共查询到20条相似文献,搜索用时 15 毫秒
1.
HUANG Wei-Yuan WU Yong-Miug LIU Jin-TaoShanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai China 《中国化学》1995,13(3):251-262
Perfluoroalkylated glycerol (5, 9) and crown ethers (22, 23, 24) were synthesized starting from glycerol. 5 was synthesized by allylation of glycerol 1,2-acetonide followed by perflu-oroalkylation initiated with sodium dithionite, reduction of iodide and hydrolysis in good overall yield and was shown to poccess good surface activities. Glycerol bis-ether (9) was synthesized in a similar way. Allyloxymethyl crown ethers (15, 16, 18) were prepared as key intermediates through multi-step reactions, which were then perfluoroalkylated to give the title crown ethers 22, 23 ,24. 相似文献
2.
P. Kuś 《Monatshefte für Chemie / Chemical Monthly》1997,128(8-9):911-917
Summary The synthesis and spectroscopic characterization of seven new tetraphenyl-porphyrins (1–7) derivatized with 12-crown-4, 14-crown-4, 15-crown-5, or 18-crown-6 ether units inortho orpara position of one of the phenyl rings is described.
In einem Phenylring mit Kronenethern monosubstituierte Tetraphenylporphyrine. Synthese und Charakterisierung
Zusammenfassung Die Synthese und die spektroskopische Charakterisierung sieben neuer Tetraphenylporphyrine (1–7), die mit 12-Krone-4, 14-Krone-4, 15-Krone-5 oder 18-Krone-6 in derortho-oderpara-Position eines Phenylrings substituiert sind, werden beschrieben.相似文献
3.
We report that the surface chemical properties of muscovite mica [KAl2(Si3Al)O10(OH)2] like important multi-elemental layered substrate can be precisely tailored by ion bombardment. The detailed X-ray photoelectron spectroscopic studies of a freshly cleaved as well as 12-keV Ar+ and N+ ion bombarded muscovite mica surfaces show immense changes of the surface composition due to preferential sputtering of different elements and the chemical reaction of implanted ions with the surface. We observe that the K atoms on the upper layer of mica surface are sputtered most during the N+ or Ar+ ions sputtering, and the negative aluminosilicate layer is exposed. Inactive Ar atoms are trapped, whereas chemically reactive N atoms form silicon nitride (Si3N4) and aluminum nitride (AlN) during implantation. On exposure to air after ion bombardment, the mica surface becomes more active to adsorb C than the virgin surface. The adsorbed C reacts with Si in the aluminosilicate layer and forms silicon carbide (SiC) for both Ar and N bombarded mica surfaces. Besides the surface chemical change, prolonged ion bombardment develops a periodic ripple like regular pattern on the surface. 相似文献
4.
Strokach Yu. P. Valova T. M. Barachevsky V. A. Alfimov M. V. Gromov S. P. Vedernikov A. I. Demina O. V. Lukin A. Yu. Shevyakov S. V. Shvets V. I. Khodonov A. A. Lugtenburg J. 《Russian Chemical Bulletin》2003,52(12):2656-2660
Complexation of crown ether vinylogs containing different terminal polar groups with alkali and alkali-earth metal ions in solutions was studied by spectrophotometry. The hypsochromic shift of absorption band maxima in the UV-Vis absorption spectra indicates that the ligands containing the monobenzocrown ether fragments interact with metal ions. The scheme of complexation was proposed, and the stability constants of the complexes were determined. The efficiency of complexation depends on the metal cation size and the structure of the ionophoric fragment. 相似文献
5.
Marta Elena Díaz-García Fausto Alava-Moreno Alfredo Sanz-Medel 《Mikrochimica acta》1994,113(3-6):211-222
A new optical sensor phase for potassium ions has been developed based on the immobilization of the pH-dependent fluorogenic crown ether 4-acryloylamidobenzo-18-crown-6 on the non-ionic polymeric resin Amberlite XAD-2.Two different optical designs, a flow-through sensor and a fibre optic probetype sensor (optrode), have been constructed and their analytical performance characteristics have been evaluated. The resulting fluorimetric sensors for K+ ions exhibited detection limits of 0.4 or 0.8 M of K+ (16 g/l or 31 g/l), depending on the design, while the linear response occurred from 1 to 25 M of the metal concentrations. The precision, evaluated as the relative standard deviation of measurements of K+ levels at around ten times the detection limit (e.g. 5 M), turned out to be around ±2%.Advantageous features of this fluorimetric sensing phase and optrode include ease of construction, simplicity of use, reversibility, short response times (ca. 1 min full scale deflection) selectivity and operational stability, suitable for sensing potassium at low levels in complex matrices such as biological fluids.The fluorimetric optical sensor has been successfully applied to the direct determination of potassium in clinically important samples (serum and urine) and in natural waters. Very good accuracy has been obtained just using adequate synthetic aqueous potassium standards for calibration. 相似文献
6.
