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ATP citrate lyase (ACLY) is a key enzyme in glucolipid metabolism with therapeutic prospect for treating hyperlipidemia and various cancers. Much effort has been put into discovering ACLY inhibitors. However, current screening approaches have limitations in sensitivity, portability and high-throughput. To develop a general screening assay, we investigated series of conditions affecting the enzymatic reaction based on the ADP-Glo luminescence assay. Bovine serum albumin (0.001%) added triggered strong and stable fluorescence signal. The optimized assay was validated and applied to screen our natural product library. Two novel inhibitors were identified with IC

Muscarine acetylcholine receptors (mAChRs) regulate a variety of central and peripheral physiological functions and emerge as important therapeutic targets for a number of diseases including chronic obstructive pulmonary disease (COPD). Inspired by two active natural products, we designed and synthesized a series of 2-(2,2-diarylethyl)-cyclamine derivatives for screening M3 mAChR antagonists. On this skeleton, the structural units including N heterocycle, aryl groups and its substituents on aryl were examined and resulted in a clear structure-activity relationships on the M3 mAChR. In general, these 2-(2,2-diarylethyl)-cyclamine derivatives exhibited good to excellent M3 antagonistic potency and receptor selectivity. The most active 5b-C1 had an IC

A series of coumarin-like diacid derivatives were designed and synthesized as novel agonists of human G-protein-coupled receptor 35 (hGPR35). Active compounds were characterized to possess one acidic group on both sides of a fused tricyclic aromatic scaffold. Most of them functioned as full agonists selective to hGPR35 and exhibited excellent potency at low nanomolar concentrations. Substitution on the middle ring of the scaffold could effectively regulate compound potency. Structure-activity relationship studies and docking simulation indicated that compounds that carried two acidic groups with a proper special distance and attached to a rigid aromatic scaffold would most likely show a potent agonistic activity on hGPR35. Following this principle, we screened a list of known compounds and some were found to be potent GPR35 agonists, and compound 24 even had an EC50 of 8 nM. Particularly, a dietary supplement pyrroloquinoline quinone (PQQ) was identified as a potent agonist (EC50 = 71.4 nM). To some extent, this principle provides a general strategy to design and recognize GPR35 agonists.

A pair of new macrocyclic spermidine alkaloids, (+)-(S)-scocycamide and (-)-(R)-scocycamide, were isolated from the roots of Scopolia tangutica. Their structures were established by extensive spectroscopic data, electronic circular dichroism analyses, and chemical synthesis. They featured a unique 6/18 fused bicyclic framework with spermidine and catechol units, representing a new subtype of natural spermidine alkaloids. A plausible biosynthetic pathway was also proposed. They inhibited butyrylcholinesterase and exhibited antioxidant capacity, suggesting beneficial constituents against Alzheimer's disease and oxidation.

Ursodeoxycholic acid (UDCA) is a safe bile acid effective in reducing hepatic steatosis in non-alcoholic fatty liver disease (NAFLD). However, the mechanism of action linked to this effect is poorly defined. In the present study, we identified that UDCA acted as a free fatty acid receptor 4 (FFA4) agonist with EC

The 30 kVA/50 kV power frequency discharge system was used to trigger the trips (flashover processes) of Aluminum Conductor Steel Reinforced (ACSR) powerline segments (LGJ-400/35) in a 10.0 cm air gap under a wood crib fire (comprehensive fire source), and the characteristics and mechanisms of such line-line air gap (conductor gap) were discussed. The results show that under the wood crib fire, the breakdown voltage of conductor gap is obviously lower than that under pure air. Under the same fire source power, the breakdown voltages of different flame zones are ordered as: pure air (70.0 kV) > intermittent flame zone (top, 32.0 kV-52.4 kV) > continuous flame zone 2 (upper, 21.0 kV-28.0 kV) > continuous flame zone 1 (bottom, 14.4 kV-24.4 kV). In the same flame zone, the breakdown voltage decreases from 52.4 kV to 14.4 kV (25.1 %-79.4% reductions to those in pure air) with the increase of fire source powers (1-3 wood cribs, 121.87 kW-323.66 kW). For the single wood crib fire source, the maximum leakage currents (within the period before the conductor gap breakdown) in the flame intermittent zone, the flame continuous zones 1 and 2 are less than 1.00 mA and 2.54 mA, respectively. Many soot particles and ashes will be generated when wood crib and other ground surface vegetation fire sources burn. They will fill the gaps between power lines and be polarized by the in-service line inducing electric field. Then distorted electric field will be formed between the two polarization ends and the lines. The opposite movements and interactive convections of a large number of electrons, ions and smoke particles in fire plumes are driven to form a discharge streamer channel and cause line-line gap breakdown at proper moments.

