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991.
Dr. Yusen Li Xi Su Wenhao Zheng Dr. Jia-Jia Zheng Linshuo Guo Prof. Mischa Bonn Prof. Xingfa Gao Dr. Hai I. Wang Prof. Long Chen 《Angewandte Chemie (International ed. in English)》2023,62(10):e202216795
Targeted synthesis of kagome ( kgm ) topologic 2D covalent organic frameworks remains challenging, presumably due to the severe dependence on building units and synthetic conditions. Herein, two isomeric “two-in-one” monomers with different lengths of substituted arms based on naphthalene core (p-Naph and m-Naph) are elaborately designed and utilized for the defined synthesis of isomeric kgm Naph-COFs. The two isomeric frameworks exhibit splendid crystallinity and showcase the same chemical composition and topologic structure with, however, different pore channels. Interestingly, C60 is able to uniformly be encapsulated into the triangle channels of m-Naph-COF via in situ incorporation method, while not the isomeric p-Naph-COF, likely due to the different pore structures of the two isomeric COFs. The resulting stable C60@m-Naph-COF composite exhibits much higher photoconductivity than the m-Naph-COF owing to charge transfer between the conjugated skeletons and C60 guests. 相似文献
992.
Wei Zong Haiqi Gao Yue Ouyang Kaibin Chu Hele Guo Leiqian Zhang Wei Zhang Ruwei Chen Yuhang Dai Fei Guo Jiexin Zhu Zhenfang Zhang Chumei Ye Dr. Yue-E. Miao Prof. Johan Hofkens Dr. Feili Lai Prof. Tianxi Liu 《Angewandte Chemie (International ed. in English)》2023,62(27):e202218122
Competition from hydrogen/oxygen evolution reactions and low solubility of N2 in aqueous systems limited the selectivity and activity on nitrogen fixation reaction. Herein, we design an aerobic-hydrophobic Janus structure by introducing fluorinated modification on porous carbon nanofibers embedded with partially carbonized iron heterojunctions (Fe3C/Fe@PCNF-F). The simulations prove that the Janus structure can keep the internal Fe3C/Fe@PCNF-F away from water infiltration and endow a N2 molecular-concentrating effect, suppressing the competing reactions and overcoming the mass-transfer limitations to build a robust “quasi-solid–gas” state micro-domain around the catalyst surface. In this proof-of-concept system, the Fe3C/Fe@PCNF-F exhibits excellent electrocatalytic performance for nitrogen fixation (NH3 yield rate up to 29.2 μg h−1 mg−1cat. and Faraday efficiency (FE) up to 27.8 % in nitrogen reduction reaction; NO3− yield rate up to 15.7 μg h−1 mg−1cat. and FE up to 3.4 % in nitrogen oxidation reaction). 相似文献
993.
Youwen Rong Dr. Tianfu Liu Jiaqi Sang Dr. Rongtan Li Dr. Pengfei Wei Dr. Hefei Li Dr. Aiyi Dong Prof. Dr. Li Che Prof. Dr. Qiang Fu Prof. Dr. Dunfeng Gao Prof. Dr. Guoxiong Wang 《Angewandte Chemie (International ed. in English)》2023,62(45):e202309893
Electrochemically converting CO2 to valuable chemicals holds great promise for closing the anthropogenic carbon cycle. Owing to complex reaction pathways and shared rate-determining steps, directing the selectivity of CO2/CO electrolysis to a specific multicarbon product is very challenging. We report here a strategy for highly selective production of acetate from CO electrolysis by constructing metal-organic interfaces. We demonstrate that the Cu-organic interfaces constructed by in situ reconstruction of Cu complexes show very impressive acetate selectivity, with a high Faradaic efficiency of 84.2 % and a carbon selectivity of 92.1 % for acetate production, in an alkaline membrane electrode assembly electrolyzer. The maximum acetate partial current density and acetate yield reach as high as 605 mA cm−2 and 63.4 %, respectively. Thorough structural characterizations, control experiments, operando Raman spectroscopy measurements, and density functional theory calculation results indicate that the Cu-organic interface creates a favorable reaction microenvironment that enhances *CO adsorption, lowers the energy barrier for C−C coupling, and facilitates the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production. 相似文献
994.
