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.