Accessing Frustrated Lewis Pair Chemistry through Robust Gold@N-Doped Carbon for Selective Hydrogenation of Alkynes

Heterolytic bond activation at gold: evidence for gold(iii) H-B, H-Si complexes, H-H and H-C cleavage

Gold(iii) forms spectroscopically detectable H–B and H–Si σ-complexes; experiments and DFT calculations demonstrate heterolytic H–Si, H–H and H–C bond cleavage.

The coordinatively unsaturated gold(iii) chelate complex [(C^N–CH)Au(C₆F₅)]⁺ (1⁺) reacts with main group hydrides H–BPin and H–SiEt₃ in dichloromethane solution at –70 °C to form the corresponding σ-complexes, which were spectroscopically characterized (C^N–CH = 2-(C₆H₃Bu^t)-6-(C₆H₄Bu^t)pyridine anion; Pin = OCMe₂CMe₂O). In the presence of an external base such as diethyl ether, heterolytic cleavage of the silane H–Si bond leads to the gold hydrides [{(C^N–CH)AuC₆F₅}₂(μ-H)]⁺ (2⁺) and (C^N–CH)AuH(C₆F₅) (5), together with spectroscopically detected [Et₃Si–OEt₂]⁺. The activation of dihydrogen also involves heterolytic H–H bond cleavage but requires a higher temperature (–20 °C). H₂ activation proceeds in two mechanistically distinct steps: the first leading to 2 plus [H(OEt₂)₂]⁺, the second to protonation of one of the C^N pyridine ligands and reductive elimination of C₆F₅H. By comparison, formation of gold hydrides by cleavage of suitably activated C–H bonds is very much more facile; e.g. the reaction of 1·OEt₂ with Hantzsch ester is essentially instantaneous and quantitative at –30 °C. This is the first experimental observation of species involved in the initial steps of gold catalyzed hydroboration, hydrosilylation and hydrogenation and the first demonstration of the ability of organic C–H bonds to act as hydride donors towards gold.

Selective hydrogenation of CO2 over a Ce promoted Cu-based catalyst confined by SBA-15

Highly efficient generation of methanol and CO relying on the synergistic effect of Cu, ZnO, and CeO_x dispersed in SBA-15.

Reaction mechanisms at the homogeneous–heterogeneous frontier: insights from first-principles studies on ligand-decorated metal nanoparticles

The frontiers between homogeneous and heterogeneous catalysis are progressively disappearing.

Polydimethylsiloxane Sponge-Supported Nanometer Gold: Highly Efficient Recyclable Catalyst for Cross-Dehydrogenative Coupling in Water

Polydimethylsiloxane (PDMS, a stable hydrophobic polymer material) sponge-supported nanometer-sized gold can be used as a highly efficient recyclable catalyst for cross-dehydrogenative coupling of tertiary amines with various nucleophiles in water. This PDMS sponge nanometer gold catalyst can provide much better activity than the free nanometer gold in water. The reaction can be scaled up by using an easy-to-build continuous flow reactor. These results indicate the potential application of porous hydrophobic PDMS sponge material as a promising support for highly efficient recyclable catalysts in water.