Calix[4]resorcinarene macrocycles

Supramolecular chemistry is an interdisciplinary scientific field, including chemical, physical and biological properties of more complex chemical species than the molecules themselves. Calixarenes/calixresorcinarenes are macrocyclic compounds, consisting of ‘n’ phenolic/resorcinolic units linked together by methylene bridges; these macrocycles are often used for molecular recognition. Thus, different modifications can be made to both the lower and upper rim, allowing the construction of well-defined multivalent buildings. In this work, three calix[4]resorcinarene macrocycles were synthesized, namely C-dec-9-en-1-ylcalix[4]resorcinarene (CAL 11U), C-trans-2, cis-6-octa-1,5-dien-1-ylcalix[4]resorcinarene (CAL 9U) and C-nonylcalix[4]resorcinarene (CAL 10) by a simple condensation reaction. The compounds CAL 11U and CAL 10 have been already synthesized by researchers, while the CAL 9U has been synthesized for the first time. Their structures were confirmed using ATR-FTIR, ¹H NMR and ¹³C NMR. Thermal analysis combined with mass spectrometric evolved analysis of the vapors was used to study the thermal behavior of the different synthesized molecules, and they were the subject of characterization by X-ray powder diffraction in order to analyze their degree of crystallinity.

     

Convenient Preparation of Self-Assembled Monolayers Derived from Calix[4]resorcinarene Derivatives Exhibiting Resistance to Desorption

Crown conformers of O-carboxymethylated calix[4]resorcinarenes (CRA-CMs) bearing four perfluorooctyl- and octylazobenzene residues at the lower rim of the cyclic skeleton were synthesized to investigate the resistance to desorption of CRA-CMs forming self-assembled monolayers on aminosilylated silica substrates and the surface energy photocontrol based on E- to-Z photoisomerization of the azobenzene moiety. In comparison with CRA-CM monolayers on silica substrates, the desorption of CRA-CMs on the aminated substrate was remarkably suppressed even when CRA-CM monolayers were sonicated in polar solvents and even in water. The high desorption-resistance was attributable to multi-point adsorption of CRA-CMs through COOH/NH₂ interactions. UV-Vis spectral studies revealed that CRA-CM substituted with p-octylazobenzene exhibited high E- to-Z photoisomerizability up to 92% in self-assembled monolayers, while less photoisomerizability was observed for CRA-CM bearing p-perfluorooctylazobenzenes due to the steric hindrance of the larger perfluoroalkyl chains. Photoinduced changes of contact angles for water up to 8.3° were observed for a CRA-CM monolayer.     

Synthesis of Calix[4]resorcinarene Schiff Bases

Introduction Calix[4]resorcinarenes are cyclic tetramers in which four resorcinol units are linked via alkylmethylene bridges in the o-position to each resorcinic hydroxyl group[1]. Their structures resemble that of p-butylcalix[n]arenes and render them of interest as host compounds in many contemporary fields of supramolecular chemistry.     

Synthesis of Calix[4]resorcinarene Amide Derivatives

Three different synthetic routes were developed to introduce carbamoyloxy functional groups at the upper periphery of two calix[4]resorcinarenes. By treating activated esters 2a-b with excess corresponding amine such as 3-(dimethylamino)propylamine 3, ct-phenethylamine 4 and triethylenetetramine 5, six amide derivatives 6a-8b were obtained in high yield (Route 1). The pyridine-linked amide derivatives 9a-b were prepared by using acid chloride intermediate (Route 2).The amide derivatives 10a-b were obtained in moderate yields by direct alkylation of phenolic hydroxyl groups of la-b with N,N-dipropylchloroacetoamide in the presence of K2CO3/KI in acetone (Route 3).     

丙醛间苯二酚杯[4]芳烃烷基化衍生物的合成

以间苯二酚和丙醛为原料合成了丙醛杯[4]芳烃(1),1经不同的烷基化反应合成了新的丙醛杯[4]芳烃烷基化衍生物,其结构经1H NMR和IR表征。     

Octacis(2-hydroxyethylated) Calix[4]resorcinarenes Phosphorochloridates as Precursors in Production of Water-Soluble Calix[4]resorcinarene and Phosphoramidates

Russian Journal of General Chemistry - The reactions of organosilicon derivatives of octacis(2-hydroxyethylated) calix[4]resorcinarenes with phosphoryl trichloride and subsequent hydrolysis of the...     

