Selective complex formation of some chromogenic calix[4]arene derivatives detected by Fourier transform infrared spectroscopy 2. Solid experiments

Two chromogenic calix[4]arene derivatives having identical coordination sphere (consisting of ester groups) but different chromogenic units (pyridinium type and dinitro-phenyl type) were the subject of structural studies with sodium(I) and thallium(I) ions in solid state, both as bulk and surface complexes. Their diffuse reflectance infrared Fourier transform (DRIFTS) spectra were recorded and the characteristic changes of the vibrational spectra due to complex formation were analysed based on curve fitting.     

Membrane-active calixarenes: toward ‘gating’ transmembrane anion transport

This paper describes on-going efforts to develop calixarene amides as transmembrane anion transporters. We report on the transport of Cl⁻ anions across phospholipid membranes as mediated by some lipophilic calixarenes, all fixed in the cone conformation. We present significant findings regarding use of these calixarenes as transmembrane Cl⁻ transporters: (1) the cone conformer cone-H 2a, like its 1,3-alt and paco isomers, transports Cl⁻ across liposomal membranes; (2) the conformation of the calixarene (paco-H 1 vs cone-H 2a) is important for modulating Cl⁻ transport rates; (3) the substitution pattern on the calixarene's upper rim is crucial for Cl⁻ transport function; and (4) at least one of the four arms of the calixarene can be left unmodified without loss of function, enabling development of a pH-sensitive anion transporter (TAC-OH 3). This last finding is useful given the interest in gating the activity of synthetic ion transporters with external stimuli.     

Doubly bridged biscalix[4]arene for homotropic and heterotropic allosteric effects on ion recognition

A novel host, which shows homotropic and heterotropic allostery for Na⁺ and Ag⁺ recognition, is constructed by utilizing a biscalix[4]arene skeleton bearing bipyridine and ester moieties. The host binds two Na⁺ ions, but the second binding to Na⁺ is considerably suppressed by the first Na⁺ ion bound in the other binding site.     

Spectroscopic Study of Molecular Recognition of Ions by Chromogenic Calix[4]arene Derivatives

The complexation properties of three new chromogenic calix[4]arenes ( 1a–c) with aliphatic amines and alkali/alkali earth metal ions have been studied by UV/Vis spectroscopy. 1c shows the greatest complex forming ability and it is selective for Li⁺, Ca²⁺ and certain amines in polar solvents.     

A novel calix[4]arene fluorescent receptor for selective recognition of acetate anion

A novel bridged fluorescent calix[4]arene with 1,8-diaminoanthracene and glycine at the upper rim has been prepared, which exhibited selective recognition towards AcO⁻ over other anions such as F⁻, Cl⁻, Br⁻, , , I⁻ and by fluorescence spectroscopy and ¹H NMR method.     

单炔基桥联双杯[4]芳烃的合成与对溶剂分子的包合性能

对叔丁基杯[4]芳烃直接与1,4-二氯-2-丁炔反应,一步制备了单炔基单桥联双杯[4]芳烃和单炔基双桥联双杯[4]芳烃,并证实单桥联双杯[4]芳烃是双桥联双杯[4]芳烃的中间产物.经¹HNMR,¹³CNMR和ESI-MS分析证实了产物的结构.ESI-MS结果表明两种产物对DMF和H₂O有不同的包合能力.     

Cloud point extraction of lanthanide(III) ions via use of Triton X-100 without and with water-soluble calixarenes as added chelating agents

The use of water-soluble calixarenes: p-sulfonato thiacalixarene (ST), tetra-sulfonatomethylated calix[4]resorcinarene (SR), calix[4]resorcinarene phosphonic acid (PhR) as chelating agents in cloud point extraction (CPE) of La(III), Gd(III) and Yb(III) ions using Triton X-100 as non-ionic surfactant is introduced. The data obtained indicate that both complexation ability and structure of calixarenes govern the extraction efficiency of lanthanides. In particular ST and SR, forming 1:1 lanthanide complexes with similar stability in aqueous media, exhibit different extractability when used as chelating agents in CPE. First synthesized PhR was found to be the most efficient chelating agent exhibiting pH-dependent selectivity within La(III), Gd(III) and Yb(III) in CPE.     

Spectroscopic and spectrometric studies of anion recognition with calix[4]pyrroles in different reaction conditions

The binding studies of calix[4]pyrroles (1–6) with fluoro, chloro, bromo, iodo and sulphato anions generated from normal-tetrabutylammoniumfluoride, normal-tetrabutylammoniumchloride, normal-tetrabutylammoniumbromide, normal-tetrabutylammoniumiodide, and normal-tetrabutylammoniumsulphate respectively were investigated by electrospray ionization mass spectrometry (ESI-MS) in dichloromethane–acetonitrile in negative ion mode. The efficacy of a particular calix[4]pyrrole to bind with anions was found maximum at low cone voltage of the instrument, at high cone voltage the binding was suppressed due to removal of anion from the cavity of the macrocycles. The binding strength was found inversely proportional to the size of anion for a particular calix[4]pyrrole. The fragmentation pattern of calix[4]pyrrole was observed at higher cone voltage of ESI-MS and was interpreted. The association constants of calix[4]pyrroles and anions obtained from electronic transition studies were in good agreement with that observed from ¹H NMR titration studies.     

