منابع مشابه
Liquid crystalline crown ethers.
In this chapter, a comprehensive review over the entire reserarch on liquid crystalline crown ethers since their discovery will be given. Monomeric and polymeric molecules containing crown ethers as well as aza crown ethers, thia crown ethers and crown ethers with several different heteroatoms will be presented. Liquid crystallinity is, in most cases, caused by the substituents attached to the ...
متن کاملCrown Ethers in Enantioselective Synthesis
A number of new chiral crown compounds and lariat ethers have been synthesized starting from phenyl-D-glucopyranoside, methyl-D-glucopyranoside and galactopyranoside, methyl-D-mannopyranoside and 1,2:5,6-di-O-isopropylidene-D-mannitol, but the main emphasis was laid on their application. Some of the sugar-based macrocycles showed significant asymmetric induction as phase transfer catalysts in l...
متن کاملMagnetic nanoparticle-supported crown ethers.
Magnetic nanoparticle (MNP)-supported crown ethers were successfully prepared and evaluated as catalysts for solid-liquid phase-transfer reactions; the catalytic activities of the MNP-supported crown ethers were not inferior to those of non-supported crown ethers; after the reactions, the catalysts could be readily separated using an external magnet and reused without significant loss of cataly...
متن کاملThe discovery of crown ethers.
The discovery of the crown ethers stemmed from efforts to control the catalytic activity of vanadium and copper by complexation with multidentate ligands. The first crown ether, 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene, was obtained in 0.4% yield during an attempt to prepare a phenolic ligand from catechol and bis(2-chloroethyl)ether. This compound, which complexed with...
متن کاملCrown ethers : applications in inorganic synthesis
The ability of macroheterocyclic compounds to complex with ionic species has led to the synthesis and investigation of many multidentate macroheterocyclic species . The most stable complexes are formed between macrocyclic polyetheral ligands (crown ethers) with alkali or alkaline earth metal iona. There is an excellent correlation of the stability of these complexes with the size of the cation ...
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ژورنال
عنوان ژورنال: Nature Communications
سال: 2014
ISSN: 2041-1723
DOI: 10.1038/ncomms6389