Cinnamic acids upon irradiation in solution undergo geometric isomerization while dimerizing to different dimers in the crystalline state. Controlling the nature of the dimer formed upon irradiation remains a challenging task. We have aligned a variety of cinnamic acid molecules in a head-head fashion employing cucurbituril, a weakly water soluble host as a template. The water solubility of cucurbituril is enhanced by inclusion of water soluble cinnamic acids and positions the olefins in an arrangement that favors the formation of syn head-head cyclobutanes in near quantitative yields. This methodology works in both solid state as well as in aqueous solution. Irradiation of cinnamic acid complexes with γ-cyclodextrin has been carried out as a comparison. We find that while cucurbituril functions well both in solid state and aqueous solution, cyclodextrin works best as solid complexes only. Consistent with the postulated requirement of large cavities for templating olefins to dimerization, irradiation of complexes of cinnamic acid with cucurbituril resulted in only the corresponding cis isomers.
|Original language||English (US)|
|Number of pages||5|
|State||Published - Aug 29 2006|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces