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1.
Paul D. Beer Anthony D. Keefe 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(4):499-504
The condensation of 1,1-bis(chlorocarbonyl)metallocenes andp-tert-butylcalix[4]arene in toluene leads to novel metallocene calix[4]arenes in which the metallocene subunit bridges the opposite hydroxy groups of the parent calixarene.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on cyclodextrins, Lancaster, U.K., 20–25 July 1986. 相似文献
2.
O-Alkylation of the dinitro calix[4]arene 2, easily available by selective ipso-nitration of the di-cyanomethyl ether 1, with allylbromide (DMF/Cs2CO3) gave tetraethers 3 and 4 with anti- and syn-orientations of the two allyl ether residues. The two possible stereoisomers of in the partial cone and 1,2-alternate conformation exist as an equilibrium mixture which could be quantitatively analysed by 1H NMR spectroscopy. The temperature dependence of this equilibrium leads to deltaH0 = -7.6 to -9.7 kJ mol(-1) in different solvents (tetrachloroethane, benzene, dimethylsulfoxide). Since 3(1,2-alt) could be obtained in pure form, its isomerisation to the equilibrium mixture with 3(paco) could be followed also kinetically. An activation energy of E(a) = 110.5 kJ mol(-1) was found for this reaction in DMSO-d6. The results were confirmed by similar studies with tetraethers 5 and 6 obtained by O-allylation of 1, although exact thermodynamic and kinetic studies were not possible in this case, since the NMR signals of the respective isomers were strongly overlapping. Single crystal X-ray structures were obtained for 2, 3(1,2-alt), 4(paco) and 5(1,2-alt). 相似文献
3.
《Tetrahedron》2006,62(33):7846-7853
A facile and efficient approach to synthesize tetra-oligothiophene-substituted calix[4]arenes, Calix-OT(n) with n up to 4 using palladium-catalyzed Kumada coupling of thienylmagnesium bromide and bromo-substituted calix[4]arene as a key step has been developed. The close proximity of the tetra-oligothiophenes constructed within a calix[4]arene assembly leads to peak/band broadening, spectral shifting, i.e., blue-shift in absorption and red-shift in emission spectra as well as fluorescence quantum yield quenching as compared to those of monomers indicating the existence of chromophoric interaction. We have shown that the intra-chromophoric interaction lowers the first ionization (raises HOMO level) of an oligothiophene within an assembly. It also stabilizes the formation of a radical cation, which results in an increase in the subsequent voltammetric oxidation and the occurrence of the higher oxidation states as compared to the monomeric counterparts. This assembly can serve as a model for the investigation of molecular interaction of π-conjugated systems. 相似文献
4.
Hennrich G Murillo MT Prados P Song K Asselberghs I Clays K Persoons A Benet-Buchholz J de Mendoza J 《Chemical communications (Cambridge, England)》2005,(21):2747-2749
Rigid, highly conjugated tetraalkynyl-calix[4]arenes synthesised via Sonogashira coupling give rise to improved second-order hyperpolarizability values as determined by hyper-Rayleigh scattering--a technique that in addition to X-ray crystallography also allows for the conformational analysis of the calixarene structures in solution. 相似文献
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6.
Tetra-oligophenylene substituted calix[4]arene assemblies containing up to three phenylene units have been synthesized by a convergent approach using Suzuki cross-coupling and their optical properties were investigated and compared with the corresponding monomer. 相似文献
7.
Two novel carboxylphenyl-modified calix[4]arenes, tetrakis-carboxylphenylcalix[4]arene (TCPC) and 1,3-bis-carboxylphenylcalix[4]arene (BCPC), as well as a corresponding analogue for comparison, tetrakis-phenylcalix[4]arene (TPC), have been synthesized by palladium-catalyzed Suzuki cross-coupling of arylboronic acid and tetrabromocalix[4]arene as a key step. The binding properties of these calix[4]arene derivatives with bovine heart cytochrome c (cyt c) in dimethylformamide (DMF) was investigated by fluorescence spectroscopy. The binding affinity in the order of TCPC > BCPC ? TPC reflects a clear dependence on the number of carboxyl ligating groups attached onto a receptor and suggests the electrostatic force may be the predominant factor driving the complexing process. The stable 1:1 complexes of TCPC and BCPC with cyt c were evidenced with the binding constants of 3.15 × 106 and 5.85 × 105 L mol−1, respectively. Due to a large overlap between the emission spectrum of TCPC and the absorption spectrum of cyt c, and a short interaction distance (estimated to be 5.6 nm) between them, the fluorescence quenching of TCPC upon complexation with cyt c is attributed to an efficient energy transfer. 相似文献
8.
