نتایج جستجو برای: crown ether
تعداد نتایج: 39424 فیلتر نتایج به سال:
tin(ii)-ion-selective electrode consisting of dibenzo-18-crown-6 (db18c6) as an ionophore inpvc matrix was developed. the influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. the electrodeshowed a near nernstian response for sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 m with a slope of 27...
A silica-supported copper (Cu/SiO2) catalyst containing highly dispersed Cu nanoparticles was prepared via a crown-ether-assisted impregnation method. 12-crown-4-ether-assisted Cu/SiO2 outperformed several catalysts with various organic additives in the dehydrogenation of 2,3- and 1,4-butanediol. It found that catalytic activity, i.e., formation rate acetoin from 2,3-butanediol γ-butyrolactone ...
The quantitative analysis and identification of the radiolytic products of dicyclohexano-18-crown-6 (DCH18C6), 4',4''(5'')-di-tert-butyldicyclohexano-18-crown-6 (DtBuCH18C6) and benzo-18-crown-6 (B18C6) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C4mim][NTf2]) ionic liquid after irradiation were performed for the first time. It was found that the yield for radiolytic des...
Study of interaction between catechol and tetraethylene glycol dichloride in the n-butanol media, resulting with benzo-15-crown-5 production. Production of nitroand amino-derivatives of benzo-15-crown-5. Determination of their thermogravimetric characteristics. keywords: benzo-15-crown-5, catechol, tetraethylene glycol dichloride, crown ether, gas liquid chromatography, chromate-mass spectrometry
A liquid-crystalline benzocrown ether, 4'-[(4''-1,1,2,2-tetrahydroperfluorooctyloxy)biphenyloxycarbonyl]benzo-15-crown-5, was used as a neutral carrier of ion-selective electrodes (ISEs) to elucidate the effect of highly ordered assembling of the neutral carrier on the sensor properties through fluorophilic interactions. The properties for the membrane and the resulting ISEs based on a benzocro...
A series of unprecedented crown ether- and thiacrown ether-derivatized benzene dicarboxylic acid (H2bdc) ligands has been synthesized and incorporated into the prototypical isoreticular metal-organic framework (IRMOF) and UiO-66 materials. In the case of UiO-66, only MOFs comprised from a mixed-ligand composition, requiring both unsubstituted bdc and crown ether containing ligands, could be pre...
This paper describes the acid/base-mediated three-state translational isomerization of two [2]rotaxanes, each containing N-alkylaniline and N,N-dialkylamine centers as binding sites for threaded dibenzo[24]crown-8 units. Under neutral conditions, the dialkylamine unit predominantly recognized the crown ether component through cooperative binding of a proton; when both amino units were protonate...
In the title compound, C(7)H(10)N(+)·ClO(4) (-)·C(12)H(24)O(6), the 4-methyl-anilinium cation inter-acts with an 18-crown-6 mol-ecule forming a rotator-stator-like structure through bifurcated N-H⋯(O,O) hydrogen bonds between the ammonium group of the cation and the O atoms of the crown ether mol-ecule. All three components of the structure possess mirror symmetry. The benzene ring is inclined ...
Recently we reported the profound effects of second-sphere crown ether binding upon the redox energetics and intervalence spectroscopy of selected mixed-valence (Crowd metal complex associatino is driven primarily by ether oxygen/ ammine hydrogen interactions, where the H-bond-donating capability of NH3 is greatly enhanced by coordination to a transition-metal cation.) For delocalized species s...
The title compound, [Na(CF(3)O(3)S)(C(12)H(24)O(6))], features a sodium cation that is coordinated by eight O atoms in an irregular hexa-gonal bipyramidal environment. The equatorial positions are occupied by the six O atoms of an 18-crown-6 ether ring. In the axial positions, there is one O atom of a trifluoro-methane-sulfonate anion and an ether O atom of a symmetry-equivalent crown ether rin...
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