Newly synthesized tetraoxa-diaza crown ether derivatives versus commercialized crown ethers in the separation of positional isomers with capillary electrophoresis

2006 ◽  
Vol 41 (4) ◽  
pp. 1164-1170 ◽  
Author(s):  
Peter Forlay-Frick ◽  
Debby Mangelings ◽  
Tímea Iványi ◽  
István Lázár ◽  
Károly Héberger ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Crown Ether ◽  
Crown Ethers ◽  
Positional Isomers

Application of Crown Ethers as Buffer Additives in Capillary Electrophoresis

2010 ◽  
Vol 6 (2) ◽  
pp. 101-113 ◽  
Author(s):  
Abdalla A. Elbashir ◽  
Hassan Y. Aboul-Enein
Keyword(s):  
Capillary Electrophoresis ◽  
Crown Ethers

Crown ethers in hydrogenated graphene

2021 ◽  
Author(s):  
Kai Guo ◽  
Sitong Liu ◽  
Haoming Tu ◽  
Zhikun Wang ◽  
Liang Chen ◽  
...  
Keyword(s):  
Crown Ether ◽  
Crown Ethers ◽  
Hydrogenated Graphene ◽  
High Flexibility

Crown ethers could serve as hosts to selectively incorporate various guest atoms or molecules within the macrocycles. However, the high flexibility of crown ether molecules limits their applications in areas...

1,8-Dioxyanthracene-Derived Crown Ethers: Synthesis, Complexation with Paraquat and Assembly of a Tetracationic Cyclophane-Crown Ether Based [2]Catenane

2014 ◽  
Vol 2014 (31) ◽  
pp. 6925-6934 ◽  
Author(s):  
Bo Tang ◽  
Hong-Mei Yang ◽  
Wen-Jing Hu ◽  
Ming-Liang Ma ◽  
Yahu A. Liu ◽  
...  
Keyword(s):  
Crown Ether ◽  
Crown Ethers

ChemInform Abstract: Synthesis of Two 1,3-2,4-Calix[4]bis-crown Ethers Containing Two 1,2-Phenylene and One Pyridine or Anisole Units in Each Crown Ether Moiety.

ChemInform ◽  
2010 ◽  
Vol 31 (25) ◽  
pp. no-no
Author(s):  
Guo-Ping Xue ◽  
Jerald S. Bradshaw ◽  
Ning Su ◽  
Krzysztof E. Krakowiak ◽  
Paul B. Savage ◽  
...  
Keyword(s):  
Crown Ether ◽  
Crown Ethers ◽  
Crown Ether Moiety

Polycarboxylate crown ethers from meso-tartaric acid

1991 ◽  
Vol 69 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Frank R. Fronczek ◽  
Richard D. Gandour ◽  
Thomas M. Fyles ◽  
Philippa J. Hocking ◽  
Susan J. McDermid ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crown Ether ◽  
Tartaric Acid ◽  
Crown Ethers ◽  
Nmr Spectra ◽  
Product Distribution ◽  
Complexing Agents ◽  
Triclinic Space Group ◽  
The Stability ◽  
Ether Synthesis

The synthesis of crown ethers derived from meso-tartaric acid was investigated. The sodium salt of the bis(dimethylamide) of meso-tartaric acid reacted with diethylene glycol ditosylate to give a mixture of 18-crown-6 tetraamide and 27-crown-9 hexaamide crown ethers. The 2R,3S,11S,12R 18-crown-6 isomer crystallized in triclinic space group [Formula: see text] (a = 7.557(2), b = 8.866(2), c = 10.4133(13) Å, α = 94.13(2), β = 95.86(2), γ = 99.26(2)°, R = 0.040 for 2090 observed of 3129 unique reflections). The structures of the remaining products were then assigned from the NMR spectra. The solution conformations of the amide crown ethers were examined by NMR, and provide a rationale for the product distribution obtained. One of the 18-crown-6 isomers and a mixture of the two 27-crown-9 isomers were hydrolyzed to the respective crown ether carboxylic acids, and the stability constants for complexation of cations were determined by potentiometric titration. The meso tetra- and hexacarboxylates are remarkably nonselective and inefficient cation complexing agents, compared to related crown ethers from R,R-(+)-tartaric acid, due to the unfavorable conformational control exerted by the tartaro units. Key words: crown ether synthesis, complexation, crown ether conformation, meso-tartaric acid, crystal structure.

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