Structure-property investigations of substituted triarylamines and their applications as fluorescent pH sensors.

Fourteen triphenylamine derivatives functionalized with fluorophenyl, methoxyphenyl, and pyridinyl groups as respective donors and acceptors were synthesized and characterized. Their photophysical properties were systematically investigated in various solvents with different polarities. The solvent-dependent Stokes shifts of these compounds were observed and analyzed by the Lippert-Mataga equation. The synthesized compounds, especially tris(4-(pyridin-4-yl)phenyl) amine, presented pH-dependent absorptions and emissions, indicating that these compounds might be used as pH sensors.