Search

Amines in porous materials have been employed as active species for the selective CO2 adsorption from natural gas because of their target-specific interactions. Nevertheless, it is difficult to modulate such strong interactions to reach a high efficiency in the adsorption processes. Herein, we fabricated light-responsive adsorbents with tunable adsorbent–adsorbate interactions for CO2 capture. The adsorbents were synthesized by introducing primary and secondary amines into a mesoporous silica that had been grafted with azobenzene groups on the surfaces. The target-specific amine sites render the adsorbents significantly selective in the uptake of CO2 over CH4, and the azobenzene groups were used as light-responsive switches to influence the adsorbent–adsorbate interactions. The adsorbents can freely adsorb CO2 when the azobenzene groups are in the trans state. Ultraviolet-light irradiation makes the azobenzene groups transform to the cis configuration, which greatly hinders amines in the uptake of CO2. The caused difference of adsorption capacity can reach 34.9%. The alternative irradiation by ultraviolet- and visible-light can lead to a recyclable regulation on adsorption performance. The changes of the electrostatic potentials of amines are responsible for the light-induced regulation on adsorption.

The first rate-limiting enzyme of the serine synthesis pathway (SSP), phosphoglycerate dehydrogenase (PHGDH), is hyperactive in multiple tumors, which leads to the activation of SSP and promotes tumorigenesis. However, only a few inhibitors of PHGDH have been discovered to date, especially the covalent inhibitors of PHGDH. Here, we identified withangulatin A (WA), a natural small molecule, as a novel covalent inhibitor of PHGDH. Affinity-based protein profiling identified that WA could directly bind to PHGDH and inactivate the enzyme activity of PHGDH. Biolayer interferometry and LC–MS/MS analysis further demonstrated the selective covalent binding of WA to the cysteine 295 residue (Cys295) of PHGDH. With the covalent modification of Cys295, WA blocked the substrate-binding domain (SBD) of PHGDH and exerted an allosteric effect to induce PHGDH inactivation. Further studies revealed that with the inhibition of PHGDH mediated by WA, the glutathione synthesis was decreased and intracellular levels of reactive oxygen species (ROS) were elevated, leading to the inhibition of tumor proliferation. This study indicates WA as a novel PHGDH covalent inhibitor, which identifies Cys295 as a novel allosteric regulatory site of PHGDH and holds great potential in developing anti-tumor agents for targeting PHGDH., Graphical abstract WA is a novel covalent-allosteric inhibitor of phosphoglycerate dehydrogenase (PHGDH), and inhibits the serine synthesis pathway and proliferation of colon cancer cells with overexpression of PHGDH.Image 1

Graphical abstract, Introduction Previously, we have reported a withanolide-type steroid, named tubocapsenolide A (TA), which shows potent anti-proliferative activity in several cancer cell lines. However, its inhibitory effect on the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway and therapeutic potential on osteosarcoma have not been reported. Objectives In the present study, we aimed to investigate the effect and molecular mechanism of TA in osteosarcoma. Methods The biological functions of TA in U2OS cells were investigated using colony formation, 5-ethynyl-20-deoxyuridine (EDU) staining, and cell cycle/apoptosis assays. The interaction between TA and Src homology 2 phosphatase 2 (SHP-2) was detected by enzyme activity and validated by target-identification methods such as drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA), and biolayer interferometry (BLI). The in vivo anti-tumor efficacy of TA was analyzed in the xenograft tumor model. Western blotting analysis was performed to detect the protein expression levels. Results TA exhibited antitumor activity against osteosarcoma both in vitro and in vivo by regulating the JAK/STAT3 signaling pathway. Mechanically, TA interacted with SHP-2 directly and activated its phosphatase activity. Importantly, protein tyrosine phosphatase (PTP) inhibitor, SHP-2 inhibitor, and SHP-2 siRNA could reverse the inhibitory effect of TA on the JAK/STAT3 signaling pathway and restored the TA-induced cell death. Conclusion TA activated the phosphatase activity of SHP-2, which resulted in the inhibition of the JAK/STAT3 pathway and contributed to the antitumor efficacy of TA. Collectively, these findings suggested that TA could serve as a novel therapeutic agent for the treatment of osteosarcoma.

Solid strong bases can catalyze a variety of organic reactions under mild conditions. Their preparation consists of loading base precursors (e.g. KNO3) on porous supports followed by activating to convert base precursors to basic sites (e.g. K2O). However, high temperatures are usually required for activation, which consumes lots of energy and damages the structure of supports. Moreover, filtration or centrifugation is mainly adopted for the recovery of solid base catalysts, which is tedious and limits their applications to some extent. In this paper, we constructed multifunctional core–shell structured Fe3O4@C microspheres as the supports owing to the reducibility of carbon shell and the magnetism of Fe3O4 core, thus creating magnetically responsive solid strong bases under mild conditions. Strong basic sites can be formed at a low temperature of 400 °C due to the redox reaction between the carbon shell and the base precursor, yielding the solid base K-400@Fe3O4@C. Such a temperature is obviously lower than the temperature for the decomposition of KNO3 on the frequently used supports SiO2 (750 °C) and Al2O3 (500−700 °C). The resultant solid base K-400@Fe3O4@C exhibits excellent catalytic activity in transesterification reaction, and the yield of target product dimethyl carbonate is higher than some benchmarks like MgO, CsX, and Na2O/Al2O3. In addition, thanks to the superparamagnetism, the solid base catalysts can be recovered within 10 s with the assistance of external magnetic fields.

Four new highly oxidized sesquiterpene lactones, Argyoxynolides A–D, along with two known analogs were isolated from the leaves of Artemisia argyi H.Lev. & Vaniot. Their structures were characterized utilizing extensive spectroscopic methods. All isolates were evaluated for the LPS-induced nitric oxide (NO) production inhibitory activity and one compound exhibited activity with IC50 = 37.95 ± 4.39 μM.

Metal–organic polyhedra (MOPs) have emerged as versatile platforms for artificial models of biological systems due to their discrete structure and modular nature. However, the design and fabricatio...

