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With the development and dissemination of the concept of smart medical care, people's attention to their own health and smart medical system is gradually increasing. In medical activities, the rehabilitation assistance system is very important for patients, and the family and entertainment of the rehabilitation assistance system is the general trend. At the same time, the role of the rehabilitation assistance system is largely affected by its algorithm and function settings. Therefore, it is necessary to introduce deep learning (DL) algorithms to optimize the rehabilitation assistance system. In view of the above problems, this paper used the pre-training label pre-judgment algorithm and the sample classification training method to conduct scientific research and analysis on the limb motor function rehabilitation assistance system. At the same time, a new rehabilitation assistance system including signal acquisition system, local monitoring system and medical center monitoring system was designed. The results of the experimental test showed that this new limb motor function rehabilitation assistance system could better collect the user's biological signals because of the addition of DL. The recognition of the signal has been improved to an accuracy of about 45%, which showed that the research on the rehabilitation assistance system of limb motor function based on DL could better provide unique services for the rehabilitation of patients.

In this study, the hydrodynamic characteristics for N2 and [Bmim][NO3] in a cross flow T-shaped square microchannel were investigated experimentally. A Micro-PIV system was used to capture ionic li...

In this study, a series of Ni10MoxAl composite metal oxide (Ni10MoxAl, NiO = 10 wt.%, x = 2.5, 5, 10, 15, 20 wt.%) catalysts with different Mo content were prepared by a solvothermal method using a water—ethanol system. By employing various characterization technologies, it was confirmed that the suitable amount of the Mo element can not only promote the dispersion of the Ni species but also inhibit the formation of the inactive NiAl2O4 phase. Consequently, the hydrogenation activity of the Ni10MoxAl catalysts was affected by the particle size of the active components and the amount of the NiAl2O4 phase. As a result, the Ni10Mo10Al catalyst showed the best catalytic performance on methyl acrylate hydrogenation, and the yield of methyl propionate can be increased from 53.7% to 89.5% at 100 °C and 1 MP H2, compared with the Ni10Mo10/γ–Al2O3 catalyst prepared by a traditional impregnation method. The stability of the Ni10Mo10Al catalyst was also investigated, and the catalyst can run stably for 23 h. The novel strategy adopted in this article provides a new direction for the preparation of high activity Ni–Mo catalysts.

An ionic liquid (IL) catalyzed solvent-free process was developed for the direct synthesis of chalcone and its derivatives by using substituted acetophenones and benzaldehydes via aldol reaction under mild conditions. A series of acidic and basic ILs were selected and screened. The influences of cations and reaction conditions on product yield and selectivity were systematically investigated. The [Bmim]OH was identified as the optimal IL, with the highest yield and selectivity reaching up to 96.7% and 100%, respectively. A reaction mechanism-based kinetic model was established and regressed with experimental data, revealing the β-Hydroxylketone dehydrolysis with activation barrier of 37.8 kJ·mol−1 was observed as the rate-controlling step.

The carboxylation of unsaturated hydrocarbons using CO2 offers a highly appealing access to valuable carboxylic acids, while selectively obtaining the anti-Markovnikov product still remains a chall...

With the wide popularity of various sport items and the continuous prosperity of sport business, player transfer events are becoming more and more frequent, which gives birth to a big player transfer market with attractive attentions of spectators. However, for the purposes of business competition or concerns of privacy disclosure, the multiple parties involved in an identical player transfer event are often reluctant to release the concrete transfer fees of a player as the transfer fee is always sensitive enough for the player himself or herself as well as the involved multiple sport clubs. The hidden player transfer fees block the fair and transparent sport business trades and cheat prospective spectators to some extent, which decreases the spectator trust towards player market value and finally, lowers the spectators’ satisfaction towards sport business. In this situation, it is becoming a necessity to develop a trusted player transfer evaluation method supported by all the parties involved in player transfer events. Inspired by this challenging task, a trusted player transfer evaluation method with privacy protection is put forward in this paper, which is mainly based on Locality-Sensitive Hashing (LSH) and Blockchain technologies and named TPTELSH+B. At last, a series of simulated experiments are deployed to validate the feasibility of our proposed TPTELSH+B algorithm. Experimental results report that TPTELSH+B has a good evaluation performance with competitive approaches.

