- Luminescent behavior of pyrene-allied calix[4]arene for the highly pH-selective recognition and determination of Zn2+, Hg2+ and I-: Via the CHEF-PET mechanism: Computational experiment and paper-based device
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In this article, for the first time, we have reported a novel CHEF-PET fluorescence sensor L based on calix[4]arene containing four pyrene groups as binding sites, which is highly selective and sensitive towards Zn2+, Hg2+ and I-. This fluorescence probe was synthesized and characterized using the emission study, UV-vis titration, 1H NMR spectroscopy and ESI-MS investigation. The linear concentration range at pH 7 of L for Zn2+, Hg2+ and I- is 0-135 nM, 0-140 nM and 0-120 nM, respectively, with the detection limit of 6.43 nM for Zn2+, 2.94 nM for Hg2+ and 20.93 nM for I-. The binding ability was determined through Benesi-Hildebrand equation, which was found to be 7.535 × 108 M-1 for Zn2+, 9.001 × 108 M-1 for Hg2+ and 8.139 × 108 M-1 for I-. Further, we reported an easy-to-use, low-cost and disposable paper-based sensing device for the rapid chemical screening of Zn2+, Hg2+ and I-. The device comprises luminescent sensing probes embedded into a cellulose matrix, where the resonance energy transfer phenomenon seems to be the sensing mechanism. It opens up new opportunities for simple and fast screening in remote settings, where sophisticated instrumentation is not always available. The MOPAC-2016 software package was used to optimize the L using the well-established PM7 method and calculate the HOMO-LUMO energy band gap for structure L and L with Zn2+, Hg2+ and I- ion-based structures. The molecular docking study was carried out using HEX software.
- Sutariya, Pinkesh G.,Soni, Heni,Gandhi, Sahaj A.,Pandya, Alok
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supporting information
p. 9855 - 9864
(2019/07/04)
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- FRET-based Solid-state Luminescent Glyphosate Sensor Using Calixarene-grafted Ruthenium(II)bipyridine Doped Silica Nanoparticles
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Calixarene-functionalized luminescent nanoparticles were successfully fabricated for the FRET-based selective and sensitive detection of the organophosphorus pesticide glyphosate (GP). p-Tert-butylcalix[4]arene was grafted on the surface of [Ru(bpy)3]2+ incorporated SiNps to produce self-assembled nanosensors (RSC). FRET was switched on in the presence of GP by means of energy transfer due to binding with p-tert-butylcalix[4]arene grafted on the surface of the RSC. The FRET efficiency of the GP-RSC system was increased gradually with the addition of GP. The FRET efficiency was evaluated as 87.69 % and a high binding affinity was established by the binding constant value, 1.16×107 M?1, using a Langmuir binding isotherm plot. The estimated limit of detection (LOD) was 7.91×10?7 M, which was lower than the Environmental Protection Agency (EPA) recommendation. The probe also effectively responds to real sample analysis. The sensitivity and selectivity was realized due to the efficient FRET towards the fluorescence properties of the [Ru(bpy)3]2+ complex.
- Ashwin, Bosco Christin Maria Arputham,Saravanan, Chokalingam,Stalin, Thambusamy,Muthu Mareeswaran, Paulpandian,Rajagopal, Seenivasan
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p. 2768 - 2775
(2018/10/26)
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- Preparation and investigation of temperature-responsive calix[4]arene-based molecular gels
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A novel calix[4]arene-based tetracholesteryl derivative was synthesized, and its gelation behaviours in 30 organic solvents were studied. It showed that 1 gelled long chain alkane, some of alcohol, kerosene, ethyl acetate benzene and toluene. Interestingly the gel of 1/kerosene possessed special property, which was that the mixture solution of the compound 1/kerosene heating for a while was put on the flat contact heater and formed a gel film at 25 °C and 65 °C. Unlike ordinary film, gel film had higher strength and toughness at 65 °C, by contrast other was fragile and broken easily at 25 °C, this phenomenon was few reported before. In order to explore the phenomenon, the mechanism of the gel of 1/kerosene was discussed by Scanning Electron Microscope (SEM), High Nuclear Magnetic Resonance (H NMR), Fourier Transform Infrared Spectrometer (IR) and micro-rheology. SEM revealed that the xerogel of 1/kerosene assembled network through some long and thick fibers at 65 °C, with concentration reducing fibers become thin and its networks were clearly observed. In contrast the morphology of xerogel was porous at low concentration and was a bulk at high temperature system. According to EI data in micro-rheology, the gelation process could be divided into three stages at 65 °C and they could be that some cholesterol segments in the gelator interacting with each other formed some small aggregation in the first stage, and other cholesterol section of the gelator sufficiently were cross-linked with time and assembled into large assembly in the second plateau. In the final moment the large assembly build gel network and the system of gel tended to stable. But there are two stages at low temperature and could be some cholesterol segments that didn't take part in assembly, which may be the cause that the performance of gel was fragile.