Metal-organic frameworks (MOFs) have attracted increasing research enthusiasm owing to their tunable functionality, diverse structure characteristics, and large surface area. However, poor hydrothermal stability restricts the utilization of some MOFs in practical applications. Our work aims at improving the hydrothermal stability of a representative MOF, namely, HKUST-1, by incorporating a two-dimensional material Ti3C2Tx MXene for the first time. A new type of hybrid material is synthesized through the hybridization of HKUST-1 and Ti3C2Tx, and the obtained hybrids show improved hydrothermal stability as well as catalytic performance. The porosity of hybrids is enhanced when incorporating an appropriate amount of Ti3C2Tx, and the surface area can reach 1380 m2·g-1, while the pristine HKUST-1 is 1210 m2·g-1. After the hydrothermal treatment (hot water vapor, 70 °C), the structure of hybrid materials maintains well, while the framework of HKUST-1 is severely destroyed. When catalyzing the ring-opening reaction of styrene oxide, the conversion reaches 76.7% only for 20 min, which is much higher than that of pure HKUST-1 (23.1% for 20 min). More importantly, the catalytic activity could recover without loss even after six cycles. Our hybrid materials are promising in practical catalytic applications due to their excellent hydrothermal stability, catalytic activity, and reusability.

Enantioenriched indole derivatives are widely found in natural products, pharmaceuticals and bioactive compounds. Therefore, developing efficient methods for the synthesis of enantioenriched indole derivatives has become an important goal in the community of organic chemistry. To this end, chemists have designed and developed a variety of indole-containing platform molecules and their related catalytic asymmetric reactions. Among these approaches, vinylindoles have proved to be versatile platform molecules for accessing enantioenriched indole derivatives via catalytic asymmetric reactions, especially organocatalytic asymmetric reactions. Based on this approach, a plethora of chiral indole derivatives have been synthesized with optical purity and structural complexity. This review summarizes advances in vinylindole-based organocatalytic asymmetric reactions since 2008 and includes the applications of some methodologies in the total synthesis of natural products. In addition, this review points out the remaining challenges in this research area to be confronted by organic chemists, which will shed light on the future development of this area.

CuI-Functionalized materials show high potential in numerous applications such as adsorptive desulfurization. Nonetheless, the instability of CuI against oxidation limits its practical applications, and exposure of CuI to air can lead to the formation of CuII owing to the presence of oxygen and moisture. Herein, an unexpected way to stabilize CuI against oxidation was designed by constructing a superhydrophobic microenvironment in original hydrophilic metal–organic frameworks (MOFs) via polystyrene (PS) coating. A pre-polymerization strategy is developed to coat PS on the surface of CuI-functionalized MIL-101(Cr) (CuIM) rather than entering the pores (producing CuIM@PS), and the access of moisture to CuI is hindered, thus stabilizing CuI regardless of the existence of oxygen. CuI in CuIM@PS is stable in the air with a constant relative humidity of 75% for 200 days, while almost all CuI is converted to CuII in CuIM in only 14 days. The optimal CuIM@PS material after air exposure can adsorb 0.208 mmol g−1 of thiophene, which is much superior to that of CuIM (0.024 mmol g−1) despite the comparable adsorption capacity for unexposed materials. Moreover, the present CuIM@PS adsorbents exhibit excellent adsorption performance for water-containing model fuels.

Reproducing the highly efficient catalytic cascade system to mimic life behaviors in vitro has been intensively investigated over the past few decades. However, except for biocatalysis with enzymes, most chemocatalytic cascades in essence combine several reactions that occur over mutually independent catalytic sites in a container. Herein, with a series of control experiments and stepwise theoretical derivation based on the calculations of density functional theory and a semi-empirical method, a generalized cascade catalysis is discovered for the chemocatalytic conversion of CO2 to higher alcohols over a porphyrinic zirconium metal–organic framework, PCN-224-Cu. Two types of catalytic sites in PCN-224-Cu, i.e., the Zr6 cluster and TCPP-Cu unit, act like organelles, which can complete a class of reactions instead of particular one. The Zr6 cluster is in charge of molecular dissociation, while the TCPP-Cu unit is responsible for molecular assembly. Therefore, semi-finished intermediates repeatedly transfer between the two types of catalytic sites until the ultimate formation of ethanol with high efficiency (ethanol yield, 4.53 mmol h−1 gcat.−1 at 403 K) and selectivity (∼100%).

Hypoxia is a parameter related to many diseases. Ratiometric hypoxia probes often rely on a combination of an O2 -insensitive fluorophore and an O2 -sensitive phosphor in a polymer matrix, which require high cost and multi-step synthesis of transition metal complexes. The two-chromophore hypoxia probes encounter unfavorable energy transfer processes and different stabilities of the chromophores. Reported herein is a pure organic ratiometric hypoxia nanoprobe, assembled by a monochromophore, naphthalimide ureidopyrimidinone (BrNpA-UPy), bridged by a bis-UPy-functionalized benzyl skeleton. The joint factors of quadruple hydrogen bonding, the rigid backbone of UPy, and bromine substitution of the naphthalimide derivative facilitate bright phosphorescence (ΦP =7.7 %, τP =3.2 ms) and fluorescence of the resultant nanoparticles (SNPs) at room temperature, which enable accurate, ratiometric, sensitive oxygen detection (Ksv =189.6 kPa-1 ) in aqueous solution as well as in living HeLa cells.

Palladium (Pd)-containing catalysts have gained extensive attention because of their outstanding activity in various heterogeneous catalytic reactions. The activity of these catalysts highly correl...

Eight new germacranolides, minusolides A–H (1–8), along with two known analogues, 9 and 10, were isolated from the whole plant of Carpesium minus. Their structures were elucidated by spectroscopic ...

