Synthesis and Complexation Properties of “Zorbarene”:  A New Naphthalene Ring-Based Molecular Receptor

The syntheses of the first 2,3-dialkoxy-substituted naphthalene ring-based macrocycles which have calixarene-like structures are reported. The complexation properties of these octahomotetraoxaisocalix[4]naphthalenes were investigated. These new members of the calixnaphthalene family did not demonstrate any appreciable complexation with C60 or C70 under the conditions studied, but did so with the tetramethylammonium cation, showing relatively strong association constants suggesting among other considerations that stronger cation-π interactions versus π−π interactions are operative with these hosts. An X-ray crystal structure of the octa-O-ethoxy derivative revealed a structure having a “flattened partial-cone” conformation in which two acetonitrile guest molecules are trapped.