- Cai, Xiuqin,Xu, Yunhua,Yang, Rong,Yang, Hui
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p. 28476 - 28482
(2017/07/07)
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- Calix[4]arene-based low molecular mass gelators to form gels in organoalkoxysilanes
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Three calix[4]arene derivatives (CMA, CDA and CTA) appended with one, two or four carboxyl acid structures were prepared. Gelation behaviours of the compounds and calix[4]arene itself in ten common organoalkoxysilanes were studied. It was found that at a concentration of 2% (w/v), only the compound with the most carboxyl groups (CTA) functions as a gelator, and only this compound gels with three of the liquids tested; however, the as created gels possess smart thixotropic and thermo-reversible phase transition properties. In particular, the CTA/trimethoxyphenylsilane (PTMS) gel exhibits superior mechanical strength with a storage modulus (G′) greater than 1.9 × 106 Pa and a yield stress exceeding 3600 Pa at a concentration of 6.0% (w/v). Further testing demonstrated that the gel could be used as a substrate for sensing film fabrication, injection molding and melting-free deposition molding. Moreover, the objects from the molding and fabrication could be turned into permanent structures through further hydrolysis and condensation reactions. It is believed that the LMMGs based organoalkoxysilane gels have the potential to be used as smart materials for 3D printing and pre-cursors to a functionality-oriented solid matrix.
- Yang, Hui,Zhang, Shaofei,Liu, Kaiqiang,Fang, Yu
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p. 109969 - 109977
(2016/11/30)
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- Design, synthesis and characterization of quinoline-pyrimidine linked calix[4]arene scaffolds as anti-malarial agents
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In this paper, we report a series of quinolinepyrimidine linked calix[4]arene derivatives functionalized with 8-amino quinoline, 5-amino quinoline, 8-hydroxy quinoline, 2-amino pyrimidine and 4-amino 3-methyl quinoline. The synthesized compounds were purified and characterized by elemental analysis, FT-IR,1H NMR and ESI-MS and screened for their anti-malarial activity against plasmodium falciparum strains. Two synthesized compounds with 8-hydroxy quinoline and 2-amino pyrimidine substituents showed good antimalarial activity with IC50 0.073 and 0.043 μg/ml respectively which is comparable with the standard drug chloroquine. The present study provides valuable information for developing calix[4]arene conjugates quinoline-pyrimidine based derivatives as an effective antimalarial agents. Graphical Abstract In this paper, we report a series of quinoline-pyrimidine linked calix [4]arenes derivatives functionalised with 8-amino quinoline, 5-amino quinoline, 8-hydroxy quinoline, 2-amino pyrimidine and 4-amino 3-methyl quinoline and screened for antimalarial activity. Two synthesized compounds with 8-hydroxy quinoline and 2-amino pyrimidine substituents showed good antimalarial activity with IC50 0.073 and 0.043 μg/mL respectively, which is comparable with the standard drug chloroquine. The present study provides valuable information for developing calix[4]arene conjugates quinoline-pyrimidine derivatives.
- Shah, Rahul B.,Valand, Nikunj N.,Sutariya, Pinkesh G.,Menon, Shobhana K.
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p. 173 - 178
(2016/07/29)
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- Synthesis, structure and coordination properties of novel bifunctional carboxylic derivatives of 1,3-alternate tetrathiacalix[4]arene
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New bifunctional derivatives of 1,3-alternate tetrathiacalix[4]arene decorated with carboxylic, ester, hydrazide and/or hydrazone groups have been synthesized with good yields using the tetrathiacalix[4]arene derivatives with incorporated pairs of carboxylic and ester groups as versatile building blocks. The structural peculiarities of the obtained bifunctional compounds have been investigated by means of X-ray analysis, IR and NMR spectroscopy. The recognition ability of the synthesized macrocycles towards some alkali, alkali-earth and transition metal ions has been investigated applying a solvent extraction method. The results showed that the structure of a calix[4]arene platform as well as the nature of functional substitutes located on opposite sides of the macrocycle are critical for the coordination properties of the synthesized compounds.
