Synthesis and fluorescence sensing properties of novel pyrene-armed calix[4]arene derivatives

Fluorogenic tert-butylcalix[4]arenes bearing two pyrene pendant groups at the lower rim were synthesized. Based on ratiometric changes of monomer and excimer emissions, the pyrene amine derivative of calix[4]arene has been found to act as a selective sensor for Pb²⁺ and Cu²⁺ ions, respectively, due to a conformational change upon chelation of these ions.     

一种新型杯[4]芳烃的合成

本文通过对特丁基杯[4]芳烃的酚羟基烷基化和苯环特丁基位上的IPSO-硝化制备了一系列对硝基杯[4]芳烃烷基醚,烷基分别是n-C~4H~9(3a)、n-C~8H~1~7(3b)、n-C~1~2H~2~5(3c)和n-C~1~6H~3~3(3d)。^1HNMR表明所有新的杯[4]芳烃都具有锥形(cone)构象。     

Synthesis and binding properties of calix[4]arene telomers

Two calix[4]arene derivatives (5 and 8) and their telomers are synthesized to estimate selective extraction of alkali and transition metal cations from the aqueous to the organic phase (chloroform). Compound 5 shows selectivity toward Hg²⁺. Compound 8 and telomers 6 and 9 are not selective but are good extractants for all used transition metal ions. The observations suggest that ethylene glycol bridges are efficient for carrying transition metal cations in a two-phase solvent system. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4351–4355, 1999     

Synthesis and fluorescence sensing properties of a new naphthalimide derivative of calix[4]arene

A new naphthalimide derivative of calix[4]arene was synthesized as a highly selective fluorescent compound for Cu²⁺ among the selected metal ions. This compound was examined for its fluorescent properties toward different metal ions (Na⁺, Li⁺, Mg²⁺, Ni²⁺, Ba²⁺, Ca²⁺, Cu²⁺, Pb²⁺, Zn²⁺) and anions (F^?, Cl^?, Br^?, ${\text{H}}_2{\text{PO}}_4^{-}$, ${\text{NO}}_3^{-}$, I^?, ${\text{HSO}}_4^{-}$, CH₃COO^?) by UV, NMR and fluorescence spectroscopy.     

Synthesis of upper rim calix[4]arene carcerands

The synthesis of novel tetra-olefinic calix[4]arene carcerands is described using a synthetic strategy involving palladium catalysed Heck coupling followed by imine formation.     

四乙氧羰基甲氧基杯[4]芳烃的合成与性质

配位作用;液膜传递;四乙氧羰基甲氧基杯[4]芳烃的合成与性质     

Synthesis and crystal structure of p-acylated calix[4]arene ethers

C-acylation of calix[n]arenes is an important reaction which has been primarily utilized for their further functionalization to provide conformers with varying shapes, cavity dimensions and molecular receptor characteristics that can bind ionic and neutral species in a selective and specific manner. The length of the alkyl chain at the upper or the lower rim of calixarenes can be adjusted as required to give derivatives which can span the channels and membranes and majorly influence transport phenomenon. As a part of our program to obtain calixarene based derivatives that can span and scan artificial membranes, C-acylation of calix[4]arene has been examined to yield peracylated and partially acylated calixarene ethers. 5,11,17,23-Tetraacetyl-25,26,27,28-tetramethoxycalix[4]arene has been obtained in 80 % yield by treatment of tetramethoxycalix[4]arene with acetyl chloride in the presence of aluminum chloride using dichloromethane as the solvent. The structure was established by the conversion to corresponding phenyl hydrazones and oximes. The tetraacetyltetramethoxycalix[4]arene 2a crystallized in a monoclinic lattice, space group P2₁/C with a = 10.320(2) Å, b = 18.928(4) Å, c = 18.421(4) Å, β = 95.44(3)^o, Z = 4. The corresponding methyl substituted O7 directs inwards towards the cavities of calix[4]arene to give an inward flattened partial cone conformation. Molecular packing shows the presence of intermolecular C–H···O, H-bonding interactions between methyl and methylene hydrogens and oxygens of the acetyl groups.     

Asymmetric calix[4]-thiacalix[4]arene tubes: Synthesis and ionophore properties

Asymmetric p-tert-butylcalix[4]-p-R-thiacalix[4]arene tubes (R = tert-Bu, H, 1-adamantyl) were prepared for the first time by reaction of tosyloxyethoxy derivative of p-tert-butylcalix-[4]arene and the corresponding p-R-thiacalix[4]arenas in acetonitrile in the presence of K₂CO₃. Complex formation of compounds obtained with sodium, potassium, and rubidium iodides in CDCl₃-CD₃OD, 4:1, was studied by means of ¹H NMR. The ionophore properties of the molecule were governed by the character of substituents on the upper rim of the thiacalixarene fragment, and only the molecular tube containing a fragment of the p-(1-adamantyl)-thiacalix[4]arene quantitatively bound potassium ions (quickly) and rubidium ions (slowly).     

