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271.
Adam Jaffe Stephanie A. Mack Yu Lin Wendy L. Mao Jeffrey B. Neaton Hemamala I. Karunadasa 《Angewandte Chemie (International ed. in English)》2020,59(10):4017-4022
We show that the onset pressure for appreciable conductivity in layered copper‐halide perovskites can decrease by ca. 50 GPa upon replacement of Cl with Br. Layered Cu–Cl perovskites require pressures >50 GPa to show a conductivity of 10?4 S cm?1, whereas here a Cu–Br congener, (EA)2CuBr4 (EA=ethylammonium), exhibits conductivity as high as 2×10?3 S cm?1 at only 2.6 GPa, and 0.17 S cm?1 at 59 GPa. Substitution of higher‐energy Br 4p for Cl 3p orbitals lowers the charge‐transfer band gap of the perovskite by 0.9 eV. This 1.7 eV band gap decreases to 0.3 eV at 65 GPa. High‐pressure X‐ray diffraction, optical absorption, and transport measurements, and density functional theory calculations allow us to track compression‐induced structural and electronic changes. The notable enhancement of the Br perovskite's electronic response to pressure may be attributed to more diffuse Br valence orbitals relative to Cl orbitals. This work brings the compression‐induced conductivity of Cu‐halide perovskites to more technologically accessible pressures. 相似文献
272.
Wenjun Yang Bo Ling Bowen Hu Haolin Yin Jianyou Mao Patrick J. Walsh 《Angewandte Chemie (International ed. in English)》2020,59(1):161-166
An umpolung 1,4‐addition of aryl iodides to enals promoted by cooperative (terpy)Pd/NHC catalysis was developed that generates various bioactive β,β‐diaryl propanoate derivatives. This system is not only the first reported palladium‐catalyzed arylation of NHC‐bound homoenolates but also expands the scope of NHC‐induced umpolung transformations. A diverse array of functional groups such as esters, nitriles, alcohols, and heterocycles are tolerated under the mild conditions. This method also circumvents the use of moisture‐sensitive organometallic reagents. 相似文献
273.
Mimi Wan Qi Wang Xiaoyun Li Bo Xu Dan Fang Ting Li Yueqi Yu Leyi Fang Yue Wang Meng Wang Fenghe Wang Chun Mao Jian Shen Jia Wei 《Angewandte Chemie (International ed. in English)》2020,59(34):14458-14465
Limited tumor permeability of therapeutic agents is a great challenge faced by current cancer therapy methods. Herein, a kind of near infrared light (NIR)‐driven nanomotor with autonomous movement, targeted ability, hierarchical porous structure, multi‐drugs for cancer chemo/photothermal therapy is designed, prepared and characterized. Further, we establish a method to study the interaction between nanomotors and cells, along with their tumor permeability mechanism, including 2D cellular models, 3D multicellular tumor spheroids and in vivo models. In vivo tumor elimination results verify that the movement behaviour of the nanomotors can greatly facilitate them to eliminate tumor through multiple therapeutic methods. This work tries to establish systematic research and evaluation models, providing strategies to understand the relationship between motion behaviour and tumor permeation efficiency of nanomotors in depth. 相似文献
274.
Wei-Er Liu Dr. Mao Quan Hang Zhou Dr. Liu-Pan Yang Prof. H. Y. Au-Yeung Prof. Wei Jiang 《Chemphyschem》2020,21(20):2249-2253
The thermodynamically unstable, colourless closed-ring isomer of spiropyran can be stabilized in water by the anti-configurational isomer of amide naphthotube. The influence of the binding on the thermodynamics and kinetics of spiropyran have been studied. The complex was further used to prepare a test paper that allows naked-eye detection of toxic paraoxon. 相似文献
275.
The epoxy resin/polyurethane semi-IPN was prepared and the glass transition behavior of the semi-IPN was discussed with DSC and DMA methods. The results show that the two glass transition temperatures (Tg) referring to epoxy resin and polyurethane respectively get closer. Between the two Tg there exists another Tg related to the interface between the two polymers. SEM indicates that this semi-IPN has a two-phase continuous structure which changes with different weight compositions. This is also proved by testing the Young's modulus. It is found that the IPN system has a cellular structure. Comparatively, the compatibility between the two polymers is the best when the weight ratio of EP/PU is 70/30. © 1996 John Wiley & Sons, Inc. 相似文献
276.
Chun-Wei Chen Long Zhang Shi-Jian Su Mei-Yu Huang Su-Fen Mao Ying-Yan Jiang 《先进技术聚合物》1996,7(8):711-714
Silica-supported polysilazane (SiO2-Si-N), and its platinum complex (SiO2-Si-N-Pt) were prepared. It was found that SiO2-Si-N–Pt can catalyze hydrogenation of o-xylene under mild conditions (40–50°C, 1 atm). The products of the reaction were cis-and trans-1,2-dimethylcyclohexane. The formation of trans-1,2-dimethylcyclohexane may be adequately explained according to the ‘roll-over’ model. The stereoselectivity was influenced by temperature and catalyst concentration, the proportion of the cis isomer decreasing with an increase in each of the two factors. The effects of other reaction parameters, such as the N/Pt mole ratio in the complex, solvents and reaction time, etc. on the hydrogenation of o-xylene were also studied. The SiO2-Si-N–Pt catalyst is very stable in reaction and turnover numbers amount to 200 in 80 hr. 相似文献
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