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A large number of efficient cyanation methods have been developed because of the wide range of applications of nitriles, but conventional methods usually suffer from the need for a toxic cyanation reagent. Although difluorocarbene chemistry has received increasing attention, the use of difluorocarbene as a sources of the nitrile carbon for nitrile groups remains largely unexplored. We describe a difluorocarbene-based cyanation of aryl iodides promoted by a cheap copper source, Cu(NO3)2·2.5H2O, under an air atmosphere. Ph3P+CF2CO2 –, an easily available and shelf-stable difluorocarbene reagent, and NaNH2 are used as the carbon source and the nitrogen source for the nitrile group, respectively. The cyanation protocol is attractive because no toxic reagent is used and performing the reactions under an air atmosphere is operationally convenient.

The majority of commercial polyolefins are produced by coordination polymerization using early or late transition metal catalysts. Molecular catalysts containing these transition metals (Ti, Zr, Cr, Ni, and Fe, etc.) are loaded on supports for controlled polymerization behavior and polymer morphology in slurry or gas phase processes. Within the last few years, metal-organic frameworks (MOFs), a class of unique porous crystalline materials constructed from metal ions/clusters and organic ligands, have been designed and utilized as excellent supports for heterogeneous polymerization catalysis whose high density and uniform distribution of active sites would benefit the modulations of molecular weight distributions of high-performance olefin oligomers and (co)polymers. Impressive efforts have been made to modulate the microenvironment surrounding the active centers at the atomic level for improved activities of MOFs-based catalysts and controlled selectivity of olefin insertion. This review aims to draw a comprehensive picture of MOFs for coordination olefin oligomerization and (co)polymerization in the past decades with respect to different transition metal active centers, various incorporation sites, and finally microenvironment modulation. In consideration of more efforts are needed to overcome challenges for further industrial and commercial application, a brief outlook is provided.

Described here is the radical-mediated hydrodifluoromethylation of alkenes that occurs under transition-metal-free conditions by using the phosphonium salt [Ph3P+CF2H]Br− under the irradiation of 26 W household compact fluorescent light. The reaction lends itself to a convenient protocol for the installation of a C–CF2H bond while maintaining good functional group tolerance.

As trifluoromethylthiolation has received increasing attention recently, many CF3S-reagents and trifluoromethylthiolation methods have been developed. Herein we describe trifluoromethylthiolation of alkyl halides by using Ph3P+CF2CO2− as a fluoride and difluorocarbene source. Difluorocarbene is a versatile intermediate, but its side reactions are usually ignored and the by-products would therefore be discarded. In this work, a side reaction of difluorocarbene, the generation of a fluoride anion from difluorocarbene, was developed into a synthetic tool. Although the trifluoromethylthiolation reaction involved multi-sequential steps, the cleavage of C–F bond, the formation of CF2=S bond, F-C(S)F2 bond, and C-SCF3 bond, the conversion proceeded fast and was completed within 10 min.

Cathode design is indispensable for building Li-O2 batteries with long cycle life. A composite of carbon-wrapped Mo2C nanoparticles and carbon nanotubes is prepared on Ni foam by direct hydrolysis and carbonization of a gel composed of ammonium heptamolybdate tetrahydrate and hydroquinone resin. The Mo2C nanoparticles with well-controlled particle size act as a highly active oxygen reduction reactions/oxygen evolution reactions (ORR/OER) catalyst. The carbon coating can prevent the aggregation of the Mo2C nanoparticles. The even distribution of Mo2C nanoparticles results in the homogenous formation of discharge products. The skeleton of porous carbon with carbon nanotubes protrudes from the composite, resulting in extra voids when applied as a cathode for Li-O2 batteries. The batteries deliver a high discharge capacity of ≈10 400 mAh g−1 and a low average charge voltage of ≈4.0 V at 200 mA g−1. With a cutoff capacity of 1000 mAh g−1, the Li-O2 batteries exhibit excellent charge–discharge cycling stability for over 300 cycles. The average potential polarization of discharge/charge gaps is only ≈0.9 V, demonstrating the high ORR and OER activities of these Mo2C nanoparticles. The excellent cycling stability and low potential polarization provide new insights into the design of highly reversible and efficient cathode materials for Li-O2 batteries.