Ionic liquids (ILs) have been experimentally proved to be effective for ammonia-containing gas separation and recovery. A systematic strategy including thermodynamic models, process simulation, mul...

In recent years, coal-based one-step synthesis of methyl methacrylate (MMA) stimulated researchers’ interest due to the over-capacity of coal chemical industry. However, the high reaction temperature, low yield and selectivity, catalyst deactivation due to carbon deposition, and volatilization and polymerization of formaldehyde have been the challenging problems in this field. In this work, the cascade reactions of methanol dehydrogenation to formaldehyde, aldol condensation between formaldehyde and methyl propionate, and O2-inteerrupted hydrogenation of MMA were resolved via construction of mild and efficient cobalt complex catalyzed interrupted hydrogen borrowing system. Thus, one-step synthesis of MMA from methyl propionate and methanol in liquid phase at 80 °C with yield and selectivity of 25.7% and 92.6% was realized. The cobalt complex activation and methanol dehydrogenation mechanisms were investigated with nuclear magnetic resonance (NMR) characterization, and the C–H bond activation and breakage of methanol was identified as the rate-controlling step through kinetic isotopic effect experiments, which provided new research direction for coal-based synthesis of MMA.

Recently, fluorescent carbon dots (CDs) have emerged as novel carbon nanomaterials in terms of their unique optical properties, robust chemical inertness, and excellent biocompatibility. However, s...

Pressure swing adsorption (PSA) is an attractive technology for low-concentration CO2 removal from confined spaces. In this study, the dynamic process simulation of PSA with four adsorbents (e.g., ...

CMK-3 supported highly dispersed Au-Ag bimetallic nanoparticles with different Ag/Au ratios were prepared by a sequential impregnation–reduction method without the use of any polymer stabilizer. Th...

Sulfur-rich polymers synthesized by inverse vulcanization are promising cathodes for Li-S batteries and can suppress the shuttle effect to improve the cycling properties of Li-S batteries. However, developing a sulfur-rich copolymer with new chemical functionality to enhance performance of Li-S batteries remains a huge challenge. In this report, a sulfur-rich polymer cathode containing ionic liquid segments named poly(sulfur-co-1-vinyl-3-allylimidazolium bromide) [poly(S-co-DVIMBr)] was obtained by the inverse vulcanization of S8 with DVIMBr and used as cathode for the first time. This sulfur-rich poly ionic liquid cathode showed effective suppression of the shuttle effect through joint effects of the stable chemical bonding of C-S and strong cation absorption for lithium polysulfides, which was confirmed by DFT calculations. In particular, the Li-S cell with poly(S-co-DVIMBr) cathode delivered high capacity retention of 90.22 % even over 900 cycles. Developing sulfur-rich poly ionic liquids may provide a new strategy of introducing the functional groups with cations into the cathode materials for suppressing the shuttle effect and improving the performance of Li-S batteries.

Fe-Ni-MOFs with different amounts of Fe are synthesized through a two-step template etching method. Kinetic analysis indicates that Fe-Ni-MOF exhibits prominent intrinsic peroxidase-like activity, which could catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce oxidized TMB (oxTMB) with a blue color. As a peroxidase-mimicking MOF, Fe-Ni-MOF with its efficient stable catalysis properties is demonstrated to allow a sensitive colorimetric assay for Sn2+ ions. The mechanism is explored, whereby Sn2+ ions could reduce the peroxidase-like activity of Fe-Ni-MOF based on a redox interaction, making the oxTMB color lighter and decreasing the absorbance intensity at 652 nm. The linear determination of the Sn2+ ion concentration using a UV-vis spectrometer ranges from 0.01 mM to 1.0 mM and from 1.0 mM to 4.0 mM. The presented Fe-Ni-MOF-based assay of Sn2+ ions was successfully applied to real water samples.