- Podyachev, Sergey N.,Gimazetdinova, Gulnaz Sh.,Gubaidullin, Aidar T.,Syakaev, Victor V.,Sudakova, Svetlana N.,Gabidullin, Bulat M.,Ivanov, Vladimir T.,Gogolashvili, Edward L.,Konovalov, Alexander I.
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p. 19531 - 19544
(2016/02/27)
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- Synthesis, X-ray crystal structure and anti-tumor activity of calix[n]arene polyhydroxyamine derivatives
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Calixarene-based compounds are highly effective therapeutic agents against cancer. This study aims to prepare a series of calix [n]arene (n?=?4, 6, 8) polyhydroxyamine derivatives (3a–3m) and to study their potential antitumor activities. The single crystal structure of calixs[4]arene derivative 3a was determined through X-ray diffraction. We assessed the ability of the prepared calix [n]arene polyhydroxyamine derivatives to induce cytotoxicity in six cancer cell lines by performing cancer cell growth inhibition assays. Results demonstrated that compounds 3a–3d achieved IC50values ranging from 1.6?μM to 11.3?μM. Among the different compounds, 3a and 3b exerted the strongest cytotoxic effect in inhibiting the growth of SKOV3 cells. In relation to the underlying mechanisms of cytotoxic effects, cell cycle analysis revealed that the exposure of SKOV3 cells to 3a induced cell cycle arrest in the G0/G1 phase, suggesting a reduction in DNA synthesis. Immunofluorescent staining indicated that the protein expression levels of caspase-3 and p53 in cells significantly increased, whereas that of Bcl-2 was effectively suppressed. Meanwhile, no significant changes in Bax were observed in SKOV3 cells. These results highlight that calixarene 3a can be further studied as a potential anticancer agent.
- An, Lin,Han, Li-Li,Zheng, You-Guang,Peng, Xian-Na,Xue, Yun-Sheng,Gu, Xiao-Ke,Sun, Jing,Yan, Chao-Guo
-
-
- MATERIALS COATED WITH CALIXARENES
-
This invention relates to the direct grafting of a calixarene mostly onto the surface of a material, as well as to a grafting process, and certain calixarene intermediates useful for carrying the grafting process.
- -
-
Paragraph 0157; 0158
(2015/03/16)
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- Lower rim substituted p-tert-butyl-calix[4]arene. Part 17. Synthesis, extractive and ionophoric properties of p-tert-butylcalix[4]arene appended with hydroxamic acid moieties
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The synthesis and characterization of four p-tert-butylcalix[4]arene- hydroxamic acids are reported. The dependence of the metal ion binding, assessed by liquid-liquid extraction of the metal nitrates from water into dichloromethane in individual and competitive experiments, on the ligand structure, is presented. The results showed that those ligands could be successfully used in separation process of transition and heavy metals often present together. Two of the ligands were used as active materials in Pb-ion-selective membrane electrodes. The characteristics of these electrodes, in particular their selectivity coefficients for Pb2+ over other metal ions, are discussed.
- Kulesza,Guzinski,Bochenska,Hubscher-Bruder,Arnaud-Neu
-
-
- Low-generation dendrimers with a calixarene core and based on a chiral C2-symmetric pyrrolidine as iminosugar mimics
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The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C 2-symmetric 3, 4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supra-molecular properties of calixarenes with the advantage of a dendrimeric presentation of repetitive units opens up the possibility of generating well-defined multivalent and multifaceted systems with more complex and/or biologically relevant iminosugars.
