Steric control of conformation in self-assembly metallacalix[4]arenes derived from AlMe3 or GaMe3 with benzimidazolyl ligands

Metallacalix[4]arenes [bzimAlMe(2)](4) (1), [bzimGaMe(2)](4) (2), [mbzimAlMe(2)](4) (3) and [mbzimGaMe(2)](4) (4) were obtained by self-assembly. The larger cavity of 3 and 4 allows them to function as hosts of benzene molecules.