Molybdenum disulfide (MoS2) is expansively studied as the most promising non-precious metal catalyst for the hydrogen evolution reaction (HER) because of its excellent properties. However, the properties of MoS2 are quite distinct when the contents of the trigonal (1T) phase and hexagonal (2H) phase constituting MoS2 are different. Herein, three MoS2 representatives with different contents of the 1T phase are synthesized by a simple method, denoted as 1T-MoS2, 1T/2H-MoS2 and 2H-MoS2 from high to low contents of the 1T phase. The chemical composition and crystalline phase of the three samples are systematically analyzed and characterized. To improve charge transport between adjacent nanosheets of MoS2, silver and gold nanoparticles (Ag/AuNPs) are decorated on MoS2, denoted as 1T-MoS2@Ag/AuNPs, 1T/2H-MoS2@Ag/AuNPs and 2H-MoS2@Ag/AuNPs. The HER catalytic experiments of various MoS2 samples in 0.5 M H2SO4 show that 1T-MoS2 has the best catalytic performance compared to 1T/2H-MoS2 and 2H-MoS2. Owing to the cooperative effect of the 1T phase and Ag/AuNPs, the 1T-MoS2@Ag/AuNP nanocomposite exhibits better HER electrocatalytic activity than the other MoS2 samples because it contains a higher-percentage 1T phase and a higher charge transfer rate. This study offers an abundant foundation for designing and improvement of electrocatalysts based on MoS2 and its nanocomposites.

The direct synthesis of methyl acrylate (MA) from methyl acetate and trioxane at 350–380 °C is regarded as a supplementary route for the industrial propylene oxidation process; however, it suffers from rapid catalyst deactivation. Herein, a novel ionic liquid catalyzed mild liquid-phase system was developed for the direct synthesis of MA from methyl acetate and trioxane, where N,O-bis(trimethylsilyl)acetamide (BSA) was used as a probase for α-deprotonation and enol silyl etherification of methyl acetate. The trioxane decomposition to formaldehyde and methyl acetate enolization to 1-methoxy-1-trimethylsilyloxyethene proceeded with the catalysis of [Cation]Cl/MClx (M = Cu+, Fe3+, Zn2+ and Al3+) and [Cation]F, respectively. The cations and anions were observed to have significant effects on the yield and selectivity of MA, owing to the steric hindrance, acid site category and strength confirmed by pyridine probing FT-IR characterization. As a result, up to 60.2% yield with 94.6% selectivity of MA could be achieved when [N3,3,3,3]F and [N3,3,3,3]Cl/AlCl3 with 67 mol% AlCl3 were used in the presence of BSA at 25 °C. Kinetic studies indicated that the trioxane decomposition with the activation barrier of 41.2 ± 0.3 kJ mol−1 was the rate-determining step.

Rare earth element (Ce, Y, and La) modified Cu/SiO2 catalysts via hydrolysis precipitation and impregnation method were fabricated for the vapor-phase hydrogenation of methyl acetate to ethanol. LaOx showed the most pronounced promotion in the catalytic tests. After detailed characterizations, via N2 adsorption–desorption, XRD, N2O chemisorption, FTIR, H2-TPR, H2-TPD, TEM, XPS, and TG/DTA, we found that the addition of promoter LaOx can decrease the particle size while in turn, it can increase the dispersion of copper species. The strong interactions between copper and lanthanum atoms alter the surface chemical states of the copper species. This results in the generation of more Cu+ species and high SCu+ values, which are responsible for the excellent activity and stability during hydrogenation. In addition, the content of additive LaOx and reaction conditions (reaction temperature and LHSV) were optimized. Then, the long-term stability performance was evaluated over the selected catalyst in contrast with Cu/SiO2.

