Department of Chemistry, Okayama University of Science
Aggregation pattern of moleclules in inclusion crystals can easily be controlled by phase transition in the solid state.
Molecular aggregation of a guest molecule in its inclusion complex with a host compound was transferred into a completely different molecular aggregation by a phase transition in the solid state. For example, a photochemically unreactive inclusion crystal of 5-methyl-2-pyridone with 1,3,5-benzenetricarboxylic acid was converted in the solid state into a reactive phase by heating or by contact with MeCN vapor. A racemic complex of rac-2,2'-dihydroxy-1,1'-binaphthyl and Me4NCl was converted into a conglomerate complex by heating or by contact with MeOH vapor at room temperature. These phase transitions were studied by IR spectra and X-ray analysis.