Herein, we present a new strategy that for the first time achieved chemo- and enantio-selective hydrogenation of alkenes over arylhalides. Key to the success is that instead of using external poisons, we use the composition of the bimetallic nanocrystal catalysts to control chemoselectivity (hydrogenation of C=C bonds without cleavage of Ar-X bonds). We further show that this system combined with surface modifying chiral ligands can control the enantioselectivity. Thus, after synthesizing and screening a series of easily accessible M_xAu_y (M = Pd, Pt; x, y = 1, 3, 5) bimetallic nanocrystals (9–10 nm) supported on activated carbon, we identified that Pt₁Au₁/C is a recyclable and generally applicable catalyst for the chemoselective hydrogenation of alkenes without cleaving aryl halogen bonds. Furthermore, cinchonidine modified Pt₁Au₁/C is shown to be capable of enantioselective hydrogenation, as illustrated by the rapid and enantio-enriched synthesis of RIP1 inhibitor analogue 7-Br-O-Nec1.

The promoting effect of sulfur sources is an intriguing but poorly understood phenomenon. Herein, we studied the treatment of PdCu bimetallic nanoparticles (NPs) with different amounts of sulfur powder. Low-level sulfidation led to the generation of a Pd30Cu10S9 NP catalyst consisting of surface enriched Pd NPs, electron deficient Pd and Cu, as well as zero valence sulfur. The Pd30Cu10S9 NP catalyst showed pronouncedly enhanced activity and selectivity in the semihydrogenation of alkynes. Our study revealed for the first time a possible cause for the promoting effect of sulfur at the atomic level, suggesting a new strategy in catalyst design.

The aerobic oxidation of diaryl and aryl(hetero) methylenes into ketones, catalyzed by Ag/C nanoparticles under mild conditions, was successfully developed. This method features a wide scope of substrates, good yields, and uncomplicated recycling of the catalyst.

A highly efficient and selective bimetallic Pd_0.88Co_0.12 nanoparticle catalyst was developed for the direct N-formylation of amines by carbon monoxide. This catalyst is compatible with a wide range of substrates, affording various synthetically useful formamides under practical and mild reaction conditions.

Identification of metal cluster catalysis is a topic that is being investigated since a long time. Here, we report a Pd₃ metal cluster catalytic reaction investigated by means of operando studies. We discovered that atomically defined tri-nuclear palladium (Pd₃) is a surprisingly active catalyst for the cycloisomerization of 2-phenylethynylaniline. Operando ¹H NMR spectroscopy and X-ray extended absorption fine structure (EXAFS) measurements have indicated that the structural integrity of such a catalyst remains intact throughout the reaction, which has also been confirmed by an ex situ X-ray photoelectron spectroscopy (XPS) study and catalyst recycling experiments. Kinetic data derived from operando IR spectroscopy measurements have shown that Pd₃ is the active catalytic species. Density functional theory calculations have revealed a reaction pathway consistent with the kinetic data, further supported by NMR titration and X-ray crystal structure studies. Overall, the present study presents a clear example of metal cluster catalysis.

A general method is developed to prepare durable hybrid nanocatalysts by nanostructuring the surface of gold wires via simple alloying and dealloying. The resulting nanoporous gold/Au (NPG/Au) wire catalysts possess nanoporous skins with their thicknesses on robust metal wires specified in a highly controllable manner. As a demonstration, the as-obtained NPG/Au was shown to be a highly active, chemo-selective, and recyclable catalyst for the reduction of nitro compounds and azides using organosilanes as reducing agents.