2025/01/29 by Samuel Thompson, Stuart Burnett, Rochelle Ferns +5 · 1 voice · 1 citation
Chemical Engineering · Chemistry · Materials Science · #Carbon dioxide utilization in catalysis #Hydrogen Storage and Materials #Organoboron and organosilicon chemistry
paper · pdf · doi:10.1021/jacs.4c16041
openalex publication_date 2025/01/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/15
High Resolution Image Download MS PowerPoint Slide New approaches to achieve facile and reversible dihydrogen activation are of importance for synthesis, catalysis, and hydrogen storage. Here we show that low-coordinate magnesium oxide complexes [( RDip nacnac)Mg 2 (μ-O)] 1, with RDip nacnac = HC(RCNDip) 2, Dip = 2,6- i Pr 2 C 6 H 3, R = Me ( 1a ), Et ( 1b ), i Pr ( 1c ), readily react with dihydrogen under mild conditions to afford mixed hydride-hydroxide complexes [( RDip nacnac)Mg 2 (μ-H)(μ-OH)] 4 . Dehydrogenation of complexes 4 is strongly dependent on remote ligand substitution and can be achieved by simple vacuum-degassing of 4c (R = i Pr) to regain 1c . Donor addition to complexes 4 also releases hydrogen and affords donor adducts of magnesium oxide complexes. Computational studies suggest that the hydrogen activation mechanism involves nucleophilic attack of an oxide lone pair at a weakly bound H 2 ···Mg complex in an S N 2-like manner that induces a heterolytic dihydrogen cleavage to yield an MgOH and an MgH unit. Alternative synthetic routes into complex 4b from a magnesium hydride complex have been investigated and the ability of complexes 1 or 4 to act as catalysts for the hydrogenation of 1,1-diphenylethene (DPE) has been tested.