Head-to-head linked double calix[4]arenes: Convenient synthesis and complexation properties

Combination of calix[4]arenes functionalized at the upper rim at the 5- and 17-positions with amino and formyl groups, respectively, gives a new series of ''head-to-head'' linked double calix[4]arenes in nearly quantitative yield. The X-ray structure of a modified double calix[4]arene is reported. The novel, highly preorganized receptor molecules complex silver(I) ions (K-ass = 9.5 x 10(5) M-1 in CDCl3); the selectivity of complexation was studied by supported liquid membrane transport experiments and chemically modified field effect transistor measurements.