间苯二酚杯芳烃树枝醇类化合物的合成

用间苯二酚杯芳烃的氧代乙酸乙酯类衍生物1a～1b分别与三羟甲基甲胺和二乙醇胺在乙醇/甲苯中进行酰胺化反应, 合成了四种新型的间苯二酚杯芳烃树枝醇化合物2a～2d, 树枝醇2a～2d外缘的羟基用乙酸酐酯化, 得到全乙酰基衍生物3a～3d. 化合物结构都用¹H NMR, IR和元素分析等方法进行了表征, 对树枝醇化合物的聚集状态进行了光学显微镜观察.     

无溶剂法合成杯[4]芳烯星形化合物

以对苯二甲醛、乙酸酐为原料合成对苯二甲醛单缩醛, 接着与间苯二酚反应, 制备了含醛基杯[4]芳烯. 利用季戊四醇与含醛基杯[4]芳烯反应, 进而再与3-[4-(2,5-二氧杂环戊基)苯基]-9-[4-二(甲羰氧基)甲基苯基]-2,4,8,10-四氧杂螺环[5.5]十一烷反应, 合成了杯[4]芳烯星形化合物, 收率为65.2%. 产品结构经 IR, ¹H NMR, MS 和元素分析进行了表征.     

新型正丁醛杯[4]芳烃醚衍生物的合成

以正丁醛间苯二酚杯[4]芳烃为原料,经酯化、水解、酰氯化后再与9-蒽甲醇反应,合成了蒽单取代的正丁醛间苯二酚型杯[4]芳烃醚衍生物。其结构经1H NMR和IR表征。     

Thermochemical Investigation of Some Selected Solvates of Calix[4]resorcinarene

Lipophilic calix[4]resorcinarene derived from lauryl aldehyde forms stable crystalline solvates with a range of organic solvents: acetone, 1,4-dioxane, methylethylvketone, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, butyronitrile, methanol, 1,2-dimethoxybenzene and acetonitrile. The composition and thermal stability of these solvates was followed by thermogravimetric method, indicating a stoichiometry ranging from 1 to 3 (calixresorcinarene/solvent). The activation energy was evaluated for the selected solvates. Molecular modelling, using Hyperchem 5.0 software, was applied to the selected solvates. This revised version was published online in August 2006 with corrections to the Cover Date.     

New Calix[4]arene—Fluoresceine Conjugate by Click Approach—Synthesis and Preparation of Photocatalytically Active Solid Lipid Nanoparticles

New fluorescent systems for photocatalysis, sensors, labeling, etc., are in great demand. Amphiphilic ones are of special interest since they can form functional colloidal systems that can be used in aqueous solutions. A new macrocycle platform for click chemistry and its adduct with o-propargylfluoresceine was synthesized and characterized using modern physical techniques. Nanosized solid lipid nanoparticles (SLNs) from the calixarene—fluoresceine adduct were synthesized through the solvent injection technique and well-characterized in the solution and in solid state using light-scattering and microscopy methods. The maximum fluorescence intensity of the SLNs was found to be in the pH range from 7 to 10. The Förster resonance energy transfer (FRET) efficiency from SLNs to rhodamine 6g was found to be 97.8%. Finally, pure SLNs and the FRET system SLNs—Rh6G were tested in model photocatalytic ipso oxidative hydroxylation of phenylboronic acid under blue LED light. The SLNs—Rh6G system was found to be the best, giving an almost qualitative phenol yield, which was shown by HPLC-UV analysis.     

Head-to-tail Aggregates of Sulfonatomethylated Calix[4]resorcinarene in Aqueous Solutions

Two amphiphilic water-soluble sulfonatomethylated calix[4]resorcinarene derivatives were studied by various ¹H NMR techniques (¹H NMR titration, 2D NOESY, NMR diffusion measurements). The derivative with methyl moieties at the lower rim (1) was found to be non-aggregated in the range 0–10 mM in aqueous solutions. Lengthening of the lower rim substituent to pentyl (2) results in self-aggregation of 2 in aqueous solutions with the aggregation number varying from 3 at 1 mM to 20 at 10 mM. The 2D NOESY ¹H NMR spectroscopy data reveal an unusual head-to-tail packing mode in aqueous solutions, resulting from the cooperative effect of weak hydrophobic interactions. Binding of guests (tetramethylammonium and N-methylpyridinium) results in additional stabilization of the aggregates whilst the head-to-tail packing mode of the aggregate is retained.     