In this paper, the influence of a lightly doped p-GaN (p−-GaN) cap layer on p-GaN/AlGaN/GaN high electron mobility transistors (HEMTs) (LDP-HEMTs) was investigated. No difference in output or off-state breakdown characteristics was observed, but there was a negative shift in threshold voltage (V TH). The gate leakage (V GS = 7 V) dropped by three orders of magnitude, and the gate forward breakdown voltage and continuous operating voltage increased by 6.5 V and 2.5 V, respectively. It is worth noting that the gate characteristics are significantly optimized, which is ascribed to the employment of the p−-GaN cap layer. The simulations illustrate that the electric field is dispersed, and the electric peak is alleviated by the p−-GaN cap layer, thus suppressing the impact ionization and carrier injection in the high electric field. Furthermore, there is a negligible effect on the temperature reliability of V TH based on the temperature-dependent characteristics in LDP-HEMTs. However, the temperature stability of the gate current (V GS = 7 V) will worsen in LDP-HEMTs due to the difference in the conduction mechanism, compared with conventional p-GaN HEMTs.

Ultrasmall core-shell nanocarriers (NCs) are believed to be ideal candidates for biological applications, as proved by silica-based core-shell NCs fabricated using a single micelle as a template. Compared with inert silica, polymers with various properties play an essential and ubiquitous role in our daily life. However, the fabrication of polymer-based NCs with ultrasmall particle size (less than 20 nm) is still very limited, which is probably hindered due to the difficulty in handling the polymeric process and the soft nature of most polymers. In this study, we demonstrated the fabrication of ultrasmall single micelle@resin core-shell NCs through a single micelle template method using resorcinol-formaldehyde resins (RFRs) as model polymers. Moreover, the fluorescence properties of the ultrasmall single micelle@resin core-shell NCs could be adjusted from visible light to near-infrared through the incorporation of different dye molecules. The fluorescent single micelle@RFR core-shell NCs show extra-low cytotoxicity and great potential in both in vitro and in vivo bioimaging and photothermal therapy applications.

Traditional Chinese Medicines (TCMs) have been widely used in clinical practice, and provided a rich source for discovering new drug leads. However, efficient identification of active molecules responsible for the therapeutic effects of complex TCMs is still highly challenging. Here, we combined label-free cell phenotypic assay with two dimensional liquid chromatography (2DLC) to identify potential β2-adrenoceptor (β2-AR) agonists related to anti-asthmatic effect of Curcuma zedoaria Rosc (C.zedoaria), a commonly used TCM. The ethyl acetate extract of C.zedoaria was first fractionated into 26 fractions. Label-free cell phenotypic profiling was then used to locate the active sites. Orthogonal second-dimensional (D2) separation was performed on two fractions displaying agonistic effect at the β2-AR, combined with screening of the D2 fractions to track the activity. Finally, this approach led to the isolation of three known diarylheptanoids, among which diarylheptanoid b exhibited the most potent agonistic activity with an EC50 value of 5.93 μM. This result was further demonstrated through the chemical synthesis of diarylheptanoid b. It is the first time to discover that diarylheptanoids could activate the β2-AR, which may be responsible for the anti-asthmatic effect of C.zedoaria observed traditionally and in clinical application. This study also demonstrates the potential of this integrated strategy for identifying active ingredients and determining the basis of therapeutic materials in complex TCMs.

