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dc.contributor.authorSoláns, Xavier Luis
dc.contributor.authorChow, Catherine
dc.contributor.authorGouré, Eric
dc.contributor.authorKaya, Yasemin
dc.contributor.authorBasset, Jean-Marie
dc.contributor.authorTaoufik, Mostafa
dc.contributor.authorQuadrelli, Elsje Alessandra
dc.contributor.authorEisenstein, Odile
dc.date.accessioned2015-08-03T09:57:37Z
dc.date.available2015-08-03T09:57:37Z
dc.date.issued2012-06-19
dc.identifier.issn00201669
dc.identifier.pmid22712747
dc.identifier.doi10.1021/ic300498b
dc.identifier.urihttp://hdl.handle.net/10754/562239
dc.description.abstractDFT(B3PW91) calculations have been carried out to propose a pathway for the N2 cleavage by H2 in the presence of silica-supported tantalum hydride complexes [(≡ SiO)2TaHx] that forms [(≡SiO)2Ta(NH)(NH2)] (Science2007, 317, 1056). The calculations, performed on the cluster models {μ-O[(HO)2SiO] 2}TaH1 and {μ-O[(HO)2SiO] 2}TaH3, labelled as (≡SiO)2TaH x (x = 1, 3), show that the direct hydride transfers to coordinated N-based ligands in (≡SiO)2TaH(η2-N2) and (≡SiO)2TaH(η2-HNNH) have high energy barrier barriers. These high energy barriers are due in part to a lack of energetically accessible empty orbitals in the negatively charged N-based ligands. It is shown that a succession of proton transfers and reduction steps (hydride transfer or 2 electron reduction by way of dihydride reductive coupling) to the nitrogen-based ligands leads to more energetically accessible pathways. These proton transfers, which occur by way of heterolytic activation of H2, increase the electrophilicity of the resulting ligand (diazenido, N 2H-, and hydrazido, NHNH2-, respectively) that can thus accept a hydride with a moderate energy barrier. In the case of (≡SiO)2TaH(η2-HNNH), the H 2 molecule that is adding across the Ta-N bond is released after the hydride transfer step by heterolytic elimination from (≡SiO) 2TaH(NH2)2, suggesting that dihydrogen has a key role in assisting the final steps of the reaction without itself being consumed in the process. This partly accounts for the experimental observation that the addition of H2 is needed to convert an intermediate, identified as a diazenido complex [(≡SiO)2TaH(η 2-HNNH)] from its ν(N-H) stretching frequency of 3400 cm -1, to the final product. Throughout the proposed mechanism, the tantalum remains in its preferred high oxidation state and avoids redox-type reactions, which are more energetically demanding. © 2012 American Chemical Society.
dc.publisherAmerican Chemical Society (ACS)
dc.titleSuccessive heterolytic cleavages of H2 achieve N2 splitting on silica-supported tantalum hydrides: A DFT proposed mechanism
dc.typeArticle
dc.contributor.departmentChemical Science Program
dc.contributor.departmentKAUST Catalysis Center (KCC)
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalInorganic Chemistry
dc.contributor.institutionDepartament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
dc.contributor.institutionUniversité de Lyon, Institut de Chimie de Lyon, C2P2 (CNRS, CPE Lyon, Université Lyon 1), Ecole Supérieure de Chimie Physique Electronique de Lyon, 43 Boulevard du 11 Novembre 1918, F-69616 Villeurbanne Cedex, France
dc.contributor.institutionInstitut Charles Gerhardt, UMR 5253 CNRS, Université Montpellier 2, cc 1501, Place E. Bataillon, F-34095 Montpellier, France
dc.contributor.institutionDepartment of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, V6T 1Z1, Canada
dc.contributor.institutionLeiden Institute of Chemistry, Universiteit Leiden, P.O. Box 9502, 2300 RA Leiden, Netherlands
kaust.personBasset, Jean-Marie
dc.date.published-online2012-06-19
dc.date.published-print2012-07-02


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