The conversion of biomass and carbon dioxide to plastics is one of the key solutions to reduce the greenhouse effect and alleviate the petroleum resource depletion. However, there is still a lack of bioderived polymers with high molecular weights and excellent performance and their corresponding green synthesis processes, which limits the potential of bioderived polymers to replace petroleum-based polymers. In this study, an eco-friendly synthetic process for bioderived polycarbonate, catalyzed by amino acid ionic liquids, was developed by utilizing isosorbide (ISO) and diphenyl carbonate (DPC) as reactants, derived from a renewable resource and carbon dioxide, respectively. By using 1-ethyl-3-methylimidazole lysine ([Emim][Lys]) as a catalyst, poly(isosorbide carbonate) (PIC) with the weight average molecular weight of 150 000, the highest reported so far to the best of our knowledge, was synthesized, and the Tg of PIC was up to 174 °C. The reaction mechanism was investigated using nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS), and density functional theory (DFT) calculation. The remarkable catalytic performance was attributed to the fact that [Emim][Lys] could effectively activate the hydroxyl group of ISO and carbonyl group of DPC, and inhibit the formation of cyclic intermediates. Moreover, to overcome the brittleness of PIC, 1,4-butanediol (BD) and 1,4-cyclohexanedimethanol (CHDM) were introduced into PIC, and the copolycarbonate showed excellent Young's modulus, ultimate tensile strength, and elongation at break, which were 979 MPa, 57 MPa, and 145%, respectively, and were comparable to the commercial petroleum-based polycarbonates. Such a process provides further industrial prospects for the next generation of bioderived polycarbonate.

In this work, the as-prepared V2O5 nanobelts can sensitively quench the fluorescence of nitrogen-doped carbon dots (N-CDs) based on the inner filter effect (IFE). In the presence of ascorbic acid (AA), the fluorescence of N-CDs can recover through the redox reaction between V2O5 nanobelts and AA. Meanwhile, in the presence of both alkaline phosphatase (ALP) and ascorbyl-2-phosphate (AAP), the fluorescence of N-CDs can also restore since AAP can be hydrolyzed into AA by ALP. Under optimum conditions, the linear range for AA is from 0.01 to 2.5 μM with a detection limit of 3 nM and that for ALP is from 0.1 to 30 U/L with a detection limit of 0.04 U/L (S/N = 3). Particularly, the proposed probe could be successfully used to detect AA and ALP in human serum samples. Furthermore, N-CDs can be applied in fluorescence imaging of Human breast cancer cells with satisfactory results.

The original poly(ethylene oxide)-based polymer electrolytes normally show low ionic conductivity and inferior mechanical property, which greatly restrict their practical application in all-solid-state lithium-ion batteries (LIBs). In this work, a hyperbranched star polymer with poly(ethylene glycol) methyl ether methacrylate flexible chain segments is embedded into a three-dimensional (3D) interpenetrating cross-linking network created by the rapid one-step UV-derived photopolymerization of the cross-linker (ethoxylated trimethylolpropane triacrylate) in the presence of lithium salt. The rigid 3D network framework provides the polymer electrolyte with not only enhanced mechanical behavior, including film-forming and dendrite-inhibiting capabilities, but also nanoconfinement effects, which can speed up polymer chain segmental dynamics and reduce the crystallinity of the polymer. Depending on this unique rigid-flexible coupling network, the prepared solid polymer electrolyte shows enhanced ionic conductivity (6.8 × 10-5 S cm-1 at 50 °C), widened electrochemical stability window (5.1 V vs Li/Li+), and enough mechanical stability to suppress the growth of uneven Li dendrite (the Li symmetrical cells can operate steadily at both current densities of 0.05 and 0.1 mA cm-2 for 1000 h). Moreover, the assembled LiFePO4//Li cell also exhibited good cycle performance at 50 °C, making the hyperbranched star polymer electrolyte with a nanoconfined cross-linking structure to have potential application in high-safety and high-performance LIBs.

