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161.
A synthesis of the thromboxane A2 analog, -(9,11) ,(11,12)-dideoxa-(9,11)-methylene-(11,12)-epithio-thromboxane A2 methyl ester , is described. 相似文献
162.
Okazaki T Okubo S Nakanishi T Joung SK Saito T Otani M Okada S Bandow S Iijima S 《Journal of the American Chemical Society》2008,130(12):4122-4128
We report optical band gap modifications of single-walled carbon nanotubes upon C60 insertions by using photoluminescence and the corresponding excitation spectroscopy. The shifts in optical transition energies strongly depend on the tube diameter (dt) and the "2n + m" family type, which can be explained by the local strain and the hybridization between the nanotube states and the C60 molecular orbitals. The present results provide possible design rules for nanotube-based heterostructures having a specific type of electronic functionality. 相似文献
163.
Li Lin Xiaoyang He Prof. Xia-Guang Zhang Dr. Wenchao Ma Biao Zhang Diye Wei Prof. Shunji Xie Qinghong Zhang Prof. Xiaodong Yi Prof. Ye Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202214959
The renewable-electricity-driven CO2 reduction to formic acid would contribute to establishing a carbon-neutral society. The current catalyst suffers from limited activity and stability under high selectivity and the ambiguous nature of active sites. Herein, we report a powerful Bi2S3-derived catalyst that demonstrates a current density of 2.0 A cm−2 with a formate Faradaic efficiency of 93 % at −0.95 V versus the reversible hydrogen electrode. The energy conversion efficiency and single-pass yield of formate reach 80 % and 67 %, respectively, and the durability reaches 100 h at an industrial-relevant current density. Pure formic acid with a concentration of 3.5 mol L−1 has been produced continuously. Our operando spectroscopic and theoretical studies reveal the dynamic evolution of the catalyst into a nanocomposite composed of Bi0 clusters and Bi2O2CO3 nanosheets and the pivotal role of Bi0−Bi2O2CO3 interface in CO2 activation and conversion. 相似文献
164.
Takashi Abe Eiji Hayashi Hajime Baba Shunji Nagase 《Journal of fluorine chemistry》1984,25(4):419-434
The electrochemical fluorination of α-cyclohexenyl-substituted carboxylic esters [; R′CH3, C2H5, C3H7)] afforded both perfluoro(9-alkyl-7-oxa-bicyclo[4.3.0]nonane)s and perfluoro(8-alkoxy-9-alkyl-7-oxabicyclo[4.3.0]nonane)s in fairly good yields. As the driving force for the ring-closure in this fluorination, a mechanism which involves a resonance stabilized intermediate radical is proposed. Perfluoro(8-chloro-8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) and perfluoro(8,8-dichloro-9-ethyl-7-oxabicyclo[4.3.0]nonane) were obtained by the controlled chlorination of perfluoro(8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) with anhydrous aluminum chloride in low yields. Some new fused perfluorobicyclic ethers and a perfluoroacid fluoride obtained in this experiment have been characterized by infrared, mass and 19F nmr spectra and elemental analysis. 相似文献
165.
Poly(vinyl alcohol)-Congo Red (PVA-CR) complexes in aqueous solutions have a unique sol-gel transition behaviour. At an appropriate PVA concentration, a sol-gel-sol-gel type reentrant transition takes place with increasing CR concentration. The microscopic structure and Theological properties of these complexes were investigated by small-angle neutron scattering (SANS) and viscometry. 相似文献
166.