With the carbonization at an elevated temperature, high aromaticity of a precursor for porous carbons was traditionally thought to be crucial for the resultant perfect textural properties and ideal application performances of the porous carbons. Thus, many efforts have been done to search or to artificially prepare the polymer precursors with higher aromaticity to generate more satisfying porous carbons. However, an antiempirical case was found in this study. The copolymerization between 1,3,5-tris(chloromethyl)-2,4,6-trimethylbenzene (TCM) and cyclohexane-1,4-diamine was successfully implemented to get a polymer code-named NUT-40, in which half of the ring structures are nonaromatic, while N-doped porous carbons (NDPCs) with better textural properties (e.g., SBET = 1363 m2 g−1 for NDPC-600) and competitive CO2 capture abilities (e.g., CO2 capacity = 4.3 mmol g−1 at 25 °C and 1 bar for NDPC-600) were generated from the NUT-40, compared with the NDPC counterparts derived from the NUT-4 in a previous study (e.g., SBET = 958 m2 g−1 and CO2 capacity = 3.8 mmol g−1 at 25 °C and 1 bar for NDPC-600), in which TCM and ursol were employed as the monomers instead, and thus the ring structures in the NUT-4 was fully aromatic. With first-principle and molecular dynamics simulations, it was demonstrated that the embryo pore structure in the NUT-40 molecule can be more easily maintained during the carbonization than that of the NUT-4, which finally improves the surface area and porosity of the NUT-40 generated NDPCs.

Due to the good controllability and high energy efficiency in adsorption processes, photoresponsive adsorbents are intriguing for CO2 capture. Nevertheless, most reported photoresponsive adsorbents are designed based on weak adsorption sites, regulating CO2 adsorption through structural change or steric hindrance. In addition, ultraviolet (UV) light is commonly involved in the regulation of adsorption capacity. Here we report for the first time the smart adsorbents for CO2 capture, which makes strong adsorption sites respond to visible (Vis) light. The adsorbents were fabricated by introducing primary amine and Dispersed Red 1 (DR1, a kind of push-pull azobenzene that responds to Vis light rapidly) units to mesoporous silica, which act as strong adsorption sites and triggers, respectively. The primary amine sites make the adsorbents highly selective in the adsorption of CO2 over CH4. Without light irradiation, azobenzene is in the form of trans configuration, which leads to decreased electrostatic potential of primary amines and subsequently, exposure of active sites and liberal adsorption of CO2. Upon Vis-light irradiation, cis isomers are formed, which results in increased electrostatic potential of primary amines and subsequently shelter of active sites. Even on such strong adsorption sites, the alteration of CO2 adsorption capacity can reach 40% for the adsorbent with and without Vis-light irradiation. Moreover, the trans/cis isomerization of DR1 units can be triggered reversibly by Vis light. The present smart system endows adsorbents with selective adsorption capacity and avoids the employment of UV light, which is unlikely to be achieved by conventional photoresponsive adsorbents.

Due to the nontoxicity, low cost, and versatility, CuO-functionalized materials have received much attention. Their performances are intensely dependent on the dispersion state of CuO. Herein we re...

The zeolite Cu(I)Y is promising for adsorptive removal of thiophenic sulfur compounds from transportation fuels. However, its application is seriously hindered by the instability of Cu(I), which is easily oxidized to Cu(II) even under atmospheric environment due to the coexistence of moisture and oxygen. Here, we report the adjustment of zeolite microenvironment from hydrophilic to superhydrophobic status by coating polydimethylsiloxane (yielding Cu(I)Y@P), which isolates moisture entering the pores and subsequently stabilizes Cu(I) despite the presence of oxygen. Cu(I) in Cu(I)Y@P is stable upon exposure to humid atmosphere for 6 months, while almost all Cu(I) is oxidized to Cu(II) in Cu(I)Y for only 2 weeks. The optimized Cu(I)Y@P material after moisture exposure can remove 532 μmol g−1 of thiophene and is much superior to Cu(I)Y (116 μmol g−1), regardless of similar uptakes for unexposed adsorbents. Remarkably, Cu(I)Y@P shows excellent adsorption capacity of desulfurization for water-containing model fuel., Zeolite Cu(I)Y is attractive for adsorptive removal of sulfur compounds from fuel, however practical application is limited by instability of Cu(I). Here the authors use a coating to achieve superhydrophobicity in the zeolite, leading to improved Cu(I) stability against oxidation and thiophene removal.

Achieving efficient adsorption and desorption processes by controllably tuning the properties of adsorbents at different technical stages is extremely attractive. However, it is difficult for traditional adsorbents to reach the target because of their fixed active sites. Herein, we report on the fabrication of a smart adsorbent, which was achieved by introducing photoresponsive azobenzene derivatives with cis/trans isomers to Ce-doped mesoporous silica. These photoresponsive groups serve as “molecular switches” by sheltering and exposing active sites, leading to efficient adsorption and desorption. Ce is also doped to provide additional active sites in order to enhance the adsorption performance. The results show that the cis isomers effectively shelter the active sites, leading to the selective adsorption of methylene blue (MB) over brilliant blue (BB), while the trans isomers completely expose the active sites, resulting in the convenient release of the adsorbates. Both selective adsorption and efficient desorption can be realized controllably by these smart adsorbents through photostimulation. Moreover, the performance of the obtained materials is well maintained after five cycles.

Polycarbonate diols (PCDLs) are intermediates used in the synthesis of polyurethanes (PU), and therefore their efficient and green synthesis is a necessity. In this work, KOH/K2CO3@γ-Al2O3 catalysts were prepared and employed in the synthesis of PCDLs. A 4 wt% KOH/40 wt% K2CO3@γ-Al2O3 catalyst and a DMC: 1,4-BDO molar ratio of 1.25:1 exhibited the best activity for the reaction and gave a PCDL yield of 95% with a molecular weight of 4527 g·mol−1. Moreover, the catalyst could be reused 4 times without a significant loss of the catalytic activity in transesterification. The effects of the catalyst composition and reaction conditions on the synthesis of PCDLs were investigated. The results indicate that the catalyst amount and the molar ratio of DMC: 1,4-BDO can influence the purity of PCDLs. The reaction equation Catalyst preparation The synthesis of PCDLs using DMC and 1,4-BDO

Taxodisones A and B, C30-terpenes with an unprecedented tetracyclo[12.4.0.0.2,709,14]octodecane core, were isolated from the seeds of Taxodium distichum. Their structures, including their configurations, were unambiguously determined. Their biomimetic synthesis suggests that they stem from diterpenes and monoterpenes, and not from squalene or oxidosqualene. In addition, their bioactivities were also evaluated.

