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 pi-bridge in a symmetric way as well as the compounds containing the same substituent groups linked by a phenylenevinylene-type p-bridge. Femtosecond open aperture Z-scan measurements revealed that the two-photon absorption cross-sections sigma((2)) of the diacetylene compounds in DMSO were in the order of 10-(48) cm(4) s molecule(-1) photon(-1) in the wavelength range of 650-800 nm. The largest value was found to be 8.50 x 10(-48) cm(4) 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 p-bridge would be useful for two-photon dyes.