Kim JS Shon OJ Lee JK Lee SH Kim JY Park KM Lee SS 《The Journal of organic chemistry》2002,67(4):1372-1375
Novel 1,3-alternate calix[4]azacrowns having an azo chromophoric pendent group were synthesized, and their 1,3-alternate conformations were confirmed by X-ray crystal structure. In view of the hypsochromical UV band shifting upon cation complexation, azo-coupled calix[4]azacrown-5 (3) showed the most selective shifting with alkali and alkaline metal ions. In addition, 3 revealed K+ ion selectivity not only due to the size comparability between the K+ ion and the azacrown-5 loop but also due to a significant K+-pi interaction between the two aromatic rings and the K+ ion. The UV band shifting is also dependent on the lipophilicity of the species of counteranion used. 相似文献
9.
A novel protection/deprotection method leading to the regioselective ipso-substitution of calix[4]arenes is described. The introduction of nosyl (p-nitrobenzenesulfonyl) groups into the lower rim of partly alkylated tert-butylcalix[4]arenes leads subsequently to the exclusive ipso-nitration of the alkylated phenol rings, while the protecting groups can be easily removed in the next step. This method gives dialkoxy- or trialkoxy-substituted calix[4]arenes with nitro groups on the alkylated rings and tert-butyl groups on the remaining ones. The above substitution pattern is complementary to the isomers so far known in the chemistry of calix[4]arenes and could be used in the design of novel type of calixarene-based receptors. 相似文献
10.
The regioselective nitration of 25,27-dipropoxythiacalix[4]arene was carried out as a key step in the synthesis of thiacalix[4]arene derivative bearing two arylureido functions on the upper rim. The preorganisation of ureido units using the thiacalix[4]arene/calix[4]arene moieties as a molecular scaffold gave novel anion receptors. These compounds, albeit based on hydrogen bonding interactions, show good complexation ability even in highly HB-competitive solvent, such as DMSO. Direct comparison of otherwise identical structures 6a and 7a revealed remarkable dominance of the thiacalix[4]arene derivative over its classical analogue in anion binding. 相似文献
11.
Functionalisation of calix[4]arene at both the wide and narrow rims leads to the formation of compounds containing bipyridyl, via an amide linkage, at the wide rim and having either a butyl chain, a benzyl group or an alkyl ester functionality at the narrow rim. All compounds were characterised using 1H and 13C NMR spectroscopies. Initial binding studies with Ru(bipy)2Cl2 are reported. 相似文献
12.
Matthias H. DükerRafael Gómez Christophe M.L. Vande VeldeVladimir A. Azov 《Tetrahedron letters》2011,52(22):2881-2884
The synthesis of novel upper rim calix[4]arene-tetrathiafulvalene conjugates 1a-d has been performed by bridging the tetrachloromethylated calix[4]arene derivative 4 with the corresponding tetrathiafulvalene-dithiolates. The cyclic voltammetry of 1a-d shows a two-step oxidation behavior, whereas NMR binding titrations showed their binding affinity to pyridinium salts. X-ray structure of 4 features calixarene fixed in the pinched cone conformation; its crystal packing is defined by the network of C-H···Cl weak hydrogen bonds. 相似文献
13.
W. Wąsikiewicz G. Rokicki J. Kiełkiewicz E. F. Paulus V. Böhmer 《Monatshefte für Chemie / Chemical Monthly》1997,128(8-9):863-879
Summary New macrotricyclic compounds consisting of two calix[4]arene substructures connected by aliphatic chains of various length (three to five carbon atoms) between two oppositep-positions and two distal phenolic oxygens have been synthesized. Starting withp-tert-butyl-calix[4]arene, two O-protected phenolic units are attachedvia ether links in 1,3-position by reaction with the corresponding tosylates. After deprotection, the new calix[4]arene is formed by fragment condensation with 2,6-bisbromomethylated 4-alkylphenols. The structure of one example (8c) has been confirmed by single crystal X-ray analysis. Both calixarene parts assume the cone conformation, a molecule of acetonitrile being included in both cavities.
