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51.
Yasuhiro Morisaki 《Journal of organometallic chemistry》2004,689(16):2684-2689
Novel organometallic conjugated polymer containing (η6-arene)Cr(CO)3 and platinum in the main chain was synthesized by dehydrohalogenation coupling reaction of (η6-1,4-diethynylbenzene)tricarbonylchromium with trans-(PBu3)2PtCl2. The polymer was soluble in common organic solvents and has the number-average molecular weight of 31,000 by GPC analysis. The polymer exhibited an absorption peak derived from π-π∗ interaction at 358 nm in the UV-Vis spectrum, which showed a red shift of approximately 90 nm compared to that of the model compound. The photochemical ligand exchange reaction of the polymer was also investigated. 相似文献
52.
Stéphane Pellet-RostaingFrédéric Chitry Jean-Alexis SpitzAntoine Sorin Alain Favre-RéguillonMarc Lemaire 《Tetrahedron》2003,59(51):10313-10324
Calix-bis(benzocrown-6) 6 and 7 were converted into the water-soluble receptors 9, 10, 12 and 15 by introducing hydroxy, carboxy, sulfato or diethanolamino groups at the para position of the phenolic ring and/or on the benzo-ether moieties. The complexation properties of these ionophores were studied for all alkali cations in methanolic and aqueous media. Stability constants were calculated by UV-Vis spectroscopy. All ligands showed a more or less affinity for the larger cations, depending on the nature and the position of the substituents grafted on the benzo-ether chain only or both on the calixarene ring and the benzo-ether loop. For selective Cs+/Na+ separation, the efficiency of the ligands was evaluated by means of a nanofiltration system. In comparison with the known tetrahydroxylated bis-crown-6 calix[4]arene 1, compounds 9, 12 and 15 represent the most selective ligands for the Cs+ cation in a moderate salted medium ([NaNO3]=85 g/L). 相似文献
53.
Thawatchai Tuntulani Praput Thavornyutikarn Sirilux Poompradub Nongnuj Jaiboon Vithaya Ruangpornvisuti Narongsak Chaichit Zouhair Asfari Jacques Vicens 《Tetrahedron》2002,58(52):10277-10285
Tripodal aza crown ether calix[4]arenes, 5a, 5b, 6a and 6b, have been synthesized. The structure of protonated 5a was elucidated by X-ray crystallography to be a self-threaded rotaxane. Complexation studies of 5a and 5b towards anions using Na+ as countercation were carried out by 1H NMR titration in dimethylsulfoxide-d6 and the mixture of chloroform-d and methanol-d4, respectively. Ligands 5a and 5b were able to form 1:1 complexes with Br−, I− and NO3− and the complexation stability varied as follows: NO3−>I−>Br−. The effect of countercation on anion complexation was also investigated. The results showed that the association constants of 5a towards Br− in the presence of various cations varied as K+>Bu4N+>Na+. The enhancement in anion complexation ability of 5a may result from the rearrangement of the tripodal ammonium unit in the presence of K+. The neutral forms, 6a and 6b, were able to form complexes with transition metal ions such as Co2+, Ni2+, Cu2+ and Zn2+. The stability of the complexes followed the sequence: Ni2+2+Cu2+Zn2+. Compounds 6a and 6b may, therefore, potentially be used as either transition metal ion or anion receptors that can be controlled by pH of the solution. 相似文献
54.
S. Yordanova S. Miloshev I. Berlinova B. Diakovski 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(3-4):337-344
A novel two-step method was developed to prepare individual p-isopropenylcalix[n]arenes [n=4, 6, 8]. In the first step, linear phenolic oligomers were prepared in a basic medium from p-isopropenylphenol and paraformaldehyde. The second step, cyclization of the linear oligomers was carried out at higher temperatures.
