Chemical Science
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2025
·
IF 7.4
Shengyuan Zhang,Hong Wen,Qianru Wang,Yongli Cai,Zhao LI,Liang Liu,Xuanwei Chang,Jianping Guo,Ping Chen
For many decades, selective hydrogenation N-heterocycles using H2 has been considered the exclusive domain of d-block metals. Herein, a series of solid-state s-block metal hydrides has been demonstrated to function as transition-metal-free catalysts for hydrogenation of quinoline, affording high yields of 1,2,3,4-tetrahydroquinoline. Under relatively mild conditions, the catalytic performance of the representative barium hydride (BaH2) is good enough to compete with some recently developed Fe, Co, Ni catalysts. Moreover, this transformation is remarkably simple and does not need any sophisticated ligands, co-catalysts, and additives when compared with the existing methodology. Mechanistic studies reveal that quinoline substrate can activate BaH2 in situ, generating a kind of catalytically active organobarium hydride species that effects the hydrogenation process. With the aid of theoretical modeling, the synergistic scenario between Lewis acidic barium cation and nucleophilic hydride anion in regioselective hydrogenation of quinoline is delineated, which shows a distinct working principle from the conventional transition metal catalysis. These findings provide insights into the discovery of new catalysts and/or reactivity that is complementary to that of the transition metals.
研究领域:
催化化学
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有机化学
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无机化学
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可持续化学
·
材料化学
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高影响因子
BioDesign Research
·
2025
·
IF 4.7
Peiling Wu,Haofeng Chen,Guojun Yang,Haoyu Qin,Qian Zhang,Yuxin Chen,Dongjiang Lin,Yang Zhang,Shuyong Lin,Shizhen Wang,Jifeng Yuan
2-Hydroxyisovalerate (2-HIV) is a value-added chemical that is widely applied in the synthesis of bioactive compounds and polymers. Here, we report an underexplored metabolic route for the de novo production of S -type 2-HIV ( S -HIV) in Escherichia coli . In particular, we identified promiscuous activity of 4-hydroxymandelate synthase (HmaS) from Amycolatopsis orientalis towards the conversion of 2-keto-4-methyl-pentanoate (2-KMP, an immediate precursor for L-leucine) to S -HIV. Next, we designed a variant HmaS (S201F) with abolished activity for mandelate and 4-hydroxymandelate synthesis, thereby minimizing byproduct formation. Coupled with systematic optimization of the L-leucine biosynthetic pathway, we achieved de novo production of S -HIV at 8.1 mM (0.95 g/L) in shake flasks and 33.9 mM (4.0 g/L) in 2-L fed-batch fermentation. In summary, this work represents the first time to realize the efficient synthesis of S -configuration 2-HIV in metabolically engineered E. coli .
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Polymer Chemistry
·
2017
·Vol. 8
·期 21
·3261-3270
·
IF 5.375
Jun Zhang,Yan Xiao,Xueli Luo,Lianlei Wen,Andreas Heise,Meidong Lang
Double hydrophilic block copolymers (DHBCs) based on poly(ε-caprolactone)s, poly(6-acetoxyl-ε-caprolactone)-b-poly(4-N-piperilactone) (PCCL-b-PPIL), were synthesized via ring-opening polymerization and deprotection. The self-assembly behaviour of these block copolymers in aqueous solutions was thoroughly explored via a combination of UV-vis spectroscopy, zeta potential measurement, 1H NMR spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was observed that “schizophrenic” aggregations were formed and triggered by pH, i.e., the copolymers could self-assemble into PCCL-core micelles at acidic pH and PPIL-core micelles at alkaline pH. In addition, pendant groups in each block of copolymers facilitated further chemical modification with fluorescent dyes such as 1-(hydroxymethyl)pyrene and FITC. The fluorescence properties of pyrene-functionalized copolymers were closely related to their aggregate morphology, which could be adjusted simply by altering the environmental pH values. Meanwhile, it is expected that this novel type of degradable schizophrenic block copolymer holds potential application in stimuli-responsive fluorescent probes.