Lower rim substituted p-tert-butyl calix[4]arene; Part 14. Synthesis, structures and binding studies of calix[4]arene thioamides

A number of p-tert-butylcalix[4]arene thioamides were synthesized and characterized by ¹H-NMR and elemental analysis. Compounds 1–5 are O-substituted derivatives with –CH₂–C(=S)–N–X groups, where NX = morpholidyl, NEt₂, NHC₂H₄Ph, NHCH₂Ph and NHEt, respectively. The X-ray structures of the ligands 1, 3, 5 and of the complex 3·Pb(ClO₄)₂, (compound 6), are presented and their slightly distorted cone conformation is established. The influence of the nature of the thioamide functions (secondary or tertiary) on the extractability of some selected metal cations was investigated. Whereas all these calixarenes show the highest extraction level for Ag⁺, tertiary thioamides are more efficient extractants for Pb²⁺ than secondary thioamides.     

Supramolecular interaction between water-soluble calix[4]arene and ATP--the catalysis of calix[4]arene for hydrolysis of ATP

The catalysis effect of water-soluble calix[4]arene C[4] (calix[4]arene-5,11,17,23-tetrasulfonate) on hydrolysis of ATP in aqueous solution was studied by HPLC. Using laser photolysis and pulse radiolysis, the supramolecular interaction between water-soluble calix[4]arene and ATP was investigated.     

Unsymmetrical calix[4]arene bisporphyrin Pacman

[structure: see text] The synthesis of a Pacman heterobisporphyrin associating an octaethyl porphyrinatozinc (ZnOEP) energy donor and a triaryl porphyrinatozinc (ZntPP) energy acceptor around a calix[4]arene spacer is described. Contrary to previous symmetrical architectures, correlations between the chromophores in the unsymmetrical calixarene bisporphyrin Pacman scaffold can now be observed in ROESY experiments. Independent of the excitation wavelength, only the luminescence of the ZntPP moiety was observed corresponding to quenching of the OEP moiety's emission.     

Aminolysis reaction of calix [ 4 ] arene esters and crystal structures and conformational behaviors of calix[4]arene amides

We first make use of aminolysis of calix[4]arene esters to synthesize calix[4]arene amides. When the two ethyl esters of the calix[4]arene esters are aminolysized, the 1, 3-amide derivative is formed selectively. The crystal structures of the calix-[4]arene with two butyl amide (3b) and four butyl amide moieties (4b) were determined. The intermolecular hydrogen bonds make 4b form two-dimensional net work insolid state. The 1H NMR spectra prove that 3b is of a pinched cone conformation, while 4b and tetraheptylamide-calix[4]arene (6b) take fast interconversion between two C2v isomers in solution and appear an apparent cone conformation at room temperature. As decreasing temperature, the interconversion rate decreases gradually and, finally, the interconversion process is frozen at Tc = -10℃, which makes both conformations of 4b and 6b the pinched cone structures. The hydrogen bond improves the interconversion barrier, and the large different values of the potential barrier between 6b and 4b (or 6b) may     

Synthesis of oligophenylene-substituted calix[4]crown-4s and their silver(I) ion-induced nanocones formation

A novel series of oligophenylene OPP(n)-substituted calix[4]crown-4s bearing up to three phenylene units, 1a-d, has been efficiently synthesized by means of either microwave-assisted or silver(I) ion-assisted Pd-catalyzed Suzuki cross-coupling of tetraiodocalix[4]crown-4 and the corresponding oligophenylboronic acids. Complexation of OPP(n)-substituted calix[4]crown-4s with silver (I) ion was substantiated by 1H NMR spectroscopic and high-resolution ESI- or MALDI-TOF- MS studies. The weak binding affinities of OPP(n)-substituted calix[4]crown-4s for silver (I) ion, which were estimated from 1H NMR titrations with binding association in the range of 30-90 M(-1), allows reversible disassembling in the presence of KI at ambient temperature. Remarkably, the single-crystal X-ray structures of OPP(n)-calix[4]crown-4.Ag+ complexes indicate the atypical silver (I) ion-crown ether binding mode resulting in the formation of rigid nanocones with volume created up to approximately 1500 A(3). Our results suggested that despite the weak binding affinity of crown ether ligands for silver (I) ion, this weak interaction is still be useful as a tool to construct supramolecular architectures.     