The high temperature gas occurs behind shock or near the wall surface of vehicle in the hypersonic flight. As the temperature exceeds 2 000K, 4 000K, respectively, O2 and N2 molecules are successively dissociated. Because of variable components at different temperatures and pressures, the dissociated air is no longer a perfect gas. In this paper, a new method is developed to calculate accurate thermal physical parameters with the dissociation degree providing the thermochemical equilibrium procedure. Based on the dissociation degree, it is concluded that few numbers of equations and the solutions are easily obtained. In addition, a set of formulas relating the parameter to the dissociation degree are set up. The thermodynamic properties of dissociated air containing four-species, O2 molecule and N2 molecule, O atom and N atom, are studied with the new method, and the results are consistent with those with the traditional equilibrium constant method. It is shown that this method is reliable for solving thermal physical parameters easily and directly.

[Image: see text] G protein-coupled receptor-35 (GPR35) has emerged as a potential target in the treatment of pain and inflammatory and metabolic diseases. We have discovered a series of potent GPR35 agonists based on a coumarin scaffold and found that the introduction of a 1H-tetrazol-5-yl group significantly increased their potency. We designed and synthesized a new series of N-[2-(1H-tetrazol-5-yl)phenyl]benzamide derivatives through a two-step synthetic approach, and characterized their agonistic activities against GPR35 using a dynamic mass redistribution (DMR) assay. N-(5-bromo-2-(1H-tetrazol-5-yl)phenyl)-4-methoxybenzamide (56) and N-(5-bromo-2-(1H-tetrazol-5-yl)phenyl)-2-fluoro-4-methoxybenzamide (63) displayed the highest agonistic potency agonist GPR35 with an EC(50) of 0.059 μM and 0.041 μM, respectively. The physicochemical properties of selected compounds were calculated to evaluate their druglikeness, suggesting that compounds 56 and 63 have good druglike properties. Together, N-[2-(1H-tetrazol-5-yl)phenyl]benzamide derivatives are potentially great candidates for developing potent GPR35 agonists.

In this paper, enhancement-mode AlGaN/GaN p-type GaN cap layer high electron mobility transistors (p-GaN HEMTs) with Ti/Au gate metal are fabricated and electrically characterized. The post gate annealing (PGA) treatment at 300 °C for 10 min is utilized to improve the devices’ characteristics. As a result, the p-GaN HEMTs achieve a high drain current (IDS) of 490 mA/mm at VGS = 7 V with a high threshold voltage (VTH) of 1.9 V. Meanwhile, the pulse measurements show good dynamic characteristics, and the temperature-dependent characteristics indicate that the VTH has excellent high-temperature stability from 25 °C to 175 °C. Besides, it can be found that the temperature will affect the capacitance–voltage (C-V) and transconductance curves, which is related to the hole energy and electron mobility at different temperatures.

In this paper, multi-channel AlGaN/GaN Schottky diodes (MC-SBDs) with W/Au and Ni/Au anode metal were fabricated on the Si substrates, and the effect of post anode annealing (PAA) was investigated. The temperature of PAA varies from 300 °C to 550 °C. Benefitting from the multi-channel structure, low on-resistance (RON) of 3.11 Ω mm are obtained for Ni and W after 300 °C PAA. Meanwhile, the onset voltage (VON) of W is 0.34 V, much lower than 0.71 V for Ni. With PAA temperature rising, the VON and barrier height (φb) increase for both metals at the beginning because of the repair of etching damage. However, these parameters will decrease when the temperature exceeds the optimal value due to the deterioration of the Schottky interface. Correspondingly, the reverse current (IREV) drops first and then rises. The optimal PAA temperature is 450 °C for Ni and 500 °C for W. Furthermore, the temperature-dependent characteristics are also measured for comprehensive evaluation. The results show that the PAA has little effect on temperature-dependent forward characteristics for both Ni and W. However, the PAA can improve the high-temperature stability of IREV for Ni, whereas this advantage has not been observed on W, which is related to different leakage current mechanisms.

This work presents the temperature-dependent characteristics of the thin-barrier Al0.45Ga0.55N/GaN high electron mobility transistor (HEMT), p-type CuO gate HEMT, and high-k HfO2 metal–insulator–semiconductor HEMT (MIS-HEMT). As the temperature rises from 20 to 300 °C, the maximum trans-conductance of the HfO2 MIS-HEMT and CuO gate HEMT reduces by 56.9% and 43.2%, respectively. The sub-threshold swing of the CuO gate HEMT is smaller than that of the HfO2 device when the temperature reaches 300 °C. According to the C–V test results from 20 to 300 °C, the relative dielectric constant of CuO increases from 18.1 to 47.4, whereas HfO2 has a relatively stable dielectric constant. The calculation models are presented to investigate the effect of the dielectric constant on the drain current and the trans-conductance. The calculated results show that the maximum transconductance of the HfO2 MIS-HEMT and CuO gate HEMT decreases by 52.3% and 38.9%, respectively, which is in good agreement with the experimental results.

