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991.
低密度的高原子序数元素氧化物气凝胶由于前驱体形成端基双键而易于收缩和开裂。通过调控配位环境结合无机分散溶胶凝胶法,制备了稀土氧化物气凝胶。氧化镧基气凝胶和氧化钇基气凝胶块体的成型性好,最低密度分别为0.05g·cm-3和0.06g·cm-3。其成分分别为六方相的La(OH)3和六方相的Y(OH)3,而聚丙烯酸中的羧基与稀土离子之间以桥接的方式进行配位。两种气凝胶均存在明显的多级结构,氧化镧基和氧化钇基气凝胶的初级粒子分别为纤维状和片/球混合形貌,而其二级粒子均为球形。两种气凝胶的比表面积分别为229.1m2·g-1和229.6m2·g-1。该方法制备的稀土氧化物气凝胶具有低的密度和纳米尺度的均匀性,在背光源中有潜在的应用。 相似文献
992.
Yan‐Hong Li Juan He Yan Li Xing‐De Wu Li‐Yan Peng Ru‐Nan Du Xiao Cheng Qin‐Shi Zhao Rong‐Tao Li 《Helvetica chimica acta》2014,97(11):1481-1486
A phytochemical study of the CHCl3 extract of the dried unripe fruits of Evodia rutaecarpa (Juss. ) Benth. (Rutaceae) resulted in the isolation of three new alkaloids, evollionines A–C ( 1 – 3 , resp.), together with two known compounds, evodianinine and wuzhuyumide I. The structures of the new compounds were elucidated on the basis of detailed spectroscopic evidence and confirmed in the case of compound 1 by single‐crystal X‐ray analysis. 相似文献
993.
Synthesis and Characterization of 11‐Amino‐3‐methoxy‐8‐substituted‐12‐aryl‐8,9‐dihydro‐7H‐chromeno[2,3‐b]quinolin‐10(12H)‐one Derivatives
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Guangfan Han Jiawei Du Lizhuang Chen Lijun Zhao 《Journal of heterocyclic chemistry》2014,51(4):1094-1099
A series of 2‐amino‐7‐methoxy‐4‐aryl‐4H‐chromene‐3‐carbonitrile compounds 2 were obtained by condensation of 3‐methoxyphenol with β‐dicyanostyrenes 1 in absolute ethanol containing piperidine. The intermediate enamines 3 were prepared by compounds 2 with 5‐substituted‐1,3‐cyclohexanedione using p‐toluenesuflonic acid (TsOH) as catalyst. The title compounds 11‐amino‐3‐methoxy‐8‐substituted‐12‐aryl‐8,9‐dihydro‐7H‐chromeno[2,3‐b]quinolin‐10(12H)‐one 4 were synthesized by cyclization of the intermediate enamines 3 in THF with K2CO3 /Cu2Cl2 as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1H NMR spectra. The crystal structure of compound 4i was determined by single‐crystal X‐ray diffraction analysis. 相似文献
994.
A new 2D cadmium(II) coordination polymer {[Cd(MBD)(L)]·(H2O)2} n (1) (H2MBD = 5-methoxycarbonyl-benzene-1,3-dicarboxylic acid, L = 1,3-bis(benzimidazol-l-yl)-2-propanol) is synthesized, in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during the synthesis. In the structure of complex 1, each cadmium center is octahedrally coordinated by four O atoms from three carboxylate groups and two N of distinct L ligands. A detailed structural analysis reveales that compound 1 exhibits a unique 2D binodal (3,5)-connected (42.67.8)(42.6) topology structure. Furthermore, the 2D layer is extended into a 3D network through π-π stacking interactions. The solid-state fluorescence properties of 1 are investigated at room temperature. 相似文献
995.