I. G. Ovchinnikov O. V. Fedorova P. A. Slepukhin G. L. Rusinov 《Russian Chemical Bulletin》2008,57(1):212-214
The photoinitiated [2+2]-cycloaddition of 1,5-bis[2-(3-phenyl-3-oxoprop-1-en-1-yl)phenoxy]-3-oxapentane in solution was studied.
In the presence of potassium cations, the reaction is intramolecular and gives crown ether containing the γ-truxin-type cyclobutane
fragment (anti, head-to-head) as the major product.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 204–206, January, 2008. 相似文献
7.
The easily accessible and multi-functionalized 5,8-dimethoxy-6,7-dihydroxy methyl-1,4-dihydro-1,4-methanonaphthalene (1) has been utilized as the basic building material to synthesize the symmetric bis-methanonaphthalene-fused crown ethers 14a-d (BMN-16-crown-4, BMN-22-crown-6, BMN-28-crown-8, and BMN-34-crown-10), that are constructed based on the connection between the α,β-bis-benzylic carbon atoms of diol 1 and oligoethylene glycols (9a-d) via two synthetic routes keyed upon the method of Williamson ether synthesis. 相似文献
8.
R. Meusinger J. Heinicke K. Möhle M. Mühlstädt 《Monatshefte für Chemie / Chemical Monthly》1996,127(11):1145-1152
Summary Addition of sulfur dichloride to tetrachlorocatechol-bisallylether (1) yields the 9- and 10-ring thia crown ether derivatives2 and3, respectively, together with the dithia-18-crown-6-ether4. The 10-membered ring compound3 represents the first thia macrocycle containing bothMarkovnikov andanti-Markovnikov constitution of the -chloro-thio structural segments in the same molecule. By1H and13C NMR spectroscopy, equal amounts of two preferred conformers of the only isolated diastereomer of3 were observed at temperatures below –50°C. The signals were assigned to these conformers using COSY, HETCOR, and phase sensitive NOESY spectra at low temperatures. The preferred conformations and the relative configuration were determined using the different effects of
gauche
-and
anti
-positions in13C NMR chemical shifts and analyzing vicinal3
J
H,H coupling constants. These results were confirmed by molecular mechanics calculations.Dedicated to Prof. Dr.Rolf Borsdorf on the occasion of his 65th birthday 相似文献
9.
Zhijun Zhang Haoyun An Xiaodong Ma Xingtang Zhang Yangjie Wu Ziquiang Zhu 《Journal of inclusion phenomena and macrocyclic chemistry》1992,13(4):329-335
4-Octadecanoylbenzo-15-crown-5 (I) and four 4-alkylbenzo-15-crown-5 ligands [4-XB15C5 where X =n-C18H37 (II), X =n-C16H33 (III), X =n-C14H29 (IV), and X =n-C12H25 (V)] have been synthesized. The -A isotherms ofI andII were systematically investigated. The results indicated that the Langmuir-Blodgett (LB) films have high stability where the ratios ofI/SA andII/SA were 1 : 1 and 1 : 10, respectively, with a 6.2 pH subphase. The LB films of the crown ethers were deposited onto graphite electrodes pretreated by immersing them in liquid wax. The peak current reached the maximum value when the electrode surface was modified with five layers of the amphiphilic crown ethers. 相似文献
10.
Two chromogenic monoaza crown ethers were synthesized and investigated for their lithium extraction capabilities. The chromogenic monoaza 14-crown-4 compound exhibited the best selectivity for lithium over sodium; ca. 2800, with a detection limit of 0.08 ppm. 相似文献
11.
