The Synthesis And Properties Of Conjugate Alkynyl Aromatic Amine Photopolymerrization Sensitizers

Carbazole, triphenylamine and phenothiazine are typical aromatic amines with electron-rich. They are often used as electron donor in functional molecules. Diphenyl sulfide, diphenyl sulfoxide and diphenyl sulfone have good structural symmetry and light stability. They can increase the intramolecular charge transfer capability by introducing those structures in molecules. In this paper, we used triple bond as bridge group, synthesized a new type of conjugated dye containing aromatic amines and aromatic sulfur groups. Their photophysical properties and applications in photopolymerization were studied.These dyes can be divided into three categories. First,4,4’-dis((N-ethyl carbazole-3-yl)-ethynyl) diphenyl sulfide (Cz-S-Cz),4,4’-dis((triphenylamine-4-yl)-ethynyl) diphenyl sulfide (TA-S-TA) and 4,4’-dis((N-ethyl phenothiazine-4-yl)-ethynyl) diphenyl sulfide (PTZ-S-PTZ) use diphenyl sulfide as the conjugated center; Second,4,4’-dis((N-ethyl carbazole-3-yl)-ethynyl) diphenyl sulfoxide (Cz-SO-Cz), 4,4’-dis((triphenylamine-4-yl)-ethynyl) diphenyl sulfoxide (TA-SO-TA) and 4,4’-dis((N-ethyl phenothiazine-4-yl)-ethynyl) diphenyl sulfoxide (PTZ-SO-PTZ) use diphenyl sulfoxide as the conjugated center; Third, 4,4’-dis((N-ethyl carbazole-3-yl)-ethynyl) diphenyl sulfone (Cz-SO2-Cz), 4,4’-dis((triphenylamine-4-yl)-ethynyl) diphenyl sulfone (TA-SO2-TA) and 4,4’-dis((N-ethyl phenothiazine-4-yl)-ethynyl) diphenyl sulfone (PTZ-SO2-PTZ) use diphenyl sulfone as the conjugated center.UV-vis absorption, one-photon fluorescence and two-photon fluorescence emission spectra of the dyes were studied. The results of UV-vis spectra showed that all of the nine dyes have strong absorption between 350-450nm. The order of the maximum absorption wavelength was TA-SO2-TA (389nm)> PTZ-SO2-PTZ (387nm)> TA-SO-TA (375nm)> PTZ-SO-PTZ (371 nm)> TA-S-TA (370nm)> Cz-SO2-Cz (368nm)> PTZ-S-PTZ (362nm)> Cz-SO-Cz (352nm)> Cz-S-Cz (350nm). One-photon fluorescence spectra indicated that the fluorescence emission wavelengths were between 380nm-590nm. They had large fluorescence quantum efficiency, for example the maximum fluorescence quantum efficiency of TA-S-TA was 0.92. The two-photon excited fluorescence (TPEF) spectra in the range 700-880 nm were measured and it was found that these dyes presented clear two-photon absorptions (TPA). Among them, PTZ-SO2 possesses the maximum TPA cross-section which was 2465.5 GM.Ring-opening cationic polymerization of epoxides and free radical polymerization of acrylates upon exposure to irradiation of laser diodes at 405 nm and 455 nm were performed using dyes with iodonium salt (ONI) initiating systems. The combinations of the obtained dyes with iodonium salt exhibit high polymerization efficiency. The highest polymerization efficiency was Cz-SO2-Cz/ONI under the laser diode of 405nm. The highest polymerization efficiency was PTZ-SO-PTZ/ONI under the laser diode of 455nm. By calculating the free energy change of dyes/ONI system, the electron transfer mechanism of the system in photo polymerization was projected...