Inclusion of Alkanes with a Crystal Consisting of Exocavity Complexes of p-Tert-Butylthiacalix[4]arene with Diethylamine: Extension of Guest Scope by Changing the Structure of Inclusion Crystals

A crystal of the exocavity complex of p-Tert-butylthiacalix[4]arene (2) with diethylamine (2·Et₂NH) includes alkanes that cannot be included in a crystal of compound 2 alone and produces two types of inclusion crystals. X-ray crystallographic analysis of inclusion crystals 2·Et₂NH·(hexane)_0.5 and 2·(Et₂NH)_1.5·(heptane)_0.5·H₂O, which were chosen as representatives of the two types, reveals that hexane and heptane are captured in a space surrounded by four self-inclusion dimers of the exocavity complex and in a capsule constructed by two exocavity complexes, respectively. The crystal of 2·Et₂NH selectively includes hexane, heptane, and octane from mixtures with their branched isomers.