The application of carbon dots as a coreactant for Ru(bpy)32+ (where bpy is 2,2'-bipyridine) electrochemiluminescence (ECL) has been widely studied. However, the high cost of Ru(bpy)32+ and its derivatives has prohibited its widespread use in ECL biosensors. Herein, a novel anodic ECL system based on sulfur-doped graphitic carbon nitride nanosheets (S-g-C3N4 NSs) and nitrogen-doped carbon dots (N-CDs) is presented. In this ECL system, N-CDs serve as a new ECL coreactant that can significantly enhance the anodic ECL signal of S-g-C3N4 NSs (approximately 83 times) under optimal conditions. The possible ECL response mechanism of the S-g-C3N4 NSs/N-CDs system is proposed in detail on the basis of cyclic voltammograms, ECL-time curves, and ECL spectra. Furthermore, the ECL signal of the S-g-C3N4 NSs/N-CDs system was quenched by folic acid (FA), which was chosen as a model analyte to study the potential application of the new ECL system. The ECL intensity decreased linearly with the concentration of FA in the range from 0.05 to 200 μM. The detection limit for FA measurement is 16 nM (signal-to-noise ratio of 3). The proposed new ECL system has many advantages over traditional approaches, such as low toxicity and excellent biocompatibility. Especially, the proposed approach can detect FA in diluted human serum samples with satisfactory recoveries, indicating promising application for bioanalysis. Graphical abstract.

Lithium–sulfur batteries show high specific capacity and environmental friendliness. However, the shuttling effect and volumetric expansion of sulfur electrodes often lead to low Coulombic efficien...

Sec-amines catalyzed two-step Mannich reaction for preparation of methacrolein from propionaldehyde and formaldehyde was more attractive than the C4 selective oxidation route. Herein, a novel continuous fixed-bed process was developed for direct preparation of methacrolein from above stocks with catalysis of sec-amine grafted D301 resin. The effect of resin, sec-amine structure and grafting percentage on catalytic performance of the modified resin were detailed investigated and demonstrated by using FT-IR, TG-DTA, titration and solid-state NMR characterization methods before the optimal conditions were obtained. The grafting percentage of amine with abundant sec-amino groups onto D301 resin could reach 93.7% at optimal condition. With this new strategy, the yield and selectivity of methacrolein could attain 40.2% and 99.3%. In addition, the Mannich reaction step with activation energy of 66.3 kJ/mol was determined as the rate-controlling step through mechanism-based kinetic calculation.

Ascorbic acid (AA) is one of the most important vitamins and serves many physiological activities in the body. In this work, we propose a simple colorimetric sensor for the rapid detection of AA through the redox reaction between CoOOH nanoflakes and ascorbic acid with the 2, 2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as a colorimetric signal indicator. CoOOH nanoflakes could catalytically oxidize colorless ABTS to produce green oxidized ABTS (ox ABTS) with an absorption band at 412 nm in UV–vis spectra. The presence of AA could induce the oxidation of ABTS, resulting in a significant color fading and decrease of the absorbance at 412 nm. Thus quantitative detection of AA is realized. Under the optimal experimental conditions, the linear range is obtained from 0.5 to 15 μM with a lower detection limit of 0.16 μM (S/N = 3). Particularly, this colorimetric assay is capable of detecting AA in different vitamins C tablet and fresh kiwi fruit samples. Hence, the fast response, high sensitivity and easy operation of the proposed colorimetric sensor make it suitable for further application in bioassay.

