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931.
Yeon‐Ju Lee Dong‐Geun Lee Hyun Soo Rho Vladimir B. Krasokhin Hee Jae Shin Jong Seok Lee Hyi‐Seung Lee 《Journal of heterocyclic chemistry》2013,50(6):1400-1404
Three new 5‐hydroxyindole alkaloids ( 1 , 2 , 3 ) along with seven known analogs ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ) were isolated from a Dokdo marine sponge Scalarispongia sp. The elucidation of the structures of the new compounds by spectroscopic analyses indicated that these compounds were an indole glyoxylate ( 1 ), a mono‐indole analog of hyrtinadine A ( 2 ), and a symmetrical bis‐indole with pyridine linker ( 3 ). The comparison of IC50 values for obtained compounds against a human leukemia cell line revealed that the bis‐indole structure is a requirement for cytotoxicity. 相似文献
932.
Wei Xu Ping Liu Chunhui Guo Chao Dong Xiuhua Zhang Shengfu Wang 《Mikrochimica acta》2013,180(11-12):1005-1011
We describe a molecularly imprinted electrochemical sensor for selective and sensitive determination of β2-agonists. It is making use of a combination of single-wall carbon nanotubes (SWNTs) with a molecularly imprinted sol–gel. The SWNTs were introduced in order to enhance electron transport and sensitivity. The imprinted sol–gel film with its specific binding sites acts as a selective recognition element and as a preconcentrator for β2-agonists. The morphology of the imprinted film was characterized by scanning electron microscopy. The optimized sensor displays high sensitivity and excellent selectivity for the β2-agonists as shown for their determination in human serum samples. Figure
A molecularly imprinted electrochemical sensor was constructed for selective and sensitive determination of β2-agonists. The optimized sensor displays high sensitivity and excellent selectivity for the β2-agonists as shown for their determination in human serum samples. 相似文献
933.
A selective and effective oxidation of alcohols into the corresponding aldehydes and ketones, respectively, with a new reagent, ferric(III) nitrate supported on kieselguhr, under heterogeneous conditions is reported. 相似文献
934.
Hong WooLee Tae WonKang Eung-Nam Kim Jaewook Shin Kyung HoiCha Dong OckCho 《合成通讯》2013,43(23):4345-4354
A method for preparing cephalosporin derivatives by reacting cephalosporin alkaline metal salts with organic halide in the presence of quarternary ammonium salts catalyst is disclosed. Δ3 to Δ2 isomerization, a side reaction commonly reported in preparation of cephalosporin derivatives, was successfully eliminated. The desired Δ3 was obtained as a sole product in the reaction. 相似文献
935.
Aasif Helal Hyun Gon Kim Manik Kumer Ghosh Cheol-Ho Choi Sung-Hong Kim Hong-Seok Kim 《Tetrahedron》2013
Two new reactive and highly selective turn-on fluorescent chemosensors based on the position of ring annulation of the naphthalene–thiazole moiety for aluminum ions in ethanol, were synthesized and investigated. It was found that sensors 2 and 4 exhibited a remarkable enhancement of emission upon complexation with Al3+. A TD-B3LYP/6-31G(d,p) calculation was performed to characterize the nature of the fluorescence behavior of sensors 2 and 4 upon Al3+ complexation. The mechanism of fluorescence was based on the cation promoted hydrolysis of ester and subsequent complexation. The combination of experimental and computational analyses provides a more complete understanding of the molecular level origin of these types of unique photophysical properties. 相似文献
936.
937.
Bi‐Dong Wu Zun‐Ning Zhou Yan‐Gang Bi Li Yang Jian‐Guo Zhang Tong‐Lai Zhang 《无机化学与普通化学杂志》2013,639(5):799-803
The intriguing multi‐ligand compound [Cu(IMI)4Cl]Cl ( 1 ) with the ligand imidazole (IMI) was synthesized and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure was determined by X‐ray single crystal diffraction and the crystallographic data showed that the compound belongs to the monoclinic P21/n space group [α = 8.847(2) Å, b = 13.210(3) Å, c = 13.870(3) Å, and β = 90.164(3)°]. Furthermore, the CuII ion is five‐coordinated by four nitrogen atoms from four imidazole ligands and a chlorine atom. The thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetric (TG‐DTG) analysis. The non‐isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa's method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) were measured and calculated. 相似文献
938.
Xiaoyu Dong Liang Cui Yunjing Shi Shilie Pan Zhongxiang Zhou Zhihua Yang Bingbing Zhang Xiangzhan Jiang Yun Yang Zhaohui Chen Zhenjun Huang 《无机化学与普通化学杂志》2013,639(6):988-993
The single crystals of Ba2Cd(B3O6)2 were grown by the spontaneous crystallization method for the first time. They crystallize in the centrosymmetric trigonal space group R$\bar{3}$ with a = 7.143(3) Å, c = 17.405(16) Å, and Z = 3. The structure is characterized by isolated B3O6 units, and the Ba2+ and Cd2+ cations connect with B3O6 rings to form three dimensional structure. The TG/DSC and XRD results reveal that Ba2Cd(B3O6)2 melts congruently. First‐principles electronic structure calculation performed with the density functional theory (DFT) method shows that the calculated bandgaps are 4.66 eV, which is in good agreement with the UV/Vis/NIR experimental value 4.59 eV. The calculation shows that the Ba2Cd(B3O6)2 crystal has a large birefringence (Δn = 0.0875–0.0569 from 270 nm to 2600 nm), which demonstrates that Ba2Cd(B3O6)2 is a potential birefringence crystal. 相似文献
939.
Weifu Dong Piming Ma Shifeng Wang Mingqing Chen Xiaoxia Cai Yong Zhang 《Polymer Degradation and Stability》2013
Poly(β-hydroxybutyrate) (PHB) is a bio-based and biodegradable aliphatic polyester, however its application is limited by some disadvantages such as high price, brittleness, poor processability and low melt-strength due to serious thermal degradation. Partial crosslinking initiated by dicumyl peroxide (DCP) was applied in this work to improve the performance of poly(β-hydroxybutyrate)/poly(d,l-lactic acid) (PHB/PDLLA) blends. The partial crosslinking of the blends and its effect on the properties, morphology, rheology and thermal behavior of the blends were investigated. The tensile strength and impact toughness of the PHB were increased by incorporation of the PDLLA, which were improved further after the partial crosslinking because of an increased compatibility between the PHB and the PDLLA phases. The rheological study revealed that the storage modulus (G′) and complex viscosity (η*) of the blends were increased after addition of the DCP. On the other hand, the crystallization of PHB in the blends was restricted to a certain extent by the formation of partially crosslinked network while its crystal form was not modified. 相似文献
940.
The main goal of this work is to identify two polyamides (PA11 and PA1012) by mass spectrometry including pyrolysis-GC/MS and MALDI-TOF MS. PA11 and PA1012 have similar properties and cannot be distinguished by many other methods. Using pyrolysis-GC/MS, the pyrograms of PA11 and PA1012 at 600 °C were compared. Specific pyrolyzates for PA11 and PA1012 were obtained, 2-azacyclotridecanone for PA11 and 1,10-diaminodecane, 1,10-dicyanodecane for PA1012, respectively, which was the basis to distinguish them. Meanwhile, MALDI-TOF MS can give specific repeat unit for these two polyamides, dehydrated 11-aminoundecanoic acid (M = 183) for PA11, acetylate of dodecanedioic acid and diaminodecane (M = 366) for PA1012, which can be another means of identifying them. 相似文献