- Marradi, Marco,Cicchi, Stefano,Sansone, Francesco,Casnati, Alessandro,Goti, Andrea
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supporting information; experimental part
p. 951 - 957
(2012/08/29)
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- Synthesis and cation binding properties of fluorescent calix[4]arene derivatives bearing tryptophan units at the lower rim
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The fluorescent peptidocalixarenes, 5,11,17,23-tetra-tert-butyl-25,26,27, 28-tetrakis(O-methyl-L-tryptophanylcarbonylmethoxy) calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,27-di(O-methyl)-26,28-bis(O-methyl-L- tryptophanylcarbonylmethoxy) calix[4]arene (2), were prepared by introducing tryptophan subunits at a lower calixarene rim. Coordination abilities of 1 and 2 towards Eu(III) and alkali metal cations were studied by spectrophotometric, spectrofluorimetric, conductometric and potentiometric titrations in acetonitrile at 25°C. Rather strong complexation was observed for smaller alkali metal cations Li+ and Na+ (logKLi1 > 6, log KLi2 > 6, log KNa1 = 8.25, logKNa2 = 6.94), and moderate for K+ (logKK1 = 5.09, log K K2 = 4.09). Larger Rb+ and Cs+ cations did not fit in the ion binding site of 1 so no complexation was detected, whereas the more flexible ligand 2 accommodated Rb+ cation (logKRb2 = 3.44). The fluorescence of 1 (λex = 280 nm, λem = 340 nm) was remarkably quenched by Eu(III). Stability constant of 1:1 (Eu3+:1) complex determined spectrofluorimetrically amounted to log KEu1 = 6.16.
- Galic, Nives,Buric, Natas,Tomas, Renato,Frkanec, Leo,Tomisic, Vladislav
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scheme or table
p. 389 - 397
(2012/04/10)
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- Synthesis and extraction properties of new 'proton-switchable' tri-?and tetra-substituted calix[4]arene derivatives bearing pyridinium units
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The article describes the syntheses and complexation properties of new calixarene-based extractants, which have been synthesized?from 5,11,17,23-tetra-tert-butyl-25,26,27-tris(chlorocarbonylmethoxy)-28- hydroxycalix[4]arene and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(chlorocarbonylmethoxy) calix[4]arene by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine, respectively. p-tert-Butylcalix[4]arene teraamide was converted to its methyl iodide salt by refluxing with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7-/Cr2O7 2- anions. The complexing properties of the extractants toward selected alkali/transition metal cations and HCr2O7-/Cr2O7 2- anions are reported. It has been observed that both receptors do not extract alkali metal cations but show excellent selectivity toward transition metals. The protonated pyridinium forms of the receptors are effective for transferring the HCr2O7-/Cr2O7 2- anions from an aqueous into a dichloromethane layer.
- Tabakci, Mustafa,Memon, Shahabuddin,Yilmaz, Mustafa
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p. 6861 - 6865
(2008/02/07)
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- A novel calix[4]arene-dipyrrole conjugate designed for complexation of ion pairs
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A novel calixarene derivative with dipyrromethane moieties on the lower rim was prepared. NMR spectroscopy revealed a high selectivity towards sodium cations and the ability to bind ion pairs.
- Budka, Jan,Curinova, Petra,Rong, Gu,Lhotak, Pavel,Stibor, Ivan,Schraml, Jan,Dehaen, Wim
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p. 439 - 446
(2008/09/21)
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- CALIXARENE-BASED PEPTIDE CONFORMATION MIMETICS, METHODS OF USE, AND METHODS OF MAKING
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A class of topomimetic calixarene-based peptide mimetics is described. Calixarene-based peptide mimetics have various biological activities such as, for example, bactericidal activity, antiangiogenic activity, and/or antitumor activity. Methods of use and methods of designing calixarene-based peptide mimetics are described.
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Page/Page column 40-41
(2008/06/13)
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- Novel synthesis of calix[n]arene amidoazobenzene derivatives
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A series of calix[n]arenas and calix[4]resorciarenes containing azo chromophores on the lower rim were synthesised with two routes. The first direct route involved alkylating calixarenes with 4-chloroacetoaminoazobenzene. The second indirect route was by acylating 4-aminoazobenzene with calix[n]arylacetyl chloride. Their extracting abilities for transition metal ions were tested.
