Two-photon absorption properties of 2,6-bis(styryl)anthracene derivatives: Effects of donor-acceptor substituents and the π center

A series of 2,6- and 2,7-bis-(styryl)anthracene derivatives with the donors at the styryl group and acceptors at the 9,10-positions have been synthesized, and their two-photon cross sections (φδ_max) were determined. These compounds exhibit a peak two-photon absorptivity (δ_max) in the range of 700-2500 GM at 780-1030 nm. Values of λ_max and Stokes shifts increase as the acceptor is changed to a stronger one. There is also a parallel increase in λ_max ⁽²⁾ and δ_max with the same variation of the chromophore structure. Both λ_max⁽²⁾ and φδ_max have been optimized by introducing donor-substituted styryl groups at the 2,6-positions and p-cyanophenyl groups at the 9,10-positions, respectively. The effect of a π center on the two-photon absorption properties has been assessed by comparing the existing data for a variety of D-π-D derivatives.