reagents, which not only demonstrates the fidelity of this donor platform but also provides an efficient method for investigating future H2Se donor motifs. Taken together, this work provides an early example of an H2Se donor that functions through a well-defined and characterized mechanism.