- An, Lin,Cai, Ya Hua,Wang, Min-Hua,Yan, Chao Guo
-
-
- Efficient synthesis of water-soluble calixarenes using click chemistry
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(Chemical Equation Presented) Several water-soluble calix[4]arenes were synthesized via Huisgen 1,3-dipolar cycloaddition between azides and alkynes. Cationic, anionic, and nonionic calixarenes were prepared from a common azidocalixarene intermediate. Azidocalixarenes performed better than alkynylcalixarenes as precursors. The aggregation behavior of the water-soluble calixarenes was studied by 1H NMR spectroscopy.
- Ryu, Eui-Hyun,Zhao, Yan
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p. 1035 - 1037
(2007/10/03)
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- Solvent-tunable binding of hydrophilic and hydrophobic guests by amphiphilic molecular baskets
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Responsive amphiphilic molecular baskets were obtained by attaching four facially amphiphilic cholate groups to a tetraaminocalixarene scaffold. Their binding properties can be switched by solvent changes. In nonpolar solvents, the molecules utilize the hydrophilic faces of the cholates to bind hydrophilic molecules such as glucose derivatives. In polar solvents, the molecules employ the hydrophobic faces of the cholates to bind hydrophobic guests. A water-soluble basket can bind polycyclic aromatic hydrocarbons including anthracene, pyrene, and perylene. The binding free energy (-ΔG) ranges from 5 to 8 kcal/mol and is directly proportional to the surface area of the aromatic hosts. Binding of both hydrophilic and hydrophobic guests is driven by solvophobic interactions.
- Zhao, Yan,Ryu, Eui-Hyun
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p. 7585 - 7591
(2007/10/03)
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- Novel anion receptors based on thiacalix[4]arene derivatives
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Starting from the thiacalix[4]arene tetraacetate, novel derivatives bearing four ureido or thioureido functions on the lower rim have been prepared. As proven by NMR titrations, these compounds can bind anions via hydrogen bonding interactions and represent the first example of anion receptors in the thiacalixarene series. The thiacalix[4]arene-tetraacetates or diacetates (cone) serve as a starting point for novel thiacalixarenes derivatives bearing urea or thiourea units on the lower rim. As revealed by NMR titration experiments, these compounds are preorganised for anion recognition in organic solvents.
- Zlatu?ková, Petra,Stibor, Ivan,Tkadlecová, Marcela,Lhoták, Pavel
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p. 11383 - 11390
(2007/10/03)
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- Extraction of technetium(VII) by calix[4]arene tetraketones and tetraesters from acidic and basic media
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Tetrasubstituted on the lower rim calix[4]arenes, containing carbonyl and ester groups, and existing in a cone conformation are selective and efficient extracting agents for TcVII extraction from both acidic and basic solutions.
- Antipin,Solovieva,Stoikov,Vershinina,Pribylova,Tananaev,Myasoedov
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p. 127 - 132
(2007/10/03)
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- Molecular scaffolds for di-metallic complexation: The synthesis, characterisation and complexation properties of tetrakis-terpyridinyl-calix[4]arene
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The ligand tetrakis-terpyridinyl-calix[4]arene is used as a rigid scaffold and pre-organiser of supramolecular assemblies by complexation of the Ni(II), Cu(II) and Co(II) cations. The ligand synthesis was carried out using peptide synthesis conditions by coupling 4′-(2-aminoethoxy)-2,2′/6′,2′′-terpyridine to the tetra-succinimidoyl activated ester of p-tert-butylcalix[4]arene. The studies on complexation by UV show the existence of M2L-type complexes.
- Molard, Yann,Parrot-Lopez, Hélène
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p. 6355 - 6358
(2007/10/03)
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- Synthesis and spectroscopic properties of porphyrin-(thia)calix[4]arene conjugates
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Calix[4]arene diacetate and tetraacetate together with their tetrathia-analogs served as starting compounds for the synthesis of novel porphyrin-calixarene conjugates. The introduction of monoaminotetraphenylporphyrin gave corresponding calixarene derivatives, bearing two or four porphyrin units on the lower calixarene rim. These compounds, immobilized in the cone conformation, possess interesting photophysical properties. The absorption and fluorescence emission spectra of the synthesized diporphyrins and tetraporphyrins reveal exciton coupling between the porphyrin units. The flexibility of the amidic bridges accounts for tuning of the degree of porphyrin coupling by the solvent polarity.
