نتایج جستجو برای: calix 8 arene
تعداد نتایج: 658226 فیلتر نتایج به سال:
Cone-shaped calix[4]arene-tetrol 3 has the ability to form open structures due presence of four OH groups at upper rim, which allows construction H-bonded supramolecular organic frameworks (SOFs). In water, SOF-1 is formed, contains hydrophilic channels (mean diameter 8.5 Å) contoured by p-phenolic groups. acetonitrile, SOF-2 smaller hydrophobic 6.6 delimited aromatic walls. The Na+@3 complex, ...
This work reports a new method to covalently attach calix[4]arene derivatives onto MCM-41, using a diisocyanate as a linker. The modified mesoporous silicates were characterized by fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalently attached to the mesoporous sil...
Calixarenes are a readily available and important class of macrocycles in supramolecularchemistry. Calixarenes have generated considerable interest due to their basket shaped structureand as useful building blocks to synthesize selective receptors for the guest species, notably alkali,alkaline earth, lanthanide and transition metal cations. In this work studied on the complexingproperties of a ...
Stable pi-dimers are formed upon oxidation of the model units of proposed calix[4]arene-based molecular actuators in a solvent of low dielectric constant (CH 2Cl 2) at room temperature. Evidence from UV-vis, EPR, and DPV are all in agreement with the pi-dimer formation. In addition, pi-dimer formation is dependent upon the conformational flexibility of the calix[4]arene hinge.
The synthesis and cation-binding properties of a series of Calixarene derivatives possessing alkyl chain groups, ester groups and crown ether rings have been investigated. The syntheses of Calix[4]arene crown ethers and Calix[6]arene derivatives possessing alkyl chain, ester group and crown ether ring have been described. In order to evaluate their monovalent cation binding abilities, solvent e...
The binding efficiency of a series of monotopic () and heteroditopic () calix[4]arene-based receptors has been evaluated in chloroform solution toward N-methylpyridinium ion pairs using NMR and UV/vis spectroscopic techniques. These experiments provided evidence that, due to a positive cooperative effect, the presence of a phenylurea H-bond donor group on the upper rim of the calix[4]arene macr...
the adsorption of pyrazolone(hpmsp), calix[4]-arene,cu and cs, on carbon nanotube(cnt) atroom temperature has been investigated using spectroscopy.uv spectroscopy indicated that pyrazolone molecules adsorbed on carbon nanotube at roomtemperature in compared calix[4]- arene molecules adsorbed approximately same.the amount ofpyrazolone(hpmsp) adsorb 3.8. le mol/g and amount calix[4]-arene adsorbe...
In the title compound, C(56)H(44)Br(4)O(4), the calix[4]arene unit displays the 1,2-alternate conformation with crystallograpically imposed inversion symmetry. The four phen-oxy rings of the calix[4]arene unit are twisted about the mean plane defined by the four methyl-ene C atoms bridging the benzene rings, with dihedral angles of 46.73 (6) and 66.11 (5)°. The dihedral angle between adjacent p...
We describe the calixarene-cyclodextrin-coupling via click reaction starting from 5,11,17,23-tetra-tert-butyl-25,27-dipropargylether-26,28-hydroxy-calix[4]arene (calix[4]arene-dipropargylether) (2) onto 6I-azido-6I-deoxycyclomaltoheptaose (3) under microwave assisted conditions. The coupling was proven by MALDI-TOF mass spectrometry, ¹H NMR and IR-spectroscopy. The pH dependent supramolecular c...
An amphiphilic calix[4]arene bearing branched 3,4,5-tris(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)benzamide groups at the upper rim was synthesized and could increase the solubility of naproxen and ibuprofen in water through hydrogen bonding and π-π stacking interactions. The interactions between amphiphilic calix[4]arene and carboxylic acids such as naproxen and ibuprofen could reverse the directio...
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