Synthesis and Solid-State Conformation of a Calix[8]arene 1,5-Diquinone Derivative

Abstract

The first example of a calix[8]quinone derivative, hexamethoxy-p-tert-butylcalix[8]-1,5-diquinone 5, has been synthesized from p-tert-butylcalix[8]arene 1by exploiting a protection-deprotection procedure. The structure of the 5·toluene inclusion compound has been determined by a single crystal X-ray diffraction study. The calix[8]arene molecule possesses a crystallographic inversion centre and assumes a ‘pseudo-chair-like’ conformation, with two opposite 3/4-cone moieties, which resembles the previously reported chair-like conformation of p-tert-butylcalix[8]arene. The 4 toluene molecules per unit cell occupy interstitial voids and are released in the temperature range of 30–160 °C.