6-Aryldibenzo[b,d]pyrylium salts: synthesis and characterization of a reversible pH-driven optical and spectroscopic response

This preliminary report describes the synthesis of three 6-aryldibenzo[b,d]pyrylium salts, a relatively unexplored structural unit. The optical and spectroscopic properties of the 6-aryldibenzo[b,d]pyrylium salts were examined as a function of pH. All three compounds displayed bright colors under acidic conditions and were colorless under basic conditions. The halochromism of the molecules was shown to be reversible.