Structure-photophysics correlation in a series of 2,6-dimethyl-4-arylpyrylium derivatives

Photophysical properties of a group of closely related pyrylium cations, 1–5, are reported. Our results indicate that these cations have two excited states with similar energies and that the substituent determines which of these has the lowest energy. For cations 1 and 2, the lowest excited state has TICT character. In the case of 3–5, the photophysical properties are better explained by invoking a planar excited state.