研究领域:
高分子化学
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纳米医学
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生物材料
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药物递送
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分子影像
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刺激响应系统
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2023
·Vol. 34
·期 10
·3125-3136
·
IF 3.4
Longwei Shi,Zheng Zhao,Lishuai Zong,Jinyan Wang,Xigao Jian
Limiting molecules' polarized motion effectively reduces the dielectric loss of materials. This article synthesized side chains with different lengths using p-ethoxyphenol, p-hydroxybenzoic acid, and long-chain halohydrins through a two-step process. These chains' movement was almost unaffected by the main chain of polymers, so they can fill up the free volume of polymers under certain conditions. 1,2-dihydro-4-(4-hydroxyphenyl)phthalazine-1-(2H)-one(DHPZ), 4,4'-Difluorophenyl sulfone(DFS), and 4,4-Bis(4-hydroxyphenyl) valeric acid(HPV) obtained three polymers with different carboxyl groups (10%, 30%, and 50%) through nucleophilic substitution. They were then grafted and treated with hot-pressing. The introduction of side chains could reduce the free volume of polymers under hot-pressing conditions, so further reducing the dielectric loss of materials. Polymer with the shortest and least (10%) side chains showed the most obvious dielectric loss tangent, the reduction rate of the film's dielectric loss tangent was 13.11% (at T g + 15°C, while the non-grafted one was only 3.69%) and 20.70% (at T g + 80°C, while the non-grafted one was only 8.35%), respectively. In addition, WXRD and DMA tests showed that films' intermolecular chain spacing (“ d ”) and T g changed after the hot-pressing process, respectively. The change law of both was consistent with that of dielectric loss tangent. Confirm that grafting high-motility side chains can significantly reduce polymer's dielectric loss by enhancing the free volume reduction effect after hot-pressing.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Zhili Li,Jiye Zhang,Pengfei Luo,Jiayi Chen,Bowen Huang,Yuzhe Sun,Jun Luo
Silver chalcogenides demonstrate great potential as flexible thermoelectric materials due to their excellent ductility and tunable electrical and thermal transport properties. In this work, we report that the amorphous/crystalline phase ratio and thermoelectric properties of the Ag2SxTe1–x (x = 0.55–0.75) samples can be modified by altering the S content. The room-temperature power factor of the Ag2S0.55Te0.45 sample is 4.9 μW cm–1 K–2, and a higher power factor can be achieved by decreasing the carrier concentration as predicted by the single parabolic band model. The addition of a small amount of excessive Te into Ag2S0.55Te0.45 (Ag2S0.55Te0.45+y) not only enhances the power factor by decreasing the carrier concentration but also reduces the total thermal conductivity due to decreased electronic thermal conductivity. Owing to the effectively optimized carrier concentration, the thermoelectric power factor and dimensionless figure of merit zT of the sample with y = 0.007 reaches, respectively, 6.2 μW cm–1 K–2 and 0.39, while the excellent plastic deformability is well maintained, demonstrating its promising potential as a flexible thermoelectric material at room temperature.
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CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Qingxia Yuan,Hong Li,Qian Wang,Shujing Sun,Ziyu Fang,Hao Tang,Xiaohuo Shi,Jing Wen,Lianghua Huang,Meng Bai,Shengping Zhong,Yonghong Liu,Chenghai Gao,Longyan Zhao
Stichopus monotuberculatus is a tropical sea cucumber species and used as a folk medicine and tonic food . In this study, a fucosylated glycosaminoglycan (SmFG), the depolymerized SmFG (dSmFG) and its oligosaccharide fractions were prepared. The SmFG and its depolymerized products were comprised of a chondroitin-sulfate-E backbone, and various sulfated fucose side chains, including an unusual disaccharide side chain connected to the C-3 position of D-glucuronic acid (GlcA) or GlcA-ol. A peeling reaction occurred during the deaminative depolymerization process. The dSmFG and its fractions showed strong anticoagulant activity by selectively inhibiting intrinsic tenase complex, and had no anti-factor IIa, Xa and VIIa activity. The anticoagulant activity reduced with the decrease of molecular weight , and the unusual branch and novel reducing end may enhance the anticoagulant activity. These findings can provide significant information for development and utilization of depolymerized products from SmFG in food and pharmaceutical industries .
