Single crystals of two calix[4]arene derivatives, that is, 5,11,17,23-tetra-tert-butyl- 25,27-bis[2-[N-(3-methoxy-4-methoxy-benzylidene)-amino]ethoxy]-26,28- dihydroxy calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,27-bis[2-[3- pyridine carbonyl-amino]ethoxy]-26,28-dihydroxy calix[4]arene (2), were prepared and their crystal structures have been determined by X-ray crystallographic study. As compared with calix[4]arene derivative 1 possessing CN functional group, compound 2 bearing the NH group could form not only intermolecular hydrogen bonds between the hydrogen atom in NH group and the oxygen atom in CO of an adjacent calix[4]arene molecule, but also intramolecular hydrogen bonds between the N—H⋯OC moieties in solid state, giving a rare linear molecular aggregation. 相似文献
A variety of novel upper rim functionalized calix-[4]arenes have been synthesized, using the Tscherniac-Einhorn amidomethylation reaction. Partially or fully alkylated calix [4]arenes bearing propyl or ethoxyethyl substituents could be easily condensed with various N-methylol-amides and -imides under mild conditions. The resulting methyl-acetamido- ( 4a , 4b , 7a ), methylchloroacetamido ( 4c , 4d , 7b , 7c , 9 methylphthalimido ( 4e , 4f , 4h )and methylchloroacetamido methylphthalimido functionalized calix[4]arenes ( 5 ) were obtained in yields varying from 30 till 97%. The amidomethylation reactions were proven to be independent of the conformation of the calix[4]arene. 相似文献
The synthesis of 5,11,17,23‐amino‐25,26,27,28‐propoxycalix[4]arene (calix[4]amine, 4 ) starting from 5,11,17,23‐nitro‐25,26,27,28‐propoxy‐calix[4]arene ( 3 ) via microwave‐assisted transfer hydrogenation is reported. Furthermore, the calix[4]amine ( 4 ) is functionalized with an acrylamide moiety. The swelling behavior in water, the influence on the glass transition temperature, and the shear modulus of a crosslinked N,N‐dimethylacrylamide (NDA) polymer with 5,11,17,23‐acrylamido‐25,26,27,28‐propoxycalix[4]arene ( 5 ) and EGDMA, respectively, are investigated.
Abstract The selective liquid-liquid extraction of Fe3+ cation from the aqueous phase to the organic phase was carried out by using p-tert-butylcalix[4]arene [L1], ca-lix[4]arene [L2], p-nitro-calix[4]arene [L3], calix[4]arene p-sulfonic acid [L4], p-(diethylamino)methylcalixt4]arene [L5], tetramethyl-p-tert-butylcalix[4]arene tet-raketone [L6], 25,27-dimethyl-26,28-dihydroxy-p-tert-butylcalix[4]arene diketone [L7], calix[4]arene-bearing dioxime group on the lower rim [L8], and a monooxime [L9]. The effect of varying pH upon the extraction ability of calixarenes substituted with electron-donating and electron-withdrawing groups at their p-position was examined. Observed results were compared with those found for unsubstituted calix[4]arene. 相似文献
Chlorine dioxide and thallium trifluoroacetate are shown to be useful reagents for the preparation of calixquinones. p-H-Calix[4]arene( 1a ),p-H-calix[5]arene ( 1b ), and p-H-calix[6]arene ( 1c ) are oxidized in modest yields by ClO2 to the fully quinonoid compounds calix[4]tetraquinone ( 2a ), calix[5]pentaquinone ( 2b ), and calix[6]hexaquinone ( 2c ), respectively. Although Tl(OCOF3)3 is less effective for the oxidation of 1a-c , it proves to be the reagent of choice for converting partially etherified or esterified calixarenes carrying p-tert-butyl groups directly to partially quinonoid calixarenes. Thus, monosubstituted calix[4]arenes yield triquinones; disubstituted calix[4]arenes yield diquinones; trisubstituted calix[4]arenes yield monquinones; and tetrasubstituted calix[6]arenes yield diquinones. The structures of the calixquinones have been established by elemental analysis, 1H NMR spectroscopy, mass spectroscopy, and in the case of 2c by X-ray crystallography. Since the starting materials are readily accessible, the calixquinones become easily available compounds for further study. 相似文献