N-doped porous carbon-based materials (NPCMs) with hierarchical pore structures have been considered to be a suitable alternative to meet the ever-increasing demands for supercapacitors; however, the universally low yield of the NPCMs has restricted their practical applications. Herein, a series of NPCMs with hierarchical pore structures are synthesized with significantly increased yields through the carbonization of the copolymer made from 2,4,6-tris(chloromethyl)mesitylene and p-phenylenediamine. The development of the hierarchical pore structures and the N content of the NPCMs show opposite dependences on the increasing carbonization temperature. The NPCM exhibits the best capacitive ability only if the sufficiently developed hierarchical structures and moderate N content are achieved simultaneously. Therefore, NPCM-600 that is carbonized at 600 °C with an excellent yield of 53.6% (wt.), large specific surface area of 1778 m2 g−1, and N content of 4.13% (wt.) yields an ideal specific capacitance of 298 F g−1 at the current density of 1 A g−1 and a perfect cycling stability of the capacitance after 10,000 cycles at 10 A g−1. The yield of the NPCM-600 is considerably higher than those for many other recently reported NPCMs. NPCM-600 also shows better capacitance than those of the other reported NPCMs, such as NOPC-bis-CN-3 (167 F g−1) and CHCPB-K-600 (260 F g−1).

Manganese monoxide (MnO) has attracted much attention as anode materials in lithium ion (Li+) batteries (LIBs) due to its high theoretical capacity and being environmentally friendly. However, the low electrical conductivity, as well as structural collapse during the lithiation/delithiation process, limits its application. In this study, a novel MnO/C composite was feasibly synthesized by employing renewable petal cells as bioscaffolds. Mn(II) ions were firstly infiltrated into the confined space in the cellular walls of camellia petals, then transformed into MnO nanoparticles (average size of 22 nm) after calcination under nitrogen. At the same time, the camellia petal biotemplate was changed to the biocarbon in the composite, forming a C/MnO/C “layer–particle–layer” sandwich-like structure. Composition of the composite and chemical environment for the elements was further characterized by TG, FT-IR, Raman and XPS. When the composite is used as anode material in a half-cell LIB, the carbon layer can improve the conductivity of the electrode, and the unique sandwich-like structure can alleviate the volume expansion of MnO during the electrochemical cycling. As a result, the special MnO/C composite achieves a good specific capacity (445 mAh g−1 at 100 mA g−1 for more than 300 cycles) with excellent cycle stability. Quantitative analysis reveals that capacitance and diffusion mechanisms both account for Li+ storage.

2,4-Dichlorophenylacetic acid is synthesized in high yield via the carbonylation of 2,4-dichlorobenzyl chloride, and various experimental conditions are evaluated. Xylene, bistriphenylphosphine palladium dichloride, tetraethylammonium chloride and sodium hydroxide in solution are added to the reaction system and held at 80 °C under a CO atmosphere. 2,4-Dichlorophenylacetic acid is obtained in a maximum yield of 95%, and a mechanism for 2,4-dichlorobenzyl chloride carbonylation is proposed. The reaction system provides a mild, effective and novel means by which to prepare phenylacetic acid derivatives from their corresponding benzyl chloride derivatives.

Reducing the nitrogen-containing compounds (NCCs) in fuel oils to ultralow level is essential for preventing the oil refining catalysts from being poisoned and for protecting the environment. Adsorptive denitrogenation is proved to be an effective mean to reduce the NCCs content. Herein, a series of N-doped porous carbons (NDPCs) in possession of proper pore structures, large surface area and moderate N species, which is verified through a series of characterization, are synthesized on the basis of the precursor copolymerized between 2,4,6-tris(chloromethyl)mesitylene and ethylenediamine. The NDPC-700 produced from the copolymer carbonization at 700 °C exhibits a record high adsorptive capacity of 7.35 mmol·g−1 for indole in the model oils, and the stable performance on the NCC adsorption is observed after 10 cycles of regeneration and reusage. The excellent adsorption capacity is attributed to the synergistic effect between porosities and N-containing sites. Moreover, the first-principle simulation proves that the N species, in particular the N-5 species, is helpful to the improvement of the adsorption capacity for indole.

MXenes, an emerging class of two-dimensional (2D) transition-metal carbide materials, have received increasing attention for their interesting physiochemical properties. For not only MXenes but also other 2D materials, delamination is a requisite step for the exploitation of their unique properties. In this work, a facile method for exfoliating Ti3C2Tx MXene to nanosheets of small size with the aid of poly(vinylpyrrolidone) (PVP) is designed, which has never been reported to our knowledge. Since both hydrophobic methylene groups and hydrophilic amide groups are provided with PVP, this method is applicable in a wide range of solvents, such as ethanol, water, and chloroform. Considering the charge detrapping and trapping behavior of 2D transition-metal materials in PVP dielectric, a memory device with the configuration of reduced graphene oxide (rGO)/Ti3C2Tx-PVP/Au is directly fabricated with these well-dispersed Ti3C2Tx-PVP composites by the solution process technique. Interestingly, the resultant device exhibits a typical bistable electrical switching, ultralow switching voltage (∼0.9 V), and a nonvolatile rewritable memory effect with the function of flash. This work might pave the way of using MXenes for future data storage, which is an indispensable field nowadays.