To lower the overpotential of a lithium-oxygen battery, electron transport at the solid-to-solid interface between the discharge product Li2O2 and the cathode catalyst is of great significance. Here we propose a strategy to enhance electron transport property of the cathode catalyst by the replace of oxygen atoms in the generally used metal oxide-based catalysts with nitrogen atoms to improve electron density at Fermi energy after nitridation. Hierarchically porous CoN nanorods were obtained by thermal treatment of Co3O4 nanorods under ammonia atmosphere at 350 °C. Compared with that of the pristine Co3O4 precursor before nitridation, the overpotential of the obtained CoN cathode was significantly decreased. Moreover, specific capacity and cycling stability of the CoN nanorods were enhanced. It is assumed that the discharged products with different morphologies for Co3O4 and CoN cathodes might be closely associated with the variation in the electronic density induced by occupancy of nitrogen atoms into interstitial sites of metal lattice after nitridation. The nitridation strategy for improved electron density proposed in this work is proved to be a simple but efficient way to improve the electrochemical performance of metal oxide based cathodes for lithium-oxygen batteries.

A large number of trifluoromethylthiolation methods have been developed, but a trifluoromethylthiolation reagent usually has to be used in these methods. Herein we describe a difluorocarbene-based trifluoromethylthiolation of terminal alkynes to construct a Csp SCF3 bond catalysed by a copper complex. Ph3P+CF2CO2−/S8/F− was used as a reagent system to form the CF3S− anion, and the sequential formation of CF2 S, F CF2S and C SCF3 bonds was achieved in a one-step process.

The selective hydrodechlorination of tetrachloromethane (CCl 4 ) was performed over supported platinum–gallium catalysts with a support of MgF 2 to improve CHCl 3 selectivity and catalytic stability. In order to better understand the behavior of the Ga and MgF 2 support, hydrogen chemisorption, temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) measurements were conducted to characterize the catalysts. It was found that the electron-deficient Pt species are formed on the catalyst surface during the hydrodechlorination reaction due to the adsorption of active chlorine. The addition of Ga into the catalysts results in forming Pt–Ga assemblies such as PtGa alloys on the catalyst surface, and generates a Pt–Ga interaction as confirmed by TPR and XPS. The Ga addition will significantly increase the dispersion of Pt and create more Pt sites exposed to the reaction atmosphere on the catalyst surface in effect. The influence of Ga on the CHCl 3 selectivity and the conversion of CCl 4 can be ascribed to the modification of Ga to the electronic properties of the Pt active sites by changing the electronic environment surrounding the Pt atoms via the Pt–Ga interaction. The modified Pt species are believed to be beneficial to form a fast desorption step for the adsorbed * CCl 3 species (a commonly accepted precursor to generate CHCl 3 ) under the assistance of hydrogen. The adsorption of reactant CCl 4 will be weakened on the catalyst surface and cause a lower conversion of CCl 4 .

Supported palladium phosphine complexes [Pd(PPh 3 ) 2 X 2 /MgF 2 ] (X = Cl or SCN) were prepared as precursor catalysts for hydrodechlorination of CCl 2 F 2 by a method of in situ synthesis of palladium complex on support (ISPS) and using environmentally benign solvents. Their performance and activities were compared to those of catalysts prepared via traditional incipient wetness impregnation method by catalytic reaction and characterization results, including FT-IR, XPS, XRD and H 2 -chemisorption. After an induction period, during which the Pd(II) precursors are converted to active species by being put in contact with substrate CCl 2 F 2 and H 2 , stable catalytic activities and improved selectivities to CH 2 F 2 (>93% on Pd(PPh 3 ) 2 (SCN) 2 /MgF 2 ) are achieved. The improvement of catalytic performance was ascribed to the more homogenous distributing of catalyst precursor on the surface of the support, where the amounts of the sites that induce side reactions are decreased. The XPS results revealed that there exist two kinds of active Pd sites on the surface of catalysts. One is Pd(0) site for the activation of hydrogen, and the other is the Pd site of high electrovalence, i.e. electron-deficient palladium for the activation of CCl 2 F 2. High dispersion (∼90%) of Pd particles results in a strong interaction between Pd and the support, and creates electron-deficient palladium sites being of high selectivity to CH 2 F 2 .

Supported palladium phthalocyanine was found to be an interesting catalyst with good stability for selective conversion of CCl2F2 into CH2F2 under flowing hydrogen. Relatively high selectivities towards CH2F2 formation over palladium phthalocyanine catalysts with fluoride supports were achieved at limited conversion levels (

Novel supported palladium catalysts were prepared through organometallic Pd compounds including dichlorobistriphenylphosphine palladium (DCTPPP) and dithiocyanatobistriphenylphosphine palladium (DTTPPP) for the hydrodechlorination of CFC-12. These catalysts exhibited excellent catalytic activities in hydrodechlorination of CFC-12. Particularly, high selectivities of CH2F2 formation were achieved over the catalysts, DCTPPP/MgF2 with 88.1% and DTTPPP/MgF2 with 85.8%, at a limited conversion level (