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Bimetallic Cooperative Cleavage of Dinitrogen to Nitride and Tandem Frustrated Lewis Pair Hydrogenation to Ammonia
Author(s) -
Doyle Laurence R.,
Wooles Ashley J.,
Liddle Stephen T.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201902195
Subject(s) - frustrated lewis pair , chemistry , ammonia borane , phosphine , catalysis , bimetallic strip , cleavage (geology) , bond cleavage , boranes , isotopic labeling , lewis acids and bases , medicinal chemistry , crystallography , photochemistry , organic chemistry , dehydrogenation , boron , materials science , fracture (geology) , composite material
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.