Ethylene glycol was used as medium, and sodium tetraborate-decahydrate as the catalyst. O-Acetylated derivatives were obtained
by acetylation of the phenolic hydroxyl groups of p-isopropenylcalix[n]arenes [n=4, 6, 8]. The p-isopropenyl-calix[n]arenes and their acetylated derivatives were characterized by IR, 1H NMR and UV spectroscopy, and elemental analysis. Their ability to extract metal cations from aqueous solutions was evaluated
via metal picrate extraction experiments. A parallel investigation of the cation-binding ability of the p-tert-butylcalix[n]arenes [n=4, 6, 8] and their acetylated derivatives was also performed. The p-isopropenylcalix[6]arene hexaacetate is the most effective extracting agent for metal picrates, and shows strong affinity
towards Rb cation. 相似文献
55.
Mine Sulak Ak Hasalettin Deligöz 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(1-2):115-123
Four new azocalix[4]arenes {5,11,17,23-tetrakis[(2-hydroxy-5-tert-butylphenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (1), 5,11,17,23-tetrakis[(2-hydroxy-5-nitro phenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (2), 5,11,17,23-tetrakis[(2-amino-5-carboxylphenylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(1-amino-2-hydroxy-4-sulfonicacidnapthylazo)]-25,26,27,28-tetrahydroxycalix[4]arene (4)} have been synthesized from p-tert-butylphenol, p-nitrophenol, p-aminobenzoic acid and 1-amino-2-hydroxy-4-sulphonic acid by diazo coupling reaction with p-aminocalix[4]arene. The resulting ligands (1–4) were treated with three transition metal salts (e.g., CuCl2·2H2O, NiCl2·6H2O or CoCl2·6H2O). Cu(II), Ni(II) and Co(II) complexes of the azocalix[4]arene derivatives were obtained and characterized by UV-vis, IR,
1H-NMR spectroscopic techniques and elemental analysis. All the complexes have a metal:ligand ratio of 2:1. The Cu(II) and
Ni(II) complexes of azocalix[4]arenes are square-planar, while the Co(II) complexes of azocalix[4]arenes are octahedral with
water molecules as axial ligands. The solvent extraction of various transition metal cations from the aqueous phase to the
organic phase was carried out by using azocalix[4]arenes (1–4). It was found that, azocalix[4]arenes 1, 2 and 3 examined selectivity for transition metal cations such as Ag+, Hg+ and Hg2+. In addition, the thermal stability of metal:azocalix[4]arene complexes were also reported.
Dedicated to Prof. Dr. Mustafa Yılmaz on the occasion of his 50th birthday 相似文献
56.
Narinder Singh 《Tetrahedron》2004,60(25):5393-5405
New podands based on the p-tert-butylcalix[4]arene unit with substitution at the lower rim incorporating imine units, have been synthesized in high yield by simple condensation method. These podands have been shown to extract and transport Ag+ selectively over alkali, alkaline earth metal cations, Zn2+, Pb2+ and Hg2+ ions, from neutral aqueous phase to organic phase. In all the ligands the calix unit has been found to be present in a cone conformation except for the one having pyridine as end group, at the ortho position. It has been isolated in two conformations; cone and 1,2-alternate. To the best of our knowledge, this may be the first 1,3-lower rim substituted calix[4]arene to exist in a 1,2-alternate conformation and is among a few known compounds with this conformation in the general class of calix[4]arenes. A complex of this ligand, which happens to be the highest extractant of Ag+ has been isolated and characterized using mass, 1H and 13C NMR spectroscopy's and elemental analysis. The spectroscopic evidence and molecular modelling studies performed on the complex suggest a participation of the imine and pyridine nitrogens and two of the ether oxygens in coordination to the metal ion. The X-ray crystal structures of three of the ligands establish the formation of inclusion complexes with polar acetonitrile solvent molecules. The 1H and 13C NMR spectra of all the compounds, taken in CDCl3, show the presence of acetonitrile molecules in the cavity of the calix[4]arene, indicating inclusion of the neutral guest molecules in the solution phase as well. For one of the podands X-ray crystal structure has shown a formation of clatharate complex of chloroform with the ligand which has rarely been found in the case of calix[4]arenes. 相似文献
57.
