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.