The N-functionalized ordered mesoporous carbons could be readily obtained by post-synthesis with nitrogen loading as high as 8.6 wt% and well preserved mesopore structure. Using NH 3 as nitrogen source dramatically increased BET surface area and pore volume of the resultant hybrid material, however, N-doping with melamine as a source resulted in the contrary results. These N-doping carbons were used as supports to immobilize small-sized Pd nanoparticles, which provided a unique platform to investigate the influences of metal nanoparticle size, mesostructural properties and N-functionalized supports on the selective hydrogenation of phenol to cyclohexanone, an important intermediate in the production of nylon 6 and nylon 66 in chemical industry. The catalyst with ultrasmall (about 1.2 nm) PdNPs gave the best reaction activity and selectivity under mild conditions. In addition, present multifunctional catalyst demonstrated excellent catalytic stability and could be used for six times without loss of product yields. These outstanding catalytic performances could be attributed to the synergetic effects of mesoporous structure, N-functionalized supports and the stabilized ultrasmall PdNPs. This work might open new avenues for the development of functionalized catalysts with supported ultrasmall metal nanoparticles and hybrid porous support as well as their clean catalyses.

Highly dispersed copper nanoparticles supported on silica were successfully prepared by a simple and convenient precipitation−gel technique, and their physicochemical properties and activity were compared to those of a catalyst prepared by the conventional impregnation method. As a consequence of the preparation method, the texture (BET), dispersion (dissociative N2O adsorption), morphology (TEM), reduction behavior (TPR, XRD), state of copper species (XPS), and catalytic performance (glycerol hydrogenolysis) differ between samples. Both samples showed high selectivity (>98%) toward 1,2-propanediol in glycerol reaction. Because of a much smaller particle size, a higher dispersion of copper species with a strong metal−support interaction, and more resistance to sintering, the CuO/SiO2 catalyst prepared by precipitation–gel method presented a much higher activity and remarkably better long-term stability in glycerol reaction than did the catalyst prepared by impregnation method. The catalytic behavior of calcined and reduced samples and the structure changes of these samples after reaction allow the understanding of the stability toward sintering as well as the possible mechanism of the reaction.

A magnetically separable palladium catalyst was simply synthesized through a wet impregnation incorporating palladium nanoparticles and superparamagnetic Fe3O4 nanoparticles in KBH4 solution, which is a highly efficient catalyst for the carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes under phosphine-free conditions. This catalyst is completely magnetically recoverable due to the super paramagnetic behavior of Fe3O4 and can be reused with sustained selectivity and activity.

The synthetic control and functions of porous organic polymers (POPs) with N-heterocyclic carbene gold(I) (Au-NHC@POPs) are described in this article. A series of Au-NHC@POPs with tunable physical properties such as surface area and pore size distribution were first synthesized via Sonogashira chemistry by differing monomer strut lengths and concentration during polymerization; a controllable transition from nonporous to microporous and the coexistence of micro-and mesoporous structures in the framework were realized by varying the monomer concentration. To explain this phenomenon, we put forward a model assumption of a branch−branch cross effect. Additionally, Au-NHC@POPs1 was found to have superior catalytic activity in alkyne hydration reactions, and the catalyst could be used six times with a slight loss of activity.

A deoxygenative gem-diborylation and gem-silylborylation of aldehydes and ketones is described. The key for the success of this transformation is the base-promoted C-O bond borylation or silylation of the generated α-oxyboronates. Experimental and theoretical studies exhibit that the C-O bond functionalization proceeds via an intramolecular five-membered transition-state (9-ts) boryl migration followed by a 1,2-metalate rearrangement with OBpin as a leaving group. The transformation occurs with an inversion on the carbon center. Direct conversion of aldehydes and ketones to gem-diboron compounds was achieved by combining copper catalysis with this base-promoted C-OBpin borylation. Various aldehydes and ketones were deoxygenatively gem-diborylated. gem-Silylborylation of aldehydes and ketones were achieved by a stepwise operation, in which Bpin initially react with those carbonyls followed by a silylation with Bpin-SiMePh.

A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C-H as well as tertiary C-H oxidation with hydrogen peroxide as the oxidant in the presence of acetic acid as additive. (18)O labeling experiments suggest the reaction may proceed via a high-valent manganese-oxo intermediate.

We report a remarkable Brønsted acid effect in the epoxidation of olefins by nonheme manganese catalysts and aqueous hydrogen peroxide. More specifically, a mononuclear nonheme manganese complex bearing a tetradentate N4 ligand, Mn(II)(Dbp-MCP)(OTf)2 (Dbp-MCP = (1R,2R)-N,N'-dimethyl-N,N'-bis((R)-(3,5-di-tert-butyl-phenyl)-2-pyridinylmethyl)cyclohexane-1,2-diamine; OTf(-) = CF3SO3(-)), is a highly efficient catalyst in the epoxidation of olefins by aqueous H2O2 in the presence of H2SO4 (1-3 mol %). The yields of epoxide products as well as the chemo- and enantioselectivities increase dramatically in the presence of H2SO4; no formation of epoxides is observed in the absence of H2SO4. In addition, the product yields and enantioselectivities are dependent significantly on the manganese catalysts and Brønsted acids. The catalytic epoxidation of olefins by other oxidants, such as peracids, alkyl hydroperoxides, and iodosylbenzene, is also affected by the presence of H2SO4; product yields and enantioselectivities are high and similar irrespective of the oxidants in the presence of H2SO4, suggesting that a common epoxidizing intermediate is generated in the reactions of [Mn(II)(Dbp-MCP)](2+) and the oxidants. Mechanistic studies, performed with (18)O-labeled water (H2(18)O) and cumyl hydroperoxide, reveal that a high-valent manganese-oxo species is formed as an epoxidizing intermediate via O-O bond heterolysis of Mn-OOH(R) species. The role of H2SO4 is proposed to facilitate the formation of a high-valent Mn-oxo species and to increase the oxidizing power and enantioselectivity of the Mn-oxo oxidant in olefin epoxidation reactions. Density functional theory (DFT) calculations support experimental results such as the formation of a Mn(V)-oxo species as an epoxidizing intermediate.

A ferrocene-based ionic liquid (Fe-IL) is used as a metal-containing feedstock with a nitrogen-enriched ionic liquid (N-IL) as a compatible nitrogen content modulator to prepare a novel type of non-precious-metal-nitrogen-carbon (M-N-C) catalysts, which feature ordered mesoporous structure consisting of uniform iron oxide nanoparticles embedded into N-enriched carbons. The catalyst Fe(10) @NOMC exhibits comparable catalytic activity but superior long-term stability to 20 wt % Pt/C for ORR with four-electron transfer pathway under alkaline conditions. Such outstanding catalytic performance is ascribed to the populated Fe (Fe3 O4 ) and N (N2) active sites with synergetic chemical coupling as well as the ordered mesoporous structure and high surface area endowed by both the versatile precursors and the synthetic strategy, which also open new avenues for the development of M-N-C catalytic materials.