Propane σ‐Complexes on PdO(101): Spectroscopic Evidence of the Selective Coordination and Activation of Primary CH Bonds. (30th September 2015)

• Record Type: Journal Article
• Authors: Zhang, Feng; Pan, Li; Choi, Juhee; Mehar, Vikram; Diulus, John T.; Asthagiri, Aravind; Weaver, Jason F.
• Is Part Of: Angewandte Chemie. Volume 127:Number 47(2015)
• Page Start: 14113
• Page End: 14117
• Publication Date: 2015-09-30
• Subjects: Alkane -- C‐H‐Aktivierung -- Heterogene Katalyse -- Palladium -- Palladiumoxid; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201505237
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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. Abstract : Die strukturelle Evolution von Propan‐σ‐Komplexen auf PdO(101) wurde mit Reflexions‐Absorptions‐IR‐Spektroskopie und DFT‐Rechnungen untersucht. Günstige dative Bindungen mit den Oberflächen‐Palladiumatomen verursachen eine außergewöhnlich hohe Selektivität für die Aktivierung primärer C‐H‐Bindungen.