Acid vapor–responsive supramolecular gels of hydrogen-bonding D–A type fluorenones

Abstract In this study, we investigated the gelation properties and stimulus-responsive behavior of donor–acceptor–donor-type (D–A–D-type) fluorenone derivatives bearing urethane units. The fluorenone derivatives exhibited characteristic photophysical properties that originate from π–π* and intramolecular charge transfer transitions, and dilute solutions exhibited fluorescence solvatofluorochromic behavior. In addition, the donor–acceptor–donor-type fluorenone derivatives formed supramolecular gels in appropriate organic solvents; these gels also exhibited acid vapor–responsive functional variations.