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41.
Exceedingly Fast Copper(II)‐Promoted ortho CH Trifluoromethylation of Arenes using TMSCF3 下载免费PDF全文
Ming Shang Shang‐Zheng Sun Dr. Hong‐Li Wang Dr. Brian N. Laforteza Prof. Dr. Hui‐Xiong Dai Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2014,53(39):10439-10442
The direct ortho‐trifluoromethylation of arenes, including heteroarenes, with TMSCF3 has been accomplished by a copper(II)‐promoted C? H activation reaction which completes within 30 minutes. Mechanistic investigations are consistent with the involvement of C? H activation, rather than a simple electrophilic aromatic substitution (SEAr), as the key step. 相似文献
42.
Yingrui Shang Jing Zhao Jingqing Li Zhonghua Wu Shichun Jiang 《Colloid and polymer science》2014,292(12):3205-3221
The influence of annealing on the microstructure and mechanical properties of β-form isotactic polypropylene (iPP) was investigated via in situ synchrotron small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). Transition of β-iPP to α-iPP was investigated via recrystallization at high annealing temperatures (T a?>?120 °C). And crystallinity, crystal sizes, and long period of ordered structure increased with increasing annealing temperature. Abrupt changes were found in both mechanical properties and structural features at the same T a range (~120 °C). The in situ synchrotron SAXS and WAXD shows that the destruction of b phase at yielding and after yielding should account for the ductility of β-iPP. The thermodynamics and kinetics of annealing were investigated with DSC and X-ray synchrotron experiments. A characteristic annealing time was investigated, which measures the rate of phase evolution in annealing of β-iPP. Eventually, a hypothesized model can be used to describe the property/structure relations during this process. 相似文献
43.
超级电容器具有功率密度高、充放电速度快、循环寿命长和维护成本低的特点,在电动车动力电池领域具有潜在的应用前景。超级电容器性能主要由其电极材料所决定。聚苯胺易合成、理论比容量高,而且导电性能优异,作为超级电容器电极材料有很高的应用价值。但是,在长期使用过程中,它的体积容易发生膨胀或收缩,循环寿命差。为了解决这个问题,将聚苯胺与石墨烯复合可以扬长避短,充分利用两者之间的协同效应,赋予复合材料优异电化学电容性能。本文综述了超级电容器用石墨烯-聚苯胺复合材料的制备方法,包括原位聚合法、油水界面合成法、电化学合成法、层层自组装法等;提出了三维网状石墨烯和对石墨烯-聚苯胺复合材料进行改性来提高复合材料的电化学电容性能的思路。 相似文献
44.
Lei Guo Shang Jia Christian S. Diercks Xuejing Yang Sultan A. Alshmimri Omar M. Yaghi 《Angewandte Chemie (International ed. in English)》2020,59(5):2023-2027
Three new post‐synthetic modification reactions, namely amidation, esterification, and thioesterification, were demonstrated on a novel highly crystalline two‐dimensional covalent organic framework (COF), COF‐616, bearing pre‐installed carboxyl groups. The strategy can be used to introduce a large variety of functional groups into COFs and the modifications can be carried out under mild reaction conditions, with high yields, and an easy work‐up protocol. As a proof of concept, various chelating functionalities were successfully incorporated into COF‐616 to yield a family of adsorbents for efficient removal of several contaminants in the water. 相似文献
45.
Nan Wen Bojun Jiang Xiaojing Wang Zhifu Shang Dawei Jiang Lu Zhang Caiying Sun Zijian Wu Hui Yan Chuntai Liu Zhanhu Guo 《Chemical record (New York, N.Y.)》2020,20(8):773-792
The properties of polyvinyl alcohol (PVA) nanocomposite hydrogels influenced by nanoparticles are reviewed. Various kinds of nanoparticles with excellent mechanical and electrical properties have been introduced into PVA hydrogel to produce stretchable and conductive PVA nanocomposite hydrogel. Understanding the mechanism between the matrix of PVA hydrogel and nanoparticles is therefore critical for the development of PVA nanocomposite hydrogels. This review focuses on the nanoparticles include carbon nanotubes, graphene oxide and metal nanoparticles, and describes the effects of nanoparticles on the mechanical and conductive properties of PVA nanocomposite hydrogels. A new promising area of soft stretchable PVA nanocomposite hydrogel is highlighted for possible applications. Finally, a brief outlook for future research is presented. 相似文献
46.
XuanLin Meng Yang Li Chongchong Lu Man Zhao Ming Li ShaoLi Wang ChangBao Zhao Bao Lin LuYue Shang Zhaohui Chu Xinhua Ding 《Journal of separation science》2020,43(12):2311-2320
In a recent study, anthocyanins, which have a strong free radical‐scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis–trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this “DM130‐LH20‐C18 system” can be used to obtain a cinnamic acid‐derived cis–trans anthocyanin, petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside cis–trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis–trans anthocyanin was dozens of times higher than that of vitamin C. 相似文献
47.
Correction for ‘Cu-catalyzed C–C bond formation of vinylidene cyclopropanes with carbon nucleophiles’ by Jichao Chen et al., Chem. Sci., 2019, 10, 10601–10606.We regret that in the original article the structure of compound 1 in Tables 1–3 was incorrect. The correct structure is given below.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. 相似文献
48.
A rare case of thermodynamic miscibility has been demonstrated in the amorphous state (quenched glass as well as molten state) of a ternary blend system formed by poly(ether imide) and semicrystalline poly(ethylene terephthalate) and poly-(butylene terephthalate). A single glass transition temperature (Tg) in the ternary blends was observed using differential scanning calorimetry and dynamic mechanical analysis. 相似文献
49.
Hu Yinlong Hua Tianyang Chen Michael Z. Q. Shi Shang Sun Yonghui 《Nonlinear dynamics》2021,105(1):99-112
Nonlinear Dynamics - In this paper, the instability of semi-active control systems caused by the utilization of semi-active inerters is analyzed. The purpose of this study is to demonstrate the... 相似文献
50.