Mechanistic Insights into Catalytic H Oxidation by Ni Complexes Containing a Diphosphine Ligand with a Positioned Amine Base.
The mixed-ligand complex [Ni(dppp)(PN)](BF), 3, (where PN is 1,5-dibenzyl-3,7- diphenyl-1,5-diaza-3,7-diphosphacyclooctane and dppp is 1,3-bis(diphenylphosphino)propane) has been synthesized. Treatment of this complex with H and triethylamine results in the formation of the Ni complex, Ni(dppp)(PN),...
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 16; pp. 5935 - 5946 |
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| Autores principales: | , , , , , , |
| Formato: | Artículo |
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American Chemical Society
4/29/2009
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=39794836&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 39794836 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 4/29/2009 vid: 131 iid: 16 pid: 997 pub: American Chemical Society artinfo: ui: 39794836 10.1021/ja900483x ppf: 5935 ppct: 11 formats: tig: atl: Mechanistic Insights into Catalytic H Oxidation by Ni Complexes Containing a Diphosphine Ligand with a Positioned Amine Base. aug: au: Yang, Jenny Y. Bullock, R. Morris Shaw, Wendy J. Twamley, Brendan Fraze, Kendra DuBois, M. Rakowski DuBois, Daniel L. affil: Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 Department of Chemistry, University of Idaho, Moscow, ID 83844 Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309 su: Ligands (Chemistry) Amines X-ray research Optical diffraction Atoms sug: subj: Ligands (Chemistry) Amines X-ray research Optical diffraction Atoms ab: The mixed-ligand complex [Ni(dppp)(PN)](BF), 3, (where PN is 1,5-dibenzyl-3,7- diphenyl-1,5-diaza-3,7-diphosphacyclooctane and dppp is 1,3-bis(diphenylphosphino)propane) has been synthesized. Treatment of this complex with H and triethylamine results in the formation of the Ni complex, Ni(dppp)(PN), 4, whose structure has been determined by a single-crystal X-ray diffraction study. Heterolytic cleavage of H by 3 at room temperature forms [HNi(dppp)(PN(μ-H)N](BF), 5a, in which one proton interacts with two nitrogen atoms of the cyclic diphosphine ligand and a hydride ligand is bound to nickel. Two intermediates are observed for this reaction using low-temperature NMR spectroscopy. One species is a dihydride, [(H)Ni(dppp)(PN)](BF), 5b, and the other is [Ni(dppp)(PNH)](BF)2, 5c, in which both protons are bound to the N atoms in an endo geometry with respect to nickel. These two species interconvert via a rapid and reversible intramolecular proton exchange between nickel and the nitrogen atoms of the diphosphine ligand. Complex 3 is a catalyst for the electrochemical oxidation of H in the presence of base, and new insights into the mechanism derived from low-temperature NMR and thermodynamic studies are presented. A comparison of the rate and thermodynamics of H addition for this complex to related catalysts studied previously indicates that for Ni complexes containing two diphosphine ligands, the activation of H is favored by the presence of two positioned pendant bases. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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