Abstract
About 20 % of the ammonia production is used as the chemical feedstock for nitrogen-containing chemicals. However, while synthetic nitrogen fixation at ambient conditions has had some groundbreaking contributions in recent years, progress for the direct conversion of N2 into organic products remains limited and catalytic reactions are unknown. Herein, the rhenium-mediated synthesis of acetonitrile using dinitrogen and ethyl triflate is presented. A synthetic cycle in three reaction steps with high individual isolated yields and recovery of the rhenium pincer starting complex is shown. The cycle comprises alkylation of a nitride that arises from N2 splitting and subsequent imido ligand centered oxidation to nitrile via a 1-azavinylidene (ketimido) intermediate. Different synthetic strategies for intra- and intermolecular imido ligand oxidation and associated metal reduction were evaluated that rely on simple proton, electron, and hydrogen-atom transfer steps.
If it’s broke, fix it: In contrast to synthetic NH3 synthesis, the catalytic conversion of N2 with concomitant C−N bond formation into organic products remains unknown and stoichiometric examples are scarce. Several routes for the rhenium mediated synthesis of acetonitrile at ambient conditions via N2 splitting and alkylation are now possible, leading up to a full synthetic cycle in three steps with more than 50 % overall yield.
Tomson Group Literature 