N-H Bond Dissociation Enthalpies and Facile H Atom Transfers for Early Intermediates of Fe-N₂ and Fe-CN Reductions.

ABSTRACT: Fe-mediated biological nitrogen fixation is thought to proceed via either a sequence of proton and electron transfer steps, concerted H atom transfer steps, or some combination thereof. Regardless of the specifics and whether the intimate mechanism for N₂-to-NH₃ conversion involves a distal pathway, an alternating pathway, or some hybrid of these limiting scenarios, Fe-N_xH_y intermediates are implicated that feature reactive N-H bonds. Thermodynamic knowledge of the N-H bond strengths of such species is scant, and is especially difficult to obtain for the most reactive early stage candidate intermediates (e.g., Fe-N═NH, Fe═N-NH₂, Fe-NH═NH). Such knowledge is essential to considering various mechanistic hypotheses for biological (and syn

SUBMITTER: Rittle J 

PROVIDER: S-EPMC5517100 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature