A new calix[4]arene binding site. Strong cooperativity in cation binding by a two site receptor
Abstract
The new calix[4]arene derivatives 6 and 9, which are both readily prepared from the cone conformations of calix[4]arene tetra-ethers, are both ionophores which show some Na+/K+ selectivity; the derivative 6 with two cation binding sites shows evidence for cooperativity between the two mechanically linked sites.