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991.
Anna G. Scott Diogo Alves Galico Isabel Bogacz Paul H. Oyala Junko Yano Elizaveta A. Suturina Muralee Murugesu Theodor Agapie 《Angewandte Chemie (International ed. in English)》2023,62(49):e202313880
Atomically defined large metal clusters have applications in new reaction development and preparation of materials with tailored properties. Expanding the synthetic toolbox for reactive high nuclearity metal complexes, we report a new class of Fe clusters, Tp*4W4Fe13S12 , displaying a Fe13 core with M−M bonds that has precedent only in main group and late metal chemistry. M13 clusters with closed shell electron configurations can show significant stability and have been classified as superatoms. In contrast, Tp*4W4Fe13S12 displays a large spin ground state of S=13. This compound performs small molecule activations involving the transfer of up to 12 electrons resulting in significant cluster rearrangements. 相似文献
992.
Daigo Hayashi Dr. Tomohiro Tsuda Prof. Dr. Ryo Shintani 《Angewandte Chemie (International ed. in English)》2023,62(50):e202313171
A palladium-catalyzed skeletal rearrangement of 2-(2-allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5-C−Pd/C−Si bond exchange. The reaction pathways can be switched toward 4-membered ring-forming C(sp2)−H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C−Pd/C−Si bond exchange. 相似文献
993.
Yunchuan Pu Mingang Zhao Xu Liang Shaoyu Wang Dr. Hongjian Wang Ziting Zhu Dr. Yanxiong Ren Zhiming Zhang Prof. Guangwei He Prof. Dan Zhao Prof. Zhongyi Jiang 《Angewandte Chemie (International ed. in English)》2023,62(22):e202302355
We report a covalent organic framework (COF) induced seeding strategy to fabricate metal–organic framework (MOF) membranes. Contrary to graphene oxide nuclei-depositing substrate, COF substrate has uniform pore size, high microporosity and abundant functional groups. We designed a series of charged COF nanosheets to induce the formation of ZIF-8@COF nanosheet seeds with high aspect ratio over 150, which were readily processed into a compact and uniform seed layer. The resulting ZIF-8 membranes with thickness down to 100 nm exhibit an ultrahigh C3H6/C3H8 separation performance and superior long-term stability. Our strategy is also validated by fabricating ultrathin ZIF-67 and UiO-66 membranes. 相似文献
994.
应用一种反映分子局部微环境描述子--原子电性相互作用矢量(vector of atomic electronegative interaction,AEIV)和原子杂化状态指数(Atomic Hybridation State Index, AHSI)对饱和脂肪酮类化合物的55种分子中的153个13C NMR谱建模模拟,应用多元线性回归方法得到定量结构波谱关系(QSSR)模型的复相关系数RMM=0.997, 标准偏差为SDMM=7.155. 采用留一法交互检验的结果是RCV=0.993,SDCV=10.195. 并随机抽出三部分分子进行检验,得到的相关系数分别是RMM1=0.996,RMM2=0.996,RMM3=0.999. 研究结果表明使用AEIV和AHSI所建模型预测能力是相当稳定的. 相似文献
995.
996.
This study was to investigate the optimal additions of the cellulose decomposition reaction to obtain the most yield of 5-HMF and other furan derivatives in various biphasic systems with FeCl_3-CuCl_2 mixed catalysts,and explore its depolymerization kinetics.A series of controllable reactions have been performed under mild environmentally friendly atmosphere.The experiment results showed that49.13 wt% of 5-HMF was the maximum production along with 2.98 wt% other furan derivatives catalyzed by mixed Lewis acid FeCl_3-CuCl_2 under the two phases which included high concentration NaCl aqueous phase and n-butanol organic phase at 190℃ for 45 min.The conclusion suggested that two-phase systems benefited the yield of 5-HMF,furan derivatives via extracting the target products from reaction phase to organic phase to avoid rehydration of 5-HMF.The kinetic calculation revealed the conversion with mixed catalysts had lower reaction apparent activation energy(21.65 kJ/mol,190-230℃) and the reaction rate was faster than that with acid-based catalysts.Based on experiment exploration,the probable mechanism of cellulose decomposition with FeCl_3-CuCl_2 was proposed. 相似文献
997.
