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991.
The abnormal structure conversion of CaCO3 from calcite to aragonite was investigated with a mixture of polyacrylamide (PAM) and cetyltrimethylammonium bromide (CTAB) as additives by a hydrothermal method. A novel morphology of aragonite, "magnified" cubic shape, was observed. In order to investigate the effects of PAM and experimental temperature on the morphology and phase of CaCO3, the samples were synthesized without any additives and with PAM as template at 90 and 120 degrees C, respectively. The results indicate that both the interaction between the mixed template and the CaCO3 and the elevated experiment temperature play important roles in the process of polymorph transformation. 相似文献
992.
In search of an appropriate position for the fluorescent labeling, six chemically available positions of the flavonone core of naringenin have been examined. A number of azido-containing naringenin derivatives were accordingly prepared in various site-specific fashions, and the mild Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition successfully served as the common "Click" labeling tool in the final steps. On the basis of the biological activities of the first batch of labeled compounds, further optimization at the C-6 position of naringenin finally afforded naringenin-flu (27), which acquired 20% of the potency of naringenin and presented good optical properties. Entry of naringenin-flu into living Rhizobium cells was demonstrated by in vitro fluorescent imaging experiments. 相似文献
993.
Xiu-Feng Hou Peng-Cheng Zhang Shu Liu Hui Wang Yue-Jiang Lin Guo-Xin Jin 《Journal of organometallic chemistry》2008,693(8-9):1462-1468
Five binuclear half-sandwich cobalt complexes, [(η5-C5H4)Co(CO)I2]2SiMe2 (3), [(η5-C5H4)Co(S2C2B10H10)]2SiMe2 (4), [(η5-C5H4)]2Co2(μ2-S2C2B10H10)SiMe2 (5), [(η5-C5H3)CoI2](μ-I)[(η5-C5H3)Co(CO)I](SiMe2)2 (8), [(η5-C5H3)Co(S2C2B10H10)]2(SiMe2)2 (9), were successfully synthesized in moderate yield by the reactions of corresponding ligands, (C5H5)2SiMe2 (1) and (C5H4)2(SiMe2)2 (6), respectively. The molecular structures of 3, 5, 6, 8 and 9 was determined by X-ray crystallographic analysis, which distinctly depict various molecular structures containing the Cp rings and the metal centers with halide or 1,2-dicarba-closo-dodecaborane-1,2-dithiolato ligands. For the (η5-C5H4)2SiMe2 complexes, coordination of the fragments CpCo favors a exo conformation. With the rigid structure of the di-bridged ligand (C5H4)2(SiMe2)2, only cis isomers of the corresponding (η5-C5H3)2(Si2Me2)2 complexes are formed. All the complexes have been well characterized by elemental analysis, NMR and IR spectra. 相似文献
994.
Shaolei Ding Yingbo Shi Baochao Yang Min Hou Dr. Haibing He Prof. Dr. Shuanhu Gao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202214873
We report herein the asymmetric total synthesis of periglaucines A–C, N,O-dimethyloxostephine and oxostephabenine. The key strategies used include: 1) a RhI-catalyzed regio- and diastereoselective Hayashi-Miyaura reaction to connect two necessary fragments; 2) an intramolecular photoenolization/Diels–Alder (PEDA) reaction to construct the highly functionalized tricyclic core skeleton bearing a quaternary center; 3) a bio-inspired intramolecular Michael addition and transannular acetalization to generate the aza[4.4.3]propellane and the tetrahydrofuran ring. 相似文献
995.
Xingyue He Qing Wu Chen Hou Min Hu Qigang Wang Xia Wang 《Angewandte Chemie (International ed. in English)》2023,62(15):e202218766
Some cellular enzymatic pathways are located within a single organelle, while most others involve enzymes that are located within multiple compartmentalized cellular organelles to realize the efficient multi-step enzymatic process. Herein, bioinspired by enzyme-mediated biosynthesis and biochemical defense, a compartmented nanoreactor (Burr-NCs@GlSOD) was constructed through a self-confined catalysis strategy with burr defect-engineered molybdenum disulfide/Prussian blue analogues (MoS2/PBA) and an interfacial diffusion-controlled hydrogel network. The specific catalytic mechanism of the laccase-like superactivity induced hydrogelation and cascade enzyme catalytic therapy were explored. The confined hydrogelation strategy introduces a versatile means for nanointerface functionalization and provides insight into biological construction of simulated enzymes with comparable activity and also the specificity to natural enzymes. 相似文献
996.