N-doped porous carbons (NPCs) are characterized by well-developed porosity and N-doped active sites, which makes them suitable for CO2 capture. However, their application in practice is obstructed by the relatively low N-doped content and unsatisfactory adsorption capacity. Herein, we report the synthesis of NPCs through the rational design of the precursor NUT-21 (NUT means Nanjing Tech University) with a record-high N content (up to 46.16%, wt). The NUT-21 was fabricated by the polymerization of two simple monomers of 2,4,6-tris(bromomethyl)mesitylene and 3,5-diamino-1,2,4-triazole with an unusually high N content of 70.67% (wt). With the carbonization of NUT-21 at different temperatures (500, 600, and 700 °C, respectively), a series of NPCs possessing various porosity and N contents are produced, successfully. For the NPC generated at 600 °C, the N content can reach 7.41% (wt), the surface area is 2208 m2/g, the micropore volume is 0.791 cm3/g, and the CO2 capacity is up to 8.3 mmol/g at 273 K and 1 bar, which is much higher than those of benchmarks including 13X zeolite (4.1 mmol/g) and activated carbon (2.8 mmol/g), and most carbon-based adsorbents reported till now. It was proved in our previous studies that the ultrahigh N content of the precursor was beneficial for both the formation of developed porosity and the generation of abundant N-doped sites, which can give rise to superior capacity and selectivity of CO2 capture. The NPCs obtained may offer to be highly promising candidates for CO2 separation from gas mixtures including natural gas and flue gas.

Because of their nontoxicity, economic applicability, and excellent performance on adsorptive desulfurization, the fabrication of Cu(I) sites onto porous supports has drawn much attention. However, high temperatures (usually ≥700 °C) are required for the formation of Cu(I) sites from Cu(II) species through the traditional autoreduction method, which is unworkable for thermolabile metal-organic frameworks (MOFs). Here, we report a strategy named vapor-induced reduction (VIR) to convert Cu(II) species to Cu(I) in MIL-101(Cr), in which ethanol is used as an environmentally benign reductant. The entire formation of Cu(I) from Cu(II) with more than 96% selectivity is allowed, at a relatively low temperature of 200 °C, and well-maintains the structure of the MOF. Moreover, the generated Cu(I) sites exhibit good performances in adsorption desulfurization with regard to both activity and reusability.

Because of their high stability, abundant porosity, and tailorable surface properties, N-doped porous carbons (NPCs) have played a crucial part in CO2 capture. Development of an efficient and low-cost method to fabricate NPCs remains a significant challenge. Herein, we report for the first time the preparation of NPCs through the rational design of the N-enriched polymer NUT-20-EDA (NUT, Nanjing Tech University; EDA, ethylenediamine) as the precursor. The NUT-20-EDA was obtained by polymerization of two simple monomers of mesitylene and formaldehyde dimethyl acetal, followed by post-synthetic ammonification. Through carbonization at temperatures ranging from 600 °C to 800 °C, NPCs with different porosity and N contents are fabricated, successfully. The reference porous carbons (rPCs) are also synthesized based on the polymer NUT-20 without post-synthetic ammonification. For the representative sample generated at 700 °C (NPC-700), the surface area is up to 1852 m2/g, which is much larger than its counterpart rPC-700 (1324 m2/g). Moreover, the CO2 uptake of NPC-700 (7.1 mmol/g at 0 °C and 1 bar) is higher than that of rPC-700 (5.9 mmol/g), and also superior to those of many benchmarks reported, including 13X zeolite (4.1 mmol/g) and activated carbon (2.8 mmol/g). Therefore, it is proved that, as a pore-foaming agent during the carbonization, the amino groups incorporated play a significant role in the formation of abundant porosity of the NPCs, which is one of the crucial factors for CO2 adsorption, and the N-species doped in NPCs can work as the CO2-philic sites to enhance the CO2 capture.

Because of their sufficient surface areas, developed porosities, and high stabilities, N-doped porous carbons (NDPCs) have presented an excellent CO2 adsorption ability. NDPCs are usually fabricated through the carbonization of N-containing polymers. The effect of N species enlarging surface areas and foaming pores has been confirmed. However, traditional polymer precursors of NDPCs must have a relatively high N content and give unsatisfactory structural characters and CO2 capacities of their NDPCs. In this study, an NDPC precursor code-named NUT-50-EDA with a N content of only 6.4 wt % is prepared, while the amino groups in the precursor still play a significant role in the porogen during the carbonization process. The generated NDPCs show more abundant micropores, larger surface areas, and higher CO2 adsorption capacities compared to those of the counterpart porous carbons (PCs) made from the precursor without ammonification. With a relatively low N content (1.5 wt %), NDPC-700 with a large surface area...

Mesoporous solid strong bases are quite attractive due to their good catalytic performance for applications as environmentally friendly catalysts in various reactions. However, pretty harsh conditions are usually compulsory for the fabrication of strong basicity by using traditional thermal activation (e.g., 700 °C for the activation of base precursor KNO3 supported on mesoporous Al2O3). This is energy intensive and harmful to the mesoporous structure. In this study, we report a strategy of endowing supports with reducibility (ESWR) by doping low-valence Cr3+ into mesoporous Al2O3, so that the activation temperature for basicity generation is decreased significantly. Fascinatingly, KNO3 on mesoporous Al2O3 can be motivated to basic sites completely at the temperature of 400 °C via the ESWR strategy, which is much lower than the conventional thermal activation (700 °C). We have demonstrated that the redox reciprocity between KNO3 and Cr3+ is responsible for the low-temperature conversion, and Cr6+ is formed quantitatively as the oxidation product. The obtained solid bases possessing ordered mesostructure and strong basicity provide promising candidates for base-catalyzed synthesis of dimethyl carbonate via transesterification. The catalytic activity is obviously higher than a typical solid base like MgO as well as a series of reported basic catalysts containing alkali metal and alkaline-earth metal oxides.

The use of porous carbons for selective CO2 separation attracts increasing attention. Owing to low thermostability of porous polymers, low yield is the major concern of porous carbons. To obtain po...

