Heterocyclic quinol-type fluorophores. Dramatic solid-state fluorescence enhancement behaviour of imidazoanthraquinol-type clathrate hosts upon inclusion of various kinds of organic solvent molecules

The crystals of novel imidazoanthraquinol- type clathrate hosts exhibit sensitive colour change and fluorescence enhancement behaviour upon enclathration of various kinds of organic solvent molecules. The optical changes are greatly dependent on the identity of the enclathrated guest molecules. To elucidate the enclathrated guest effects on the fluorescence properties of the crystals, the X- ray crystal structures of the guest- free and guest- inclusion compounds have been determined. On the basis of the spectral data and the crystal structures, the effects of the enclathrated guest on the solid- state photophysical properties of the clathrate compounds are discussed.