Conversion of Dinitrogen to Acetonitrile at Ambient Conditions

Abstract

About 20% of the ammonia production provides the chemical feedstock for nitrogen containing chemicals. However, while synthetic nitrogen fixation at ambient conditions faced some groundbreaking contributions in recent years, progress for the direct conversion of N2 to organic products remains limited and catalytic reactions are unknown. Here, the rhenium mediated synthesis of acetonitrile using dinitrogen and ethyl triflate as reagents 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.