In this paper, a high-performance multi-channel heterostructure based on lattice-matched AlInN/GaN has been reported. The stacking of five heterostructures yields a high two-dimensional electron gas density of 3.67 × 1013 cm−2 and a small sheet resistance (RSH) of 74.5 Ω/sq. Compared with the AlGaN/GaN sample with the same number of heterojunctions, the AlInN/GaN sample reduces the RSH by 51.2%. Since the AlInN barrier and GaN channel are lattice-matched, the strain defects caused by piezoelectric strain can be alleviated. The high-resolution x-ray diffraction results show that the total dislocation density in AlInN/GaN multi-channels is reduced by 18.9%. The calculation models of multiple-channel heterostructures are obtained to investigate the electron population and energy band diagram, and the calculated results are roughly consistent with the experimental results. With a gate–drain spacing of 11.5 μm, the on-resistance (RON) of the AlInN/GaN multi-channel HEMT was only 2.26 Ω mm, indicating that the lattice-matched multi-channel AlInN/GaN heterostructure can substantially enhance the current drive efficiency and improve the output performance of the devices.

In this paper, we report a high-performance AlGaN/GaN Schottky barrier diode (SBD) based on super-lattice structure. The stacking of five AlGaN/GaN heterostructures yields a small sheet resistance (RSH) of 120 Ω/sq. The fully recessed anode structure is used to contact all the current channels, leading to a small turn-on voltage (VON) of 0.44 V. Besides, the ohmic contact with a contact resistance (RC) of 0.17 Ω mm is obtained by etching the cathode region. The on-resistance (RON) of the device is reduced by 63.8%, down to 1.7 Ω mm, and a forward voltage (VF) as low as 0.81 V is achieved. To the best of our knowledge, this VF is the lowest value among all the GaN SBDs. These results are superior to the conventional single heterojunction devices, showing the great potential of the GaN-based super-lattice structures for achieving low forward conduction losses.

PbZr0.2Ti0.8O3 (PZT) gate insulator with the thickness of 30 nm is grown by pulsed laser deposition (PLD) in AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs). The ferroelectric effect of PZT AlGaN/GaN MIS-HEMT is demonstrated. The polarization charge in PZT varies with different gate voltages. The equivalent polarization charge model (EPCM) is proposed for calculating the polarization charge and the concentration of two-dimensional electron gas (2DEG). The threshold voltage (V th) and output current density (I DS) can also be obtained by the EPCM. The theoretical values are in good agreement with the experimental results and the model can provide a guide for the design of the PZT MIS-HEMT. The polarization charges of PZT can be modulated by different gate-voltage stresses and the V th has a regulation range of 4.0 V. The polarization charge changes after the stress of gate voltage for several seconds. When the gate voltage is stable or changes at high frequency, the output characteristics and the current collapse of the device remain stable.

The silylation for reducing the pore entrance size is crucial for the success encapsulation of molecular catalysts. Herein, we reported the preparation of an efficient solid catalyst for epoxide hydration via encapsulation of Co III (salen)-OTs in the nanocages of FDU-12 using prehydrolyzed tetramethylorthosilicate (TMOS) as silylation reagent under mild condition. Co III (salen)-OTs in nanocages could afford TOF of 2760 h −1 in the hydration of propylene epoxide (PO), which is the highest ever reported at low PO/H 2 O molar ratio. Comparison of the activity of Co III (salen)-OTs accommodated in nanocages with different microenvironments suggests that Co III (salen)-OTs in hydrophilic microenvironment was more active than that in hydrophobic microenvironment in the hydration of propylene epoxide. Moreover, studies show that the deactivation rate of Co III (salen)-OAc is lower than that of Co III (salen)-OTs in nanocages due to the confinement effect of the nanoreactor.