新型间苯二酚杯芳烃硫脲衍生物对阴离子的识别

通过间苯二酚杯芳烃连续三步反应, 以较高产率合成了分子中连有8个和12个硫脲端基的间苯二酚杯芳烃的酰胺衍生物. 用紫外可见光谱法研究了两个代表性化合物4,6,10,12,16,18,22,24-八[6-(苯基硫脲基)-己氨甲酰基甲氧基]-2,8,14,20-四苯基杯[4]间苯二酚芳烃(THBC)和4,6,10,12,16,18,22,24-八[2-(苯基硫脲基)-1-甲基乙基-1-氨甲酰基甲氧基]-2,8,14,20-四苯基杯[4]间苯二酚芳烃(TPBC), 对各种阴离子(AcO^－, H₂PO₄^－, HSO₄^－, H₂PO₄^2－, C₁₂H₂₅-C₆H₄-SO₃^－, Cr₂O₇^2－, B₄O₇^2－, Cl^－, Br^－)的识别性能, 结果表明它们对AcO^－, H₂PO₄^－, HSO₄^－等阴离子有较好的配位作用, 能形成1∶3的配合物.     

Calix[4]resorcinarene Ionophore in the Ion-Selective Electrodes with Plasticized Poly(vinylchloride) Membranes

Synthetic ionophore calix[4]resorcinarene was incorporated into the poly(vinyl chloride) (PVC) plasticized membrane of an ion-selective electrode (ISE). Calixarene interactions with quaternary ammonium and alkaline metals cations in the organic and water-organic media were carefully investigated by various authors. We studied the effects of choline and Na⁺ cations present in the working solution on the ionophore which was incorporated into a membrane phase. Due to the pH sensitivity of the ionophore, a study was undertaken in a wide range of pH values. The different characteristics of calix[4]resorcinarene interactions with these cations were discovered by the ISE with the PVC plasticized membrane containing this ionophore, which respond to both the choline and Na⁺ cations due to the variation of working solution pH.     

Biosensors for the Rapid Repetitive Detection of Adrenaline Using Stabilized Bilayer Lipid Membranes (BLMs) with Incorporated Calix[4]resorcinarene Receptor

This work uses lipid film based biosensors with incorporated calix[4]resorcinarene receptor (lipophilic macrocyclic host molecule) for the rapid electrochemical detection of adrenaline. Freely‐suspended and metal supported BLMs (composed of egg phosphatidylcholine (PC) and 35% (w/w) dipalmitoyl phosphatidic acid) modified with the resorcin[4]arene receptor were used as one shot sensors to rapidly detect this catecholamine. The interactions of this compound with freely‐suspended BLMs were found to be electrochemically transduced in the form of a transient current signal with duration of seconds, which reproducibly appeared about 14 s after exposure of the membranes to adrenaline. The response time for these BLMs without incorporated receptor for adrenaline was about 1.5 min. The magnitude of the transient current signal was related to the concentration of adrenaline in bulk solution in the micromolar range. Differential scanning calorimetric (DSC) experiments were performed to explore the mechanism of interactions of BLMs with incorporated receptor with adrenaline. The interactions of adrenaline with surface‐stabilized bilayer lipid membranes (sBLMs) with incorporated receptor produced electrochemical ion current increases, which reproducibly appeared within a few seconds after exposure of the membranes to the stimulant. The use of the receptor in sBLMs increased the sensitivity of the method 6‐fold. The current signal increases were related to the concentration of adrenaline in bulk solution in the micromolar range. Stabilized lipid membranes formed by polymerization on glass fiber microfilters were used as practical chemical biosensors for the rapid detection of adrenaline. The interactions of polymerized lipid films with adrenaline were also found to provide transient current signals similar to those of freely‐suspended BLMs. The magnitude of the transient current signal was also related to the concentration of the stimulating agent in bulk solution in the micromolar range and these stabilized lipid films can be used again after storage in air. No interferences from ascorbic acid were noticed because of the negatively charged lipids in membranes. The effect of other compounds such as proteins and other compounds closely related to adrenaline was also investigated. Results of recovery experiments using human urine have shown recoveries ranged between 94 to 105%, which shows no interferences from matrix effects due to the presence of urine constituents. The present sensor based on stabilized lipid films can be used for the rapid repetitive detection of this pharmaceutical substance and keep prospects for the selective determination of catecholamines in biofluids.     

The Inclusion Properties of a New Watersoluble Sulfonated Calix[4]resorcinarene towards Alkylammonium and N-Methylpyridinium Cations

The inclusion behaviour of a new water-soluble sulfonated calix[4]resorcinarene towards alkylammonium and N-methylpyridinium cations has been investigated on the basis of ¹H NMR spectroscopy and pH-potentiometry data. The inclusion of the N-methylpyridinium cation has been found to be dependent on pH with the preferable inclusion of the methyl substituent in alkaline and the aromatic ring in neutral aqueous media.     

