meta-Substituted triphenylamines as new dyes displaying exceptionally large Stokes shifts

A straightforward synthesis of fluorescent tris-meta-substituted triphenylamines (m-TPAs) is presented. These new fluorophores display a unique feature that is a remarkably high Stokes shift up to 250 nm, as compared to their para counterparts. Although the meta substitution is made at the expense of the quantum yield, the latter is maintained at an appreciable level (5%) making the m-TPAs a new class of fluorophores adaptable to a large range of applications from biology to materials science.