An efficient and stable oil/water Pickering emulsion system was constructed for hydroformylation of 1-octene with surface modified mesoporous silica nanospheres as stabilizer and Rh-TPPTS as catalyst. Compared to the neat water–oil biphasic system, the Pickering emulsion system exhibits much higher activity (TOF: 392 h−1 versus 56 h−1) and aldehyde selectivity (79.0% versus 45.7%) in hydroformylation of 1-octene under non-stirring conditions due to the greatly increased interface area. It was found that dimethyloctadecylammonium group is more efficient than octadecyl group for emulsion catalytic system, which is mainly attributed to its enrichment effect for anionic Rh-TPPTS on the interface of two phases. The higher activity and aldehyde selectivity were obtained with mesoporous silica as stabilizer than with nonporous silica, which is attributed to the enhanced diffusion rate of the reactants by the mesopore and uniform distribution of Rh-TPPTS in the mesopore. The Pickering emulsion system could be easily recycled without obvious loss of activity and aldehyde selectivity.

Water oxidation is a crucial reaction step in solar-to-chemical energy conversion processes such as photocatalytic water splitting and carbon dioxide reduction. In natural photosynthesis, the water oxidation reaction is catalyzed by μ-oxido-Mn4Ca clusters in photosystem II (PSII). Herein, we report the fabrication of nanostructured biomimetic calcium manganese oxides (CaxMnOy) via a simple process under mild conditions utilizing H2O2 as an oxidant and TMAOH (tetramethylammonium hydroxide) as an alkaline source. CaxMnOy materials with x higher than 0.26 are composed of nanoparticles with particle sizes ranging from 15 to 30 nm according to the result of HRTEM. The results of X-ray absorption fine structure (XAFS) indicate that calcium manganese oxides have similar structural motifs to the catalytically active site for water oxidation in PSII. It was also found that the content of Ca and the concentration of H2O2 in the initial mixture could affect the crystallinity and the average Mn valence state of calcium manganese oxides. Water oxidation experiments for both chemical and photocatalytic systems suggest that the disordered structure of calcium manganese oxides and a modest valence state of Mn (+3.7 to +3.8) are necessary for achieving high activity. Our method provides a strategy for synthesis and modulation of nanostructured biomimetic water oxidation catalysts.

Research on transition metal–nitrogen–carbon (M–N–C) materials revealed their potential as catalysts in several important traditional reactions. However, the activity of M–N–C still needs to be further improved and the real active center of M–N–C catalysts is still under debate. In this work, an efficient Fe–N–C@CNTs for the hydrogenation of nitroarenes was prepared by pyrolysis of FeCl3, phenanthroline and CNTs. Fe–N–C supported on CNTs is much more active than that supported on activated carbon, showing the promotion effect of CNTs. The characterization results suggest that the high activity of Fe–N–C is mainly attributed to the formation of e-Fe3N, which is the active site for the hydrogenation reaction. Nitrogen/carbon atoms contacted to the active centers could serve as bridges to transport the dissociated hydrogen atoms via spillover effect. The catalytic performance of Fe–N–C was also tested on fixed bed reactor under continuous flow condition for the first time and could smoothly catalyze the reaction for over 300 hours.

Three types of E-mode AlGaN/GaN MIS-HEMTs with different barrier depths and conventional HEMT were fabricated on the Si substrates. HfO2 gate insulator with a thickness of 30 nm was grown by plasma enhanced atomic layer deposited (PEALD). Characteristics of the four devices with different recess depths are analyzed. The MIS-HEMT with barrier layer thickness of 3 nm features good comprehensive performance. The threshold voltage (Vth) is 1.8 V, the drain current density is 480 mA/mm and the figure of merit (FOM) is 363 MW/cm2. When the barrier thickness is 0 nm, the Vth is up to 3.7 V. A calculation model of threshold voltage for recessed MIS-HEMTs is proposed. When the barrier layer thickness is 6 nm, the calculated value of Vth was 0.3 V which is in good match with the experimental value of 0.4 V. The proposed model provides guidelines for the AlGaN/GaN MIS-HEMTs designs.

