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201.
Organic nanocrystals of 1,3,5-triphenyl-2-pyrazoline(TPP) with a series of sizes were synthesized by reprecipitation method.The luminescence quantum efficiency of TPP nanocrystals increases from 24.2% for the nanocrystals with an average size of 300nm to 34.6% for those with an average size of 20nm.Surface capping by polyvinyl pyrrolidone(PVP) will improve the quantum efficiency of TPP nanocrystals.The size-dependence and capping-induced variation of the luminescence quantum efficiency was elucidated in viewpoint of aggregation quenching and the equilibrium between the TPP monomers and the aggregates in TPP nanocrystals. 相似文献
202.
Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropxy)-calix[4]arene(3) and 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-5,11,17,23-tetra-tert-butylcalix[4] arene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes(ISEs).ISEs based on 3 and 4 as neutral ionophores were prepared,and their selectivity coefficients for Ag^ (lg KAg,M^pot)were investigated against other alkali metal,alkaline-earth metal,aluminum,thallium(Ⅰ),Lead and some transition metal ions using the separate solution method (SSM).These ISEs showed excellent Ag^ seletivity over most of the interfering cations examined,except for Hg^2 and Fe^2 having relative smaller interference(lg KAg,M^pot≤-2.1). 相似文献
203.
The relationship among intrinsic surface reaction constant (K) in 1-pK model, point of zero net charge (PZNC) and structural charge density (σst) for amphoteric solid with structural charges was established in order to investigate the effect of σst on pK. The theoretical analysis based on 1-pK model indicates that the independent PZNC of electrolyte concentration (c) exists for amphoteric solid with structural charges. A common intersection point (CIP) should appear on the acid-base titration curves at different c, and the pH at the CIP is pHPZNC. The pK can be expressed as pK=-pHPZNC log[(1 2αPZNC)/(1-2αPZNC)], where αPZNC≡σst/eNANs, in which e is the elementary charge, NA the Avogadro‘s constant and Ns the total density of surface sites. For solids without structural charges, pK=-pHPZNC. The pK values of hydrotalcite-like compounds (HTlc) with general formula of [Mg1-xFex(OH)2](Cl,OH)x were evaluated. With increasing x, the pK increases, which can be explained based on the affinity of metal cations for H^- or OH^- and the electrostatic interaction between charging surface and H^- or OH^-. 相似文献
204.
(Z)-1-[2-(Tri-o-tolylstannyl)vinyl]-1-indanol (1) and (Z)-1-[2-(tri-p-tolylstannyl)vinyl]-l-indanol (2) were synthesized by the addition reaction of 1-ethynylindanol with tri-o-tolyltin and tri-p-tolyltin hydride. The aryl groups in compound 1 and 2 were substituted by Br2 or I2 to yield monohalide derivatives (3-6). The compounds 1-6 were characterized by elemental analysis, ^1H NMR and FT-IR spectroscopy. The crystal structures of 1, 2 and 4 have been determined by single crystal X-ray diffraction analysis. The Sn atom in 1 and 2 exhibits a tetrahedral geometry distorted towards trigonal bipyramid due to a weak intramolecular interaction between Sn and the hydroxyl O atoms [0.2839(4) nm and 0.2744(5) nm], while the Sn atom in 4 adopts a trigonal bipyramidal geometry with a significant O→Sn(1) interaction [0.2552(5) nm]. 相似文献
205.
SUN Weimin LUO Juntao HUANG Wenqiang State Key Laboratory of Functional Polymer Material for Adsorption Separation Institute of Polymer Chemistry Nankai University Tianjin China 《Chinese Journal of Reactive Polymers》2002,(1)
1. INTRODUCTION A solid phase organic synthesis (SPOS) has increasingly attracted chemist抯 attention over the past decades [1~3]. It was found that the compounds with biological activity are mostly derived from heterocycle structures. It is therefore no… 相似文献
206.
Qi FANG* Hong LEI Wen XU State Key Laboratory of Crystal Materials Shandong University Jinan School of Information Science Engineering Shandong University Jinan 《中国化学快报》2003,(11)
It was commonly thought that a molecular conductor or semiconductor should be composed of at least two components to make the conducting component in partially charged state. However, this idea became questionable by the recent report of the single-component molecular conductor [Ni(tmdt)2]1 as well as several reports about single-component molecular semiconductors such as [Ni(ptdt)2]2 and [Ni(C10H10S8)2]3. In fact, as early as 1985, [Ni(dmit)2] as a by-product in synthesizing TTF[Ni(dmit… 相似文献
207.
报道了用脉冲反应研究Ni/Al2O3催化剂上CH4/CO2重整反应的结果。脉冲反应显示,在还原的Ni/Al2O3催化剂上,CH4在673K就开始发生分解,并有C2H6、C2H4生成,1023K下,CH4几乎完全分解,单纯的CO2则很难在还原的催化剂上发生反应,在973K以上的高温下才会有少量C胜成CO.CHCO2的脉冲反应表明,当CH4在较低温度下开始分解时,CO2也会发生分解,并生成CO。脉冲反 相似文献
208.
209.
TIAN Yan-Ni YANG PinInstitute of Coordination Chemistry The State Key Laboratory of Coordination Chemistry Nanjing University Nanjing Jiangsu ChinaLI Qing-Shan ZHAO Chun-GuiInstitute of Molecular Science Shanxi University Taiyuan Shanxi China 《中国化学》1996,14(5):428-436
New complexes,of bis(2,2'-diamino-4,4'-bithiazole)sulfate nickel(Ⅱ) and bis(2,2'-diami-no-4,4'-bithiazole)sulfate cobalt(Ⅱ),have been prepared.The complexes were characterized by infrared and UV-Vis spectroscopy,1H NMR,elemental analyses and molar conductivity.The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation.The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells.In order to provide a molecular basis for understanding the biological effects,the probe,[trana-en2Os(η2-H2)](CF3SO3)2 (en,ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2'-deoxyguanosine-5'-monophosphate (dGMP). 相似文献
210.
Synthesis of 6-substituted 1-alkoxy-5-alkyluracils 2a-c have been achieved from readily accessible 2-alkyl-3,3-di(methylthio)acryloyl chlorides 4a,b in high overall yields. Treatment of 4a,b with silver cyanate followed by reaction of the resulting isocyanates 5a,b with an appropriate alkoxyamine afforded N-alkoxy-N′-[2-alkyl-3,3-di(methylthio)acryloyl]ureas 6a,b in 85–88% yields. Cyclization of 6a,b in acetic acid containing methanesulfonic acid followed by oxidation with 3-chloroperoxybenzoic acid gave high yields of 1-alkoxy-5-alkyl-6-(methylsulfonyl)uracils 9a,b. Nucleophillic addition-elimination reaction of 9a,b with sodium azide, phenylthiol, or phenylselenol produced 6-azido-1-butoxythymine ( 2a , 98%), 5-ethyl-1-(2-phenoxyethoxy)-6-(phenylthio)uracil ( 2b , 95%), or 5-ethyl-1-(2-phenoxyethoxy)-6-(phenylselenenyl)uracil ( 2c , 91%). 相似文献