Potentiometric sensors based on poly(3,4-ethylenedioxythiophene) (PEDOT) doped with sulfonated calix[4]arene and calix[4]resorcarenes

Potentiometric ion sensors have been prepared by galvanostatic electrosynthesis of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with p-sulfonated calix[4]arene (C[4]S) and p-methylsulfonated calix[4]resorcarenes (R_n[4]S) with alkyl substituents of different chain length (R₁=CH₃; R₂=C₂H₅; R₃=C₆H₁₃). The bowl-shape of these doping ions makes them suitable as ionic recognition sites, and their bulky character is expected to prevent them from leaching out of the conducting polymer membrane. For comparison, sensors based on PEDOT doped with poly(styrene sulfonate) (PSS) and poly(vinyl sulfonate) (PVS) were also constructed. The resulting GC/PEDOT electrodes were conditioned in 0.01 mol L^–1 AgNO₃ and their performance as Ag⁺ ion-selective electrodes (ISEs) studied. Results reveal that selectivity and lifetime of the electrodes is affected by the doping anion structure, although all electrodes show selectivity towards Ag⁺ ions. Interaction of Ag⁺ with sulfur atoms present in the conducting polymer backbone is considered to be the main reason for this behavior. A second set of electrodes was constructed and conditioned in 0.1 mol L^–1 KCl. These electrodes were tested in chloride solutions of quaternary ammonium cations, showing that C[4]S and R₂[4]S exhibit significant sensitivity towards pyridinium.Dedicated to Professor György Horányi on the occasion of his 70th birthday in recognition of his outstanding contributions to electrochemistry     

Calixarenes: Structure of an acetonitrile inclusion complex and some transition metal rimmed derivatives

The hostt-butylcalix[4]arene,1a, forms a 11 inclusion compound with acetonitrile as guest. The inclusion compound has been isolated and characterised by X-ray analysis of a twinned crystal at 123 K. The acetonitrile guest lies on a crystallographic four-fold symmetry axis passing through the centre of the bowl of1a which adopts a regular cone conformation. A known tetradentate and a new tridentate phosphinitocalix[4]arene derivative,2a and2c respectively, have been synthesized from1a and Ph₂Cl. Both2a and2c show a strong ability to coordinate with late transition metals and new complexes of gold(I), palladium(II) and platinum(II) are reported. Supplementary Data relating to this paper have been deposited with the British Library as Supplementary Publication No. SUP 92171 (5 pp.)This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes.     

Selective recognition of the ditopic trimethylammonium cations by water-soluble aminocalix[4]arene

In this Letter, the role of the depth of the cavity in the recognition processes of the guests by the hosts has been investigated. The hosts 2, 3 interact with both the cationic function and the aromatic moiety in the guests 5, 6 but with a slight preference for the cationic functions. The host 4 selectively recognizes the trimethylammonium functions of the guests 5 and 6. However, the host 1 selectively recognizes the aromatic moiety of the ditopic trimethylammonium guests 5 and 6. The recognition and orientation of the guest in the cavity of the host are directly dependent on the depth of the hydrophobic cavity of the host.     

Calix[4]quinones. Part 4: The ClO2 oxidation of calix[4]arene dialkyl ethers

Except for the special case of calix[4]arene diethyl ether 1, the chlorine dioxide oxidation of dialkyl ethers 2-5 yielded only the corresponding calix[4]diquinone dialkyl ethers 8-11. Chlorine dioxide oxidation of calix[4]arene diethyl ether 1 produced two isomeric products 6 and 7, which were stable enough to be isolated by column chromatography. However, a slow conformational interconversion between isomeric pair 6 and 7 was observed at room temperature, and the equilibrium was reached after 400 h at 18 °C with an amount of 5:3 in favor of syn-isomer.     

邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性？…

杯芳烃是继冠醚、环糊精之后的第三代主体分子 [1] .据文献 [2 ,3]报道 ,在杯 [4]芳烃下沿酚氧原子上连接乙酸酯得到的四取代衍生物对 Na+ 有很高的选择性 ,核磁与晶体结构研究均证实这是由于羧酸酯的羰基和酚氧基参与了对 Na+ 的配位 ,而且配位基团所形成的包络空间大小与钠离子相匹配 .一般认为 ,随着包络空间改变 ,对金属离子的识别作用会有所变化[4] .但目前对这方面的工作并没有给予更多的重视 .我们发现 ,用 2 -溴甲基苯甲酸甲酯与杯 [4 ]芳烃反应 ,得到了一种新的四取代杯 [4]芳烃衍生物 2 ,萃取研究结果表明 ,该化合物对钾离子有较…     

Comparative study of calix[4]arene derivatives: implications for ligand design

The first comparative theoretical study of three parent calix[4]arene analogues (calix[4]arene, thiacalix[4]arene, and homooxacalix[4]arene) has been performed using molecular dynamic simulations and density functional theory (MPWB1K/6-311G^∗∗//B3LYP/6-311G^∗∗) methods. The theoretical observations herein including optimized geometry, polarity, and atomic charge data provide that homooxacalix[4]arene would offer more efficient platform for metal ion recognition compared to thiacalix[4]arene or calix[4]arene.     