α, β-unsaturated esters were often synthesized from aldehydes and esters in the presence of strong organic base that was very sensitive to air and moisture via aldol reaction. Trioxane was very useful C1 resource, however, the decomposition of it was always the challenging problem that facing researchers. Herein, a novel synthetic methodology for α, β-unsaturated ester preparation from trioxane and ester with mild catalysis of generated ammonium trifluoromethanesulfonate ionic liquid. The enolization of ester as well as the decomposition of trioxane could proceed easily in the presence of boryl trifluoromethanesulfonate and amine at 20–25 °C. Then the enolate and decomposed formaldehyde occurs aldol reaction to form α, β-unsaturated ester. With this strategy, the yield and selectivity of product from various substrates including aliphatic esters, lactones and thioester could reach up to 85.2% and 90.1%. Keywords: α, β-unsaturated ester, Trioxane, Ionic liquid, Aldol reaction, Enolization

A novel recyclable hyperbranched adsorbent for selective adsorption of Pb2+ ions is fabricated by a facile single-step crosslinking reaction. The as-synthesized adsorbent has porous structure and large of amino groups which beneficial for the removal of Pb2+ ions in aqueous solution and the removal efficiency is 99.2%. The result also indicates that adsorption ability of the obtained adsorbent increased with the increase of pH from 1 to 6 and temperature from 278 K to 308 K, respectively. The adsorption process of Pb2+ ions onto PPEI-2-AG followed the Langmuir isotherm model, and a kinetic study indicates that the process fitted pseudo-second order model well. The removal of Pb2+ ions by PPEI-2-AG is mainly controlled by the specific interactions between Pb2+ ions and amino functional groups, which could be further confirmed by X-ray photoelectron spectroscopy (XPS). The results demonstrate that PPEI-2-AG holds high potential in environmental remediation.

Au supported on monoclinic ZrO2 (Au/m-ZrO2) prepared by deposition–precipitation method showed excellent catalytic performance in the aerobic oxidation of amino alcohols to amino acids, i.e., glyci...

The activation and selectivity are the challenging problems always existing in the utilization of methanol as C1 resource. Herein, a novel cobalt complex catalyzed process for preparation of methyl acrylate from methyl acetate and methanol at 50 °C–80 °C was firstly developed. Such cobalt complex stabilized with a PN5P-type pincer ligand, which can be easily prepared in gram scale, has high catalytic performance with the loading amount of only 5 mol.%. Systematic mechanism investigation revealed the cobalt complex activated by sodium methoxide via salt elimination could simultaneously interact with and catalyze the dehydrogenation of two-fold methanol into formaldehyde, followed by proceeding aldol condensation with methyl acetate in the presence of sodium methoxide. Besides the reaction atmosphere of O2 was proved to be crucial for preventing the further hydrogenation of methyl acrylate into methyl propionate. Also, the mechanism-based kinetic model indicated the dehydrogenation of methanol was rate-controlling step with the activation energy of 89.0 ± 1.1 kJ/mol.

Biodegradable ionic liquid (IL) choline acetate shows highly efficient delignification ability in cornstalk pretreatment process. Cellulose-rich products with 98% holocellulose and 2% lignin decreased from original 13% could be directly obtained from the IL-cornstalk solution by the simple, non-toxic, and green process.

The esterification of methacrylic acid with methanol catalyzed by NKC-9 resin (a cation-exchange resin with sulfonate groups) was conducted in a stainless stirred batch reactor. The effects of cata...