Dr. Tingting Xu Dr. Xudong Hou Dr. Yi Han Dr. Haipeng Wei Dr. Zhengtao Li Prof. Dr. Chunyan Chi 《Angewandte Chemie (International ed. in English)》2023,62(38):e202304937
Polycyclic hydrocarbons consisting of two or more directly fused antiaromatic subunits are rare due to their high reactivity. However, it is important to understand how the interactions between the antiaromatic subunits influence the electronic properties of the fused structure. Herein, we present the synthesis of two fused indacene dimer isomers: s-indaceno[2,1-a]-s-indacene ( s -ID ) and as-indaceno[3,2-b]-as-indacene ( as -ID ), containing two fused antiaromatic s-indacene or as-indacene units, respectively. Their structures were confirmed by X-ray crystallographic analysis. 1H NMR/ESR measurements and DFT calculations revealed that both s -ID and as -ID have an open-shell singlet ground state. However, while localized antiaromaticity was observed in s -ID , as -ID showed weak global aromaticity. Moreover, as -ID exhibited a larger diradical character and a smaller singlet-triplet gap than s -ID . All the differences can be attributed to their distinct quinoidal substructures. 相似文献
997.
Xiao Ling Guo Yun Yin Niu Qing Li Wang Ben Lai Wu Hong Yun Zhang Hong Wei Hou Yi Han Ling Fang Wang 《中国化学快报》2008,19(5):604-606
A novel co-ordination polymer based on IB metal thiocyanates, [Ag2(NCS)2(4,4'-bipy)]. (1)(4,4'-bipy = 4,4'-bispyridine), has been synthesized by the pre-assembly method and characterized by X-ray crystallography. The complex exists as a three- dimensional network consisting of (AgSCN). undulating layers linked by 4,4'-bipy bridges. 相似文献
998.
GUO Lifei HE Minqiang CHEN Yongqiang SONG Chengcheng WAN Jincheng LI Chunxiang 《反应性高分子(英文版)》2008,17(1):66-73
The non-covalent interaction between aPigenin (API) and different functional monomers (α-methylacrylic acid (MAA), acrylamide (AM), 2-vinylpyridine (2-Vpy) and combined functional monomers (AM/2-Vpy)) was determined by UV spectrometry, and a series of apigenin molecularly imprinted polymers (API-MIPs) was synthesized with different functional monomers through molecular imprinting technology. The relationship between the non-covalent interaction of template/functional monomer and absorption of MIPs also was studied. The results showed that the order of the strength of the non-covalent interaction between API and different functional monomers in tetrahydrofuran (THF) is as follows: 2-Vpy〉 AM/2-Vpy〉AM〉MAA, which is positive correlation to the absorption capability of corresponding MIPs, and 2-Vpy is the optimum functional monomer among the used monomer for preparing API- MIPs. 相似文献
999.
管敏强 《广东微量元素科学》2008,15(2):1-5
锌是机体必需的微量元素,它对动物免疫系统的正常发育和功能方面有重要作用。综述了微量元素锌对动物免疫器官、免疫细胞和免疫分子等的可能作用机制和对免疫功能的影响。 相似文献
1000.
Highly sensitive amperometric detection of dihydronicotinamide adenine dinucleotide (NADH) by using novel synthesized carbon nanofibers (CNFs) without addition of any mediator has been proposed. The CNFs were prepared by combination of electrospinning technique with thermal treatment method and were applied without any oxidation pretreatment to construct the electrochemical sensor. In amperometric detection of NADH, a linear range up to 11.45 μM with a low detection limit of 20 nM was obtained with the CNF‐modified carbon paste electrode (CNF‐CPE). Good selectivity was exhibited for the simultaneous detection of NADH and its common interferent of ascorbic acid (AA) by differential pulse voltammogram. The attractive electrochemical performance and the versatile preparation process of the CNF‐CPE made it a promising candidate for designing effective NADH sensor. 相似文献