84992-94-9Relevant academic research and scientific papers
Ligands for the Alkali Metals. Part 6. Some Bis(crown) Schiff Bases which form Pocket Complexes with Alkali-metal Cations of Appropriate Size
Handyside, Timothy M.,Lockhart, Joyce C.,McDonnell, Martin B.,Rao, P. V. Subba
, p. 2331 - 2336 (1982)
Three homologous series of bis(crowns) have been produced by condensation of the appropriate formylbenzocrown with long-chain α, ω-diaminoalkanes.The ligands may be viewed as pocket or crevice sites for alkali-metal cations, lined with donor groups to provide ion-dipole interaction and terminated by a hydrophobic methylene chain.The interaction of these ligands with alkali-metal cations has been investigated by spectroscopic techniques and solvent extraction.Pocket complexes of these bis(crowns) with alkali-metal cations were apparently formed in 'best-fit' situations: thus bis(crown-5) compounds formed pocket complexes with cations larger than sodium, while bis(crown-6) ligands formed pocket complexes with cations larger than potassium.The bis(crown-4) ligands did not appear to complex strongly with any cation.The rates of trapping and release of alkali-metal cations from some of these ligands in methanol solution, investigated by temperature-jump techniques, indicate behaviour distinct from that of any of the crown and cryptand types described in the literature.
