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991.
Yinghao Liu Xingxing Wang Dr. Junyan Li Dr. Qiang Zhang Zijian Niu Dr. Sen Wang Yanjing Gao Mingkun Gao Dr. Risheng Bai Dr. Yida Zhou Dr. Weibin Fan Prof. Osamu Terasaki Prof. Jun Xu Prof. Jihong Yu 《Angewandte Chemie (International ed. in English)》2023,62(49):e202312131
Creation of intrapenetrated mesopores with open highway from external surface into the interior of zeolite crystals are highly desirable that can significantly improve the molecular transport and active sites accessibility of microporous zeolites to afford enhanced catalytic properties. Here, different from traditional zeolite-seeded methods that generally produced isolated mesopores in zeolites, nanosized amorphous protozeolites with embryo structure of zeolites were used as seeds for the construction of single-crystalline hierarchical ZSM-5 zeolites with intrapenetrated mesopores (mesopore volume of 0.51 cm3 g−1) and highly complete framework. In this strategy, in contrast to the conventional synthesis, only a small amount of organic structure directing agents and a low crystallization temperature were adopted to promise the protozeolites as the dominant growth directing sites to induce crystallization. The protozeolite nanoseeds provided abundant nucleation sites for surrounding precursors to be crystallized, followed by oriented coalescence of crystallites resulting in the formation of intrapenetrated mesopores. The as-prepared hierarchical ZSM-5 zeolites exhibited ultra-long lifetime of 443.9 hours and a high propylene selectivity of 47.92 % at a WHSV of 2 h−1 in the methanol-to-propylene reaction. This work provides a facile protozeolite-seeded strategy for the synthesis of intrapenetrated hierarchical zeolites that are highly effective for catalytic applications. 相似文献
992.
Fangzhou Li Dr. Errui Li Dr. Krishanu Samanta Zhaoxi Zheng Dr. Lianqian Wu Albert D. Chen Prof. Dr. Omar K. Farha Dr. Richard J. Staples Prof. Dr. Jia Niu Prof. Dr. Klaus Schmidt-Rohr Prof. Dr. Chenfeng Ke 《Angewandte Chemie (International ed. in English)》2023,62(50):e202311601
Boron trifluoride (BF3) is a highly corrosive gas widely used in industry. Confining BF3 in porous materials ensures safe and convenient handling and prevents its degradation. Hence, it is highly desired to develop porous materials with high adsorption capacity, high stability, and resistance to BF3 corrosion. Herein, we designed and synthesized a Lewis basic single-crystalline hydrogen-bond crosslinked organic framework (HCOF-50) for BF3 storage and its application in catalysis. Specifically, we introduced self-complementary ortho-alkoxy-benzamide hydrogen-bonding moieties to direct the formation of highly organized hydrogen-bonded networks, which were subsequently photo-crosslinked to generate HCOFs. The HCOF-50 features Lewis basic thioether linkages and electron-rich pore surfaces for BF3 uptake. As a result, HCOF-50 shows a record-high 14.2 mmol/g BF3 uptake capacity. The BF3 uptake in HCOF-50 is reversible, leading to the slow release of BF3. We leveraged this property to reduce the undesirable chain transfer and termination in the cationic polymerization of vinyl ethers. Polymers with higher molecular weights and lower polydispersity were generated compared to those synthesized using BF3 ⋅ Et2O. The elucidation of the structure–property relationship, as provided by the single-crystal X-ray structures, combined with the high BF3 uptake capacity and controlled sorption, highlights the molecular understanding of framework-guest interactions in addressing contemporary challenges. 相似文献
993.
