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A mesoporous ZnIn2S4 photocatalyst shows notable activity for photoreforming of PLA, PET and PU to generate small organic chemicals and H2 fuel under simulated sunlight at room temperature.

The Friedel–Crafts alkylation strategy was used to prepare a hypercrosslinked polymer catalyst, which showed superior performance towards the cycloaddition reaction of CO2 with epoxides.

The activation of dioxygen is the major challenge in the catalytic oxygenation of hydrocarbons under mild conditions. In this study, the catalytic efficiency for the aerobic oxidation of toluene and its derivatives by using cobalt meso-tetraphenylporphyrin was enhanced by using acetylacetone as the oxygen activator. The influences of reaction conditions such as solvent, different metalloporphyrin catalysts, temperature, pressure and acetylacetone loading were studied, as well as the kinetics of the oxidation. Various toluene derivatives could also be oxidized to the corresponding products in satisfactory yields with this catalytic system. Based on the characterization of in situ electron paramagnetic resonance (EPR) and in situ UV-vis spectroscopy, the catalytic mechanism was also proposed, in which acetylacetone served as the key initiator of the free radical in activating dioxygen.

A tubular MOF with adequate active sites is prepared by the bending of metal-coordinated honeycombed frameworks via titration and shows fast catalytic kinetics with lower catalytic loading for CO2 conversion. The TON is observed to be 2300 and the corresponding TOF of up to 173 h-1 is achieved for the first time.

In this study, convenient and selective oxidation of alcohols using aqueous hydrogen peroxide to yield carbonyl compounds was studied. Using the ruthenium-(4-methylphenyl-2,6-bispydinyl) pyridinedicarboxylate complex [Ru(mpbp)(pydic)] as a catalyst, primary and secondary alcohols were oxidized to aldehydes and ketones at room temperature with a satisfactory yield and excellent selectivity. The influence of various reaction parameters, such as solvent, catalyst and oxidant amount on both the activity and selectivity was also evaluated. Kinetic studies showed that the oxidation of alcohol was first order in terms of the substrate and hydrogen peroxide, and was second order in terms of the catalyst. A plausible mechanism involving ruthenium–oxo species with electrophilic character was proposed based on the in situ UV-vis spectroscopy studies and Hammett plots.

An imidazolium-based ionic liquid (IL) functionalized zinc porphyrin catalyst was successfully synthesized for the first time, and was employed as an efficient catalyst for CO2 transformation including both the chemoselective synthesis of cyclic carbonates from various epoxides and the regioselective synthesis of 5-aryl-2-oxazolidinones from N-substituted aziridines. Detailed studies demonstrated that the intramolecular cooperative effect between the coordinated zinc center (electrophile) and flexible bromine anions (nucleophile) could mediate these reactions effectively under solvent-free and mild conditions. More importantly, the IL-based catalyst could be readily recovered by solvent precipitation and reused with retention of high activity and selectivity more than ten times based on the concept of “one-phase catalytic coupling with two-phase separation”.

On the basis of the development of function-oriented synthesis (FOS), we presented for the first time an efficient and one-pot construction of functional ionic polymers (FIPs) through the phenol–formaldehyde condensation process (pre-synthetic approach); FIPs had high density of Bronsted acidic and ionic sites. Considering the electrophilic–nucleophilic dual activation of phenolic hydroxyl groups and bromide anions, the imidazolium-based FIP-Im exhibited high activity for metal-, solvent- and additive-free synthesis of cyclic carbonates from CO2 and epoxides under mild conditions. Then, to obtain higher ionic density and a more flexible skeleton, FIP-Im@QA was also prepared by implanting quaternary ammonium (QA) in the framework of FIP-IMvia the Williamson ether synthesis (post-synthetic modification), which demonstrated high efficiency in the N-formylation reaction of multitudinous secondary amines with CO2 and PhSiH3 at ambient temperature. More interestingly, these function-oriented catalysts were compatible with the target transformation under low CO2 concentration (15% in 85% N2, v/v) and were also reused for more than six times without a significant loss of activity and selectivity. Therefore, this study could not only facilitate the design and construction of FIPs, but also provide sustainable protocols for efficient production of value-added chemicals from CO2 under mild conditions.

Generally, gaseous propylene is hard to oxidize directly in liquid phase by dioxygen under mild conditions. Here, the liquid phase epoxidation of propylene to propylene oxide (PO) using molecular oxygen catalyzed by manganese porphyrins (MnTPPCl) in the presence of benzaldehyde was developed. Manganese(III) porphyrin exhibited excellent activity for the selective oxidation of propylene under mild conditions. The conversion of propylene and selectivity towards PO can reach 38% and 80%, respectively. The turnover frequency (TOF) of MnTPPCl catalyst reached 1840 h−1. Experiment evidences that the generation of peroxide and Mn(IV) oxo species during propylene epoxidation occurred, which was confirmed by in situ IR, in situ UV and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). On the basis of the experimental results, the mechanism for the epoxidation of propylene in the presence of metalloporphyrins and benzaldehyde with dioxygen was proposed. The mechanism is also supported by density functional theory (DFT) calculations.

A series of novel zinc complexes were prepared by covalent linkage of various imidazolium-based ionic liquid moieties with the 2,2′-bipyridine ligand on the two sides of the 4,4′-position. The zinc(II) complexes containing the rigid N-chelating ligand proved to be stable, highly efficient and easy-to-handle catalysts towards the synthesis of cyclic carbonate from epoxide and CO2 without the use of any co-catalyst or organic solvent. The catalysts can be easily recovered and reused without significant loss of activity and selectivity by control of the solvent. The kinetic study uncovered that the reaction was first-order with respect to the epoxide. Moreover, a plausible reaction mechanism was proposed, in which the zinc center could promote ring-opening of the epoxide for the synergetic effect with the anion X− in ILs.

A series of monometallic salen aluminum complexes were prepared by covalent linkage of the imidazolium-based ionic liquid moieties containing various polyether chains with the salen ligand at the two sides of the 5,5′-position. The salen aluminum complexes proved to be efficient and recyclable homogeneous catalysts towards the organic solvent-free synthesis of cyclic carbonates from epoxides and CO2 in the absence of a co-catalyst. The catalysts presented excellent “CO2 capture” capability due to the molecules containing polyether chains and the metal aluminum center, in which >90% yield of cyclic carbonate could be obtained under mild conditions. The catalysts can be easily recovered and six times reused without significant loss of activity and selectivity. Moreover, based on experimental and previous work, the “CO2 capture and activation” cycloaddition reaction mechanisms by monometallic or bimetallic salen aluminum complexes were both proposed.