Yapei Gao Zheming Liu Dr. Tao Li Prof. Wanxiang Zhao 《Angewandte Chemie (International ed. in English)》2023,62(49):e202314006
Mixed-valence (MV) dimers have been extensively investigated, however, the structure and properties of purely organic MV trimers based on open-shell polycyclic aromatic hydrocarbons remain elusive. Herein, unprecedented MV BN-doped corannulene radical cations [ BN-Cor1 ]3⋅⋅2+ ⋅ 2[BArylF4]− and [ BN-Cor2 ]3⋅⋅2+ ⋅ 2[BArylF4]− were synthesized via chemical oxidation, and their structures were unambiguously confirmed by single-crystal X-ray diffraction. These uncommon radical cations consist of three corannulene cores and two [BArylF4]− anions, and three corannulene motifs [ BN-Cor1 ]3⋅⋅2+ and [ BN-Cor2 ]3⋅⋅2+ in the unit cell exhibit a trimer structure with a slipped π-stacking configuration. Detailed structural analyses further revealed that the corannulene cores exhibit an infinite layered self-assembly configuration, allowing their potential applications as building blocks for molecular conductors. The detection of a forbidden transition (Δms=±2) by electron paramagnetic resonance (EPR) spectroscopy further confirmed the existence of two unpaired electrons in the π-trimers and the MV characteristic of these two species. Variable-temperature EPR and conductivity measurements suggested that the BN-doped π-trimers exhibited antiferromagnetic coupling and conductivity properties. 相似文献
995.
Liangxu Lin Liang Huang Chang Wu Yu Gao Naihua Miao Chao Wu Aaron T. Marshall Yi Zhao Jiazhao Wang Jun Chen Shixue Dou Gordon G. Wallace Wei Huang 《Angewandte Chemie (International ed. in English)》2023,62(49):e202315182
The exploration of inexpensive and efficient catalysts for oxygen reduction reaction (ORR) is crucial for chemical and energy industries. Carbon materials have been proved promising with different catalysts enabling 2 and 4e− ORR. Nevertheless, their ORR activity and selectivity is still complex and under debate in many cases. Many structures of these active carbon materials are also chemically unstable for practical implementations. Unlike the well-discussed structures, this work presents a strategy to promote efficient and stable 2e− ORR of carbon materials through the synergistic effect of lattice distortion and H-passivation (on the distorted structure). We show how these structures can be formed on carbon cloth, and how the reproducible chemical adsorption can be realized on these structures for efficient and stable H2O2 production. The work here gives not only new understandings on the 2e− ORR catalysis, but also the robust catalyst which can be directly used in industry. 相似文献
996.
Three new emitters,namely 10,10'-(quinoline-2,8-diyl)bis(10 H-phenoxazine)(Fene),10,10'-(quinoline-2,8-diyl)bis(10 H-phenothiazine)(Fens) and 10,10'-(quinoline-2,8-diyl)bis(9,9-dimethyl-9,10-dihydroacridine)(Yad),featuring quinoline as a new electron acceptor have been designed and conveniently synthesized.These emitters possessed small singlet-triplet splitting energy(ΔEst) and twisted structures,which not only endowed them show thermally activated delayed fluorescence(TADF)properties but also afforded a remarkable aggregation-induced emission(AIE) feature.Moreover,they also showed aggregation-induced delayed fluorescence(AIDF) property and good photoluminescence(PL) property,which are the ideal emitters for non-doped organic light-emitting diodes(OLEDs).Furthermore,high-performance non-doped OLEDs based on Fene,Fens and Yad were achieved,and excelle nt maximum external quantum efficiencies(EQE_(max)) of 14,9%,13.1% and 17,4%,respectively,were obtained.It was also found that all devices exhibited relatively low turn-on voltages ranging from 3.0 V to3.2 V probably due to their twisted conformation and the AIDF properties.These results demonstrated the quinoline-based emitters could have a promising application in non-doped OLEDs. 相似文献
997.
Dr. Yafei Gao Prof. Wei-Tsung Lee Dr. Veronica Carta Dr. Chun-Hsing Chen Prof. Joshua Telser Prof. Jeremy M. Smith 《欧洲无机化学杂志》2023,26(8):e202200675
Reduction of the cobalt(II) chloride complex, Ph2B(tBuIm)2Co(THF)Cl ( 1 ) in the presence of tBuN≡C affords the diamagnetic, square planar cobalt(I) complex Ph2B(tBuIm)2Co(C≡NtBu)2 ( 2 ). This is a rare example of a 16-electron cobalt(I) complex that is structurally related to square planar noble metal complexes. Accordingly, the electronic structure of 2 , as calculated by DFT, reveals that the HOMO is largely dz2 in character. Complex 2 is readily oxidized to its cobalt(II) congener [Ph2B(tBuIm)2Co(C=NtBu)2]BPh4 ( 3 -BPh4), whose EPR spectral parameters are characteristic of low-spin d7 with an unpaired electron in an orbital of dz2 parentage. This is also consistent with the results of DFT calculations. Despite its 16-electron configuration and the dz2 parentage of the HOMO, the only tractable reactions of 2 involve one electron oxidation to afford 3 . 相似文献
998.
