仲碳伯胺萃取铈(Ⅳ)机理的~1H,~(15)N核磁共振谱研究

仲碳伯胺N_(1923)萃取铈(Ⅳ)的~1H,~(15)N-NMR研究表明,在萃取铈(Ⅳ)时也同时萃取H_2O和H_2SO_4进入有机相,当铈(Ⅳ)浓度较高时,铈(Ⅳ)与N_(1923)生成配合物。

原子吸收光谱法测定人参中15个微量元素

本文研究了火焰原子吸收,石墨炉原子吸收,结合基体改进剂和平台技术,测定了人参中Pb、Ca、Co、Ni、Cr、Ba、K、Na、Cd、Mg、Fe、Cu、Zu、Mn、Sr等十五个微量元素,结果满意。

Pr_xLa_(1-x)P_5O_(15)晶体的荧光动力学研究

本文利用 Pr~(3+)离子在 Pr_xLa_(1-x)P_5O_(14)晶体中的光谱性质和能级,在考虑~3P_o-~1D_2和~3H_4-~3H_6,~1D_2-~1D_4和~3H_4-~3F_4两个能级对交叉弛豫的情况下,详细研究了 Pr~(3+)离子的荧光动力学过程,给出了~3P_o,~1D_2和~1G_4能级的荧光发射规律。

稀土硝酸盐15-冠-5络合物的一些性质

稀土冠醚络合物的组成和稳定性不但与稀土离子直径和冠醚孔径是否匹配,而且也和阴离子及合成用的溶剂有关.因15-冠-5(简写15C5)的孔径(2.2?)和大部分稀土离子直径相近.因此它们的络合物是研究孔径匹配关系的理想模型. Bunzli在乙腈中合成了大部分镧系硝酸盐15C5络合物,轻镧系(La-Gd)生成1:1无水络合物,重镧系(Tb-Lu)为含1—3分子水的1:1络合物.我们在无水丙酮中制备

Diterpenes, sesquiterpenes, and a C-15-acetogenin from the marine red alga Laurencia mariannensis

In addition to 10 known compounds (7-16), one new brominated diterpene, 10-hydroxykahukuene B (1), two new sesquiterpenes, 9-deoxyelatol (2) and isodactyloxene A (3), one new brominated C-15-acetogenin, laurenmariallene (4), and two new naturally occurring halogenated sesquiterpenes (5 and 6) that were previously obtained as intemediates in a biomimetic synthetic study of rhodolaureol and rhodolauradiol have been isolated and identified from the organic extract of the marine red alga Laurencia mariannensis. The structures of these compounds were established by spectroscopic methods. The antibacterial and antifungal activities of new compounds 1-4 were evaluated.

Laurendecumallenes A-B and laurendecumenynes A-B, halogenated nonterpenoid C-15-Acetogenins from the marine red alga Laurencia decumbens

Four new halogenated nonterpenoid C-15-acetogenins, 4:7,6:13-bisepoxy-9,10-diol-1,12-dibromopentadeca-1,2-diene (1, laurendecumallene A), 4:7,6:12-bisepoxy-9,10-diol-1,13-dibromopentadeca-1,2-diene (2, laurendecumallene 13), (3Z)-6:10,7:13-bisepoxy-12-bromo-9-hydroperoxylpentadeca-3-en-1-yne (3, laurendecumenyne A), and (3Z)-6:10,9:13-bisepoxy-12-bromo-7-chloropentadeca-3-en-1-yne (4, laurendecumenyne 13), together with one known halogenated C-15-acetogenin elatenyne (5) were isolated and identified from the organic extract of the marine red alga Laurencia decumbens. Their structures and relative stereochemistry were established by means of spectroscopic analysis including UV, IR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and ID and 2D NMR techniques. All these metabolites were submitted for the cytotoxic assay against tumor cell line A549 (human lung adenocarcinoma), but all of them were found inactive (IC50 > 10 mu g/mL).

Halogenated Terpenes and a C-15-Acetogenin from the Marine Red Alga Laurencia saitoi

Seven parguerane diterpenes: 15-bromo-2,7,19-triacetoxyparguer-9(11)-en-16-ol (1), 15-bromo-2,7,16,19-tetraacetoxyparguer-9(11)-ene (2), 15-bromo-2,19-diacetoxyparguer-9(11)-en-7,16-diol (3), 15-bromo-2,16,19-triacetoxyparguer-9(11)-en-7-ol (4), 15bromo-2,16-diacetoxyparguer-9(11)-en-7-ol (5), 15-bromoparguer-9(11)-en-16-ol (6), 15-bromoparguer-7-en-16-ol (7), two polyether triterpenes: thyrsiferol (8) and thyrsiferyl 23-acetate (9), and one C15-acetogenin, neolaurallene (10), were isolated from a sample of marine red alga Laurencia saitoi collected off the coast of Yantai. Their structures were established by detailed NMR spectroscopic analysis and comparison with literature data.