Mustafa Bulut Birsen Yilmaz Mehtap Yapici M. Vezir Kahraman 《Journal of inclusion phenomena and macrocyclic chemistry》1996,26(1-3):39-46
The presented ethylenedioxy compounds5a,5d,6a and6c are examples of novel cyclic ethers, while macrocyclic polyethers represent new crown ether analogues. New coumestan-crowns5a-f, derivatives of 6,7-dihydroxy-3,4-dihydro-2H-dibenzofuran-1-one and 6,7-dihydroxy-3,3-dimethyl-3,4-dihydro-2H-dibenzofuran-1-one6a-e were synthesized from the correspondingo-dihydroxy compounds3a-b,4a-b and ditosylates or dichlorides of di- or triethylene glycol in the presence of K2CO3, in DMF/H2O (15/1) solutions at 65–75 °C for 35 hours. The structure of the macrocyclic ethers obtained were confirmed by1H-NMR,13C-NMR, IR spectra and elemental analyses.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995. 相似文献
12.
The syntheses of four aza-15-crown-5 ethers bearing phenyl and phenoxymethyl moieties attached to a stereogenic centre on the crown ring were achieved. Macrocycles have exhibited strong binding ability (Ka = 5364–12,969 M? 1) and modest enantiomeric discrimination towards the enantiomers of amino acid methyl ester salts by UV titration method in CHCl3 at 25°C. Computer modelling results supported experimental data providing a detailed understanding of the molecular recognition mode between hosts and guests and the likely binding sites involved. Macrocycles were used for chiral discrimination of amino acids in their zwitterionic forms or as potassium and sodium salts in transport experiments across a bulk chloroform membrane with satisfactory selectivity. 相似文献
13.
14.
Harry W. Gibson William S. Bryant Sang‐Hun Lee 《Journal of polymer science. Part A, Polymer chemistry》2001,39(12):1978-1993
Poly[(methyl acrylate)‐rotaxa‐(30‐crown‐10)] ( 5 ) and poly[(methyl methacrylate)‐rotaxa‐(30‐crown‐10)] ( 6 ) were synthesized by azobisisobutyronitrile‐initiated free‐radical bulk polymerizations of the respective monomers in the presence of 30‐crown‐10 ( 1 ; equimolar; 5 times the monomer mass). For 5 , 3.8 mass % (0.81 mol % with respect to the monomer) of the crown was incorporated versus 1.7 mass % (0.39 mol % with respect to the monomer) for 6 . Control reactions with 18‐crown‐6, which is to small to be threaded, showed that chain transfer to the crown ethers was detectable only for the acrylate but was relatively negligible and spectroscopically distinct. The threading yields were much higher with these systems than with polystyrene, most likely because of the greater compatibility of the crown ether with these polar monomers and polymers and the consequent ability to carry out the polymerizations homogeneously in the absence of added solvent; however, the threading process was still essentially statistical. Therefore, the polymerization of methacrylate monomers 8a – 8c based on tetraarylmethane moieties connected via diethyleneoxy or triethyleneoxy spacers was examined in the presence of 1 in the belief that the supramolecular semirotaxane monomer 9 formed statistically in situ could be captured more efficiently and produce higher threading yields, presumably of side‐chain polyrotaxanes, than the simple (meth)acrylate monomers. Azobisisobutyronitrile‐initiated polymerizations either neat or in toluene produced polyrotaxanes 10 with up to about 1.6 mass % and 2 mol % threaded crown ether, presumably trapped on the pendant stoppered side chains. Although primarily statistical in nature, the latter rotaxane syntheses afforded on a molar basis 3–7 times more efficient incorporation of 1 than styrene (0.33 mol %), methyl acrylate (0.81 mol %), or methyl methacrylate (0.39 mol %) monomers for the preparation of main‐chain polypseudorotaxanes and indeed even surpassed the 60‐crown‐20/polyacrylonitrile system (1.5 mol %). This was presumed to be due to the fact that the loss of the crown ether, once it was threaded onto the monomer to form 9 and the latter was polymerized, was either retarded (by the tetraphenylmethyl stopper in 10a ) or prevented completely [by tris(p‐t‐butylphenyl)phenylmethyl stoppers in 10b and 10c ]. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1978–1993, 2001 相似文献
15.
Jiumin Si Yangjie Wu Lei Cai Yizhen Liu Baoshi Du Tongsheng Xu Haoyun An 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(3):249-258
Eight new open-chain crown compounds (1–8) and two new macrocyclic crown ethers (9 and10) were synthesized from 1,5-bis(2-aminophenoxy)-3-oxapentane (15) and 1,8-bis(2-aminophenoxy)-3,6-dioxaoctane (16) which were prepared by the catalytic hydrogenation of the corresponding bis(2-nitrophenoxy) derivatives13 and14. The fluorescent property investigation of two open-chain crown ethers (7 and8) indicated that they exhibit complexing effects on Ag+ and Mn2+ cations and can be used as fluorescent reagents for the microanalysis of the metal cations. The pyrolysis kinetics measurement for compounds5 and6 in nitrogen and air was carried out, and their reaction orders and activation energy were obtained. They are one-step and two-step pyrolysis reactions in nitrogen and air, respectively. 相似文献
16.
