Crystal Polymorphism-Dependent Fluorescence Of Fluoroarene-Substituted Anthracene Derivatives

Fluorine-substituted 1-phenylanthracene derivatives were synthesized and their polymorphism-dependent fluorescence color change (B: blue and G: green) in the crystalline state was observed. For the green luminous crystals (G), a 1D linear pi-pi stacked structure of the anthracene rings and intermolecular Ar-F center dot center dot center dot H-Ar hydrogen bonding were observed. On the other hand, for the blue luminous crystals (B), weaker or no pi-pi stacked anthracene rings were observed. These crystallographic observations indicated the existence of the excimer emission and the monomer emission of the anthracene rings for the green (G) and blue (B) luminous crystals, respectively. Interestingly, thermal transformations of the green luminous crystals (G) to the blue luminous crystals (B) were observed. The mechanochromic and vapochromic properties of the obtained crystals were also evaluated.