Chao Duan Jianwei Zhang Shali Cai Junjun Xiang Prof. Xiaodi Yang Prof. Xike Gao 《European journal of organic chemistry》2023,26(5):e202201347
Linear polycyclic systems are promising candidates in the area of organic electronics. Herein, we present the syntheses of three azulene-indole (AzIn) fused polycyclic heteroaromatics (PHAs), AzIn - 1 , AzIn - 2 and DGAzIn , which have nitrogens and nonhexagonal rings simultaneously. The chemical structures, optical and electrochemical properties of three AzIn-based PHAs have been investigated, as well as their protonation behaviors with trifluoroacetic acid (TFA). All three AzIn-based PHAs exhibit narrow optical band gaps with moderate to good air stability, anti-Kasha emission and reversible stimuli-responsiveness. Furthermore, these straightforward and simple synthetic routes would provide a new entry for constructing novel azulene-embedded π-conjugates, especially for the seven-membered ring of azulene unit, wherein the regioselective transformation is not well developed. 相似文献
999.
氧化锌作为一种半导体材料,具有合适的能带结构位置,高催化效率,低成本和环境可持续性,因而广泛用于光催化领域.然而,由于氧化锌的宽带隙,可见光吸收能力差以及光生电子-空穴对的快速复合,极大地影响了其光催化效率.通过引入氧空位调控光催化剂的结构被证明是一种可以改善光生载流子的分离,从而提高光催化性能的有效方法.本文以ZIF-8为前驱体,采用两步煅烧法合成了具有不同浓度氧空位分布的ZnO纳米光催化剂,通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)、X射线光电子能谱(XPS)、电子顺磁共振(EPR)、荧光光谱仪(PL)等手段系统地分析了合成的光催化剂的理化性质,并评价了它们在可见光下光催化氧化去除NO反应性能.EPR结果表明,样品中氧空位的浓度取决于温度处理的过程.通过两步煅烧法得到氧化锌中氧空位的含量高于一步直接煅烧法所得的样品.此外,随着煅烧温度升高,合成的氧化锌晶格越完好,其氧空位含量越少.UV-Vis DRS结果表明,两步煅烧法合成的ZnO与商业的ZnO及一步法直接煅烧合成的ZnO相比,其吸光范围从紫外光拓展到了可见光,表现出了更加优异的吸光性能.光催化反应结果表明,与商业氧化锌和一步直接煅烧法所得样品相比,两步煅烧法合成的样品表现出了更优异的光催化去除NO性能,并抑制了中间产物毒性NO2的产生,促进了NO的深度氧化.具体反应路径为:在光照过程中,光生电子很容易被氧空位俘获,与O2反应产生更多的超氧自由基(·O2^-),从而将NO氧化成最终的产物硝酸盐.尤其有趣的是,先在350 ℃煅烧2小时再400℃煅烧1小时的两步法样品Z 350-400的NO去除效率分别比一步法样品Z 400(400℃煅烧)和商用ZnO高出1.5和4.6倍.这表明以MOF材料衍生的具有适当量氧空位的金属氧化物为一种高效去除NO的光催化剂具有很好的应用前景. 相似文献
1000.
Xingyi Qu Xingchen Bian Yuancheng Chen Jiali Hu Xiaolan Huang Yu Wang Yaxin Fan Hailan Wu Xin Li Yi Li Beining Guo Xiaofen Liu Jing Zhang 《Molecules (Basel, Switzerland)》2022,27(3)
Polymyxin-based combination therapy is commonly used to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections. In the present study, the bactericidal effect of polymyxin B and minocycline combination was tested in three CRAB strains containing blaOXA-23 by the checkerboard assay and in vitro dynamic pharmacokinetics/pharmacodynamics (PK/PD) model. The combination showed synergistic or partial synergistic effect (fractional inhibitory concentration index ≤0.56) on the tested strains in checkboard assays. The antibacterial activity was enhanced in the combination group compared with either monotherapy in in vitro PK/PD model. The combination regimen (simultaneous infusion of 0.75 mg/kg polymyxin B and 100 mg minocycline via 2 h infusion) reduced bacterial colony counts by 0.9–3.5 log10 colony forming units per milliliter (CFU/mL) compared with either drug alone at 24 h. In conclusion, 0.75 mg/kg polymyxin B combined with 100 mg minocycline via 2 h infusion could be a promising treatment option for CRAB bloodstream infections. 相似文献