Propane σ-Complexes on PdO(101): Spectroscopic Evidence of the Selective Coordination and Activation of Primary C-H Bonds.

Autor: Zhang F; Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 36211 (USA)., Pan L; William G. Lowrie Department of Chemical & Biomolecular Engineering, The Ohio State University, Columbus, OH 43210 (USA)., Choi J; Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 36211 (USA)., Mehar V; Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 36211 (USA)., Diulus JT; Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 36211 (USA)., Asthagiri A; William G. Lowrie Department of Chemical & Biomolecular Engineering, The Ohio State University, Columbus, OH 43210 (USA)., Weaver JF; Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 36211 (USA). weaver@che.ufl.edu.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2015 Nov 16; Vol. 54 (47), pp. 13907-11. Date of Electronic Publication: 2015 Sep 30.
DOI: 10.1002/anie.201505237
Abstrakt: Achieving selective C-H bond cleavage is critical for developing catalytic processes that transform small alkanes to value-added products. The present study clarifies the molecular-level origin for an exceptionally strong preference for propane to dissociate on the crystalline PdO(101) surface via primary C-H bond cleavage. Using reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations, we show that adsorbed propane σ-complexes preferentially adopt geometries on PdO(101) in which only primary C-H bonds datively interact with the surface Pd atoms at low propane coverages and are thus activated under typical catalytic reaction conditions. We show that a propane molecule achieves maximum stability on PdO(101) by adopting a bidentate geometry in which a H-Pd dative bond forms at each CH3 group. These results demonstrate that structural registry between the molecule and surface can strongly influence the selectivity of a metal oxide surface in activating alkane C-H bonds.
(© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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