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991.
Xian Li Zhi‐Ying Weng Yong Li Jian‐Xin Pu Sheng‐Xiong Huang Wei‐Lie Xiao Han‐Dong Sun 《Helvetica chimica acta》2008,91(6):1130-1136
Phytochemical investigation of the medicinal plant Isodon phyllostachys led to the isolation of four new ent‐kaurane diterpenoids, phyllostacins F–I ( 1 – 4 , resp.), together with 11 known compounds, rosthorin A ( 5 ), rabdoternin C ( 6 ), enmenol ( 7 ), oridonin ( 8 ), lasiocarpanin ( 9 ), xerophilusin B ( 10 ), ponicidin ( 11 ), macrocalin B ( 12 ), phyllostachysin A ( 13 ), sculponeatin C ( 14 ), and macrocalyxoformin E ( 15 ). The structures of the new compounds were established by spectroscopic methods, including extensive 1D‐ and 2D‐NMR analyses. Compounds 1, 2, 7, 10 , and 13 were evaluated for their inhibitory activity against K562 and HepG2 cell lines. 相似文献
992.
Pu KY Qi XY Yang YL Lu XM Li TC Fan QL Wang C Liu B Chan HS Huang W 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(4):1205-1215
Three new topology-varied rod-coil block copolymers, comprising the same oligo(p-phenyleneethynylene) (OPE) rod components and the same coil components, were synthesized by atom-transfer radical polymerization. Their photophysical properties were systematically studied and compared in consideration of their solid-state structures and self-assembly abilities. These copolymers have similar intrinsic photophysical properties to the OPE rods, as reflected in dilute solution. However, their photophysical properties in the solid state are manipulated to be dissimilar by supramolecular organization. Wide-angle X-ray diffraction (WAXD) and atomic force microscopy (AFM) data demonstrate that these copolymers possess different self-assembly abilities due to the molecular-architecture-dependent pi-pi interactions of the rods. Hence, the aggregates in the solid state are formed with a different mechanism for these copolymers, bringing about the discrepancy in the solid-state luminescent properties. 相似文献
993.
994.
995.
Dr. Min Zhu Dr. Pu Wang Nan Yan Xiaoqi Chai Lizhong He Yan Zhao Nan Xia Chuanhao Yao Prof. Dr. Jin Li Prof. Dr. Haiteng Deng Prof. Dr. Yan Zhu Prof. Dr. Yong Pei Prof. Dr. Zhikun Wu 《Angewandte Chemie (International ed. in English)》2018,57(17):4500-4504
Anti‐galvanic reaction (AGR) not only defies classic galvanic theory but is a promising method for tuning the compositions, structures, and properties of noble‐metal nanoparticles. Employing AGR for the preparation of alloy nanoparticles has recently received great interest. Herein, we report an unprecedented alloying mode by way of AGR, in which foreign atoms induce structural transformation of the mother nanoparticles and enter the nanoparticles in a non‐replacement fashion. A novel, active‐metal‐doped, gold nanoparticle was synthesized by this alloying mode, and its structure resolved. A CdSH motif was found in the protecting staples of the bimetal nanoparticle. DFT calculations revealed that the Au20Cd4(SH)(SR)19 nanoparticle is a 8e superatom cluster. Furthermore, although the Cd‐doping does not essentially alter the absorption spectrum of the mother nanocluster, it distinctly enhances the stability and catalytic selectivity of the mother nanoclusters. 相似文献
996.
Brønsted Acid Enabled Nickel‐Catalyzed Hydroalkenylation of Aldehydes with Styrene and its Derivatives 下载免费PDF全文
Xing‐Wang Han Tao Zhang Yan‐Long Zheng Wei‐Wei Yao Jiang‐Fei Li You‐Ge Pu Prof. Dr. Mengchun Ye Qi‐Lin Zhou 《Angewandte Chemie (International ed. in English)》2018,57(18):5068-5071
A Brønsted acid enabled nickel‐catalyzed hydroalkenylation of aldehydes and styrene derivatives has been developed. The Brønsted acid acts as a proton shuttle to transfer a proton from the alkene to the aldehyde, thereby leading to an economical and byproduct‐free coupling. A series of synthetically useful allylic alcohols were obtained through one‐step reactions from readily available styrene derivatives and aliphatic aldehydes in up to 88 % yield and with high linear selectivity. 相似文献
997.