In this work, various Co3O4-ZSM-5 catalysts were prepared by the microwave hydrothermal method (MH-Co3O4@ZSM-5), dynamic hydrothermal method (DH-Co3O4@ZSM-5), and conventional hydrothermal method (CH-Co3O4/ZSM-5). Their catalytic oxidation of dichloromethane (DCM) was analyzed. Detailed characterizations such as X-ray diffractometer (XRD), scanning microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), H2 temperature-programmed reduction (H2-TPR), temperature-programmed desorption of O2 (O2-TPD), temperature-programmed desorption of NH3 (NH3-TPD), diffuse reflectance infrared Fourier-transform spectra with NH3 molecules (NH3-DRIFT), and temperature-programmed surface reaction (TPSR) were performed. Results showed that with the assistance of microwave, MH-Co3O4@ZSM-5 formed a uniform core-shell structure, while the other two samples did not. MH-Co3O4@ZSM-5 possessed rich surface adsorbed oxygen species, higher ratio of Co3+/Co2+, strong acidity, high reducibility, and oxygen mobility among the three Co3O4-ZSM-5 catalysts, which was beneficial for the improvement of DCM oxidation. In the oxidation of dichloromethane, MH-Co3O4@ZSM-5 presented the best activity and mineralization, which was consistent with the characterizations results. Meanwhile, according to the TPSR test, HCl or Cl2 removal from the catalyst surface was also promoted in MH-Co3O4@ZSM-5 by their abundant Brønsted acid sites and the promotion of Deacon reaction by Co3O4 or the synergistic effect of Co3O4 and ZSM-5. According to the results of in situ DRIFT studies, a possible reaction pathway of DCM oxidation was proposed over the MH-Co3O4@ZSM-5 catalysts. 相似文献
998.
An interlocked M_4 L_8 coordination cage was synthesized by coordination-driven self-assembly of palladium(Ⅱ) ions with aromatic amide bidentate ligands.The reaction of the ligand and the metal at 2:1 ratio led to the monomeric M_2 L_4 cage as the kinetic product,while the thermodynamic product M_4 L_8 cage was obtained by prolongating the reaction.This conve rsion and the interlocked structure was clearly revealed by using ~1 H NMR,mass spectrometry and X-ray crystallography.The driving force of interlocking was mainly attributed to the interactions(hydrogen bonding,aromatic stacking and electrostatic interaction) arising from the aptitude of flexibility of the amide ligand. 相似文献
999.
Hua Lei Meixuan Wu Ying Liu Fan Mo Jiayao Chen Shilong Ji Yan Zou Xiaoping Dong 《中国化学快报》2021,32(7):2317-2321
Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes, however high-power light sources are generally necessary to initiate photocatalytic reaction. In this work, we employed an excellent photocatalyst of Bi2WO6 with visible light harvest and meanwhile an intrinsic ferroelectricity, which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis. Through coupling the illumination by a low-power (9 W) LED and the ultrasonic vibration (120 W) by an ultrasonic cleaner, the nanoflower-like Bi2WO6 composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis. Furthermore, the high mineralization efficiency and the good durability of the Bi2WO6 catalyst were demonstrated. The possible mechanism of photopiezocatalysis was finally proposed, where the ultrasound-induced piezoelectric field in Bi2WO6 drove photo-generated electrons and holes to diffuse along opposite directions, consequently promoting the separation efficiency of charge carriers. This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater. 相似文献
1000.
Rhodium(III)-catalyzed [4 + 1] cyclization of azobenzenes with α-Cl ketones has been developed. 3-Acyl-2H-indazoles could be easily afforded in up to 97% yields for more than 30 examples. The obtained products are potentially valuable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure. 相似文献