混合二烃基二氯化锡与水杨醛缩苯胺类Schiff碱1∶1配合物的合成和表征

由混合二烃基二氯化锡（ＲＲ＇ＳｎＣｌ＿２）与水杨醛缩苯胺类Ｓｃｈｉｆｆ碱（２－ＨＯＣ＿６Ｈ＿４ＣＨ＝ＮＡｒ）反应，合成了１４种新的有机锡配合物。经元素分析、ＩＲ、ＮＭＲ和ＴＧ－ＤＳＣ测定，确定配合物的组成是有机锡与Ｓｃｈｉｆｆ碱的１：１配合物，配体以酚羟基氧原子与锡原子配位，摩尔电导率测定表明配合物均为非电解质。     

New catalytic effect of thiourea on the oxidative cyanation of N-aryltetrahydroisoquinolines

Thiourea itself has been introduced as a mild and efficient organocatalyst for the oxidative α -cyanation of N-aryltetrahydroisoquinolines (THIQs) with trimethylsilyl cyanide (TMSCN), giving the corresponding products in good to excellent yields. Experimental investigations demonstrated that thiourea acts as a radical initiator by abstracting hydroxyl radical (OH) from tert-butyl hydroperoxide (TBHP) directly instead of non-covalent hydrogen bondings (H-bondings) activation. The use of thiourea as a radical initiator offers a new avenue for innovative chemical transformations in organocatalyzed radical chemistry.     

混合模式硅胶基质毛细管电色谱整体柱的制备及其电色谱性能研究

采用温和条件下的溶胶-凝胶技术,成功制备了阴离子交换-反相混合模式硅胶基质毛细管电色谱整体柱.通过调整反应液中不同前体的比例,优化了整体柱的制备条件.通过扫瞄电镜,对柱床进行了表征和分析.实验发现,所制备的整体柱电渗流的方向和大小可随流动相pH值的改变而改变,在酸性和中性条件下,具有从阴极流向阳极的电渗流;当流动相pH值升至约7.5时,电渗流方向发生了反转(由阳极流向阴极).在优化的实验条件下,用所制备的整体柱对所考察的酸性(中性)化合物实现了快速分离,并获得了高达160,000 N/m的柱效.     

Aqueous Knoevenagel Condensation Catalyzed by Aminopropyl-functionalized MCM-41

Since much more attention has been paid to the sustainable development, many researchers try to improve conventional chemical process and find new and more, environmentally friendly routes1. Aqueous-phase reactions are of interest as environ- mentally ben…     

具有平整表面的定向纳米碳管膜的制备

为了获得表面平整的定向纳米碳管，通过化学及物理的方法将纳米碳管膜进行反转，使其原来的AAO模板底面成为新的表面，用溶液逐步去除表面的铝和氧化铝后，获得了平整的定向纳米碳管膜表面，从而可将其作为工作面使用. 还比较了5％NaOH和6%H₃PO₄＋1.8%H₂CrO₄溶液去除氧化铝的效果.     

A New Asterosaponin from the Starfish Culcita novaeguineae

A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identitied to be sodium 6α-O-{β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-[β-D-quinovopyranosyl}-5α-pregn-9(11)-en-20-one-3β-yl-sulfate by extensive spectral analysis and chemical evidence.     

Determination of Gossypol in Trace Level by Flow Injection Analysis with Chemiluminescence Detection

Gossypol, [1, 1′, 6, 6′, 7,7′-hexahydroxyl-5,5′-diisopropyl-3,3′-dimethyl-(2,2′-binaphtha- lene)-8,8′-dicarboxaldehyde] is a polyphenolic yellow compound naturally occurring in various parts of cotton plants1. The compound has been associated with     

Comparative X-ray photoelectron spectroscopic study on the desulfurization of thiophene by Raney nickel and rapidly quenched skeletal nickel

The desulfurization of thiophene on Raney Ni and rapidly quenched skeletal Ni (RQ Ni) has been studied in ultrahigh vacuum (UHV) by X-ray photoelectron spectroscopy (XPS). The Raney Ni or RQ Ni can be approximated as a hydrogen-preadsorbed polycrystalline Ni-alumina composite. It is found that thiophene molecularly adsorbs on Raney Ni or RQ Ni at 103 K. At 173 K, thiophene on alumina is desorbed, while thiophene in direct contact with the metallic Ni in Raney Ni undergoes C-S bond scission, leading to carbonaceous species most probably in the metallocycle-like configuration and atomic sulfur. On RQ Ni, the temperature for thiophene dissociation is about 100 K higher than that on Raney Ni. The lower reactivity of RQ Ni toward thiophene is tentatively attributed to lattice expansion of Ni crystallites in RQ Ni due to rapid quenching. The existence of alumina and hydrogen may block the further cracking of the metallocycle-like species on Raney Ni and RQ Ni at higher temperatures, which has been the dominant reaction pathway on Ni single crystals. By 473 K, the C 1s peak has disappeared, leaving nickel sulfide on the surface.     

Ordered nickel oxide nanowire arrays and their optical absorption properties

Ordered NiO nanowire arrays embedded in anodic alumina membranes have been prepared by using an electrochemical deposition method. After annealing at 300 °C, the NiO nanowire arrays were characterized using SEM, TEM, SAED, and XRD. SEM and TEM observations reveal that these nanowires are dense, continuous and arranged roughly parallel to one another. XRD and SAED analysis together indicate that these NiO nanowires crystallize with a polycrystalline structure. The optical absorption band gap of NiO nanowire arrays is 3.74 eV, and no obvious blue shift or red shift with respect of that of the bulk NiO can be observed.     

In-channel indirect amperometric detection of nonelectroactive anions for electrophoresis on a poly(dimethylsiloxane) microchip

In the present paper, we describe a microfluidics-based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper (Anal. Chem. 2004, 76, 6902-6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high-voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F-, Cl-, SO4(2-), CH3COO-, H2PO4-. Based on the preliminary results, a detection limit of 2 microM and a dynamic range up to three orders of magnitude for Cl- could be achieved.