A new asymmetric perfluordiarylethene (1O) was synthesized using 4, 5-[bis-(5-ethylacetate-yl)-2-thienyl]-1H-imidazole as a functional group. 1O exhibited favorable reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light. Both of its open- and closed-ring isomers were found to be highly selective towards Cu2+ with significant absorption and color changes, which could be used as a ‘naked-eye’ colorimetric sensor for Cu2+ detection. Upon exposure to acid, its fluorescence dramatically enhanced by 14-fold with a color change from dark to bright cyan due to the formation of the protonated compound. Moreover, 1O showed obvious fluorescence “turn-on” signal response towards Al3+, and the detection limit for Al3+ was determined to be 4.8 × 10?9 mol L?1. Based on the fluorescence signals of 1O, a combinational stimuli logic circuit were designed by using the fluorescence intensity as the output signal with the inputs of lights, Al3+ and EDTA. Finally, 1O could be used as a biological probe for detecting intracellular Al3+ in a physiological environmental. 相似文献
998.
Weihua Chen Jianhua Liu Ying Wang Chunhuan Jiang Bin Yu Zhen Sun Lehui Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6356-6360
Intracellular targeting has the same potential as tissue targeting to increase therapy efficacy, especially for drugs that are toxic to DNA. By adjusting intracellular traffic, we developed a novel direct‐nucleus‐delivery platform based on C5N2 nanoparticles (NPs). Supramolecular interactions of C5N2 NPs with the cell membrane enhanced cell uptake; abundant edge amino groups promoted fast and effective rupture of early endosomes; and the appropriate size of the NPs was also crucial for size‐dependent nuclear entry. As a proof of concept, the platform was not only suitable for the effective delivery of molecular drugs/dyes (doxorubicin, hydroxycamptothecine, and propidium iodide) and MnO2 nanoparticles to the nucleus, but was also photoresponsive for nucleus‐targeting photothermal therapy (PTT) and photodynamic therapy (PDT) to further greatly increase anticancer efficacy. This strategy might open the door to a new generation of nuclear‐targeted enhanced anticancer therapy. 相似文献
999.
The models were established for the theoretical current-voltage characteristics in water dissociation process on a bipolar
membrane. Particular attention was given to the transport of the water ions and electrolyte ions as well as the membrane physical
structure and configuration. The factors on the water splitting process were adequately analysed based on the derived theoretical
current-voltage characteristics and several good suggestions were proposed for decreasing the work voltage in practical operations.
In addition, the model can give a reasonable explanation for the catalytic effect of some chemicals, such as amphiprotic hydroxide
compounds, weak polymeric acids and bases, etc. It is shown that the catalyst may be responsible for the increase in dissociation
rate constant of water and therefore enhance the water dissociation. The guidelines for choosing a proper catalyst were also
proposed.
Project supported by the Youth Foundation of USTC[1999], the Foundation of the State Kay Lab. of Func. Poly. Materials for
Adsor. & Sep., Nankai Univ. [1998], the Foundation of Post-doctoral of China (No. 1996(2)) and the National Natural Science
Foundation of China (Grand No. 2997604). 相似文献
1000.
Songhe Meng Chuping Liu Guoqian Liu Guanghui Bai Chenghai Xu Weihua Xie 《Solid State Sciences》2010,12(5):818-821
Thermal shock behavior of ZrB2–20% SiC–15% graphite and ZrB2–20% SiC–5% AlN was studied by water quenching test. Strengths of the two materials were measured with different load speeds. It presented that the material strengths decreased with an increase of load speed, and gradually approached to a constant value. A novel method was provided for predicting heat transfer coefficients and thermal stress considering dynamical behavior during quenching test. It showed that the maximum dynamical thermal stress, which determined failure of the materials, was more than two times as the maximum quasi-static one.The method provided in this work can be used to obtain more accurate thermal stress during quenching test. 相似文献