- Dudic, Miroslav,Lhoták, Pavel,Stibor, Ivan,Dvoráková, Hana,Lang, Kamil
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p. 5475 - 5482
(2007/10/03)
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- Kinetics and mechanism of the dissociation of a sodium-calix [4] arene ester complex in nonaqueous solution
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The kinetics and mechanism for the dissociation of sodium ion complexes of a calix[4]arene ester 1 were studied in nonaqueous solution by a dynamic 1H NMR. Life times τ(c) of the Na+-1 complexes and activation parameters Δ(d)H((+)) and Δ(d)S((+)) for the dissociation process were determined in five organic solvents. In methanol, the life time (8.8 x 10-3 s) of the sodium complex at 25°C was 440 times larger than that of crown ether (18C6) and was ca. 40 times less than that of cryptands (C211 and C222). The activation parameters for the dissociation process, Δ(d)H((+)) of 67, 64, 57, 57, and 46 kJ mol-1, and Δ(d)S((+)) of -22, -29, -7.7, -13, and -33 J mol-1 K-1 were determined in deuteriated nitromethane, acetonitrile, acetone, methanol, and dimethylformamide, respectively. It was observed that the activation enthalpies tend to decrease with increasing the electron- donating ability of solvents as indicated by the Gutmann donor number, while the activation enthalpies do not correlate to the donor number and all the values are negative. These results suggest that in the activated state of the Na+-1 complex, additional solvent molecules bind to the sodium ion encapsulated by ethoxycarbonylmethoxy groups in 1, and the disruption of the bonding between a sodium ion and the oxygens in the OCH2CO moieties plays a major contribution in the dissociation process. In acetonitrile, the life times of the Na+-1 complexes were not affected by the concentration of the free ligand of 1, suggesting that the dissociation proceeds via a unimolecular dissociation not a bimolecular exchange between free and complexed 1.
- Jin, Takashi
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p. 1401 - 1406
(2007/10/03)
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- Amphiphilic p-tert-butylcalix[4]arene scaffolds containing exposed carbohydrate dendrons
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The best of both worlds. Amphiphilic hybrid molecules, in which water- exposed glycodendrons are attached to a hydrophobic p-tert- butylcalix[4]arene scaffold, display strong affinities for both carbohydrate- binding proteins and polystyrene surfaces. The molecules can form monolayers useful in bioanalytical devices.
- Roy, Rene,Kim, Jin Mi
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p. 369 - 372
(2007/10/03)
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- Carbonylation (hydroformylation and hydrocarbalkoxylation) reactions in the presence of transition metal: P-tert-butyl-calix[4]arene-based phosphine and phosphinite systems
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In this study, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(2-diphenylphosphinoxy-ethoxy) calix[4]arene (5) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(2-diphenylphosphinoethoxy)- calix[4]arene (6), as well as their platinum and palladium complexes (PtCl2)2(5), (PdCl2)2(5) were synthesised and characterised. In addition to these transition metal-containing complexes the catalytic systems formed in situ, from catalytic precursors PtCl2(PhCN)2, [Rh(nbd)Cl]2 and PdCl2(PhCN)2 and the corresponding calixarene ligand, were tested as catalysts in hydroformylation and hydrocarbalkoxylation, respectively. High chemoselectivity was obtained in hydroformylation in the presence of rhodium-containing catalysts both with the above calixarene-based phosphine and phosphinite ligands. The regioselectivity towards branched aldehyde shows a strong temperature dependence in case of phosphinite derivative. Although the platinum-containing systems show much lower catalytic activity, the regioselectivities are undoubtedly higher than those obtained with PtCl2(diphosphine)-SnCl2 systems.
- Csok, Zsolt,Szalontai, Gabor,Czira, Gabor,Kollar, Laszlo
-
-
- Polysialosides scaffolded on p-tert-butylcalix[4]arene
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p-Tert-butylcalix[4]arene (1) was transformed into known tetraethyl ester 2 to provide cone-shaped calix[4]arene used for the scaffolding of tetravalent α-sialoside. Ester 2 was transformed into acid chloride 4 which after treatment with mono-Boc-1,4-butanediamine, trifluoroacetolysis and N-chloroacetylation afforded tetraamine 7. Conjugation of α-thiosialoside 9 by nucleophilic substitution and deprotection furnished water-soluble tetravalent α-thiosialoside 12 which bound strongly to the plant lectin wheat germ agglutinin.
