A bolaamphiphilic low-molecular-weight gelator based on crown ether, which could self-assemble into organogels and hydrogels, was prepared. The contribution of each part of the structure to the gelation property was investigated by designing a series of analogues. A simple framework (crown ether-hydrophobic linkage-ammonium salt) was proposed.

Crystalline complexes of S-tert-butylisothiuronium perchlorate ( t-BuSC(NH2),C104) and 18-crown-6 (18C6) and 1,3-xylyl-18-crown-5 (1,3X18C5) with a 1:l stoichiometry were obtained via extraction. X-ray diffraction analysis showed that in the solid state the guest molecule is coordinated via one of the two NH, groups to the crown ether. The second NH2 group is bound to the anion. 'H NMR spectros...

Two simple, rapid and sensitive sensors for the assay of dopamine hydrochloride have been developed. The methods are based upon the formation of the membrane sensors 12-crown-4-phosphotungestic acid (crown ether-PTA)-dopamine and 12-crown-4-tetraphenylborate (crown ether-TPB)-dopamine as neutral carriers. The sensors were stable and showed fast potential responses of 10 s, and near-Nernstian ca...

we found that dibenzo-18-crown-6 (db18c6) can be used as an ionophore to make a tin (ii)-ionselectivemembrane electrode. the electrode exhibits a near nernstian response for sn2+ ions over aconcentration range from 1.0× 10-6 – 1.0× 10-2 m with a slope of 27.5 ± 0.6 mv per concentration decadein an acidic solution (ph=1). the limit of detection was 8.0× 10-7 m. it has a response time of < 20s an...

Phenyllithium forms a mixture of tetramer and dimer in ether. Complete conversion to dimeric solvates is achieved by the addition of THF, dioxolane, DME, or TMEDA in near stoichiometric amounts. The addition of 2,5-dimethyltetrahydrofuran favors dimer, but tetramer is still detectable at 14 equiv of cosolvent. PMDTA converts PhLi to monomer in ether. In THF, PhLi is a mixture of dimer and monom...

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...