To probe the influence of structural variation within dibenzo-16crown-5-oxyacetic acids upon the selectivity of alkali metal cation separations by solvent extraction and liquid membrane transport processes, studies have now been conducted in homogeneous solution by NMR spectroscopy and titration calorimetry and in the solid state. Condensation polymerization of such proton-ionizable lariat ethe...

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...

Amelogenesis imperfecta is an autosomal dominant disorder. It is a group of hereditary diseases showing abnormal enamel density and crown malformation. This clinical report describes the oral rehabilitation of a young adult diagnosed with a variant of hypoplastic amelogenesis imperfecta with multiple impacted teeth and skeletal class III malocclusion. The treatment procedures of teeth extractio...

A series of novel resorcin-[4]arenes with extended pi systems have been synthesised and developed as potassium-selective transporters. Resorcin[4]arenes that feature crown ether moieties function as efficient carriers of K+ across bulk liquid membranes showing enhanced selectivity over the other alkali metal ions relative to a model system (benzo[15]crown-5). Incorporation of functionalities su...

The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexa-oxatri-cyclo-[20.4.0.0(9,14)]hexa-cosane aceto-nitrile disolvate), C20H36O6·2CH3CN, crystallizes from an aceto-nitrile solution of di-cyclo-hexane-18-crown-6 on evaporation. The mol-ecule is arranged around a center of symmetry with half the crown ether mol-ecule and one mol-ecule of aceto-nitrile symmetry independent. All O-...

Treatment of 3,5-diisopropyltriazole, 3,5-diphenyltriazole, 3,5-di-3-pyridyltriazole, phenyltetrazole, pyrrolidinyltetrazole, or tert-butyltetrazole with equimolar quantities of potassium hydride and 18-crown-6 in tetrahydrofuran at ambient temperature led to slow hydrogen evolution and formation of (3,5-diisopropyl-1,2,4-triazolato)(18-crown-6)potassium (88%), (3,5-diphenyl-1,2,4-triazolato)(t...

a conductance study of the interaction between cs+, rb+, nh4+, k+, t1+ and ag+ ions and18-crown-6 (18c6), benzo-18-crown-6 (b18c6), dicyclohexyl-18-crown-6 (dc18c6),dicyclohexyl-24-crown-8 (dc24c8), dibenzo-24-crown-8 (db24c8) in different binarymixtures of acetonitrile (an) with dimethylsulfoxide (dmso) and dimethylformamide (dmf)at 25 °c has been carried out. formation constants of the result...

The structures of two derivatives of the bisdioxine diisocyanate 1, the bisurea 4 and the biscarbamate 5, are established by X-ray crystallography and DFT calculations. These compounds possess endo,endo structures, in the case of the bisurea 4 with two nearly parallel pendant chains. The X-ray structures are reproduced very well by DFT calculations. Similar endo,endo conformations are calculate...

A range of complexes based on the high-nuclearity [W36] isopolyoxotungstate cluster, [H12W36O120]12-, with a triangular topology has been isolated by using the organic cation, protonated triethanolamine. In analogy to an 18-crown-6 crown ether with six oxygen donors on a ring, the cluster can form alkali and alkaline earth metal complexes [M within W36] (M = K+, Rb+, Cs+, NH4+, Sr2+ and Ba2+, 1...