نتایج جستجو برای: calixarene

تعداد نتایج: 421  

2014
Petri M. S. Pulkkinen Jukka Hassinen Robin H. A. Ras Heikki Tenhu

This paper describes a detailed study on the complexation of pyridinium derivatives with calixarenes bound to gold nanoparticles (AuNPs). The studied calixarene derivatives are mixed with alkanethiols to formmixed monolayers on AuNP surfaces. The key findings are: (i) even a small amount (less than 11 mol%) of calixarenes can retain their complexation abilities among a majority of alkanethiols ...

2008
Conrad Fischer Tobias Gruber Wilhelm Seichter Diana Schindler Edwin Weber

In the title compound, C(48)H(64)O(4)·0.5CH(2)Cl(2), both crystallographically independent calixarene mol-ecules display a partial cone conformation. Their crystal packing is stabilized by C-H⋯π contacts involving the meth-oxy groups. The solvent mol-ecule is located inter-stitially between two calixarene units with C-H⋯Cl contacts to meth-oxy and tert-butyl groups. One tert-butyl residue of ea...

Journal: :Chemical communications 2016
Lena Kaufmann Stuart R Kennedy Christopher D Jones Jonathan W Steed

We present two approaches to low-molecular-weight supramolecular gels bearing hydrophobic cavities based on calixarene-containing building blocks. Gels are formed by a calixarene based tetrahydrazide gelator or a co-gel of a calixarene diammonium salt and a bis-crown ether. The calixarene hydrophobic cavity enables the complexation of hydrophobic drug molecules in a generic fashion thus providi...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2011
Anthony B Thompson Sydney J Cope T Dallas Swift Justin M Notestein

Materials were synthesized for the recovery of n-butanol from dilute aqueous solutions, as may be useful for applications in biofuel-water separations. These materials are composed of hydrophobic, cavity-containing calixarenes covalently bound directly to porous, hydrophilic silica supports through a Si linker atom rather than a flexible organic linker, as is common, at surface coverages of up ...

Journal: :Chemical communications 2013
Karolína Flídrová Petr Slavík Václav Eigner Hana Dvořáková Pavel Lhoták

The regioselective mercuration of tetraalkylated calix[4]arenes with Hg(OCOCF3)2 leads to the formation of meta-substituted products which enabled Pd-catalysed intramolecular bridging within the calixarene skeleton. Bridged derivatives represent a completely novel substitution pattern in calixarene chemistry with extremely distorted cavities and possible applications in supramolecular chemistry.

Journal: :Organic & biomolecular chemistry 2015
Varun Rawat Konstantin Press Israel Goldberg Arkadi Vigalok

Here, we report a simple one-step access to new rigid N,O-calixarene ligands which is based on copper-catalyzed amination at the lower rim. We also present the coordination properties of these ligands with some main group and transition metals leading to new complexes with superior catalytic activity, in several organic transformations, compared with calixarene metal complexes reported in the l...

Journal: :Journal of chromatographic science 2012
Kai Hu Ajuan Yu Junqiang Zhang Fuyong Wen Song Liang Xiaolan Zhao Baoxian Ye Yangjie Wu Shusheng Zhang

Three end-capped para-benzoyl calixarene bonded silica gel stationary phases are prepared and characterized by elemental analysis, infrared spectroscopy, and thermal analysis. The comparison and selectivity of these phases are investigated by using PAHs, disubstituted benezene, and naphthalene positional isomers as probes. Possible separation mechanism based on the different interactions betwee...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2006
Justin M Notestein Alexander Katz Enrique Iglesia

Calixarenes grafted on silica are energetically uniform hosts that bind aromatic guests with 1:1 stoichiometry, as shown by binding energies that depend upon the calixarene upper rim composition but not on their grafted surface density (0.02-0.23 nm(-2)). These materials are unique in maintaining a hydrophilic silica surface, as probed by H2O physisorption measurements, while possessing a high ...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2005
P Leyton C Domingo S Sanchez-Cortes M Campos-Vallette J V Garcia-Ramos

Surface-enhanced IR (SEIR) and Raman scattering (SERS) have been employed to study the adsorption of ester functionalized tert-butyl calix[4]arenes on Ag and Au nanostructured surfaces as well as their complexes with pyrene. The influence of adsorption and complexation with pyrene on the host calixarene structure was tested for two different calixarene molecules bearing carboethoxy groups (CH(3...

2016
James P. Buttress David P. Day James M. Courtney Elliot J. Lawrence David L. Hughes Robin J. Blagg Alison Crossley Susan E. Matthews Carl Redshaw Philip C. Bulman Page Gregory G. Wildgoose

We herein report the synthesis of novel "Janus" calix[4]arenes bearing four "molecular tethering" functional groups on either the upper or lower rims of the calixarene. These enable facile multipoint covalent attachment to electrode surfaces with monolayer coverage. The other rim of the calixarenes bear either four azide or four ethynyl functional groups, which are easily modified by the copper...

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