Laurenidificin, a new brominated C-15-acetogenin from the marine red alga Laurencia nidifica

new brominated C-15-acetogenin, namely, laurenidificin, was isolated from the marine red alga Laurencia nidifica. Its structure was determined on the basis of spectroscopic methods. (C) 2010 Bin Gui Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Inheritance of 15 microsatellites in the Pacific oyster Crassostrea gigas: segregation and null allele identification for linkage analysis

Microsatellites were screened in a backcross family of the Pacific oyster, Crassostrea gigas. Fifteen microsatellite loci were distinguishable and polymorphic with 6 types of allele-combinations. Null alleles were detected in 46.7% of loci, accounting for 11.7% of the total alleles. Four loci did not segregate in Mendelian Ratios. Three linkage groups were identified among 7 of the 15 segregating loci. Fluorescence-based automated capillary electrophoresis (ABI 310 Genetic Analyzer) that used to detect the microsatellite loci, has been proved a fast, precise, and reliable method in microsatellite genotyping.

15种獐牙菜属植物中主要药用成分的高效液相色谱测定

对青藏高原和云贵高原的15种獐牙菜属植物进行了3种苦味苷,即獐牙菜苦苷(swertiamarin)、龙胆苦苷(gentiopicroside)、苦龙苷(amarogentin)、一种黄酮苷-当药黄素(swertisin)、及5种(口山) 山酮苷-芒果苷(mangiferin)、当药醇苷(swertianolin)、7-O-[α-L-吡喃鼠李糖-(1→2)-β-D-吡喃木糖]-1,8-二羟基-3-甲氧基(口山) 山酮(7-O-[α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl]-1,8-dihydroxy-3-methoxyxanthone)、7-O-β-D-吡喃木糖-1,8-二羟基-3-甲氧基(口山) 山酮(7-O-β-D-xylopyranosyl-l,8-dihydroxy-3-methoxyxanthone)、3-O-β-D-吡喃葡萄糖-1,8-二羟基-5-甲氧基(口山) 山酮(3-O-β-D-glucopyranosyl-1,8- dihydroxy-5-methoxyxanth-one)等9种主要药效成分同时进行了高效液相色谱的含量测定(Kromasil C18柱,甲醇-水梯度洗脱,二级管阵列检测);并对其主要药效成分的分布进行了比较。

Direct synthesis and characterization of titanium-substituted mesoporous molecular sieve SBA-15

Ti-substituted mesoporous SBA-15 (Ti-SBA-15) materials have been synthesized by using a new approach in which the hydrolysis of the silicon precursor (tetramethoxysilane, TMOS) is accelerated by fluoride. These materials were characterized by powder X-ray diffraction patterns (XRD), X-ray fluorescence spectroscopy (Y-RF), N-2 sorption isotherms, diffuse-reflectance UV-visible (UV-vis) and UV-Raman spectroscopy, Si-29 MAS NMR, and the catalytic epoxidation reaction of styrene. Experiments show that Ti-SBA-15 samples of high quality can be obtained under the following conditions: F/Si greater than or equal to 0.03 (molar ratio), pH less than or equal to 1.0, aging temperature less than or equal to 80 degreesC, and Ti/Si less than or equal to 0.01. It was found that the hydrolysis rate of TMOS was remarkably accelerated by fluoride, which was suggested to play the main role in the formation of Ti-SBA-15 materials of high quality. There is no stoichiometric incorporation of Ti, and the Ti contents that are obtained are quite low in the case of the approach that is proposed. The calcined Ti-SBA-15 materials show highly catalytic activity in the epoxidation of styrene.

Direct synthesis of highly ordered Fe-SBA-15 mesoporous materials under weak acidic conditions

Iron-substituted SBA-15 (Fe-SBA-15) materials have been synthesized via a simple direct hydrothermal method under weak acidic conditions. The powder X-ray diffraction (XRD), NZ sorption and transmission electron microscopy (TEM) characterizations show that the resultant materials have well-ordered hexagonal meso-structures. The diffused reflectance UV-vis and UV resonance Raman spectroscopy characterizations show that most of the iron ions exist as isolated framework species for calcined materials when the Fe/Si molar ratios are below 0.01 in the gel. The presence of iron species also has significant salt effects that can greatly improve the ordering of the mesoporous structure. Different iron species including isolated framework iron species, extraframework iron clusters and iron oxides are formed selectively by adjusting the pH values of the synthesis solutions and Fe/Si molar ratios. (c) 2005 Elsevier Inc. All rights reserved.