99624-13-2

Upstream product

• 14098-44-3 2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin 
• 60835-69-0 4'-nitrobenzo-15-crown-5 

Relevant academic research and scientific papers

Ion pair complexes and anion binding in the solution of a ditopic receptor

The synthesis and crystal structures with alkali halides of a ditopic benzo-15-crown-5 bis-urea receptor L have been presented. In addition, the anion binding properties of L and its alkali metal complexes in solution are presented. A comprehensive single-crystal X-ray crystallographic study of L, all together 13 crystal structures, including the ion pair complexes with NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, and RbI, give a detailed view of how L behaves in the solid-state with different alkali halides depending on the size of the cation and anion. In the solid-state L forms a 1 : 1 complex with a sodium cation and the anion is complexed as a contact (NaCl) or a separate ion pair (NaBr, NaI). With larger potassium and rubidium cations L assembles into a 2 : 1 complex and forms a separated ion pair complex with the anion. Reflecting the crystal structures the L forms a 1 : 1 complex with Na+ in solution, and a 2 : 1 complex with K+, which were verified by Job's plot analysis in 4 : 1 CDCl3/dimethyl sulfoxide. The binding strength of the monomeric [L·Na]+ and the dimeric [2L·K]+ toward chloride, bromide and iodide anions was studied by 1H NMR titrations in 4 : 1 CDCl3/DMSO, and a clear turn-on effect of the cation complexation compared to the neutral receptor L alone (Ka with L for Cl-, Br- and I- being 832, 174 and 32 M-1, respectively) was observed. The monomeric [L·Na]+ binds chloride 9, bromide 8, and iodide 12 times stronger than L, while for the dimeric [2L·K]+ the corresponding increase in binding is 51 (Cl-), 84 (Br-), and 22 (I-) times with the same stoichiometric ratios as observed for the ion pair complexes in the solid-state.

Ion Pair Binding in the Solid-State with Ditopic Crown Ether Uranyl Salophen Receptors

Two ditopic uranyl salophen receptors with benzo-15-crown-5 and benzo-18-crown-6 units (R1 and R2, respectively) have been synthesized from commercially available starting materials. Comprehensive studies on the solid-state ion pair complexation with various alkali and ammonium halides have been conducted. From the 19 obtained solid-state structures (6 structures with R1, 13 structures with R2), three general interaction motifs I-III have been observed. Interaction motif I has a separated ion pair with the cation coordinated to the crown ether unit, and the anion or oxygen containing solvent molecule coordinated to the uranyl center. The interaction motif II manifests a polymeric structure with a contact ion pair between the uranyl-coordinated anion and cation coordinated in the crown ether in the adjacent receptor. Interaction motif III consists of a more general stacked packing structure of the receptors with or without ion pairs. From the obtained solid-state structures, the complex R2·NaI shows an interesting formation of infinite coordination polymeric structure where the crown ether complexed sodium cations and the O=U=O units of the adjacent receptors form a nearly linear 1-D chains. In the course of this work also the first solid-state structure of uranyl salophen acetate complex was obtained (R2·KAcO).

Preparation and application of double crown ether-containing switch compound

The invention relates to a double-crown ether compound with switching performance. The general formula of the double-crown ether compound is I or II or an isomer thereof. The double-crown ether compound provided by the invention can form a complex with various metal ions, and the metal ions can be separated from the double-crown ether compound as the molecular configuration is changed after cooling or acid adding. The double-crown ether compound has a potential application in the aspects of drug sustained release, ion extraction, recognition and the like.

Sodium Ion Complexation Enforced Columnar Mesophase of Dibenzo[ a, c ]phenazine Bearing Lateral Crown Ether

The dibenzo[a,c]phenazine discogen having "π-polarization" containing a lateral crown ether and four alkoxy-peripheral side chain, DBPZ-Cn were synthesized. These metal-free crown ether DBPZ-Cn having four dodecylalkoxy side chains were found to be non-me

Self-assembled dimerization of bis(crown ether)-2,2′-bibenzimidazoles

Bis(crown ether)-2,2′-bibenzimidazole 1 and its 1-substituted derivatives were synthesized as new self-assembled motifs. UV-vis and 1HNMR titration experiments of 1 with potassium ions in a mixture of chloroform and methanol (1:1) were carried out. The stoichiometries and curve fitting analysis showed that a 2:2 complex of 1 with potassium ions was formed in a face-to-face fashion. 1-Monosubstituted bis(crown ether)-2,2′- bibenzimidazole 6a having a (dodecylaminocarbonyl)methyl group also gave a 2:2 complex with potassium ions. Structural analysis of the 2:2 complex of 6a with potassium ions was performed using various two-dimensional NMR techniques. Results suggested that, of eight or more possible conformational isomers, the one having the two substituent groups diagonally opposite each other was predominantly formed. Reversible association and dissociation of the 2:2 complex was observed after adding potassium ions and then removing them with an 18-crown-6-ether.

Synthesis and binding investigations of novel crown-ether derivatives of phenanthro[4,5- abc ]phenazine and quinoxalino[2′,3′:9,10] phenanthro[4,5- abc ]phenazine

The synthesis and binding investigation of novel crown-ether derivatives of phenanthro[4,5-abc]phenazine and quinoxalino[2′,3′:9,10] phenanthro[4,5-abc]phenazine sensors are reported. The binding studies of these sensors with an array of alkali and alkaline-earth metals are exploited using UV-vis, fluorescence and nuclear magnetic resonance spectroscopies. 2013

Synthesis, structural characterization and complexation properties of the first "crowned" dipyrrolylquinoxalines

The synthesis of four crown-substituted dipyrrolylquinoxalines 1-4 is reported. The key step in the synthesis is reaction of a 1,2-diaminobenzocrown with 1,2-bis(1H-pyrrol-2-yl)ethanedione (20). A single crystal X-ray diffraction analysis of the 18-crown-6-dipyrrolylquinoxaline 1 revealed that this molecule forms a tetramer centered around a single molecule of water, with no fewer than 10 hydrogen bonds holding the supramolecular structure together. In the case of the 15crown-5-dipyrrolylquinoxaline 2, however, X-ray diffraction analysis revealed that this species exists as a dimeric pair in the solid state, with the NH protons of one pyrrole lying within hydrogen-bonding distance of two oxygen atoms on an adjacent crown ether. A second single crystal structure of 2 was solved; it demonstrated that this system is able to coordinate a potassium cation, thereby forming an intermolecular sandwich complex, at least in the solid state. In [D6]acetone solution receptor 2 and congeners 1, 3 and 4 were also found to complex sodium and potassium cations within the crown diethyl ether binding sites, in a 1:1 manner as judged by 1H NMR spectroscopic analyses. Although systems 1-4 appear to bind fluoride anion as well as cations, the inability to obtain quantitative binding affinities of 1-4 with fluoride anion rendered the evaluation of the systems for cooperative binding impossible. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid

A general method for the nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid has been developed. Mono- and dinitro derivatives of benzo-12-crown-4, benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8 have been prepared. The role of complex formation in the regioselective tendency for the nitration of dibenzo-18-crown-6 has been demonstrated.

THE SYNTHESIS OF SOME AROMATIC CROWN ETHER DERIVATIVES AND THEIR ION-SELECTIVE ELECTRODE PROPERTIES

The synthesis of alkyl, nitro and halogeno derivatives of benzo-15-crown-5, benzo-18-crown-6 and naphtho-15-crown-5 has been reported.Also some novel ester type bis(crown ether)s have been prepared.Some of the compounds have been characterized as electroactive substances in PVC membrane ion-selective electrodes.