Heterocyclic quinol-type fluorophores:: Solid-state fluorescence change in crystals of benzo[b]naphtho[1,2-d]furan-6-one-type fluorophore upon inclusion of organic solvent molecules

The crystals of benzo [b]naphtho [1,2-d]furan-6-one-type fluorophores (1) exhibit sensitive colour and fluorescence change upon enclathration of organic solvent molecules. The crystal of fluorophore 1b (R = Bu) exhibits fluorescence decrease upon inclusion of cyclohexane; however, the crystal of fluorophore 1c (R = Ph) exhibits a drastic fluorescence enhancement upon inclusion of chloroform. To elucidate the enclathrated guest effects on the photophysical properties of the crystals, the X-ray crystal structures of the guest-free and guest-inclusion compounds were determined. On the basis of the spectroscopic data and the crystal structures, the effects of the enclathrated guest on the solid-state photophysical properties of the clathrate compounds are discussed. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).