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Dinitrogen Dissociation on an Isolated Surface Tantalum Atom

2007; American Association for the Advancement of Science; Volume: 317; Issue: 5841 Linguagem: Inglês

10.1126/science.1143078

1095-9203

Priscilla Avenier, Mostafa Taoufik, Anne Lesage, Xavier Solans‐Monfort, Anne Baudouin, Aimery de Mallmann, Laurent Veyre, Jean‐Marie Basset, Odile Eisenstein, Lyndon Emsley, Elsje Alessandra Quadrelli,

Catalytic Processes in Materials Science

Both industrial and biochemical ammonia syntheses are thought to rely on the cooperation of multiple metals in breaking the strong triple bond of dinitrogen. Such multimetallic cooperation for dinitrogen cleavage is also the general rule for dinitrogen reductive cleavage with molecular systems and surfaces. We have observed cleavage of dinitrogen at 250 degrees C and atmospheric pressure by dihydrogen on isolated silica surface-supported tantalum(III) and tantalum(V) hydride centers [(identical with Si-O)2Ta(III)-H] and [(identical with Si-O)2Ta(V)H3], leading to the Ta(V) amido imido product [(identical with SiO)2Ta(=NH)(NH2)]: We assigned the product structure based on extensive characterization by infrared and solid-state nuclear magnetic resonance spectroscopy, isotopic labeling studies, and supporting data from x-ray absorption and theoretical simulations. Reaction intermediates revealed by in situ monitoring of the reaction with infrared spectroscopy support a mechanism highly distinct from those previously observed in enzymatic, organometallic, and heterogeneous N2 activating systems.