Doppelte Calix[4]arene in Kopf-Schwanz-Verknüpfung
Zusammenfassung Neue makrotricyclische Verbindungen, in denen zwei Calix[4]aren-Einheiten durch aliphatische Ketten unterschiedlicher Länge (drei bis fünf C-Atome) zwischen zwei gegenüberliegendenp-Positionen und zwei gegenüberliegenden Phenolsauerstoffen verknüpft sind, wurden hergestellt. Ausgehend vonp-tert-Butyl-calix[4]aren werden zunächst zwei O-geschützte Phenolbausteine in 1,3-Stellung durch Umsetzung mit den entsprechenden Tosylaten etherartig gebunden. Nach Abspaltung der Benzylether-Schutzgruppe wird durch Fragmentkondensation mit 2,6-bisbrommethylierten 4-Alkylphenolen das neue Calix[4]aren gebildet. Für8c wurde die Struktur durch Einkristallröntgenstrukturanalyse bestätigt. Beide Calixarenteile nehmen diecone-Konformation ein, wobei in die beiden Hohlräume je ein Molekül Acetonitril eingeschlossen wird.相似文献
14.
New boronoalkoxycalix[4]arenes were synthesized by allylation, alkylation, hydroboration and hydrolysis of 25,26,27,28-tetrahydroxycalix[4]arene, and identified by elemental analysis, IR, 1H NMR, 13C NMR, 11B NMR, MS and UV spectra. The data of UV and fluorescence spectra showed that tctrapropoxycalix-[4]arene triboronic acid could coordinate significantly with monosaccharides. 相似文献
15.
Baklouti L Cherif J Abidi R Arnaud-Neu F Harrowfield J Vicens J 《Organic & biomolecular chemistry》2004,2(19):2786-2792
A series of mixed [2 + 2'] p-tert-butylcalix[4]arene have been synthesised by selective 1,3-dialkylation of phenolic groups using various alkylating agents such as benzyl bromide, methyl iodide, ethyl bromoacetate, and 2-methoxyethyl tosylate. The extraction and complexation properties of the synthesized calixarenes towards alkali and alkaline earth metal cations have been investigated in acetonitrile by means of UV spectrophotometry and 1H NMR spectroscopy. The results show the formation of ML and/or ML2 species depending on the ligand and the cation. The enthalpies and entropies of complexation of alkali metal cations by a tetraglycol, diglycol-dibenzyl and diglycol-diester derivatives have been obtained from calorimetric measurements. The results revealed that the formation of ML species is controlled by enthalpy while the formation of ML2 from ML is entropy driven. 相似文献
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17.
Calix[4]arenes substituted at the narrow or wide rim by eight carbamoylmethyl-phosphine oxide (CMPO) functions in a dendritic manner were synthesised and studied in extraction of Eu3+ and Am3+ from aqueous nitric acid into o-nitrophenylhexyl ether. 1H NMR relaxivity titrations for a wide rim octa-CMPO reveal the clear formation of a solvent-free 1:2 ligand/metal complex, while the wide rim tetra-CMPO formed oligomeric complexes under similar conditions. 相似文献
18.
[reaction: see text] A facile synthesis of bisformylated calix[4]arenes via ipso substitution of p-tert-butylcalix[4]arenes through treatment with hexamethylenetetramine/trifluoroacetic acid is described. Under identical conditions, p-tert-butylcalix[4]arene tetramethyl ether 4 gives proximally substituted bisformylated derivative 4a in a pinched cone conformation. 相似文献
19.
Braekers D Peters C Bogdan A Rudzevich Y Böhmer V Desreux JF 《The Journal of organic chemistry》2008,73(2):701-706
Calix[4]arenes substituted by four urea functions are self-complementary molecules that spontaneously combine in apolar solvents in the presence of an ammonium salt to form dimeric capsules held together by a belt of hydrogen bonds. In the presence of tetraethylammonium salts, the Et4N+ cation is included as a guest. The sorting between dimeric capsules formed in a mixture of calix[4]arenes directly depends on the steric crowding of the substituents grafted on the urea groups whether aromatic derivatives or aliphatic chains linking urea functions in mono-, di-, or tetraloop structures. Simple rules allow one to anticipate which capsules will be exclusively formed when calix[4]arenes are mixed in different proportions. The stabilization of the dimeric structures by hydrogen bonds is thwarted by the overlaps of aliphatic loops and/or by bulky groups that cannot pass through these loops. Despite the structural similarity of the calixarenes, the exclusive formation of dimers of well-defined compositions and clear titration breaks are observed by electrospray mass spectrometry. This technique yields reliable information on stoichiometries and composition despite measurements in the gas phase rather than in solution and it does not suffer from excessive peak overlaps in contrast with NMR. 相似文献
20.
Lhoták P Bílá A Budka J Pojarová M Stibor I 《Chemical communications (Cambridge, England)》2008,(14):1662-1664
The least accessible calix[4]arene conformers-1,2-alternates-can be very easily prepared using a proximal dialkylation and subsequent peralkylation reaction sequence. 相似文献