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991.
Zong‐gang Mu Feng Zhou Shu‐xiang Zhang Yong‐min Liang Wei‐min Liu 《Helvetica chimica acta》2004,87(10):2549-2555
A new series of diethoxyphosphinyl‐substituted imidazolium ‘room‐temperature ionic liquids’ (RTILs) were synthesized and characterized. The new compounds 1 – 12 (Table 1) were shown to have similar densities, but higher viscosities, than common ionic liquids. The new materials remain liquid over a broad temperature range, possess extremely low vapor pressures, display relatively high thermal stabilities (up to 325°), and decompose in a two‐step process. Analysis of the solid/liquid phase transition showed that all of the new RTILs possess low glass‐transition temperatures (Tg) associated with an intense change in molar heat capacity (ΔCpm). 相似文献
992.
氯苯甲酸在水-DMF混合溶剂中的电离热力学 总被引:2,自引:1,他引:2
结构上彼此相关的取代苯甲酸在非水溶剂中电离热力学性质研究一直受到广泛的重视[‘一句,但是这类酸在水一DMF混合溶剂中的电离热力学性质的研究少见报导.DMF(N,N一二甲基甲酸胺)由于其独特性质,在许多化学、化工领域中已得到广泛的应用.本文对苯甲酸和。、。一、p氯苯甲酸在水一DMF混合溶剂中的电离热力学性质进行研究,以此深入地了解溶剂和取代基对弱酸电离的影响.1实验1.11热仪器用LKB-2277BioActivityMonitor问的流动混合测量系统部分,测量精度为0.2%(300Pw量程)1.2试剂苯甲酸为分析纯试剂,含量>99.5%质… 相似文献
993.
Vesper BJ Salaita K Zong H Mirkin CA Barrett AG Hoffman BM 《Journal of the American Chemical Society》2004,126(50):16653-16658
We report the preparation of two novel H2[pz(An;B(4-n))] porphyrazines (pzs) which were designed to position themselves quite differently when attached to a surface: one to form a standard self-assembled monolayer (SAM) roughly perpendicular to a surface, the other to lie horizontally along a surface. As the former, we synthesized a pz, 1, where one pyrrole group is functionalized with two thioethers terminated in mercaptides (SR, R = (CH2)3CONH(CH2)2S-), each protected as a disulfide, and -S-Me is attached to the other pyrrole sites; the latter is a pz, 2, with dialkoxybenzo groups fused to two trans-pyrroles of the pz ring, and SR groups are attached to the other pair of pyrroles. Nanostructures of 1 and 2 were successfully patterned on gold surfaces via dip-pen nanolithography, and the predicted molecular orientation of the resulting structures was confirmed by topographic AFM images. The two pzs exhibit similar reduction potentials in solution. Both show large shifts in potential upon surface binding, with the magnitude of the shift depending on the proximity/orientation of the pz to the surface. The first reduction potential of the "vertically" aligned 1 shifts by ca. +430 mV when incorporated in a binary pz/hexanethiol SAM, while that for 2, which lies flat, shifts by ca. +800 mV; the potential thus shifts by ca. +370 mV upon taking a given pz that stands atop a two-legged insulating "standoff" in a traditional SAM and "laying it down". We suggest these observed effects can be explained by image-charge energetics, and this is supported by a simple model. 相似文献
994.
盐酸- N1,NN', N'1-二甲双胍(HDMBG∙HCl)是临床广泛应用的降血糖药物,用于非胰岛素依赖型糖尿病的治疗。本文合成了三氯三(N5-苯甲酰-N1', N'1-二甲双胍)合钕 (Nd(BDMBG)3Cl3)和一氯二(N5-邻羧基苯甲酰- N1,NN', N'1-二甲双胍)合钕(Nd(CDMBG)2Cl)两种固态配合物,并通过元素分析、ICP、IR、UV、荧光光谱等表征了它们的化学组成和结构。糖尿病小鼠模型和ESR谱测定结果显示,几种化合物的降血糖作用及对人工脂质体膜超氧自由基的清除率呈现如下顺序:Nd(SDMBG)3 [)三(N5-水杨酰-N1,N1-二甲双胍)合钕] >Nd(CDMBG)2Cl » HDMBG·HCl > Nd(BDMBG)3Cl3,表明芳酰基邻位取代基的不同对配合物的降血糖作用和对O2-的清除作用具有重要影响。 相似文献
995.
The Darzens reaction of ethyl 2‐chloroacetate ( 1 ) with aromatic aldehydes 2 in the presence of polymer‐supported or nonsupported quaternary ammonium salts proceeds under mild conditions by phase‐transfer catalysis to give the corresponding epoxides 3 in satisfactory yields (Tables 1 and 2). With both MeCN as solvent and polystyrene‐supported catalysts, diastereoselective Darzens reactions proceed in excellent yields and short times, with a fair degree of stereoinduction. 相似文献
996.
997.
998.
Mu Jie YANG Zong Wu YAO You Si CHEN Yang LI 《中国化学快报》2006,17(1):73-76
Humidity sensors have found wide applications in industry production, process control, environment monitoring, storage, electrical applications, etc.. Polymer electrolytes have been used in the preparation of resistive-type humidity sensors in the past ye… 相似文献
999.
1000.
Jin‐Kui Tang Li‐Na Zhu Xiao‐Zeng Li Wen Dong Dai‐Zheng Liao Zong‐Hui Jiang Shi‐Ping Yan Peng Cheng 《无机化学与普通化学杂志》2003,629(11):2000-2003
A novel coordination polymer {[Mn(azpy)(NCS)2(MeOH)2] · azpy}n( 1 ) (azpy = 4, 4'‐azopyridine), has been synthesized and characterized by X‐ray diffraction. It consists of a quasi two‐dimensional network structure constructed from 1‐D chains of [Mn(azpy)(NCS)2(MeOH)2]n connected by hydrogen bonds, which creates about 13.6 Å × 17.1 Å of channels. The coordination sphere of the manganese(II) ion is a distorted octahedron. The determination of the variable temperature magnetic susceptibilities (5—300 K) shows the existence of a very weak antiferromagnetic interaction with a J value of —0.03 cm—1. 相似文献