In this study, in situ sulfur-doped carbon nitride nanosheets (S-g-C3N4 NSs) are used as the signal readout for the sensitive and selective sensing of L-cysteine (L-Cys) in human serum samples based on the competitive coordination chemistry of Cu2+ between L-Cys and S-g-C3N4 NSs. S-g-C3N4 NSs are prepared by using trithiocyanuric acid as a precursor for the first time, which exhibits stronger electrogenerated chemiluminescence (ECL) intensity compared with pristine graphitic carbon nitride nanosheets (g-C3N4 NSs). The ECL signals of the S-g-C3N4 NSs can be quenched by Cu2+ and the subsequent presence of L-Cys can recover the ECL signals of the S-g-C3N4 NSs. These changes are ascribed to the higher coordination ability between Cu2+ and L-Cys than that between Cu2+ and the S-g-C3N4 NSs. On the basis of this, the concentration of L-Cys can be quantitatively determined. Under optimized conditions, the ECL intensity recovery shows a linear relationship with the L-Cys concentration range from 30 nM to 0.2 mM with a lower detection limit of 5 nM (S/N = 3). The proposed method is highly sensitive and selective and is thus particularly useful for fast and simple clinical diagnosis of diseases, such as Alzheimer's disease and cardiovascular disease.

The utilization of renewable resources and carbon dioxide (CO2) has attracted extensive attention due to global warming and continuously declining petroleum-based resources. Herein, a novel synthetic approach of bio-based polycarbonates using isosorbide (ISB) and diphenyl carbonate (DPC), derived from the renewable resources glucose and CO2, respectively, was proposed, where an ionic liquid (IL) was used as a promising green catalyst; to overcome the poor activity of the endo-hydroxyl group (endo-OH) of ISB and achieve high-molecular weight polycarbonates, a new strategy was revealed that involved the activation of the endo-OH group via a series of efficient tetrabutylphosphonium-based IL catalysts. By designing the structures of cations and anions, most of the endo-OH groups have been activated and incorporated into the polymer chain, and the ratio of endo-OH/exo-OH at the end group of the polymer chain has been decreased to 0.25, which, to the best of our knowledge, is the lowest value reported to date. Among the prepared ILs, tetrabutylphosphonium acetate in a trace amount (1.5 × 10−6 mol) exhibited highest catalytic performance, and poly(isosorbide carbonates) (PICs) with the molecular weight of up to 66 900 g mol−1, Tg of 169 °C and better thermal stability than conventional polycarbonates were achieved. Mass spectrometry and density functional theory calculations provided a deeper understanding of the underlying cation–anion synergistic catalytic mechanism. Furthermore, copolymerization of ISB, diols and DPC was performed to modify the flexibility of PIC, resulting in copolycarbonates with the high molecular weight of 110 000 using 1,10-decanediol as a copolymer monomer.

The implementation of direct and mild catalytic synthesis of products from benign materials using inexpensive catalysts is a major goal of chemists. Herein, a mild O2-interrupted hydrogen borrowing strategy using easily accessible and high efficient cobalt complex was reported for direct synthesis of α, β-unsaturated esters from unactivated esters and alcohols. This new route had good tolerance on broad substrate scope (alcohols, acetates, propionates and dios) and functional group with the highest yield of 89.1%. Systematic mechanism investigation revealed the cobalt complex was activated by t-BuOK via double deprotonation of PN5 P ligand and removal of dichloro ligands, followed by two-fold alcohols activation and dehydrogenation . Also, the oxygen atmosphere was demonstrated very crucial for such interrupted hydrogen borrowing pathway.

Fe-Ni-MOFs with different amounts of Fe are synthesized through a two-step template etching method. Kinetic analysis indicates that Fe-Ni-MOF exhibits prominent intrinsic peroxidase-like activity, which could catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce oxidized TMB (oxTMB) with a blue color. As a peroxidase-mimicking MOF, Fe-Ni-MOF with its efficient stable catalysis properties is demonstrated to allow a sensitive colorimetric assay for Sn2+ ions. The mechanism is explored, whereby Sn2+ ions could reduce the peroxidase-like activity of Fe-Ni-MOF based on a redox interaction, making the oxTMB color lighter and decreasing the absorbance intensity at 652 nm. The linear determination of the Sn2+ ion concentration using a UV-vis spectrometer ranges from 0.01 mM to 1.0 mM and from 1.0 mM to 4.0 mM. The presented Fe-Ni-MOF-based assay of Sn2+ ions was successfully applied to real water samples.