Synthesis and extraction studies of polymeric phthalimido functionalized calix[4]arene

The article comprises synthesis and extraction studies of polymeric calix[4]arene having phthalimide groups at the lower rim. The polymeric phthalimido functionalized calix[4]arene was synthesized via radical initiated reactions involving a vinylic monomer 5,11,17,23-tetra-tert-butyl-25-[4-(acrylamido)benzyloxy]-26,28-bis-(2-phthalimido-ethoxy)-27-hydroxycalix[4]arene (5) with styrene. A five atom spacer group was incorporated between the bulky calixarene core and the acrylate moiety in order to minimize steric interactions which proved to impede the polymerization. From the liquid–liquid and solid–liquid extraction studies it has been concluded that the precursor 3 (5,11,17,23-tetra-tert-butyl-25-(4-nitro benzyloxy)-26,28-bis-(3-phthalimidoethoxy)-27-hydroxy-calix[4]arene) is selective for metal cations. The order of extractability of metal cations by the ligand 3 decreases in the sequence: Hg²⁺ > Cd²⁺ > Cu²⁺ > K⁺ > Co²⁺ whereas its polymeric derivative is selective in the sequence: Hg²⁺ > Cd²⁺ > K⁺ > Co²⁺ > Cu²⁺ for the metal cations used in the experiments.     

Facile synthesis of oligophenylene-substituted calix[4]arenes and their enhanced binding properties

[reaction: see text] A facile and efficient protocol for the synthesis of oligophenylene OPP(n)-substituted calix[4]arenes (with n up to 4) via iodo-substituted oligoarylcalix[4]arenes has been developed. The cooperation effect of the proximate fluoroionophores in hexylsulfanyl end-capped OPP(n)-substituted calix[4]arene assemblies leads to metal ion binding enhancement.     

Study on thermal decomposition of calix[6]arene and calix[8]arene

Thermal decomposition kinetics of calix[6]arene (C6) and calix[8]arene (C8) were studied by Thermogravimetry analysis (TG) and Differential thermal analysis (DTA). TG was done under static air atmosphere with dynamic heating rates of 1.0, 2.5, 5.0, and 10.0 K min⁻¹. Model-free methods such as Friedman and Ozawa–Flynn–Wall were used to evaluate the kinetic parameters such as activation energy (E _a) and pre-exponential factors (ln A). Model-fitting method such as linear regression was used for the evaluation of optimum kinetic triplets. The kinetic parameters obtained are comparable with both the model-free and model-fitting methods. Within the tested models, the thermal decomposition of C6 and C8 are best described by a three dimensional Jander’s type diffusion. The antioxidant efficiency of C6 and C8 was tested for the decomposition of polypropylene (PP).     

Synthesis and Conformational Properties of Bis（calix [4] arene）

The bis(calix [4] arene)3 was synthesized in moderate yield by the reaction of p-tert-butylcalix [4] arene (1) with 1,4-bis(chloromethyl) benzene (2). The conformation of all alkylated product 4 was investigated by the variable-temperature ^1H-NMR.     

Organic clays. Synthesis and structure of Na5[calix[4] arene sulfonate] · 12 H2O,K5[calix[4]arene sulfonate]·8 H2O,Rb5[calix[4]arene sulfonate]·5 H2O,and Cs5[calix[4] arene sulfonate] ·4 H2O

The title calixarenes all exist in the solid state as bilayers of anionic calixarenes in the cone configuration. These layers alternate with inorganic regions which contain the cations and the water molecules. The overall structures bear a close resemblance to those found for clay minerals. The sodium salt crystallizes in the triclinic space groupP witha = 10.998(6),b = 13.582(5),c = 14.472(5) Å, = 74.01(3), = 89.09(4), = 86.50(4)°, andZ = 2 forD _calc = 1.72 g cm^–3. Refinement based on 4727 observed reflections led to a conventionalR = 0.050. The potassium salt crystallizes in the triclinic space groupP witha = 11.815(9),b = 13.636(6),c = 14.040(9) Å, = 100.24(5), = 111.86(9), = 95,14(9)°, andZ = 2 forD _calc = 1.77 g cm^–3. Refinement based on 2977 observed reflections led toR = 0.15. The rubidium and cesium salts are isostructural and crystallize in the monoclinic space groupP2₁/n with parameters for Rb[Cs]a = 11.603(5) [11.704(3)],b = 28.607(8) [29.747(9)],c = 12.512(5) [12.604(4)] Å, = 91.70(4) [91.63(2)°], andZ = 4 forD _calc = 2.01 [2.24] g cm^–3. Refinement based on 1750 [4257] observed reflections led toR = 0.108 [0.075]. Disorder of the cations was observed for the rubidium and cesium salts. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82074 (95 pages).     

Nanoencapsulation of calix[4]arene inclusion complexes

A hexameric resorcinarene nanocapsule in wet CDCl3 forms inclusion complexes of calix[4]arene with tetramethylammonium and trimethylsulfoxonium cations to give highly stable Russian-doll-type multicomponent assemblies. The 2D NOESY experiments revealed the size of the assembly, the close proximity of the encapsulated calix[4]arene molecule to the resorcinarene molecules of the capsule, and the inclusion of the tetramethylammonium cation in the calix[4]arene cavity.