Xiang Li Guodong Zhang Yunqiu Hua Fucai Cui Xue Sun Jiaxin Liu Hongjie Liu Yanxiao Bi Zhongjie Yue Zhongjun Zhai Haibing Xia Xutang Tao 《Angewandte Chemie (International ed. in English)》2023,62(50):e202315817
Inorganic Bi-based perovskites have shown great potential in X-ray detection for their large absorption to X-rays, diverse low-dimensional structures, and eco-friendliness without toxic metals. However, they suffer from poor carrier transport properties compared to Pb-based perovskites. Here, we propose a mixed-halogen strategy to tune the structural dimensions and optoelectronic properties of Cs3Bi2I9−nBrn (0≤n≤9). Ten centimeter-sized single crystals are successfully grown by the Bridgman technique. Upon doping bromine to zero-dimensional Cs3Bi2I9, the crystal transforms into a two-dimensional structure as the bromine content reaches Cs3Bi2I8Br. Correspondingly, the optoelectronic properties are adjusted. Among these crystals, Cs3Bi2I8Br exhibits negligible ion migration, moderate resistivity, and the best carrier transport capability. The sensitivities in 100 keV hard X-ray detection are 1.33×104 and 1.74×104 μC Gyair−1 cm−2 at room temperature and 75 °C, respectively, which are the highest among all reported bismuth perovskites. Moreover, the lowest detection limit of 28.6 nGyair s−1 and ultralow dark current drift of 9.12×10−9 nA cm−1 s−1 V−1 are obtained owing to the high ionic activation energy. Our work demonstrates that Br incorporation is an effective strategy to enhance the X-ray detection performance by tuning the dimensional and optoelectronic properties. 相似文献
994.
Quan Huang Sa Li Prof. Yuqin Jiang Dr. Xiao-Feng Xia 《European journal of organic chemistry》2023,26(23):e202300266
Described herein is the development of a desaturation and N-β-nitration reaction of cyclic amides, which is achieved by a selective hydrogen atom transfer (HAT)/oxidative desaturation/electrophilic nitration process. In this procedure, di-tert-butyl peroxide (DTBP) acted both as the oxidant and HAT reagent, and electrophilic NOBF4 as nitration source. Notably, the application of produced cyclic nitroene-sulfonamides was showcased by their efficient transformations into 3-piperidones and poly-substituted piperidine derivatives. 相似文献
995.
Sai Luo Junjie Wang Dr. Nengquan Li Dr. Xiu-Fang Song Xintong Wan Prof. Dr. Kai Li Prof. Dr. Chuluo Yang 《Angewandte Chemie (International ed. in English)》2023,62(49):e202310943
B- and N-embedded multiple resonance (MR) type thermally activated delayed fluorescence (TADF) emitters usually suffer from slow reverse intersystem crossing (RISC) process and aggregation-caused emission quenching. Here, we report the design of a sandwich structure by placing the B−N MR core between two electron-donating moieties, inducing through-space charge transfer (TSCT) states. The proper adjusting of the energy levels brings about a 10-fold higher RISC rate in comparison with the parent B−N molecule. In the meantime, a high photoluminescence quantum yield of 91 % and a good color purity were maintained. Organic light-emitting diodes based on the new MR emitter achieved a maximum external quantum efficiency of 31.7 % and small roll-offs at high brightness. High device efficiencies were also obtained for a wide range of doping concentrations of up to 20 wt % thanks to the steric shielding of the B−N core. A good operational stability with LT95 of 85.2 h has also been revealed. The dual steric and electronic effects resulting from the introduction of a TSCT state offer an effective molecular design to address the critical challenges of MR-TADF emitters. 相似文献
996.
Hui Xu Dr. Shengbo Zhang Xinyuan Zhang Min Xu Dr. Miaomiao Han Prof. Li Rong Zheng Prof. Yunxia Zhang Prof. Guozhong Wang Prof. Haimin Zhang Prof. Huijun Zhao 《Angewandte Chemie (International ed. in English)》2023,62(52):e202314414
The integration of highly active single atoms (SAs) and atom clusters (ACs) into an electrocatalyst is critically important for high-efficiency two-electron oxygen reduction reaction (2e− ORR) to hydrogen peroxide (H2O2). Here we report a tandem impregnation-pyrolysis-etching strategy to fabricate the oxygen-coordinated Fe SAs and ACs anchored on bacterial cellulose-derived carbon (BCC) (FeSAs/ACs-BCC). As the electrocatalyst, FeSAs/ACs-BCC exhibits superior electrocatalytic activity and selectivity toward 2e− ORR, affording an onset potential of 0.78 V (vs. RHE) and a high H2O2 selectivity of 96.5 % in 0.1 M KOH. In a flow cell reactor, the FeSAs/ACs-BCC also achieves high-efficiency H2O2 production with a yield rate of 12.51±0.18 mol gcat−1 h−1 and a faradaic efficiency of 89.4 %±1.3 % at 150 mA cm−2. Additionally, the feasibility of coupling the produced H2O2 and electro-Fenton process for the valorization of ethylene glycol was explored in detail. The theoretical calculations uncover that the oxygen-coordinated Fe SAs effectively regulate the electronic structure of Fe ACs which are the 2e− ORR active sites, resulting in the optimal binding strength of *OOH intermediate for high-efficiency H2O2 production. 相似文献
997.
