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991.
Huan Wang Qian‐Yun Sun Fu‐Mei Yang Chun‐Lin Long Yue‐Hu Wang Gui‐Hua Tang Fu‐Wei Zhao Hong‐Mei Niu Qiao‐Qin Huang Jin‐Jin Xu Yusuke Wataya Li‐Juan Ma 《Helvetica chimica acta》2010,93(11):2183-2188
Three new chromanone derivatives, calopolyanic acid ( 1 ), isocalopolyanic acid ( 2 ), and isorecedensic acid ( 3 ), were isolated from the pericarps of Calophyllum polyanthum Wall . ex Choisy , along with seven known compounds, apetalic acid, blancoic acid, chapelieric acid, methyl isoapetalate, isoapetalic acid, isocalolongic acid, and recedensic acid. All of these compounds were reported from C. polyanthum for the first time. The structures of 1 – 3 were elucidated by spectroscopic methods. 相似文献
992.
993.
Gui LC Wang XJ Ni QL Wang M Liang FP Zou HH 《Journal of the American Chemical Society》2012,134(2):852-854
Nanospheric hydroxo-bridged clusters of [M(20)(OH)(12)(maleate)(12)(Me(2)NH)(12)](BF(4))(3)(OH)·nH(2)O (M = Co (1), Ni (2)) with O(h) symmetry were afforded under hydrothermal condition with Co(BF(4))(2)·6H(2)O/Ni(BF(4))(2)·6H(2)O and fumaric acid in a DMF/EtOH mixed solvent. They are characterized by elemental analysis, IR, and X-ray diffraction. X-ray single crystal diffraction analyses show that these two complexes are isostructural containing an ideally cubic M(8) core in that each two M atoms are doubly bridged at the edges by one OH(-) and one maleate, while these OH(-) and maleate groups are coordinated further by exterior identical 12 M atoms which construct a perfect M(12) icosahedron to encapsulate the cubic core. To our knowledge, such large clusters with O(h) symmetry are seldom. The variable-temperature magnetic susceptibility studies reveal that these two isostructures exhibit antiferromagnetic interactions. 相似文献
994.
995.
Wenbo Wu Shanghui Ye Gui Yu Yunqi Liu Jingui Qin Zhen Li 《Macromolecular rapid communications》2012,33(2):164-171
With the aim to develop new tetraphenylethylene (TPE)‐based conjugated hyperbranched polymer, TPE units, one famous aggregation‐induced emission (AIE) active group, are utilized to construct hyperbranched polymers with three other aromatic blocks, through an “A2+B4” approach by using one‐pot Suzuki polycondensation reaction. These three hyperbranched polymers exhibit interesting AIEE behavior and act as explosive chemsensors with high sensitivity both in the nanoparticles and solid states. This is the first report of the AIE activity of the TPE‐based conjugated hyperbranched polymers. Their corresponding PLED devices also demonstrate good performance. 相似文献
996.
In this paper, we consider a nonlinear sublinear Schrödinger equation at resonance in . By using bounded domain approximation technique, we prove that the problem has infinitely many solutions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
997.
A simple and convenient procedure for the synthesis of 14‐aryl or alkyl‐14H‐dibenzo[a. j]xanthene derivatives is described through a one‐pot condensation of β‐naphthol with various aryl or alkyl aldehydes in the presence of HBF4‐SiO2 as the catalyst under thermal and solvent‐free conditions. 相似文献
998.
Jiangwen Li Faqiong Zhao Guangyin Wang Zhe Gui Fei Xiao Baizhao Zeng 《Electroanalysis》2009,21(2):150-156
A novel composite was fabricated through dispersing multiwalled carbon nanotubes (MWNTs) in gold nanoparticle (GPs) colloid stabilized by chitosan and ionic liquid (i.e., 1‐butyl‐3‐methylimidazolium tetrafluoroborate, BMIMBF4). Transmission electron microscopy (TEM) experiment showed that the GPs highly dispersed on the MWNTs probably due to the electrostatic interaction among GPs, MWNTs and the imidazolium cation of BMIMBF4. X‐ray photoelectron spectroscopy (XPS) indicated that thus‐formed gold nanostructure was mediated by BMIMBF4. When glucose oxidase (GOD) was immobilized on the composite (MWNTs‐GPs) its ultraviolet‐visible absorption spectrum kept almost unchanged. The immobilized GOD coated glassy carbon electrode (GOD/MWNTs‐GPs/GC) exhibited a pair of well‐defined peaks in 0.10 M pH 7.0 phosphate buffer solution (PBS), with a formal potential of ?0.463 V (vs. SCE). The electrochemical process involved two‐electron transfer. The electron transfer coefficient was ca.0.56 and the electron transfer rate constant was 9.36 s?1. Furthermore, the immobilized GOD presented good catalytic activity to the oxidation of glucose in air‐saturated PBS. The Km and Im values were estimated to be 13.7 μM and 0.619 μA. The GOD/MWNTs‐GPs/GC electrode displayed good stability and reproducibility. 相似文献
999.
1000.
Hui Zhang Gui‐Ling Zhang Jing‐Yao Liu Miao Sun Bo Liu Ze‐Sheng Li 《Journal of computational chemistry》2010,31(2):403-411
The multiple‐channel reactions SiH3 + SiH3CH3 → products and SiH3 + SiH2(CH3)2 → products are investigated by direct dynamics method. The minimum energy path (MEP) is calculated at the MP2/6‐31+G(d,p) level, and energetic information is further refined by the MC‐QCISD method. The rate constants for individual reaction channels are calculated by the improved canonical variational transition state theory (ICVT) with small‐curvature tunneling (SCT) correction over the temperature range of 200–2400 K. The theoretical three‐parameter expression k1(T) = 2.39 × 10−23T4.01exp(−2768.72/T) and k2(T) = 9.67 × 10−27T4.92exp(−2165.15/T) (in unit of cm3 molecule−1 s−1) are given. Our calculations indicate that hydrogen abstraction channel from SiH group is the major channel because of the smaller barrier height among eight channels considered. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献