نتایج جستجو برای: calixarene
تعداد نتایج: 421 فیلتر نتایج به سال:
The effect of macrocycle size on the structure-property relationships was studied for inclusion compounds of tert-butylcalix[n]arenes (n=4,5) with volatile organic guests having various molecular size and group composition. Vapor-sorption isotherms, guest-inclusion stoichiometry and Gibbs energy, thermostability parameters and decomposition enthalpies were determined for host-guest compounds (c...
The calixarene derivative used in this study (tetra-p-guanidinoethylcalix[4]arene) shows vitro activity against different Gram-positive and Gram-negative bacteria. interaction between bacterial cell membranes the water-soluble was investigated using model lipids spread as monomolecular films at air–water interface. Compression adsorption experiments, well Brewster angle microscopy, polarization...
Capsules derived from the reversible assembly of calixarene tetraureas have been characterized by electrospray ionization mass spectrometry. Ion labeling was achieved through the encapsulation of ammonium ions as guest molecules. The gas-phase ion structure of the parent calixarene was determined by isotope pattern analysis, inclusion of labeled guests, and collision experiments. Competition ex...
Two possible types of cadmium sulphide ~CdS! nanostructures can be formed within Langmuir– Blodgett ~LB! films of calixarene Cd salt as a result of exposure to H2S gas: nanoclusters with the size of about 1.5 nm or two-dimensional planes with the thickness of about 1.7 nm. Transmission electron microscopy and electron diffraction studies on calixarene/CdS LB films show that CdS particles are no...
A nanoparticle-based strategy has been demonstrated using structurally-tailored tert-butylcalixarenes immobilized on gold nanoparticles to tune the guest access to the calixarene cone cavity for cationic recognition. This strategy exploits the interparticle charge-induced aggregation upon selective capture of metal cations into the nanoparticle-immobilized tert-butylcalixarenes, which produces ...
As the field of anion transport develops, it becomes increasingly important to understand mechanistic and structure-function relationships for those synthetic compounds that facilitate transmembrane anion transport. We define some key structural aspects that control the Cl anion transport function of an acyclic calixarene analog, triamide 2.We find that the secondary amide NH groups are necessa...
The conductometric sensor based on 25,27-di-(5-thio-octyloxy)calix[4]arene-crown-6 was developed for the quantitative analysis of ammonium. The calixarene was immobilized on the surface of the planar interdigitated electrodes by attachment of its dialkyl sulfide groups to the surface of the gold electrodes. The intrinsic ability of the calixarene to capture ammonium was studied in the conductom...
We have calculated the electron energy deposition distribution in Calixarene negative resist and analyzed the development profile in order to improve the resolution of pattern. From the trajectories and energy deposition distribution in resist at various beam diameters, it is obvious that the thinner resist film should be adopted for formation of very fine dots. The analysis of relationship bet...
Four novel calix[4]arene-based glycoclusters were synthesized by conjugating the saccharide units to the macrocyclic scaffold using the CuAAC reaction and using long and hydrophilic ethylene glycol spacers. Initially, two galactosylcalix[4]arenes were prepared starting from saccharide units and calixarene cores which differ in the relative dispositions of the alkyne and azido groups. Once the m...
Introduction Calixarene is a macrocycle or cyclic oligomer based on a hydroxyl alkylation product of phenols and aldehydes. Calixarenes have hydrophobic cavities that can hold smaller molecules or ions and belong to the class of cavitands known as host-guest chemistry. In 1940s, Zinke & Ziegler discovered base-induced reaction of p-alkylphenols with formaldehyde, which yields cyclic oligomers. ...
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