Jong Won Kim Sangkeun Son Gil Soo Kim Junnosuke Otaka Yuzuki Miura Atsuya Muranaka Masanobu Uchiyama Jung-Sook Lee Mina Jang Sung-Kyun Ko Shunji Takahashi Hiroyuki Osada Jae-Hyuk Jang Jong Seog Ahn 《Tetrahedron letters》2019,60(45):151227
LC/MS-based chemical screening of fungal extract fraction library led to identification of three 2,3-aryl substituted furanone metabolites (1–3), including one known butenolide glycoside (1) whose stereochemistry remained unsolved and two new compounds gotjawaside and gotjawalide (2 and 3), from Auxarthron sp. KCB15F070, a fungus isolated from a soil sample of the volcanic island Jeju, Korea. Their planar structures were elucidated by 1D- and 2D-NMR spectroscopic and HRESIMS spectrometric techniques, and the absolute configurations of three compounds were solved using a combination of chemical derivatizations and computational analysis of vibrational circular dichroism (VCD) spectra. 相似文献
167.
Azulene derivatives reacted with 2-indolinones in the presence of triflic anhydride (Tf2O) to afford 1-(indol-2-yl)azulenes in good yields. In the cases of the reaction of 6-tert-butyl-1-(methylthio)azulene (11) and 1-(1,4-dihydropyridin-4-yl)azulene 14, 1,1′-biazulene derivative 24 and 1-(indol-2-yl)azulene (2) were obtained under the similar reaction conditions, respectively, instead of the presumed electrophilic substitution products. 相似文献
168.
Preparation, photocatalytic activities, and dye-sensitized solar-cell performance of submicron-scale TiO2 hollow spheres 总被引:1,自引:0,他引:1
Kondo Y Yoshikawa H Awaga K Murayama M Mori T Sunada K Bandow S Iijima S 《Langmuir : the ACS journal of surfaces and colloids》2008,24(2):547-550
We prepared submicron-scale spherical hollow particles of anatase TiO2 by using a polystyrene-bead template. The obtained particles were very uniform in size, with a diameter of 490 nm and a shell thickness of 30 nm. The Brunauer-Emmett-Teller surface area measurements revealed a large value of 70 m2/g. The photocatalytic property was investigated by the complete decomposition of gaseous isopropyl alcohol under UV irradiation. It was indicated that the activity of the hollow spheres was 1.8 times higher than that of the conventional P25 TiO2 nanoparticles with a diameter of 30 nm. Furthermore, we fabricated a dye-sensitized solar cell (DSC) using an electrode of the TiO2 hollow spheres, and examined the photovoltaic performance under simulated sunlight. Although the per-area efficiency was rather low (1.26%) because of a low area density of TiO2 on the electrode, the per-weight efficiency was 2.5 times higher than those of the conventional DSCs of TiO2. 相似文献
169.
Three novel anti-angiogenic steroidal alkaloids, cortistatins J (1), K (2), L (3), have been isolated from the Indonesian marine sponge Corticium simplex. The chemical structures of cortistatins J (1), K (2), and L (3) were determined by 2D-NMR analysis to be unique abeo-9(10-19)-androstane-type steroidal alkaloids having isoquinoline unit instead of the side chain part, respectively. Cortistatin J (1) showed cytostatic anti-proliferative activity against human umbilical vein endothelial cells (HUVECs) at 8 nM, in which the selective index was 300-1000-fold in comparison with other cell lines. 相似文献
170.
Cortistatins A, B, C, and D, anti-angiogenic steroidal alkaloids, from the marine sponge Corticium simplex 总被引:2,自引:0,他引:2
Aoki S Watanabe Y Sanagawa M Setiawan A Kotoku N Kobayashi M 《Journal of the American Chemical Society》2006,128(10):3148-3149
Four novel steroidal alkaloids named cortistatins A (1), B (2), C (3), and D (4) consisting of a 9(10-19)-abeo-androstane and isoquinoline skeleton have been isolated from the marine sponge Corticium simplex. The absolute stereostructures of 1-4 were elucidated by detailed 2D NMR, CD, and X-ray crystallographic analyses. Cortistatins A-D inhibited proliferation of human umbilical vein endothelial cells (HUVECs) with high selectivity. Among the four substances, cortistatin A (1) showed the strongest anti-proliferative activity (IC50 = 0.0018 muM) against HUVECs, in which the selective index was more than 3000-fold in comparison with that of normal fibroblast or several tumor cell lines. 相似文献