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Dr. Shan Tang Siyuan Wang Yichang Liu Dr. Hengjiang Cong Prof. Dr. Aiwen Lei 《Angewandte Chemie (International ed. in English)》2018,57(17):4737-4741
Dehydrogenative C?H/N?H cross‐coupling serves as one of the most straightforward and atom‐economical approaches for C?N bond formation. In this work, an electrochemical reaction protocol has been developed for the oxidative C?H amination of unprotected phenols under undivided electrolytic conditions. Neither metal catalysts nor chemical oxidants are needed to facilitate the dehydrogenation process. A series of triarylamine derivatives could be obtained with good functional‐group tolerance. The electrolysis is scalable and can be performed at ambient conditions. 相似文献
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Movements in molecular machines are usually diverse and coupled, but some of them are often implicit and hard to be observed in experiments. In the present work, the two-or three-dimensional free-energy landscapes characterizing the coupled shuttling and other movements of a series of pH-triggered rotaxanes composed of a crown ether and an H-shaped axle with distinct number of phenyl rings(n=1-3) have been explored. The results show that although the calculated free-energy barriers against shuttling in the rotaxanes(n=2 and 3) change slightly, the movements coupled with the shuttling vary significantly with the axle length. At high pH, the shuttling in the rotaxane of n=2 is coupled with the isomerization of the wheel, while the shuttling in the one of n=3 is accompanied by both the isomerization and the rotation of the macrocycle. In addition, the crown ether underwent greater conformational change during shuttling at low pH compared to that at high pH. These results indicate that disentangling the coupled movements is important to reveal the underlying molecular mechanism of the shuttling. 相似文献
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本文通过稀土高氯酸盐与L-丙氨酸(L-Ala)及咪唑(Im)反应,合成了标题配合物RE(Ala)_4(Im)(ClO_4)_3·2H_2O(RE=Pr,Nd,Sm),测定了配合物的红外光谱,对其主要吸收带进行了归属。红外光谱的研究结果表明,丙氨酸以内盐的形式存在于配合物中,通过羧基与稀土离子配位,且随着RE原子量的增大,羧基与RE~(3 )间配位键离子性逐渐减弱,共价性逐渐增大;咪唑环上的N参与了配位。 相似文献
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Mei Wu Haifeng Han Lingli Ni Songlan Zhang Shuang Li Yuqi Wang Jinlong Jiang Yichang Pan Jing Chen 《Russian Journal of Applied Chemistry》2018,91(5):758-763
A nove l mesoporous zirconium phosphonate hybrid bentonite (MZrPHB ) catalyst was prepared for the removal of trace olefins from refining aromat ic oil. Pyridine-FTIR, NH3?TPD, XRD, and N2 adsorptiondesorption analysis were applied to characterize acidic properties and textural properties of catalysts. And its olefins removal performance of MZrPHB catalyst was evaluated in comparison with commercial clay catalyst. It is found that the MZrPHB catalyst possesses an abundance of weak Lewis acid centers, large surface area, and regular mesopore, and thus, exhibits a longer treat life and higher olefins conversion compared to commercial clay catalyst. MZrPHB prepared in this report can be considered as a promising and superior alternative material to commercial clays for the purification of aromatics. 相似文献
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RE〔Ala)4(Im)(ClO4)3·2H2O固体配合物的合成及其红外光谱研究 总被引:4,自引:2,他引:2
本文通过稀土高氯酸盐与L-丙氨酸(L-Ala)及咪唑(Im)反应,合成了标题配合物RE(Ala)4(Im)(ClO4)3*2H2O(RE=Pr,Nd,Sm),测定了配合物的红外光谱,对其主要吸收带进行了归属.红外光谱的研究结果表明,丙氨酸以内盐的形式存在于配合物中,通过羧基与稀土离子配位,且随着RE原子量的增大,羧基与RE3+间配位键离子性逐渐减弱,共价性逐渐增大;咪唑环上的N参与了配位. 相似文献
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ICP-AES法测定粗氧锑中砷硒 总被引:4,自引:0,他引:4
3用浓硫酸溶解粗氧锑,ICP-AES法直接测定砷。对于样品中的痕量硒,先以次磷酸钠还原单质,并与砷共沉淀,经浮选分离后再测定。对硒的分离条件进行了优化。考察了基体锑的干扰及共存杂质的影响。方法运用于粗氧锑样品中砷、硒测定、结果满意。 相似文献
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Yichang Ma Dr. Chuan Hu Guiqin Yi Zhangtang Jiang Dr. Xiangyu Su Prof. Qinglin Liu Dr. Ju Yeon Lee Dr. So Young Lee Prof. Young Moo Lee Prof. Qiugen Zhang 《Angewandte Chemie (International ed. in English)》2023,62(41):e202311509
Anion exchange membrane fuel cells (AEMFCs) and water electrolysis (AEMWE) show great application potential in the field of hydrogen energy conversion technology. However, scalable anion exchange membranes (AEMs) with desirable properties are still lacking, which greatly hampers the commercialization of this technology. Herein, we propose a series of novel multiblock AEMs based on ether-free poly(biphenyl ammonium-b-biphenyl phenyl)s (PBPA-b-BPPs) that are suitable for use in high performance AEMFC and AEMWE systems because of their well-formed microphase separation structures. The developed AEMs achieved outstanding OH− conductivity (162.2 mS cm−1 at 80 °C) with a low swelling ratio, good alkaline stability, and excellent mechanical durability (tensile strength >31 MPa and elongation at break >147 % after treatment in 2 M NaOH at 80 °C for 3750 h). A PBPA-b-BPP-based AEMFC demonstrated a remarkable peak power density of 2.41 W cm−2 and in situ durability for 330 h under 0.6 A cm−2 at 70 °C. An AEMWE device showed a promising performance (6.25 A cm−2 at 2 V, 80 °C) and outstanding in situ durability for 3250 h with a low voltage decay rate (<28 μV h−1). The newly developed PBPA-b-BPP AEMs thus show great application prospects for energy conversion devices. 相似文献
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As a revolutionary observation tool in life science, biomedical, and material science, optical microscopy allows imaging of samples with high spatial resolution and a wide field of view. However, conventional microscopy methods are limited to single imaging and cannot accomplish real-time image processing. The edge detection, image enhancement and phase visualization schemes have attracted great interest with the rapid development of optical analog computing. The two main physical mechanisms that enable optical analog computing originate from two geometric phases: the spin-redirection Rytov-Vlasimirskii-Berry (RVB) phase and the Pancharatnam-Berry (PB) phase. Here, we review the basic principles and recent research progress of the RVB phase and PB phase based optical differentiators. Then we focus on the innovative and emerging applications of optical analog computing in microscopic imaging. Optical analog computing is accelerating the transformation of information processing from classical imaging to quantum techniques. Its intersection with optical microscopy opens opportunities for the development of versatile and compact optical microscopy systems. 相似文献