Studies on extraction equilibrium constants at different temperatures and thermodynamic parameters of solvent extraction of Pb2+ ion with carboxylic acid derivatives of different ring size calixarenes and structure related monomeric compound have been carried out. The extraction equilibrium constants corresponding to calix[n]arene (n?=?4, 5, 6) derivatives decrease in the order [5]arene > [6]arene > [4]arene. In all cases, the complexation process is primarily enthalpy driven. The favorable enthalpic contribution for extraction of Pb2+ is in the order hexamer ≈ monomer > tetramer > pentamer. However, the unfavorable entropic loss follows the order: monomer > hexamer > tetramer > pentamer. Overall stability of the host-guest complex is the function of entropy-enthalpy compensation and the free energy of complexation is minimum for the pentamer, followed by tetramer ≈ hexamer and monomer. Although the carboxylic acid derivative of calix[4]arene is more preorganized than the calix[5]arene derivative, extraction of Pb2+ ion with the tetramer passes through greater entropic loss than that with the pentamer and the degree of preorganization of calix[4]arene derivative is far from perfect for the complexation and extraction of Pb2+ ion. As compared to tetrameric and hexameric counterparts, the structural features of the carboxylic acid derivative of calix[5]arene prior to complexation contribute much to interact with the Pb2+ ion and form a thermodynamically stable complex. Supplementary materials are available for this article. Go to the publisher's online edition of Solvent Extraction and Ion Exchange to view the supplemental file. 相似文献
A new synthetic strategy for the construction of an inherently chiral, sulfur-bridged calix[4]arene molecular framework was presented by oxidation of one of the four epithio bonds of a tetrathiacalix[4]arene derivative of 1,3-alternate conformation: Tetra(carboxymethyl) ether of p-tert-butyltetrathiacalix[4]arene of 1,3-alternate conformation ( 7 ) was converted to the tetra(l-menthoxycarbonylmethyl) ether ( 8 ). Oxidation of the tetra l-menthyl ester 8 by treatment with NaBO3 (1.1 molar equiv.) afforded a pair of diastereomers of the monosulfinyl derivatives ( 9 ) in 58% yield, which were readily separable by silica-gel column chromatography. Removal of the l-menthyl moieties followed by methyl esterification gave enantiomerically pure samples of inherently chiral (-)- and (+)-monosulfinyltrithiacalix[4]arene derivatives ((-) -10 and (+) -10 ) in 62 and 56% yield, respectively. 相似文献
The water-soluble p-sulfonated sodium salt of calix[8]arene (III) was synthesized. The product was characterized by FT-IR, NMR and UV–Vis spectra.Then
the electrochemical behaviors of p-sulfonated sodium salt of calix[8]arene in NaAc+HAc (pH = 4) buffer solution was studied. In aqueous solution, p-sulfonated calix[8]arene can be oxidized when the potential is more than 0.7 V vs SCE. It was confirmed that the reaction
was a two-electron irreversible electrochemical reaction. The transfer coefficient, α, was measured as 0.7. At 25°, the diffusion
coefficient of p-sulfonated calix[8]arene was determined as 8.6 × 10−7 cm2 s−1. The diffusion activation energy of p-sulfonated calix[8]arene was 18.9 kJ mol−1 at pH = 4. 相似文献
Copolyethers and polyurethanes containing lower and upper rim calix[4]arene units in the fixed cone conformation were prepared in good yield by polycondensation reactions of distal calix[4]arene diols with bisphenol-A/dibromomethane and 2,4-tolylendiisocyanate (TDI), respectively. In a similar way were prepared calix[4]arene-crown-5 and -crown-6 polyurethanes in the fixed 1,3-alternate conformation by condensation of TDI with lower rim calixcrown-5 and calixcrown-6 diols. However, the poor solubility in common organic solvents of the copolyether derivatives (Mw=11,100-11,600 g/mol) hampered further studies on their ionophoric properties. Aiming to obtain model compounds for the investigation of both extraction abilities and ionophoric properties of the polyurethane materials, several bis-urethanes were also synthesized by reaction of the calix[4]arene diols with p-tolylisocyanate (TI). The extraction ability measurements of monomeric and polymeric calix[4]arene urethanes (Mw=12,300-83,500 g/mol) towards alkali metal cations (Li+, Na+, K+, Rb+, Cs+) and Ag+showed a remarkable efficiency and selectivity of calixcrown-6 polyurethane toward Rb+, Cs+and Ag+. 相似文献