- Meunier, Serge J.,Roy, Rene
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p. 5469 - 5472
(2007/10/03)
-
- Metal-Controlled Aggregation-Deaggregation in Calixarene-Based Self-Assemblies
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Supramolecular self-assemblies of complementary components 1 or 2 (calixarene derivatives with two or four 2,6-diaminopyridine units, respectively) and 3 (5,5-dialkyl barbituric acids) in chloroform-acetonitrile solution were confirmed by 1H NMR spectroscopy and light scattering.While derivative 1 interacts with 3 only after addition of Na(1+) cation, which disrupts intramolecular hydrogen bonds, compound 2 creates a complex with 3 even without the presence of Na(1+) cation, indicating much weaker intramolecular bonds in this derivative.
- Lhotak, Pavel,Shinkai, Seiji
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p. 4829 - 4832
(2007/10/02)
-
- A Novel Calixarene Tetraester with Fluorescent Response to Complexation with Alkali Metal Cations
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A new metal sensing compound, a calixarene having four anthracene moieties on the lower rim has been synthesized; the intensity of its fluorescence spectrum is markedly affected by alkali metal ion complexation.
- Perez-Jimenez, Consuelo,Harris, Stephen J.,Diamond, Dermot
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p. 480 - 483
(2007/10/02)
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- Syntheses and Ion Selectivity of All Conformational Isomers of Tetrakis((ethoxycarbonyl)methoxy)calixarene
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We have found that the conformer distribution in tetra-O-alkylation of 5,11,17,23-tetra-tert-butylcalixarene-25,26,27,28-tetrol by ethyl bromoacetate is remarkably affected by the metal cation present in the base.In general, the cone conformer predominantly results when the base contains template metal cations whereas the partial-cone and 1,3-alternate conformers result when the base contains nontemplate metal cations.In acetone solvent one can realize the change from the 100percent cone selectivity to the 100percent partial-cone selectivity.By combining the metal template effect with a protection-deprotection method with a benzyl group, we de veloped synthetic routes to all of the four conformers.Two-phase solvent extraction established that the cone conformer shows Na(1+) selectivity whereas the remaining three conformers show K(1+) selectivity. (1)H NMR studies established that the 1,3-alternate conformer can form both a 1:1 and a 2:1 metal/calixarene complex and the two metal-binding sites display negative allostericity.This paper thus demonstrates that the metal selectivity of ionophoric calixaryl esters can be changed not only by the change in the ring size but also by the conformational change.
- Iwamoto, Koji,Shinkai, Seiji
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p. 7066 - 7073
(2007/10/02)
-
- Synthesis and cation complexation selectivity of bis(syn-proximally) functionalized calixarenes
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A general method has been developed for the preparation of bis(syn-proximally) functionalized calixarenes (6,8-10).Starting from p-tert-butylcalixarene 1a and calixarene 1b syn-proximally dialkylated calixarenes 2a and 2b, 4, and 5, respectively, were obtained by treatment with 4.2 equiv of NaH and 2.2 equiv of alkylating reagent in DMF.The syn-proximal substitution pattern was unequivocally proven by an X-ray structural determination of 2b.Furthermore the influence of different bases on the functionalization of the free hydroxyl groups of 2b with chloroacetone was studied.Cs2CO3 as the base gave the bis(syn-proximally) functionalized calixarene 6 in the highest yield (82percent).Cation complexation studies, with the picrate extraction method, showed that subtle changes in the regioselective functionalization influences the selectivity for Na+ considerably.
- Brunink, Jos A. J.,Verboom, Willem,Engbersen, Johan F. J.,Harkema, Sybolt,Reinhoudt, David N.
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p. 511 - 516
(2007/10/02)
-
- Remarkable metal template effects on selective syntheses of p-t-butylcalix[4]arene conformers
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It was found that the conformer distribution in tetra-O-substitution of p-t-butylcalix[4]arene is remarkably affected by metal species in base: in particular, 100% 'cone' selectivity in the presence of Na2CO3 is changed to 100% 'partial cone' selectivity in the presence of Cs2CO3 in the reaction with ethyl bromoacetate.
