Fulleropillar[4]arene: The Synthesis and Complexation Properties

A multihydroquinone ether dialdehyde derivative 2 was incidentally obtained through an unexpected ring opening of pillar[4]­arene[1]­quinone 1. And the Prato reaction of 2 with [60]­fullerene led to [60]­fullerene bisadducts, from which trans-4 cyclic regioisomer 3 was isolated and characterized. The fulleropillar[4]­arene 3 showed a larger cavity and can accommodate a viologen derivative C₁₂V²⁺ with a much stronger affinity than permethyl pillar[5]­arene (MP5) and pillar[4]­arene[1]­quinone 1.