Single-Crystal-to-Single-Crystal Transformation of Di(isopropylammonium) (Z,Z)-Muconate into the (E,E)-Muconate during One-Way Photoisomerization in the Solid State

The solid-state EZ photoisomerization of di(isopropylammonium) ( Z,Z )-muconate ( ZZ-1a ) into the corresponding EE isomer ( EE-1a ) via a single-crystal-to-single-crystal reaction process was investigated. The molecular motion based on a bicycle-pedal model was directly observed during the photoisomerization in the crystals by an X-ray single crystal structure analysis. The photoirradiation of ZZ-1a provided EE-1a in a quantitative yield via a one-way isomerization mechanism, being different from the solution products in the photostationary state. The isomerization reactivity was discussed for the ammonium and ester derivatives of muconic acid.