With an increasing demand for green chemistry and sustainable development, it is needed to design a solid base with high catalytic activity, excellent stability and reusability. In this work, a new kind of magnetic solid basic catalyst KF/CaO–CoFe2O4 was prepared by the method including co-precipitation and isochoric impregnation, and it was successfully applied in the preparation of polycarbonate diol (PCDL) from the transesterification of 1,4-butanediol with dimethyl carbonate. The characteristics and properties of the catalyst were examined and analyzed by XRD, TEM, CO2-TPD and VSM. The effects of various parameters such as shell-core mole ratio, KF loading, calcination temperature, catalyst dosage, and the mole ratio of the raw materials on the yield of PCDL were investigated and the yield of PCDL can reach to 71.2% under the optimal reaction conditions. In addition, the catalyst can be easily separated by an external magnet after reaction, and the catalytic activity of the catalyst can well be maintained for 4 cycles.

Photoresponsive metal-organic polyhedra (PMOPs) have attracted expanding interests due to their modular nature with tunable functionality and variable responsive behaviors tailored conveniently by external-stimulus. However, their photoresponsive efficiency is often compromised after activation because of desorption-triggered aggregation into bulk PMOPs, which limits their utility in stimuli-responsive applications. Here, we report a case system that can overcome the aggregation problem and achieve maximized photoresponsive efficiency by polyhedral isolation in the nanoscaled spaces of mesoporous silica (MS). Through confinement, amount-controllable PMOPs are well dispersed in the nanoscaled spaces of MS, avoiding aggregation that commonly takes places in bulk PMOPs. Furthermore, reversible trans/ cis isomerization of photoresponsive groups can be realized freely during ultraviolet/visible light irradiation, maximizing control over photoresponsive guest adsorption behaviors. Remarkably, after trans/ cis isomerization, the confined PMOP-1 shows 48.2% of change in adsorption amount for propene with small molecular size and 43.9% for brilliant blue G (BBG) with large molecular size, which is significantly higher than that over bulk PMOP-1 with 11.2% for propene and 7.8% for BBG, respectively. Therefore, our work paves a way for the design and construction of multifunctional composite materials toward efficient stimuli-responsive needs.

Mesitylene, a representative heavy carbon by-product in the course of C1 chemical downstream processes, is proposed to be employed in this study, as the initial material to synthesize the porous carbons that have played a crucial part in the adsorptive carbon capture process but are generally made from natural carbon resources, instead of fed to the traditional refining process such as hydroprocessing. Based on molecular dynamics calculation, it is proved that once the mesitylene monomers are linked by the flexible methylene groups, the generated polymer can closely mimic the lignin macromolecular behaviors in terms of spatial configuration and atomic thermal motions, which gifts the great potential of the mesitylene-based polymer as applicable a precursor of porous carbon as the biomass-based material. The experimental facts further demonstrate that the porous carbons produced through the routine carbonization of the mesitylene-based polymer can possess desired textural peculiarities, in particular the finely developed micropores that give rise to perfect capacity and selectivity of CO2 capture, of which underlying mechanism is revealed by the first-principle calculation. The porous carbon generated at 700 °C can reach the CO2 capture capacity of 6.16 mmol g−1 at 0 °C and 1 bar, which is much higher than many benchmark materials reported, including some biomass-based porous carbons (2.8 mmol g−1, at 0 °C and 1 bar).

Direct oral anticoagulants are widely used to treat and prevent thromboembolic disorders. With rising clinical application, monitoring concentrations of direct oral anticoagulants are necessary in certain clinical conditions. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of dabigatran etexilate, dabigatran, rivaroxaban, edoxaban, and apixaban, in human plasma. Protein precipitation with methanol was performed for sample preparation. The direct oral anticoagulants and internal standards were separated under gradient conditions using a C18 column, at an analytical run time of 8 min. The mobile phase was composed of 0.1% (v/v) formic acid in water (solvent A) and 0.1% (v/v) formic acid in acetonitrile (solvent B) at a flow rate of 0.3 mL/min. Mass detection was performed in multiple reaction monitoring using positive ionization mode. The method was validated over a range of 1.0–500 ng/mL for dabigatran etexilate, 0.1–500 ng/mL for dabigatran, and 0.5–500 ng/mL for edoxaban, rivaroxaban, and apixaban. The method detection limits of five analytes were in the range of 0.05–0.5 ng/mL. The lower limits of quantification of five analytes ranged from 0.1 to 1 ng/mL. The linearity (r2 values) was higher than 0.997. The accuracy of the low, medium, and high quality control samples were between 85.9 and 114%, and intra- and inter-day precision were below 9.47%. This validated method was successfully used to determine the plasma concentrations of rivaroxaban in 32 patients, and of dabigatran etexilate and dabigatran in 1 patient.

To date, some attempts have been made to synthesize hierarchically porous metal-organic frameworks (HPMOFs), and in most cases, mesopores are formed in microporous frameworks. However, mass transfer and diffusion are still limited in such HPMOFs since micropores connect mesopores and mesopores are noncontinuous. Here, we fabricate a new hierarchical structure through the formation of microporous MOFs within continuous mesoporous channels. Confined space in the as-prepared mesoporous silica-containing template was used to prepare well-dispersed metal precursor of ZnO. The strategy of ligand vapor-induced crystallization was then designed to construct MOFs inside mesoporous channels, in which vapored ligand at elevated temperature diffuses and reacts with metal precursor. Our results indicate that framework isomerism is controllable by adjusting the crystallization conditions. In comparison to their microporous and mesoporous counterparts, the hierarchically porous materials show obviously enhanced adsorption performance on a series of bulky molecules including dye, enzyme, and metal-organic polyhedron.