A new catalyst separation and recycling protocol combining magnetic nanoparticles and host‐guest assembly was developed. The catalyst, (η6‐arene)[N‐(para‐toluenesulfonyl)‐1,2‐diphenylethylenediamine]ruthenium trifluoromethanesulfonate [Ru(OTf)(TsDPEN)(η6‐arene)] bearing a dialkylammonium salt tag, was easily separated from the reaction mixtures by magnet‐assisted decantation, on basis of the formation of a pseudorotaxane complex by using dibenzo[24]crown‐8‐modified Fe3O4 nanoparticles. The ruthenium catalyst has been successfully reused at least 5 times with the retention of enantioselectivity but at the expense of relatively low catalytic activities in the asymmetric hydrogenation of 2‐methylquinoline. 相似文献
The combination of calixarene‐derived surfactants and neutral rhodium complexes containing a hemispherical “1,3‐calix‐diphosphite” ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1‐octene were obtained when using [tetra(p‐sulfonato)]‐(tetra‐n‐butoxy)‐calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1‐octene)⋅ mol(Rh)−1⋅h−1]. 相似文献
The chiral calix[4]arene derivative (6) bearing an L-prolinamido group has been designed and proved to be a water compatible efficient organocatalysts for a direct enantioselective aldol reaction. Compound 6 catalyzes the aldol reaction of cyclohexanone and a variety of aromatic aldehydes yielding anti-aldol products in high yield with enantioselectivities of up to 93% and diastereoselectivity of up to 95:5. 相似文献
In this article, calix[4]arene (4) was prepared by debutylation and hydrolyses reacting from 25,27-dibenzoyl-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl)calix[4]arene (2). Azocalix[4]arenes (6a-c) were coupled by linking 4-methoxy, 4-ethyl, and 4-nitroaniline to calix[4]arene (4) through a diazo-coupling reaction. Thermal behavior characteristics and decomposition routes of 25,26,27,28-tetrahydroxy-11,23-di(tert-butyl)-5,17-(p-substitue phenyl)azocalix[4]arene (6a-c) were investigated in air atmosphere by means of thermogravimetry (TG), differential thermogravimetry (DTG), and differential thermal analysis (DTA) analyses. It was found that the decomposition of all compounds complete with two exothermic stages which corresponded to removal of substitute groups (methoxy-, ethyl-, nitro-) and second stage rest of structure decomposition. 相似文献
Abstract A novel extraction chromatographic resin for the separation and preconcentration of cesium from acidic nitrate media comprising an inert polymeric substrate impregnated with 1,3‐calix[4]bis‐o‐benzo‐crown‐6 (“BC6B”) in a chlorinated diluent is described. Cesium is shown to be both strongly and selectively retained by the resin at low (<1 M) acid concentrations and readily eluted from it using 6 M HNO3. Only potassium ion (at concentrations exceeding ca. 0.01 M) exerts a significant adverse impact on cesium retention. Unexpectedly, cesium uptake by the resin does not exhibit the acid dependency anticipated from liquid‐liquid extraction data. This is also the case for a resin employing a related macrocyclic extractant, calix[4]arene‐bis‐(t‐octylbenzocrown‐6) (“BobCalix”), prepared and partly characterized in an effort to overcome certain limitations of the BC6B‐based material. Despite this, the resin is shown to be well suited to the isolation of radiocesium from acidic solution for subsequent determination or for the removal of cesium intereference in the quantitation of other radionuclides. 相似文献