Highly preorganized bis(benzocrown ether)s for the binding of metal ions

Article abstract of DOI:10.1016/0040-4039(94)88220-7

Several bis(crown ethers)s consisting of benzo-12-crown-4, benzo-15-crown-5, and benzo-18-crown-6, were prepared and their complexation properties with Na⁺ and K⁺ were determined by the liquid-liquid extraction method. The remarkable 'biscrown effect' was observed in the extractions of both Na⁺ and K⁺ using bis(benzo-12-crown-4) and bis(benzo-15-crown-5). Unsymmetrical bis(crown ether)s also exhibit much higher extractabilities of both Na⁺ and K⁺ than the corresponding mono(benzocrown ether)s.