Synthesis, structure, and redox properties of a quinone-bridged calix[6]arene

The bridged calix[6]arene 1, where a 1,4-benzoquinone moiety is covalently anchored in the cavity of the calix[6]arene macrocycle with a rigid cone conformation, was synthesized and its structure was determined by X-ray analysis. The cyclic voltammogram showed that the reduction potential of 1 is negatively shifted in comparison with the reference compounds without the calixarene macrocycle, whose shift can be explained in terms of the interaction between the quinone moiety and the oxygen atoms at the lower rim of the calixarene framework.