A New Tubular Arrangement of a Dimethylsilyl Bridged Calix[4]resorcinarene

Abstract

The functionalization of calix[4]resorcinarene 1 (R ₁=H, R ₂=Me) with dichlorodimethylsilane leads to the formation of the dimethylsilyl-bridged cavitand 2 which, during the work up of the reaction product, encapsulates a molecule of water 2·H₂O crystallizes in the C2/c system (a = 23.892 Å, b = 8.493 Å, c = 43.035 Å, β = 100.05°, reflections: 5385, 2376 (F>4.0 [sgrave](F)), R=9.17%, calculated density=1.213 Mg/m³) with eight molecules per unit cell. The main feature of the crystal packing is the alternating pairs of up-down disposed cavitands along the c direction and well developed columns in the b direction. The molecules of water are completely encapsulated, but there are some close contacts with the methylene bridge from the upper molecule. Molecular orbital calculations show that the lowest energy conformer of cavitand 2 is that with all four silicon atoms oriented inward and the energies of the other conformers are so high that they cannot be accessed at normal temperature. Ab initio calculated electrostatic potentials correlate well with the relative positions of the cavitands in the crystal structure.     

Structural Characterization of l-proline and Morpholine Appended Chiral Calix[4]resorcinarene Molecules

Calix[4]resorcinarenes serve as host molecules for small guest molecules. Recently calixarenes have been appended to chiral molecules in an attempt to promote chiral recognition. To take advantage of both cavity host and chiral substituent properties the position of the chiral moiety is important. We report the synthesis and structural characterization of two calix[4]resorcinarene based molecules that have helical chirality in the solid state. The calix[4]resorcinarene 1 has chiral l-proline ethyl ester substituents positioned perpendicular to the cavity whereas the calix[4]resorcinarene 2 has morpholines positioned parallel to the cavity which extend the depth of the cavity. Compound 1 is one of the first compounds to show the position of chiral centers with respect to the calixarene cavity. 1H and 13C NMR spectroscopy indicate that the helical chirality of 2 is retained at low temperature in nonpolar solvents.     

Effect of C-Tetramethyl Calix[4]resorcinarene Acrylate on Curing Behavior and Film Properties of Thiol-acrylate Coating System

An octa-functional acrylate of C-tetramethyl calix[4]resorcinarene(CMC-4-RA) was facilely synthesized and characterized with 1H NMR, 13C NMR and FTIR spectroscopy. The CMC-4-RA was added to a thiol-acrylate system with different mass ratios, and exposed to a middle pressure mercury lamp. The maximum photopolymerization rate and final vinyl group conversion in the cured film increased greatly along with CMC-4-RA addition that was monitored with Photo-DSC. The tensile strength and pendulum hardness were impro...     

The Influence of Triton X-100 on Protolytic Properties of Aminomethylated Calix[4]resorcinarene and Its Interaction with Copper(II)

The influence of Triton X-100 (concentration 5 mM) on acid-base properties of aminomethylated calix[4]resorcinarene (H₈L) containing alkyl (R¹ = C₁₁H₂₃) and dimethylaminomethyl (R² = CH₂N(CH₃)₂) substituents and interaction of H₈L with copper(II) is studied by potentiometry and mathematical simulation of equilibria in solutions. It is found that the presence of a nonionic surfactant favors the aggregation of H₈L (the degree of aggregation is higher than four), whereas, in 80% isopropanol at the same pH ≈ 10.2, a neutral species of the compound is only dimerized. The addition of Triton X-100 affects both the composition and stability of formed copper(II) complexes. The fraction of the highly charged tetranuclear [Cu₄(H₄L)]⁴⁺ complex sharply decreases. The formation of a large amount of [Cu(H₇L)]⁺ complex appears to be preferable compared to [Cu(H₈L)₂]²⁺ complex containing two ligands in the coordination sphere (pH ≈ 5.7). An enhancement of the acidic properties of protonated species of the compound and a decrease in the apparent constants of H₈L-copper(II) complex formation in Triton X-100 solutions compared to those in water-alcohol solutions are attributed to the formation of mixed micelles.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 4, 2005, pp. 527–533.Original Russian Text Copyright © 2005 by Sal’nikov, Boos, Ryzhkina, Lukashenko, Tiforova.