The 16th International Conference on the Chemistry of the Organic Solid State

"ASSEMBLY MODES OF HELICAL TAPES IN BRUCINE INCLUSION CRYSTALS"

Tsuyoshi WATABE, Norimitsu TOHNAI and Mikiji MIYATA

Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka,

Suita, Osaka 565-0871, JAPAN,

Tel: +81-6-6879-7406  Fax: +81-6-6879-7404

    Many chemists have been much interested in the prediction of organic crystal structures. It is anticipated that the analysis of their hierarchical structures will serve as the first step to dissolve the crystal structures theoretically. In this study we focus on the hierarchical structure of brucine crystals.

    Brucine was recrystallized from various organic solvents.  It was confirmed that brucine forms inclusion compounds with neutral guest molecules, such as aliphatic alcohols, ketones, esters, aromatic compounds and so on.  X-ray crystallographic studies of the resulting crystals indicate that there exists a common helical tape as their host framework. The asymmetric tape has a distinguishable direction, because brucine has an asymmetric molecular structure with three distinguishable directions.  When such asymmetric helical tapes assemble, we can theoretically estimate many assembly modes.  Some of them were observed, depending on guest molecules in volume, shape and polarity.  The analysis of the assembly modes may enable us to predict hierarchical structures of brucine inclusion crystals.