Photoisomerization of cyclopentene-based β-(2-furanyl)- and β-(2-thienyl)enones

Abstract

The potential of photoisomerization of β-(2-furanyl)- and β-(2-thienyl)enones in the field of optical memory was explored by synthesis and thorough studies of the cyclopentene-based series with different substituents on the aryl moiety. X-ray crystallographic analysis of the synthesized β-(2-furanyl)- and β-(2-thienyl)enones established the constant conformation of the molecule in the crystal for all studied compounds with a dependency neither on the heteroatom of the 5-membered ring, nor on the nature of the substituent on the aromatic ring. In solution under UV irradiation, the presence of the electron-withdrawing nitro group not only promotes a photoisomerization of the β-(2-thienyl)enone skeleton but also stabilizes the photoproduct of the corresponding β-(2-furanyl)enone. This photoproduct, fully characterized and studied in different solvents, shows a remarkable dependence of its fluorescent properties on the polarity of the media. Large Stokes shift values and minimal overlapping of absorption and fluorescent bands of the photoproduct in polar solvents suggest potential applications of the studied photoreaction in optical data storage.