《Electroanalysis》2003,15(4):287-293
Homooxacalix[3]arene derivatives are effective ionophores for constructing serotonin‐selective membrane electrodes. An electrode based on one of the derivatives, tris(methoxyphenylpropyloxy)hexahomooxacalix[3]arene‐triethyl ether, with potassium tetrakis(p‐chlorophenyl)borate (20 mol% relative to the ionophore) as an ionic additive and bis(2‐ethylhexyl) sebacate as a solvent mediator in a poly(vinyl chloride) membrane matrix, displayed much better selectivity for serotonin than for various organic ammonium ions and inorganic cations. The electrode exhibited a near‐Nernstian response to serotonin in the concentration range of 2×10?4 to 1×10?2 M with a slope of 56.4 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM Na2HPO4/NaH2PO4 (pH 7.4). The limit of the detection was 8×10?5 M. The selectivity pattern of this electrode was quite different from that of an electrode using calix[6]arene‐hexaacetic acid hexaethyl ester, a well‐known ionophore for primary organic ammonium ions, which did not induce an enhanced response to serotonin. The developed electrode was used for the active loading of serotonin in liposomes induced by transmembrane pH gradients. 相似文献
58.
Novel macrocyclic monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a were synthesized by the reaction of calix[4]arene dibromides 1-5 with the disodium salt of bis(2-selenylethyl)ether in the yields between 28% and 64%. Their structures were characterized by proton and carbon NMR spectra. X-Ray structure analysis of la further confirmed the cone conformation of compounds 1a-5a. An interesting host-guest complex of la with dichloromethane via CH/π and C1/π interactions was elucidated. Extraction experiments showed that these novel monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a had strong extraction ability towards mercury ion. The interaction of Hg^2+with the calix ligand has also been investigated by 1^H NMR titration. 相似文献
59.
Marine Rémy Dr. Iwona Nierengarten Boram Park Dr. Michel Holler Dr. Uwe Hahn Dr. Jean-François Nierengarten 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(33):8492-8499
Stable pillar[5]arene-containing [2]rotaxane building blocks with pentafluorophenyl ester stoppers have been efficiently prepared on a multi-gram scale. Reaction of these building blocks with various nucleophiles gave access to a wide range of [2]rotaxanes with amide, ester or thioester stoppers in good to excellent yields. The rotaxane structure is fully preserved during these chemical transformations. Actually, the addition-elimination mechanism at work during these transformations totally prevents the unthreading of the axle moiety of the mechanically interlocked system. The stopper exchange reactions were optimized both in solution and under mechanochemical solvent-free conditions. While amide formation is more efficient in solution, the solvent-free conditions are more powerful for the transesterification reactions. Starting from a fullerene-functionalized pillar[5]arene derivative, this new strategy gave easy access to a photoactive [2]rotaxane incorporating a C60 moiety and two Bodipy stoppers. Despite the absence of covalent connectivity between the Bodipy and the fullerene moieties in this photoactive molecular device, efficient through-space excited state interactions have been evidenced in this rotaxane. 相似文献
60.
Hui Qiang Tao Chen Zhuo Wang Wenqian Li Yunzhe Guo Jie Yang Xueshun Jia Hui Yang Weibo Hu Ke Wen 《中国化学快报》2021,31(12):3225-3229
The development of heterogeneous catalysts with substrate shape, size or electronic constitution selectivity is a huge challenge in photocatalysis. Reported herein is a host-guest interaction strategy to endow photocatalysts with special selectivity. By adjusting the precursors, conjugated macrocycle polymers (CMPs) with pillar[5]arene struts (CMP-1 and CMP-2) and a corresponding non-pillar[5]arene-contained conjugated organic polymer (COP-1) were prepared and the photocatalytic activities toward sulfide derivatives were investigated. The sulfides showed similar conversions when COP-1 was used as a photocatalyst, but exhibited significant differences when it turned to the CMPs. Remarkably, the conversion yield of S-1 achieved near 18 folds over the one of S-2 when CMP-2 was used as a catalyst. Mechanism studies confirmed that the “host-guest” effect of pillar[5]arene struts in CMPs was the main cause of the difference. The present work establishes CMPs as novel heterogeneous photocatalysts with substrate selectivity, and such a method will inspire the researchers concerning preparation of heterogeneous catalysts with excellent selectivity. 相似文献