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高影响因子
Coatings
·
2022
·Vol. 12
·期 9
·1263
·
IF 3.236
Honggang Xia,Dongbin Wang,Aixian Tian,Yingde Xu,Hao Gong,Zhaoyang Li,Jun Miao
Medical tools and implants used in clinics can be contaminated with bacteria even with disinfection treatment. To avert this situation, titanium (Ti) plates modified with a MoS2(S)–Ag3PO4coating were designed to killStaphylococcus aureus(S. aureus) andEscherichia coli(E. coli) effectively under near-infrared (NIR) light irradiation. The introduction of Ag3PO4nanoparticles (NPs) reduced the bandgap of MoS2and suppressed the recombination of the photogenerated electron–hole pairs. Therefore, Ti–MoS2(S)–Ag3PO4exhibited a higher photocatalytic performance, leading to the generation of more radical oxygen species (ROS). Furthermore, cooperating with the good photothermal performance of MoS2, the MoS2(S)–Ag3PO4coating exhibited a high antibacterial efficacy of 99.76 ± 0.15% and 99.85 ± 0.09% againstS. aureusandE. coli, respectively, for 15 min in vitro. Moreover, the MoS2(S)–Ag3PO4coating had no apparent toxicity to cells. The proposed strategy may provide new insights for rapidly eradicating bacteria on medical tools and superficial implants.Keywords:bacteria-killing;Ag3PO4;MoS2;photocatalytic;photothermal
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Xiaojun Dai,Sheng Feng,Wei Wu,Yun Zhou,Zhiwei Ye,Xun Cao,Yang Wang,Chengdeng Yang
In this study, ZnCo 2 S 4 (ZCS) nanoparticles were coupled on the surface of TiO 2 by simple solvothermal method to form S-scheme heterojunction. Compared with ZCS and TiO 2 , the photocatalytic performance of ZCS/TiO 2 under simulated sunlight is significantly improved, and its hydrogen evolution efficiency reaches 5580 μmol·g −1 ·h −1 with the apparent quantum efficiency (AQY) up to 11.5% at 420 nm, which is 88.3 times and 54.3 times that of TiO 2 and ZCS, respectively. Moreover, ZCS/TiO 2 also has excellent performance in the photocatalytic degradation of tetracycline (TC). The enhancement of photocatalytic performance of ZCS/TiO 2 is mainly due to S-scheme heterojunction. On the one hand, the S-scheme electron transfer path not only improves the electron-hole separation efficiency, but also improves the charge transfer efficiency. On the other hand, ZCS significantly enhances the visible light absorption of ZCS/TiO 2 . The photocatalytic mechanism and S-scheme heterojunction structure is confirmed by XPS , EPR , ultraviolet photoelectron spectroscopy (UPS) and energy band structure . This work provides a new idea for designing and constructing S-scheme heterojunction to improve the performance of photocatalytic hydrogen evolution and TC degradation.
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POLYMER
·
2022
·
IF 4.432
Shan Jiang,Li Liu
Poly(hydroxyurethane-urea)s (PHUUs), which have complementary thermal and mechanical properties with poly(hydroxyurethane)s (PHUs) and polyureas, are of great potential for practical applications. Herein, several novel PHUUs were synthesized through polyaddition reaction from 5-membered dicyclic carbonates and amino-terminal polyurea oligomers , and corresponding PHUs were also synthesized as controls. It was worth noting that carbon dioxide was starting materials in the synthesis of both 5-membered dicyclic carbonates and amino-terminal polyurea oligomers. The structures and properties of PHUUs and PHUs were characterized by FTIR , 1 H NMR, SEC , water contact angle measurement, TGA , DSC , and tensile test. The urethane-to-urea ratio of PHUUs depended on the diamines used in the synthesis of amino-terminal polyurea oligomers. With the introduction of urea moieties, PHUUs exhibited improved surface hydrophobicity and thermal properties. Meanwhile, the introduction of urea moieties and the structure of selected diamine influenced glass transition temperature (T g ) and mechanical properties of PHUUs. This work offered a fascinating option for preparing PHUUs and might contribute to tackling climate change.
