Synthesis and photophysical properties of new two-photon absorption chromophores containing a diacetylene moiety as the central π-bridge

We report two-photon absorption properties of newly synthesized compounds consisting of styrylpyridines or their triflates linked by a diacetylene π-bridge in a symmetric way as well as the compounds containing the same substituent groups linked by a phenylenevinylene-type π-bridge. Femtosecond open aperture Z-scan measurements revealed that the two-photon absorption cross-sections σ(2) of the diacetylene compounds in DMSO were in the order of 10−48 cm4 s molecule−1 photon−1 in the wavelength range of 650–800 nm. The largest value was found to be 8.50 × 10−48 cm4 s molecule−1 photon−1 at 764 nm for the methoxy-substituted triflate of the diacetylene compound. This value is one of the largest values obtained for molecules of a similar size by use of femtosecond pulses, indicating that the incorporation of the diacetylene moiety as the π-bridge would be useful for two-photon dyes.