Increasing evidence have reported that NLRP3 inflammasome has a crucial role in various kinds of immunological diseases including colitis. However, there have only a few drug candidates directly targeting inflammasomes for the therapy of colitis. Here, we first reported that Tubocapsanolide A (TA), a natural small molecule, as a novel inhibitor of NLRP3 inflammasome for the treatment of colitis. TA inhibited the activation of NLRP3 inflammasome and suppressed the secretion of IL-1β and IL-18 in macrophages. Moreover, the ASC oligomerization was inhibited by TA. The assembly of the NLRP3 inflammasome was also restrained by TA, while had little effects on potassium and chloride efflux. Biolayer interferometry analysis showed that TA could directly bind to NLRP3. Importantly, LC-MS/MS analysis further demonstrated that TA covalently bound to the cysteine 514 residue (Cys514) of NLRP3. In vivo experiments showed that TA remarkably ameliorated DSS-induced experimental colitis in mice. However, the protection of TA against DSS-induced experimental colitis was abrogated in NLRP3-deficient (Nlrp3-/-) mice. Taken together, this study indicates TA as a novel inhibitor of NLRP3, which identifies Cys514 as a novel regulatory site of NLRP3 and suggests TA as a promising candidate compound for the treatment of colitis.

OBJECTIVE To explore the effect of miR-873-5p on proliferation, apoptosis, migration, and invasion of tongue squamous cell carcinoma (TSCC) by targeting SEC11A. METHODS Tongue squamous cell carcinoma tissues were collected and performed by qRT-PCR and Western blotting to determine the expression of miR-873-5p and SPC18. SCC9 and CAL-27 cells were transfected and divided into Mock, mimic NC, miR-873-5p mimic, SEC11A, and miR-873-5p mimic + SEC11A groups. Then, a series of experiments including cell count kit 8 (CCK-8), wound healing, Transwell, and flow cytometry were conducted. Besides, Western blotting was used to detect the expression of SPC18 and EGFR pathway-related proteins. RESULTS MiR-873-5p was downregulated while SPC18 was upregulated in TSCC, and miR-873-5p was negatively correlated with SPC18. Dual luciferase reporter gene assay confirmed SEC11A to be a target of miR-873-5p. Cell proliferation, migration, and invasion of SCC9 and CAL-27 cells in miR-873-5p mimic group were decreased with increased cell apoptosis, presenting with downregulations of SPC18 and EGFR pathway-related proteins, while cells in SEC11A group manifested totally different changes. Moreover, the inhibitory effect of miR-873-5p mimic on TSCC cell growth was abolished by SEC11A overexpression. CONCLUSION Overexpression of miR-873-5p may suppress cell proliferation, migration, and invasion, but facilitate apoptosis in TSCC via targeting SEC11A.

Two new phthalide dimers (1 and 2) were obtained from the rhizomes of Ligusticum sinense Oliv., along with three known dimeric phthalides (3–5). Their structures were determined with the aid of the spectroscopic data, and their absolute configurations were elucidated based on the comparison of calculated and experimental electronic circular dichroism (ECD) spectra. All the compounds were evaluated in vitro for their inhibitory activities against NO production in LPS-treated RAW264.7 macrophages. Among them, compounds 1 and 3 showed potent NO prohibitive activity with IC50 values at 4.86 ± 0.29 μM and 4.87 ± 0.32 μM, respectively.

Novel withangulatin A (WA) derivatives were synthesized and evaluated for antiproliferative activity against four human cancer cell lines (U2OS, MDA-MB-231, HepG2, and A549). Among these derivatives, 10 exhibited the most potent antiproliferative activity, with an IC50 value of 74.0 nM against the human breast cancer cell line MDA-MB-231 and potency that was 70-fold that of WA (IC50 = 5.22 µM). Moreover, 10 caused G2-phase cell cycle arrest in a concentration-dependent manner and induced the apoptosis of MDA-MB-231 cells by increasing intracellular reactive oxygen species (ROS). Compound 10 showed a high selectivity index (SI = 267.03) for breast cancer MDA-MB-231 cells. These results suggest that 10 is a promising anticancer agent.

Objective: Herpes simplex viruses (HSVs) are widely spread throughout the world, causing infections from oral, and genital mucous membrane ulcerations to severe viral encephalitis. Glycoprotein B (gB) was the first HSV envelope glycoprotein identified to induce cell fusion. This glycoprotein initiates viral entry and thereby determines the infectivity of HSV, as well as oncolytic HSV (oHSV). Clarifying its molecular characterization and enlarging its motif reservoir will help to engineer oHSV and in cancer treatment applications. Only in recent years has the importance of gB been acknowledged in HSV infection and oHSV engineering. Although gB-modified oHSVs have been developed, the detailed molecular biology of gB needs to be illustrated more clearly in order to construct more effective oHSVs. Method: Here, we performed a systematic comparative sequence analysis of gBs from the 9 HSV-1 and 2 HSV-2 strains, including HSV-1-LXMW, which was isolated by our lab. Online software was implemented to predict gB secondary structure and motifs. Based on extensive literature reviews, a functional analysis of the predicted motifs was performed. Results: Here, we reported the DNA and predicted amino acid sequences of our recently isolated HSV-1-LXMW and found that the strain was evolutionarily close to HSV-1 strains F, H129, and SC16 based on gB analysis. The 22 novel motifs of HSV gB were identified for the first time. An amino acid sequence alignment of the 11 HSV strains showed that the gB motifs are conserved among HSV strains, suggesting that they are functional in vivo. Additionally, we found that certain amino acids within the 13 motifs out of the 22 were reported to be functional in vivo. Furthermore, the gB mutants and gB-engineered oHSVs were also summarized. Conclusion: Our identification of the 22 novel motifs shed light on HSV gB biology and provide new options for gB engineering to improve the efficiency and safety of oHSVs.

We isolated a novel lectin (AHL) from Artocarpus hypargyreusHance and showed its immunomodulatory activities. In this study, the amino acid sequence of AHL was determined by cDNA sequencing. AHL cDNA (875bp) contains a 456-bp open reading frame (ORF), which encodes a protein with 151 amino acids. AHL is a new member of jacalin-related lectin family (JRLs), which share high sequence similarities to KM+ and Morniga M, and contain the conserved carbohydrate binding domains. The antitumor activity of AHL was also explored using Jurkat T cell lines. AHL exhibits a strong binding affinity to cell membrane, which can be effectively inhibited by methyl-α-D-galactose. AHL inhibits cell proliferation in a time- and dose-dependent manner through apoptosis, evidenced by morphological changes, phosphatidylserine externalization, poly ADP-ribose polymerase (PARP) cleavage, Bad and Bax up-regulation, and caspase-3 activation. We further showed that the activation of ERK and p38 signaling pathways is involved for the pro-apoptotic effect of AHL.