Yicong Luo Yuqi Ma Guanlin Li Xiaohong Huo Wanbin Zhang 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313838
Fluorinated amino acids and related peptides/proteins have been found widespread applications in pharmaceutical and agricultural compounds. However, strategies for introducing a C−F bond into amino acids in an enantioselective manner are still limited and no such asymmetric catalysis strategy has been reported. Herein, we have successfully developed a Pd/Cu/Li ternary system for stereodivergent synthesis of chiral fluorinated amino acids. This method involves a sequential desymmetrization of geminal difluoromethylenes and allylic substitution with amino acid Schiff bases via Pd/Li and Pd/Cu dual activation, respectively. A series of non-natural amino acids bearing a chiral allylic/benzylic fluorine motif are easily synthesized in high yields with excellent regio-, diastereo-, and enantioselectivities (up to >20 : 1 dr and >99 % ee). A density functional theory (DFT) study revealed the F−Cu interaction of the allylic substrate and the Cu catalyst significantly influence the stereoselectivity. 相似文献
998.
Gangya Wei Dr. Yunxiang Li Dr. Xupo Liu Jinrui Huang Mengran Liu Dr. Deyan Luan Prof. Shuyan Gao Prof. Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313914
Precise manipulation of the coordination environment of single-atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two-step strategy to fabricate a series of hollow carbon-based SACs featuring asymmetric Zn−N2O2 moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn−N2O2−S). Systematic analyses demonstrate that the synergetic effects between the N2O2 species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O2 reduction to H2O2. Remarkably, the Zn−N2O2 moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H2O2 generation. Consequently, the Zn−N2O2−S SAC exhibits impressive electrochemical H2O2 production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm−2 in the flow cell, it shows a high H2O2 production rate of 6.924 mol gcat−1 h−1 with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h. 相似文献
999.
Xinlin Huang Chuang Wang Dr. Chuanfa Li Dr. Meng Liao Jiaxin Li Haibo Jiang Yao Long Xiangran Cheng Kun Zhang Pengzhou Li Prof. Bingjie Wang Prof. Huisheng Peng 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303616
Fiber lithium-ion batteries represent a promising power strategy for the rising wearable electronics. However, most fiber current collectors are solid with vastly increased weights of inactive materials and sluggish charge transport, thus resulting in low energy densities which have hindered the development of fiber lithium-ion batteries in the past decade. Here, a braided fiber current collector with multiple channels was prepared by multi-axial winding method to not only increase the mass fraction of active materials, but also to promote ion transport along fiber electrodes. In comparison to typical solid copper wires, the braided fiber current collector hosted 139 % graphite with only 1/3 mass. The fiber graphite anode with braided current collector delivered high specific capacity of 170 mAh g−1 based on the overall electrode weight, which was 2 times higher than that of its counterpart solid copper wire. The resulting fiber battery showed high energy density of 62 Wh kg−1. 相似文献
1000.
Xuejian Li Bangzhong Wang Dr. Dong Li Dr. Jinfeng Zhao Prof. Dr. Jingping Qu Prof. Dr. Yuhan Zhou 《European journal of organic chemistry》2023,26(15):e202201452
An efficient and environmentally friendly methodology for 3,3-dichlorination and 2-oxidation of indole derivatives is described. Using KI as promotor, MCl (M=K, Na) as chlorine source, and oxone as oxidant, the reaction proceeds smoothly affording various functionalized 3,3-dichloro-2-oxindoles in moderate to excellent yields. This strategy can also be extended to 3-substituted indoles. With a broad substrate scope, it is a practical approach to 3,3-disubstituted-2-oxindoles. 相似文献