Two-photon absorption properties of 9,10-disubstituted 2,6-bis(p-dihexylaminostyryl)anthracene derivatives. Effect of 9,10-substituents.

A series of 2,6-bis(p-dihexylaminostyryl)anthracence derivatives having phenyl, styryl, and phenylethynyl groups at 9,10-positions (1-4) have been synthesized and their two-photon cross-sections were determined. Overall, the wavelengths of the longest wavelength absorption band and emission spectra increase with increase in the conjugation length and the electron withdrawing ability of the 9,10-substituents. All compounds show two-photon cross sections in the range of 740-3940 GM at 780-960 nm, which increase significantly by the donor and acceptor groups at 9,10-positions. In addition, Ph and phenylethynyl groups are better when compared to the styryl group at the 9,10-positions in terms of the two-photon action cross section. From a practical perspective, 1a, 2a-c, and 4b showed significant two-photon action cross-section and are most useful for applications that use two-photon excited fluorescence.