- Iwamoto,Fujimoto,Matsuda,Shinkai
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p. 7169 - 7172
(2007/10/02)
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- Synthesis, X-ray Crystal Structures, and Cation-Binding Properties of Alkyl Calixaryl Esters and Ketones, a New Family of Macrocyclic Molecular Receptors
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Calixarenes (N=4,6,8) have been converted into polyfunctional esters and ketones in a search for new macrocycles capable of showing ionophoric activity.Treatment with alkyl bromoacetates furnished the calixaryl acetate series, whereas chloroacetone-potassium iodide, phenacyl chloride, 1-adamantyl bromomethyl ketone, and bromopinacolone were used to make the calixaryl ketones series.The crystal structures of ethyl calixaryl acetate (7), methyl calixaryl acetate (13), ethyl calixaryl acetate (11), and calixaryl methyl ketone (20) have been determined.Thecrystals of 7 are triclinic, space group P, with two molecules in the unit cell of dimensions a = 12.434(2) Angstroem, b = 15.033(3) Angstroem, c = 17.286(4) Angstroem, α = 103.01(2) deg, β = 102.97(1) deg and γ = 94.68(1) deg.The crystals of 13 are monoclinic, space group C2/c, with eight molecules in the unit cell of dimensions a = 27.066(6) Angstroem, b = 21.392(6) Angstroem, c = 21.348(7) Angstroem, and β = 119.32(2) deg.The crystals of 11 are monoclinic, space group C2/c, with four molecules in the unit cell of dimensions a = 21.906(4) Angstroem, b = 11.805(2) Angstroem, c = 23.534(4) Angstroem, and β = 91.79(2) deg.The crystals of 20 are orthorhombic, space group Pbcn, with four molecules in the unit cell of dimensions a = 19.644(7) Angstroem, b = 12.712(3) Angstroem, and c = 22.115(7) Angstroem.Both 11 and 20 have crystallographically imposed 2-fold molecular axes.The analysis establishes that all three tetramer derivatives possess the cone conformation in the solid state where the pendant-functionalized side chains are mutually syn with respect to the calixarene substructure and are thus preorganized for ionreception.NMR measurements confirm the existence of the cone conformation for these tetramers in solution at room temperature.In contrast, the centrosymmetric hexamer ester 11 has three adjacent groups syn, but the inversion symmetry places the other three ester groups in the anti position on the opposite side of the macrocycle.Extraction studies with alkali metal picrates from aqueous solution into dichloromethane, transport studies with alkali metal thiocyanates through a dichloromethane membrane, and stability constant measurements with alkali metal salts by UV absorption spectroscopy in methanol and acetonitrile were used to assess the ionophoric activity of these calixarene derivatives.The tetramer esters and ketones display peak selectivity for the sodium ion, the tetraketones being generally more efficient binders than the tetraesters.The hexaester extracts K(1+) better than Na(1+) and displays a plateau selectivity after K(1+).The octamers are the least effective ionophores.The selectivities shown by the picrate extraction technique are broadly mirrored in the transport studies.Stability constants range from 2 to 6, ...
- Arnaud-Neu, Francoise,Collins, Elizabeth M.,Deasy, Mary,Ferguson, George,Harris, Stephen J.,at al.
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p. 8681 - 8691
(2007/10/02)
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- Molecular receptors with the calix[4]arene substructure. Synthesis of derivatives with mixed ligating functional groups
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p-t-Butylcalix[4]arene has been derivatised regioselectively at positions 1 and 3 of the four equivalent phenolic groups using electrophiles such as ethyl bromoacetate, chloroacetone, bromopinacolone, and chloroacetonitrile; the products are useful precursors for the synthesis of tetrasubstituted calixarenes with mixed ligating functional groups.
- Collins, Elizabeth M.,McKervey, M. Anthony,Harris, Stephen J.
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p. 372 - 374
(2007/10/02)
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- Synthesis, X-Ray Crystal Structures, and Cation Transfer Properties of Alkyl Calixaryl Acetates, a New Series of Molecular Receptors
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Calix-, -, and -arenes have been converted into a series of alkyl acetates which show significant phase-transfer activity and selectivity towards alkali metal picrates; the X-ray crystal structures of two members of the series, (1b) and (2d), have been determined.
- McKervey, M. Anthony,Seward, Eileen M.,Ferguson, George,Ruhl, Barbara,Harris, Stephen J.
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p. 388 - 390
(2007/10/02)
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