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Crown ether intercalations with phyllosilicates


IT has been discovered in the past decade that some macrocyclic polyethers (crown ethers) act as ligands to form stable complexes with salts of numerous metals. These are the first synthetic compounds able to coordinate to alkaline cations1–3. The cyclic structure of the crown ethers creates a circular cavity of oxygen atoms to which the cations coordinate. The diameter of this cavity as well as the relative size of the cation, determine the stability of the resulting complexes, and the cationic selectivity depends on it. The most studied crown ethers are derived from so called 15-crown-5 and 18-crown-6: We have shown experimentally and report here that the crown ethers are able to intercalate between the layers of the 2:1 phyllosilicates, saturated with alkaline or alkaline-earth cations, showing an unusual stability. The complexes were obtained mainly by immersion of homoionic montmorillonites (Wyoming bentonite), in different solutions of crown ethers. Hectorite and vermiculite were also tested with positive results.

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  1. Pedersen, C. J. J. Am. chem. Soc. 89, 7017–7036 (1967).

    Article  CAS  Google Scholar 

  2. Kappenstein, C. Bull. Soc. Chim. 89–109 (1974).

  3. Christensen, J. J., Eatough, D. J. & Izatt, R. M. Chem. Rev. 74, 351–384 (1974).

    Article  Google Scholar 

  4. McEwan, D. M. C. Trans. Faraday Soc. 44, 349–367 (1948).

    Article  Google Scholar 

  5. Mortland, M. M. Adv. Agronom. 22, 75–117 (1970).

    Article  CAS  Google Scholar 

  6. Theng, B. K. G. The Chemistry of Clay-Organic Reactions (Adam Hilger, London, 1974).

    Google Scholar 

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RUIZ-HITZKY, E., CASAL, B. Crown ether intercalations with phyllosilicates. Nature 276, 596–597 (1978).

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