Control of molecular aggregation in inclusion crystals by phase transition

Department of Chemistry, Okayama University of Science
â—‹Fumio Toda

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.