Traditional Chinese Medicines (TCMs) have been widely used in clinical practice, and provided a rich source for discovering new drug leads. However, efficient identification of active molecules responsible for the therapeutic effects of complex TCMs is still highly challenging. Here, we combined label-free cell phenotypic assay with two dimensional liquid chromatography (2DLC) to identify potential β

This paper reports the chemical identity and mechanism of action and formation of a cell growth inhibitory compound leached from some single-use Erlenmeyer polycarbonate shaker flasks under routine cell culture conditions. Single-use cell culture vessels have been increasingly used for the production of biopharmaceuticals; however, they often suffer from issues associated with leachables that may interfere with cell growth and protein stability. Here, high-performance liquid-chromatography preparations and cell proliferation assays led to identification of a compound from the water extracts of some polycarbonate flasks, which exhibited subline- and seeding density-dependent growth inhibition of CHO cells in suspension culture. Mass spectroscopy, nuclear magnetic resonance spectroscopy, and chemical synthesis confirmed that this compound is 3,5-dinitro-bisphenol A. Cell cycle analysis suggests that 3,5-dinitro-bisphenol A arrests CHO-S cells at the G1/Go phase. Dynamic mass redistribution assays showed tha...

Rh-PPh3-polymer@mesosilica composites were prepared by the polymerization of mixtures of divinylbenzene (DVB) and 4-vinyl-triphenylphosphine monomer in the nanopores of mesoporous silicas followed by coordination with Rh(acac)(CO)2 (acac =acetylacetonate). These catalysts were characterized by XRD, N2 sorption, TEM, FT-IR, and TG, and could efficiently catalyze the hydroformylation of 1-octene with higher activity than a pure polymer catalyst because of their high surface area and large pore volume, which were beneficial for the exposure of active sites and mass transport. Through the control of pore size and pore connectivity by using different mesoporous silica (MCM-41, SBA-15, and FDU-12), the activity and selectivity can be controlled. Rh-PPh3-polymer@FDU-12 with a cage-like mesostrucuture showed lower activity but slightly higher selectivity than the catalyst with a 2-D hexagonal mesostructure (Rh-PPh3-polymer@SBA-15 or Rh-PPh3-polymer@MCM-41). By varying the polymer content in the nanopores of the mesosilica, the activity and selectivity (92%–96%) can also be tuned. The solid composite catalyst can be recycled without loss of activity, but a decrease in selectivity was observed.

To explore new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-derived metal-organic frameworks (MOFs), we employed 2,6-dicarboxyl-1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (H2L) as a ligand to successfully synthesize five coordination polymers, namely, {[Zn2(L)2(bpp)]·2H2O·2EtOH}n (1), {[Cd2(L)2(bpp)]·2H2O·EtOH}n (2), {[Cd2(L)(bpe)3(NO3)2]·2H2O·DMF·EtOH}n (3), {[Cd(L)(bpe)0.5(DMF)(H2O)]}n (4), and {[Cd(L)(bpe)0.5]·1.5H2O·DMF}n (5) (bpp = 1,3-bi(4-pyridyl)propane, bpe = 1,2-bi(4-pyridyl)ethane). Except for two 2D-layer coordination polymers 3 and 4, the rest samples exhibit 3D metal-organic frameworks with certain pore sizes, especially MOFs 1 and 5. Spectroscopic and crystallographic investigations demonstrate that the absorption and emission energies of the BODIPY chromophores are sensitive to the coordination modes. Moreover, in case 2, the transition metal centers coordinated with the dicarboxylate ligands L(2-) are capable of forming the two BODIPY units in coplanar arrangements (θ = 37.9°), simultaneously suppressing the uncommon J-dimer absorption band centered at 705 nm with a long tail into the near-infrared region at room temperature. On the other hand, in comparison with the ligand H2L, the emission of monomer-like BODIPY in case 3 is enhanced in the solid state by a considerably long distance between the parallel BODIPY planes (about 14.0 Å).

The Noyori catalyst RuCl2(R-Binap)(dmf)n has been successfully encapsulated in C-FDU-12 by using the active chlorosilane Ph2Cl2Si as the silylating agent. 31P-NMR results show that there is no strong interaction between the molecular catalyst and the solid support, thus the encapsulated molecular catalyst could move freely in the nanoreactor during the catalytic process. The solid catalyst exhibits high activity and enantioselectivity for the asymmetric hydrogenation of a series of β-keto esters due to the preserved intrinsic properties of RuCl2(R-Binap)(dmf)n encapsulated in the nanoreactor. The solid catalyst could be recycled by simple filtration and be reused at least four times.

