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

Although reductive cleavage of dinitrogen (N 2 ) to nitride (N 3− ) and hydrogenation with dihydrogen (H 2 ) to yield ammonia (NH 3 ) 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 N 2 to give a dinitride dititanium dimagnesium ditriamidoamine complex. Tandem H 2 splitting by a phosphine–borane frustrated Lewis pair (FLP) shuttles H atoms to the N 3− , evolving NH 3 . Isotope labelling experiments confirmed N 2 and H 2 fixation. Though not yet catalytic, these results give unprecedented insight into coupling N 2 and H 2 cleavage and N−H bond formation steps together, highlight the importance of heterobimetallic cooperativity in N 2 activation, and establish FLPs in NH 3 synthesis.