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Abstract

Acetylene bridged acceptor-π-bridge-donor-π-bridge-acceptor (A-π-D-π-A) dyes (DBPs) based on benzophenone were designed and synthesized via Sonogashira coupling reaction utilizing carbazole/phenothiazine/triphenylamine as electron donating groups. The photophysical properties, photochemistry characteristics, as well as the two-photon absorption properties were studied. All dyes exhibited excellent intra-/intermolecular charge transfer properties upon excitation, and large two photon absorption cross sections in the wavelength range of 720~860 nm. Significant differences in fluorescence and photochemistry properties were found depending on the electron donating groups. The rigid carbazole favored hybridization of benzophenone like local excited state and intramolecular charge transfer excited state, which resulted in abnormal changes in fluorescence quantum yield, poor photostability, and good initiating ability both as Norrish Ⅱ initiator and as sensitizer for iodonium salt. However, the butterfly-shaped phenothiazine and propeller-shaped triphenylamine facilitated intramolecular charge transfer excited states, which resulted in typical positive solvatochromism effect, good photostabilities, and lacking of initiating ability as Norrish Ⅱ initiator.