Structural identification of a new piperazino-crown ether derivative using 23Na nuclear magnetic resonance

1989 ◽  
Vol 30 (33) ◽  
pp. 4333-4336 ◽  
Author(s):  
Harald D.H. Stöver ◽  
Christian Detellier
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Crown Ether ◽  
Structural Identification ◽  
Ether Derivative ◽  
Nuclear Magnetic

13C nuclear magnetic resonance spectra in the solid state of 18-crown-6•NaNCS•H2O, some dicyclohexyl-18-crown-6 ethers, and their complexes with phenoxides and phenol

1987 ◽  
Vol 65 (11) ◽  
pp. 2564-2567 ◽  
Author(s):  
G. W. Buchanan ◽  
M. Z. Khan ◽  
J. A. Ripmeester ◽  
J. W. Bovenkamp ◽  
A. Rodrigue
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Crown Ether ◽  
Solid Phase ◽  
Chemical Shifts ◽  
Nuclear Magnetic Resonance Spectra ◽  
Symmetry Properties ◽  
13C Nuclear Magnetic Resonance ◽  
Torsional Angles ◽  
Nuclear Magnetic

High resolution 13C CPMAS spectra for three configurationally isomeric dicyclohexyl-18-crown-6 ethers and three complexes derived therefrom are presented. Spectra are consistent with conformationally locked crown ether structures at 298 K. Data are discussed in terms of the symmetry properties of the macrocycles and stereochemical effects on 13C chemical shifts in the solid phase. For the complex of 18-crown-6 with NaSCN and H2O, a single line is observed at 298 K. Temperature reduction removes the chemical shift averaging as the different torsional angles of the solid crown ether undergo distortions that become slow on the nuclear magnetic resonance timescale.

scholarly journals Membrane transport systems. VI. Complexation of cations by lipophilic crown ether carboxylic acids

1984 ◽  
Vol 62 (3) ◽  
pp. 507-514 ◽  
Author(s):  
Thomas M. Fyles ◽  
Dennis M. Whitfield
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Crown Ether ◽  
Carboxylic Acids ◽  
Electrostatic Interactions ◽  
Chloroform Solution ◽  
Ion Pair ◽  
Transport Systems ◽  
Resonance Spectroscopy ◽  
Nuclear Magnetic

The complexation of alkali metal and alkaline earth cations by crown ether carboxylic acids has been studied by potentiometric titration and by infrared and nuclear magnetic resonance spectroscopy. Complexation in methanol–water solution is governed by the electrostatic interactions between the cation and the carboxylate, hence discrimination among cations on the basis of ionic radius is poor. The isomers syn and anti (8NH)218-6A2 exhibit differing complexation behaviour towards cations with the anti isomer giving the stronger complexes. Interaction between the carboxylates across the face of the macrocycle of syn (8NH)218-6A2 can be inferred from the potentiometric data. Combined infrared and nuclear magnetic resonance studies of the complexes in chloroform solution show that the cation is held as an asymmetric tight ion pair with the carboxylate. The dimeric salt (4NH18-6)2Ca exhibits both a tight and a symmetric or loose ion pair between the cation and the two carboxylates. The substituents on the macrocycle are pseudoaxially disposed and in some cases gauche ethylenedioxy units can be recognized from the spectra. The complexes are monomeric in solution and in most cases the conformations are unaffected by small amounts of water in the chloroform solution. The structural results correlate with observations from transport experiments.

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