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Frontiers in Chemistry
·
2022
·
IF 5.545
Han XiaoLe,Yu Fan,Lei JiaWen,Zhu Jiahua,Fu HaiYan,Hu JunCheng,Yang Xiao-Long
Water-soluble Cu-In-Zn-S quantum dots (CIZS QDs) with orange fluorescence have been synthesized with a glutathione (GSH) as stabilizer via facile a one-step hydrothermal method. The optimal reaction conditions of CIZS QDs including temperature, time, pH, and the molar ratios of precursors were studied. TEM results indicate that the aqueous-dispersible CIZS QDs are quasi-spherical, and the average diameters are 3.76 nm with excellent fluorescent stability. Furthermore, the cytotoxicity of CIZS QDs was investigated by the microcalorimetry combining with TEM and the IC50 was 10.2 μM. CIZS QDs showed a promising perspective in applications such as a fluorescent probe for bioimaging and biolabeling due to the low cytotoxicity and good biocompatibility. Moreover, the CIZS QDs can distinguish Pb2+ ion from other ions, offering great potentials in lead ion determination in drinking water. According to the results of UV, XRD, FL, PL, and ITC methods, the mechanism of CIZS QDs-Pb2+ assay is due to hydrogen bonding or van der Waals forces in the formation of Pb2+ and CIZS QDs.
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高影响因子
MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Yue-Jie Bai,Li-Ying Liu,Xun-Kai Duan,Guang-Xuan Zhang,Chao Wang,Xin-Yu Zhou,Changhao Wang,Bing-Rong Wang,Xiao-Lin Wei,Ru-zhi Wang
To further develop sensing materials for NO 2 gas detection practical application, the operating temperature of the sensor should be significantly reduced. In this paper, In 2 O 3 flowers were prepared by the microwave-assisted hydrothermal method . Then, In 2 O 3 was doped using TAA (thioacetamide). The prepared S-doped In 2 O 3 flowers have good gas sensitivity and significantly reduced operating temperature. When exposed to 10 ppm NO 2 gas, the corresponding response was 250 at 118 °C. It can be demonstrated by the first principle calculations, in which the doping of S atoms changes the electron structure of In 2 O 3 from semiconductor to metal with a lower potential barrier. Then, significantly affects the electron crossing the intergranular potential barriers. Therefore, the operating temperature of the sensor can be reduced. Our research results will provide new research ideas and technical approaches for designing, fabricating, and applying a new generation of In 2 O 3 gas sensors.
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高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 19
·10425-10434
·
IF 11.9
Ke Yang,Chan Li,Haoyuan Qi,Yunfei Dai,Yuhong Cui,Yibo He
The shuttle effect of polysulfides seriously hinders the practical application of lithium–sulfur (Li–S) batteries, and separator modification is supposed to be an effective way to solve this issue. Herein, MXene quantum dots (MQDs) were self-assembled on the surface of g-C3N4 sheets (g-C3N4@MQDs) by electrostatic adsorption principles to construct a functional layer on a Celgard separator. Making MXene into quantum dots was conducive to solving the agglomeration issue of its sheets, providing more active sites to capture the dissolved polysulfides. Moreover, the MQDs could also work as an electrocatalyst to further facilitate the Li2S catalytic conversion, obtaining a high deposition current and capacity (257.4 mA h g−1). Attributed to the regulation effect of MQDs toward the kinetic behavior of polysulfides, the shuttle effect was effectively mitigated. An as-fabricated Li–S battery with a heterostructured g-C3N4@MQD-based separator achieved a high specific capacity of 1433 mA h g−1 at 0.1 C, excellent rate performance (532 mA h g−1 at 4 C), and good cycling performance (0.024% capacity fading per cycle after 1000 cycles at 2 C). The rational design of the g-C3N4@MQD-based separator not only broadens the application of MQDs, but also presents new insights to develop high-performance Li–S batteries.
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