Tao Liu Ling-Li Han Chun-Mei Du Zhang-Yu Yu 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(7):1085-1090
Dopamine (DA) can be oxidized to dopamine quinone (DAquinone) through a one-step, two-electron redox reaction. The electron transfer property of DA and its supramolecular complex with aspartic acid (Asp) has been investigated by the theoretical calculations. We calculated the standard redox potentials (E o) of DA/DAquinone at the MP2/6-31G(d,p)//B3LYP/6-31G(d,p), MP2/6-31+G(d,p)//B3LYP/6-31+G(d,p), MP2/6-31G(d,p)//B3LYP/6-311G(d,p), and MP2/6-311+G(d,p)//B3LYP/6-311+G(d,p) levels. Comparing the experimental value, the redox potentials of DA/DAquinone obtained at MP2//B3LYP/6-311G(d,p) and MP2//B3LYP/6-311+G(d,p) levels can be considered as the upper and lower estimates. DA can form supramolecular complex (DA-Asp) with Asp through hydrogen bond (H-bond). Therefore, the values of 0.631 and 0.628 V obtained at MP2//B3LYP/6-311G(d,p) and MP2//B3LYP/6-311+G(d,p) levels for DA-Asp/DAquinone-Asp can be proposed as the upper and lower estimates of a probable (about 0.630 V) value of the corresponding redox potential. The calculated E o values of DA-Asp/DAquinone-Asp at the four theoretical levels are upper than those of DA/DAquinone, which indicates that the formation of H-bonds weaken the electron-donating ability of DA. 相似文献
996.
In this paper, CE coupled with electrochemiluminesence (ECL) detection using a 76‐μm Pt disk as working electrode was developed for nicotine (NIC) determination. The major metabolite of NIC is cotinine (COT), which has a similar tertiary amine structure to NIC. However, there is a carbonyl group attached in the structure of COT, which leads to the great decrease in ECL response. In order to improve the ECL response of COT, NaBH4 was used for carbonyl reduction. After reduction, NIC and COT were separated and detected by CE‐ECL. ECL response plotted with NIC concentration was linear between 5.0×10?7 and 5.0×10?5 mol/L (81–8100 μg/L), with LOD of 5.0×10?8 mol/L (8.1 μg/L). The developed CE‐ECL method was applied for NIC determination in urine and cigarette samples. 相似文献
997.
Developing chemicals that inhibit checkpoint kinase 1 (Chk1) is a promising adjuvant therapeutic to improve the efficacy and selectivity of DNA-targeting agents. Reliable prediction of binding-free energy and binding affinity of Chk1 inhibitors can provide a guide for rational drug design. In this study, multiple docking strategies and Prime/Molecular Mechanics Generalized Born Surface Area (Prime/MM-GBSA) calculation were applied to predict the binding mode and free energy for a series of benzoisoquinolinones as Chk1 inhibitors. Reliable docking results were obtained using induced-fit docking and quantum mechanics/molecular mechanics (QM/MM) docking, which showed superior performance on both ligand binding pose and docking score accuracy to the rigid-receptor docking. Then, the Prime/MM-GBSA method based on the docking complex was used to predict the binding-free energy. The combined use of QM/MM docking and Prime/MM-GBSA method could give a high correlation between the predicted binding-free energy and experimentally determined pIC(50) . The molecular docking combined with Prime/MM-GBSA simulation can not only be used to rapidly and accurately predict the binding-free energy of novel Chk1 inhibitors but also provide a novel strategy for lead discovery and optimization targeting Chk1. 相似文献
998.
999.
1000.
Fangdi Cong Zixiang Cui Li Li Junshan Gao Xiguang Du Kezhi Xing 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(1-2):225-230
In order to include phthalocyanine macromolecule in MCM-41 molecular sieve, a inclusion-suitable phthalocyanine derivative tetra-β-(2-(diethylamino)ethoxy) nickel phthalocyanine was synthesized, in two steps, from 4-nitrophthalonitrile and 2-(diethylamino)ethanol, and characterized by mass spectra, 1H nuclear magnetic resonance spectroscopy, ultraviolet visible spectroscopy, infrared spectroscopy and elemental analysis, which confirmed the proposed molecular structure. The inclusion of synthesized phthalocyanine compound in MCM-41 was carried out by the in situ synthesis method using cetyltrimethyl ammonium bromide as structure template and tetraethyl orthosilicate as silica source in presence of this phthalocyanine compound. The inclusion material was studied by means of X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption isotherm measurements, etc. Results showed that the macromolecular compound was successfully included into MCM-41, the obtained inclusion material displayed mainly prisms and globes, and the material was a kind of mesoporous materials with regularly hexagonal honeycomb array of uniform cylindrical pores and high surface area. 相似文献