Results 221 to 230 of about 300,802 (279)
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1996
Abstract Crown ethers are perhaps the most widely used family of host compounds in supramolecular chemistry-the chemistry of the non-covalent bond. The fortuitous discovery of the macrocyclic polyethers by Pedersen in 1967 laid the foundation for an exhaustive study of their preparation and complexing abilities, primarily with metal ...
David B Amabilino +2 more
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Abstract Crown ethers are perhaps the most widely used family of host compounds in supramolecular chemistry-the chemistry of the non-covalent bond. The fortuitous discovery of the macrocyclic polyethers by Pedersen in 1967 laid the foundation for an exhaustive study of their preparation and complexing abilities, primarily with metal ...
David B Amabilino +2 more
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Crown ethers of low symmetry. Spiro crown ethers and 16-crown-5 derivatives
The Journal of Organic Chemistry, 1983Synthese des spirocrowns; evaluation de leur aptitude a la coordination pour l'etude de l'extraction des picrates alcalins. Equilibres d'extraction.
Mikio Ouchi +5 more
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AIP Conference Proceedings, 2012
We use the combined conformational and vibrational analysis methodology to predict in what conformation different crown ethers and some of their complexes exist. Comparison between the structure of some of the low and high energy conformations allows the prediction of the factors that affects the conformational stability of the studied crown ether ...
A. A. El-Azhary +5 more
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We use the combined conformational and vibrational analysis methodology to predict in what conformation different crown ethers and some of their complexes exist. Comparison between the structure of some of the low and high energy conformations allows the prediction of the factors that affects the conformational stability of the studied crown ether ...
A. A. El-Azhary +5 more
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Liquid Crystalline Crown Ethers
2011In 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.
Martin, Kaller, Sabine, Laschat
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The synthesis of anthracene crown ethers derived from benzo-crown ethers
Tetrahedron, 1998Abstract The sulfuric acid-promoted reaction of benzo-15-crown-5 (3) and benzo-18-crown-6 (6) with aliphatic aldehydes, leading to the formation of anthracene crown ethers, was studied. A substantial substituent effect on the reaction course was found.
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The synthesis of novel crown ethers, part ix, 3‐phenyl chromenone‐crown ethers
Journal of Heterocyclic Chemistry, 2001Abstract3‐Phenyl‐ and 3‐(p‐methoxyphenyl)‐7,8‐dihydroxy and ‐6,7‐dihydroxychromenones were prepared from ethyl 3‐oxo‐2‐phenylpropanoate, ethyl 3‐oxo‐2‐(4‐methoxyphenyl)‐propanoate and the trihydroxy benzenes in H2SO4. 3‐Aryl‐7,8‐ and 3‐aryl‐6,7‐dihydroxy‐2H‐chromenones reacted with the bis‐dihalides of poly‐glycols in DMF/MeCO3 to afford 12‐Crown‐4, 15‐
M. Bulut, Ç L. Erk
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Dibenzotetraaza Crown Ethers: A New Family of Crown Ethers Based on o-Phenylenediamine
The Journal of Organic Chemistry, 2005Dibenzotetraaza (DBTA) crown ethers possess two o-phenylenediamine moieties. They are homologues of dibenzo crown ether phase-transfer catalysts and were prepared from the condensation of benzimidazoles with oligo(ethyleneglycol) dichlorides and oligo(ethyleneglycol) ditosylates.
Sven H, Hausner +3 more
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ChemInform Abstract: Novel Crown Ethers by Oxidative Cycloaddition of Thiopheno Crown Ethers.
ChemInform, 1995AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Y. Q. LI +3 more
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2017
In this chapter, we demonstrated different strategies toward the construction of photochromic crown ethers in order to obtain the capability to recognize the chemical guest while retaining the photoswitchability. The complex formation in photochromic crown ether can be either spontaneous or stimulated by irradiation with light of the photochromic part.
Olga Fedorova +2 more
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In this chapter, we demonstrated different strategies toward the construction of photochromic crown ethers in order to obtain the capability to recognize the chemical guest while retaining the photoswitchability. The complex formation in photochromic crown ether can be either spontaneous or stimulated by irradiation with light of the photochromic part.
Olga Fedorova +2 more
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Russian Journal of General Chemistry, 2002
Studies on mesomorphic crown ethers, their analogs, published during the past two decades'are briefly summarized and correlated. Speicific features of mesophase formation, as influenced by the structure of the macrorings, are analyzed. The effect of structural factors on formation of various types of liquid crystals is discussed.
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Studies on mesomorphic crown ethers, their analogs, published during the past two decades'are briefly summarized and correlated. Speicific features of mesophase formation, as influenced by the structure of the macrorings, are analyzed. The effect of structural factors on formation of various types of liquid crystals is discussed.
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