Bimetallic Cooperative Cleavage of Dinitrogen to Nitride and Tandem Frustrated Lewis Pair Hydrogenation to Ammonia

Although reductive cleavage of dinitrogen (N2) to nitride (N3−) and hydrogenation with dihydrogen (H2) to yield ammonia (NH3) is accomplished in heterogeneous Haber–Bosch industrial processes on a vast scale, sequentially coupling these elementary reactions together with a single metal complex remains a major challenge for homogeneous molecular complexes. Herein, we report that the reaction of a chloro titanium triamidoamine complex with magnesium effects complete reductive cleavage of N2 to give a dinitride dititanium dimagnesium ditriamidoamine complex. Tandem H2 splitting by a phosphine–borane frustrated Lewis pair (FLP) shuttles H atoms to the N3−, evolving NH3. Isotope labelling experiments confirmed N2 and H2 fixation. Though not yet catalytic, these results give unprecedented insight into coupling N2 and H2 cleavage and N−H bond formation steps together, highlight the importance of heterobimetallic cooperativity in N2 activation, and establish FLPs in NH3 synthesis. Die Reaktion eines Chlortitantriamidoamin‐Komplexes mit Magnesium ermöglicht die vollständige reduktive Spaltung von N2 und ergibt einen Dinitrid‐Dititan/Dimagnesium‐Komplex (siehe Schema, Mitte). Durch eine gekoppelte H2‐Spaltung mit einem Phosphin/Boran‐basierten frustrierten Lewis‐Paar werden H‐Atome auf das N3−‐Ion übertragen und NH3 wird freigesetzt.