title: Single-crystal-to-single-crystal E --> Z isomerization of tiglic acid in a supramolecular framework.
abstract: The single-crystal-to-single-crystal E --> Z photoisomerization of tiglic acid (2,3-dimethylacrylic acid) occurs in the supramolecular crystals CECR-HTA x 2MeOH x 1.5H(2)O (1) (where HTA = tiglic acid, CECR = C-ethylcalix[4]resorcinarene) with the preservation of the crystal lattice, indicating the ;scaffolding effect' of the molecular framework, which holds the crystal together notwithstanding the change in shape of the embedded guest molecules. A photostationary state is reached at a concentration of ca 30% of the Z isomers. A kinetic analysis shows the Z --> E back-reaction to proceed with a larger rate constant than the E --> Z isomerization.
authors.affiliation: Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA.
authors.forename: Shao Liang
authors.initials: SL
authors.lastname: Zheng
authors.forename: Marc
authors.initials: M
authors.lastname: Messerschmidt
authors.forename: Philip
authors.initials: P
authors.lastname: Coppens