Spectral luminescence characteristics, viz., quantum yields and luminescence lifetime, of the Yb3+ and Nd3+ ions in aqueous-methanolic solutions of their complexes with chromophoric benzo-15-crown-5 derivatives were determined. The efficient 4f-luminescence (exc = 337 nm) is due to the intramolecular transfer of the excitation energy from the chromophoric moiety of the molecule to the Ln3+ ion. 相似文献
17.
Phase transfer catalyzed interfacial reaction of the polysaccharide dextran (C6H10O5)n with organotitanium and organotin dichlorides to form metal-containing carbohydrate polymers has been carried out in the presence of two bases, sodium hydroxide and triethylamine. Interfacial systems employing sodium hydroxide with a crown ether phase transfer catalyst (PTC) gave generally greater yields compared with the analogous systems without a PTC. The trend of maximum yield for triethylamine systems with organotin dichloride not containing a PTC was different from that observed for the sodium hydroxide systems without a PTC, probably because of the ability of triethylamine to act as a PTC. 相似文献
18.
Hans-Jurgen Buschmann 《Journal of solution chemistry》1986,15(6):453-461
The complexation of alkaline-earth cations by different crown ethers, azacrown ethers, and cryptands has been studied in methanol solutions by means of calorimetric and potentiometric titrations. The smallest monocyclic ligands examined form 21 complexes (ratio of ligand to cation) with cations which are too large to fit into the ligand cavity. With the smallest cryptand, only Sr2+ and Ba2+ ions are able to form exclusive complexes. In the case of the reaction of cryptand (211) with Ca2+, a separate estimation of stability constants for the formation of exclusive and inclusive complexes was possible for the first time. Higher values for stability constants are found for the reaction of alkaline-earth cations with cryptands compared to the reaction with alkali ions. This increase is only caused by favorable entropic contributions. 相似文献
19.
Copolyfluorene PFC containing pendant crown ether moieties was prepared by the palladium‐catalyzed Suzuki coupling reaction. The photo‐physical and electrochemical properties were investigated by absorption, photoluminescence (PL) spectroscopy, and cyclic voltammetry to elucidate the influence of the crown ether groups. In film state, its PL spectra (peaked at 430 and 452 nm) show noticeable red‐shift relative to 423 and 448 nm of poly(9,9‐dihexylfluorene) ( PF ). Thermal annealing leads to appearance of new emission at about 520 nm which has been attributed to formation of excimer. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of PFC were estimated to be ?5.68 and ?2.65 eV which contributed to balanced charges injection. Double‐layer electroluminescent device using PFC as emitting layer (ITO/PEDOT:PSS/ PFC /Ca/Al) revealed maximum luminance (7910 cd/m2) and maximum luminance efficiency (2.3 cd/A) superior to those of PF device (860 cd/m2, 0.29 cd/A). Moreover, inserting a PFC layer between the PF emitting layer and calcium cathode led to reduced turn‐on voltage (4.1 V), much lower than 7.1 and 6.6 V of the double‐layer PFC and PF devices, respectively, and enhanced device performance (2800 cd/m2 and 0.53 cd/A). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2985–2995, 2009 相似文献
20.
L. F. Kosyanchuk T. E. Lipatova V. A. Vilensky Y. S. Lipatov V. I. Shtompel 《Journal of polymer science. Part A, Polymer chemistry》1998,36(9):1379-1386
Two types of crosslinked polyurethanes (PU) have been synthesized: (a) PU crosslinked by metal ions (Cu2+ and Co2+), and (b) PU crosslinked by the complexes of metals with crown ether. Using X-ray scattering under small and wide angles the peculiarities of the structure of networks have been investigated. It was found that PU crosslinked by the metal crown ether complexes have a looser structure because of the bulky crosslink and diminished molecular mobility of the chains between two crosslinks, as was proven by the dielectric spectroscopy method. The X-ray and IR data have allowed proposing a scheme of the structure of the crosslinked PU with various types of crosslinks. The structures discovered may be considered as similar to metal catenandes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1379–1386, 1998 相似文献