Investigation of the interaction of macrocyclic polyethers with water by PMR spectroscopy

Golovkova, L. P.; Telyatnik, A. I.; Bidzilya, V. A.

doi:10.1007/bf00592815

Cited by 1 publication

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“…The NMR studies performed by Golovkova et al 15 in CDCl 3 investigated several compounds also covered in our work (15C5, 18C6, and DCH18C6). In their work, singlephase measurements were made with a constant water concentration and varying ligand concentrations.…”

Section: Resultsmentioning

confidence: 84%

“…Proton nuclear magnetic resonance (NMR) is a very precise analytical technique for measuring the amount and chemical environment of water in organic solvents. Early NMR studies by de Jong et al and Golovkova et al have shown that various crown ethers interact with water to form 1:1 complexes in CHCl 3 . An IR study by Moyer et al has likewise demonstrated formation of a 1:1 water−crown ether complex in CCl 4 .…”

Section: Introductionmentioning

confidence: 99%

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Partition Coefficients and Equilibrium Constants of Crown Ethers between Water and Organic Solvents Determined by Proton Nuclear Magnetic Resonance

et al. 2004

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The extraction of water by several crown ethers into chloroform + carbon tetrachloride mixtures has been investigated using a proton NMR technique. The equilibrium is well described by formation of a 1:1 water−crown complex in rapid exchange with uncomplexed ligand and water. The fraction (k) of crown ether complexed with water increases with crown cavity size, varying from (15 ±1)% for 12-crown-4 to (97 ± 5)% for 18-crown-6. Addition of carbon tetrachloride to chloroform lowers the k value for all crown ethers in equilibrium with water, and the value is close to zero in pure CCl4. The partition coefficient follows the opposite trend: the amount of crown ether in the organic phase increases with the percentage of CCl4 in this phase. The chemical shifts of free and complexed water also vary with solvent composition. Interaction of water with crown ether depends on solvation environment and may play a significant role in liquid−liquid extraction of metal ions using macrocyclic polyethers as extractants.

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Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%