Synthesis of Flavin–Calix[4]arene Conjugate Derivatives

The synthesis of two new flavin substituted calix[4]arene derivatives, 9 and 10 , is described. The first flavin substituted calix[4]arene derivative 9 was synthesized by the reaction of 3‐methylalloxazine ( 5 ) with 25,27‐bis(3‐bromopropoxy)‐26,28‐dihydroxy‐5,11,17,23‐tetra(tert‐butyl)calix[4]arene ( 4 ) in high yield (92%). The other derivative 10 was prepared from 3‐methylalloxazine‐1‐acetic acid ( 7 ) and 25,27‐bis(3‐cyanopropoxy)calix[4]arene ( 3 ). All new compounds were characterized by a combination of FT‐IR and ¹H‐NMR spectroscopy, and elemental‐analysis techniques.     

邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性能研究

杯芳烃是继冠醚、环糊精之后的第三代主体分子[1].据文献[2,3]报道,在杯[4]芳烃下沿酚氧原子上连接乙酸酯得到的四取代衍生物对Na+有很高的选择性,核磁与晶体结构研究均证实这是由于羧酸酯的羰基和酚氧基参与了对Na+的配位,而且配位基团所形成的包络空间大小与钠离子相匹配.一般认为,随着包络空间改变,对金属离子的识别作用会有所变化[4].但目前对这方面的工作并没有给予更多的重视.我们发现,用2-溴甲基苯甲酸甲酯与杯[4]芳烃反应,得到了一种新的四取代杯[4]芳烃衍生物[2]萃取研究结果表明,该化合物对钾离子有较好的选择性.此外,在合成该衍生物的过程中,还得到了另一新的二取代衍生物(3).     

Calix[4]arene Polyaza Derivatives: Novel Effective Neutral Receptors for Cations and (a)-Amino Acids

Introduction Calixarenes are one of the most important supramolecular building blocks, which can be modified by introducing different functional and/or structrual groups to create a specific interaction between the host and the target molecules, such as metal cations and small organic molecules[1,2]. In particular, the recognition of amino acids is an interesting theme in biomimetic chemistry[3].     

Calix [ 4 ] arene Polyaza Derivatives： Novel Effective Neutral Receptors for Cations and α-Amino Acids

IntroductionCalixarenes are one of the most important supra-molecular building blocks, which can be modified byintroducing different functional and/or structural groupsto create a specific interaction between the host and thetarget molecules, such as meta…     

Synthesis and Crystal Structure of Complex of Sodium Perrhenate with Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate

Recently,theconformationofthecalixarenehasbeenshowntobeimportantincontrollingtheseIectivityofthereceptor.Forexample,sodiumioncouldbeboundverystronglybyesterderivativesofcalix[4]areneintheconeconformationl.Wehavefoundthatinthepresenceofcertainamountofsodiumion,microamountofReO4-canbequantitativelyextractedintol,2-dichloroethanebytheligandtetraethylp-tert-butylcalix[4]arenetetraacetate(L).ItshowsthatthepresenceofNa inaqueoussolutioncanpromotetheformationofhydrophobiccomplex[NaL] .ReO'-whichc…     

Alternative methods of modifying the calixarene conformation. The synthesis and molecular structures oft-butylcalix[4]arene methyl ether complexed with aluminum alkyl species

The configurations of calix[4]arenes may be modified by the formation of donor-acceptor complexes which make use of the basicity of the oxygen atoms of the macrocycle. The complex [t-butylcalix[4]arene methyl ether][AlMe₃]₂,2, exhibits the previously unseen 1,2-alternate geometry, while [t-butylcalix[4]arene methyl ether][MeAlCl₂]₂,3, and [t-butylcalix[4]arene methyl ether][EtAlCl₂]₂,4, show the 1,3-alternate configuration.2 crystallizes in the triclinic space groupPl witha=11.14(1),b=11.60(1),c=12.02(1) Å, =77.32(8), =67.91(8), and =69.34(8)^o withD _c =1.06 g cm^–3 forZ=1. Refinement based on 1270 observed reflections led toR=0.106.3 as the benzene solvate belongs to the monoclinic space groupC2/c witha=12.116(2),b=21.557(7),c=23.470(6) Å, and =104.05(2)^o withD _c =1.13 g cm^–3 forZ=4. Refinement based on 2335 observed reflections led toR=0.075.4 crystallizes in the monoclinic space groupC2/c witha=12.062(4),b=21.175(6),c=21.596(5) Å, and =100.78(4)^o withD _c =1.18 g cm^–3 forZ=4. Refinement based on 2529 observed reflections gaveR=0.082. The Al-O lengths in all three complexes are normal for donor-acceptor interactions. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82053 (45 pages).