The asymmetric multicomponent catalyst, Rh-MonoPhos, was successfully encapsulated in the nanocages of mesoporous silicas with cage-like structure (FDU-12 and C-FDU-12). The resulting solid catalyst exhibits excellent activity (TOF 2052 h−1) and enantioselectivity (93% ee) in the asymmetric hydrogenation of olefin derivatives. The solid catalyst with Rh(MonoPhos)2 in nanocages affords considerably higher activity than that with Rh(MonoPhos)1 or Rh(MonoPhos)3 in nanocages. Combined with the ESI-MS results, it could be supposed that RhL2(nbd) may be active species or the precursors for active species. Moreover, the solid catalyst with C-FDU-12 (inner surface modified by a thin carbon layer) as host material shows considerably higher activity and enantioselectivity than that with pure silica FDU-12 as host material in the asymmetric hydrogenation of different types of olefin derivatives, indicating that the microenvironment modification is one of the key factors for improving the catalytic performance of the solid catalyst. The solid catalysts possess high stability and could be reused for at least 7 times.

A highly efficient chiral solid catalyst was synthesized via in situ polymerization of a chiral monomer (1R,2R)-N1-(4-vinylbenzenesulfonyl)-1,2-diphenylethane-1,2-diamine (VBS-DPEN) together with divinylbenzene (DVB) in the nanocages of mesoporous silica (FDU-12) followed by coordination with a metal precursor [Cp*RhCl2]2 (Cp* = pentamethylcyclopentadiene). The solid chiral catalyst with hydrophilic outer and hydrophobic inner surface properties could be well dispersed in aqueous solution and facilitate the adsorption of hydrophobic ketones in it. As a result, it could efficiently catalyze the aqueous asymmetric transfer hydrogenation (ATH) of ketones to afford 94% ee and a much higher TOF than homogeneous Rh-TsDPEN (TOF 585 versus 340 h−1). Our studies suggest that the dispersion of polymers in the nanopores of mesoporous silica could provide a new approach to the synthesis of high performance solid catalysts for organic reactions in water.

Efficient and stable solid acids have been successfully synthesized by sulfonation of polystyrene (PS) in the hollow interiors of silica-based hollow nanostructures. It was found that larger and smaller inner void spaces result in the formation of PS-SO3H@phenylenesilica respectively with double-shell (DSNs) and yolk–double-shell nanostructure (YDSNs). PS-SO3H@phenylenesilica with DSNs and YDSNs nanostructure shows comparable activity and is more active than Amberlyst-15 in the esterification reaction. PS-SO3H@phenylenesilica with YDSNs nanostructure affords higher activity than that with DSNs nanostructure in the Friedel–Crafts alkylation of toluene with 1-hexene, which is mainly attributed to the fact that the unique YDSNs nanostructure could slow down the swelling rate of PS-SO3H during the catalytic process. More importantly, PS-SO3H@phenylenesilica with YDSNs nanostructure showed much higher recycle stability than Amberlyst-15 in the Friedel–Crafts alkylation of toluene with 1-hexene, probably due to the high thermal stability of the sulfonic acid group and the unique YDSNs nanostructure.

Via very simple and facile adsorption, Rh–MonoPhos was successfully immobilized on mesoporous silicas with channel-like and cage-like pores. The resulting solid catalyst showed higher activity (TOF: 4800 vs. 936 h−1) and enantioselectivity (96.0% vs. 94% ee) than its homogeneous counterpart in the asymmetric hydrogenation of itaconic acid dimethyl ester under similar conditions, probably due to the high dispersion of Rh–MonoPhos on mesoporous silicas. Significant rate enhancement was observed with Rh–MonoPhos immobilized on mesoporous silicas with cage-like pores in comparison with channel-like pores, reflecting that cage-like pores could facilitate the mass transport. The solid catalyst could be recycled several times without an obvious decrease in both activity and enantioselectivity.