Photoresponsive metal-organic frameworks (PMOFs) are of interest for tailorable CO2 adsorption. However, modulation of CO2 adsorption on PMOFs is based on steric hindrance or structural change owing to weak interactions between CO2 and active sites. It is challenging to fabricate PMOFs with strong but tailorable sites for CO2 adsorption. Now, the construction of PMOFs with target-specific (strong) active sites is achieved by introducing tetraethylenepentamine into azobenzene-functionalized MOFs for tailorable CO2 adsorption. Amines are specific active sites for CO2 , contributing to capture CO2 selectively. Cis/trans isomerization of azobenzene motifs trigged by UV/Vis light adjusts the electrostatic potential of amines significantly, leading to exposure/shelter of amines and modulation of CO2 adsorption on strong active sites. This system enables us to design adsorption processes for CO2 capture from mixtures, which is impossible to realize by traditional PMOFs.

Cobalt-based catalysts are highly promising for the oxygen evolution reaction (OER) in terms of both cost and performance. The dispersion state of Co3O4 impacts the catalyst performances directly, while development of an efficient method for Co3O4 dispersion remains a pronounced challenge. In this study, it is the first time that the confined space strategy (CSS) is employed to make highly dispersive Co3O4 on the mesoporous silica (MS) SBA-15. The precursor of Co3O4 is successfully introduced into the confined space inherent in as-prepared SBA-15 (between the silica walls and the template). The CSS facilitates the formation of Co3O4 with extremely high dispersion after the decomposition of Co precursor. Up to 4 mmol of Co3O4 can be dispersed in per gram of MS without any X-ray diffraction lines (the obtained sample is denoted as 4CoAS), while obvious diffraction lines are detected in the counterpart prepared from calcined SBA-15 (the sample is denoted as 4CoCS). Further calculation indicates that the size...

A pair of novel C23 terpenoid epimers, officinalins A (1) and B (2), together with a biogenetically related known diterpenoid (3), was isolated from the leaves of Salvia officinalis. The epimers feature an unprecedented carbon skeleton with a tetracycline-[9.6.0.03,8.012,16]-heptadecane core and a peroxide bridge. Their structures were unequivocally established by extensive spectroscopic analyses, including electronic circular dichroism (ECD) calculations and ROESY correlation analogy with model compounds for the configuration assignment. Possible biosynthetic pathways of 1 and 2 were proposed. Compound 1 exhibited potent NO inhibitory activity with an IC50 value of 2.02 ± 0.87 μM.

The photo-induced polymerization to covalently link metal-organic polyhedra (MOPs) by flexible polymer chains is reported for the first time, which endows MOPs with enhanced processability, dispersity, and hydrostability. The resultant hybrid material exhibits 9 times higher capacity and much better reusability than bulk MOPs in the adsorption of methylene blue.

The empiricism that extrinsic or doped materials universally perform much better than their intrinsic counterparts has been verified to be feasible in the adsorptive CO2 capture. Thus, a variety of N-doped solid adsorbents are well-engineered to adsorb CO2. However, the true nature of the N-doped sites in the aggregation state and the underlying mechanism of CO2 adsorption therein are difficult to determine. In the present study, four well-defined azacyclo copolymers with peculiar textural characteristics, uniformly arrays and tunably effective N-doped sites were fabricated to experimentally determine the precise relation between adsorbed CO2 molecules and the N-doped sites incorporated into an adsorbent. With multifaceted quantum chemical computations, induction forces were proven to account for the improved CO2 adsorption on the N-doped sites instead of the conventionally assumed generalized acid–base interaction. The negative electrostatic potentials were demonstrated to be the real cause for improving the CO2 adsorption and a robust indicator for the effectiveness of the N-doped sites. Besides, a precise linear function is proposed to quantitatively describe this subject–object relationship for the first time.

Selective adsorption of CO2 from natural gas results in increased calorific value, decreased gas volume, and reduced corrosion. For this purpose, the development of high-performance adsorbents with regard to both adsorption capacity and CO2/CH4 selectivity receives great attention. Herein, two new conjugated microporous polymers (CMPs) were prepared by Yamamoto homocoupling and Sonogashira–Hagihara cross-coupling reaction. The significant role of homo- and cross-coupling in CMPs in selective CO2 separation was investigated. Notably, the cross-coupled CMP (NUT-15, NUT means Nanjing Tech University) shows CO2 uptake around twice that of homocoupled CMP (NUT-14) under the analogous conditions. Furthermore, the importance of KOH-activation and temperature-controlled carbonization in efficient CO2 capture was studied. For this, NUT-15 was further subjected to carbonization and highly active porous carbons (PCs) were obtained. It is noteworthy that PC-800 with high carbonization yield (78%) and suitable pore st...

Metal–organic frameworks (MOFs) have drawn much attention for their highly promising applications, but the applications are often obstructed by the congenitally hydrothermal instability of the MOFs. Hybridizing the MOFs with other materials has been proved to be effective to solve the hydrothermal problems. Herein, a vapor-induced crystallization (VIC) method is employed for the first time to fabricate the hybrid MOFs based on the Cu-BTC and the natural clay attapulgite (NCA). Compared with the traditional solvothermal method for the hybridization, the VIC one has the obvious advantages of both reducing the solvent consumption and inducing the crystals self-repairing to generate perfect crystals of the hybrid MOFs. With an appropriate content of the NCA, the hybrid MOFs are proved to be highly stable even undergoing the hot water vapor (90 °C) for 12 h. The hybrid MOFs also exhibit the improved catalytic activity in catalyzing the styrene oxide ring-opening. The molar conversion of the styrene oxide over ...