A series of D-π-A type sulfonium salt photoacid generators with different π-conjugated structures, such as triphenyl, phenylstilbene, styryl-biphenyl, and stilbene, were designed to determine the effect of molecular...A series of D-π-A type sulfonium salt photoacid generators with different π-conjugated structures, such as triphenyl, phenylstilbene, styryl-biphenyl, and stilbene, were designed to determine the effect of molecular structures on the photochemical and photophysical properties. The mechanisms of photochemical generation of H＋ were studied by UV-Vis spectroscopy, theoretical calculations, and fluorescence spectroscopy. It is found that the frontier orbits determine the absorption, the molar extinction coefficients, and the quantum yields of photoacid generation. Triphenyl systems connected with sulfonium are beneficial to increase the quantum yields of acid generation. The photoreactivity of four sulfonium salts was further evaluated through the polymerizations of various epoxide monomers at different irradiation wavelengths （365- 425 nm） by using the real-time infrared spectroscopy with light-emitting diodes. The high quantum yields for acid generation （ФH＋ = -0.32 to 0.58） and the high molar extinction coefficients （ε = -23500 L.mol-1.cm-1 to 31000 L.mol-1.cm-1） of the sulfonium salts lead to high conversion rates （over 50%-80%）. Hence, these photoinitiators exhibit potential for the photocuring applications.展开更多
A stimuli-responsive supramolecular polymer network has been constructed based on the host-guest interactions between the copolymer poly-P[5]A with pendent pillararene units and bis(sulfonium)diction guest G2.The form...A stimuli-responsive supramolecular polymer network has been constructed based on the host-guest interactions between the copolymer poly-P[5]A with pendent pillararene units and bis(sulfonium)diction guest G2.The formation mechanism of the supramolecular polymer network has been explored by the intensive study.With the addition of the competitive molecules and heating,the supramolecular polymer network could be dissociated and lead to clear changes in NMR spectroscopy and viscosity property.展开更多
The photochemical and photophysical behaviors of tri(4-tert-butoxycarbonyl oxyphenyl) sulphonium salts have been investigated. In argon-satureted acetonitrile, the quantum yields of Bronsted acid formed during photoly...The photochemical and photophysical behaviors of tri(4-tert-butoxycarbonyl oxyphenyl) sulphonium salts have been investigated. In argon-satureted acetonitrile, the quantum yields of Bronsted acid formed during photolysis of these compounds was abount 0.5. In the transient absorption spectrum excited by 266nm in mathanol and dioxane an evident absorption peak at 360 nm decayed in accordance with pseudo-first-order reac tion was observed. In the presence of poly-p-hydroxystyrene or diphenyl sulphide, the apparent second-order reaction decay rate constants were 107 and 108 L·mol-1 ’s-1 t re spectively. Results indicated that the transient absorption peak at 360nm was attributed to the diphenyl sulphide radicaJ cations formed in photolysis of sulphonium salts, which were proposed by abstraction of hydrogen from solvent or polymer to yield the protonic acid and diphenyl sulphide as listed in eqns. (1) and (2). The influence of non-nucleophilic anions of title compounds on their photochemical behavior was just less important.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51173134 and 51573139)Fundamental Research Funds for the Central Universities and the Open Measuring Fund for Large Instrument and Equipment(No.0002015033)of Tongji University
文摘A series of D-π-A type sulfonium salt photoacid generators with different π-conjugated structures, such as triphenyl, phenylstilbene, styryl-biphenyl, and stilbene, were designed to determine the effect of molecular structures on the photochemical and photophysical properties. The mechanisms of photochemical generation of H＋ were studied by UV-Vis spectroscopy, theoretical calculations, and fluorescence spectroscopy. It is found that the frontier orbits determine the absorption, the molar extinction coefficients, and the quantum yields of photoacid generation. Triphenyl systems connected with sulfonium are beneficial to increase the quantum yields of acid generation. The photoreactivity of four sulfonium salts was further evaluated through the polymerizations of various epoxide monomers at different irradiation wavelengths （365- 425 nm） by using the real-time infrared spectroscopy with light-emitting diodes. The high quantum yields for acid generation （ФH＋ = -0.32 to 0.58） and the high molar extinction coefficients （ε = -23500 L.mol-1.cm-1 to 31000 L.mol-1.cm-1） of the sulfonium salts lead to high conversion rates （over 50%-80%）. Hence, these photoinitiators exhibit potential for the photocuring applications.
基金supported by National Natural Science Foundation of China(Nos.21702153 and 21801194).
文摘A stimuli-responsive supramolecular polymer network has been constructed based on the host-guest interactions between the copolymer poly-P[5]A with pendent pillararene units and bis(sulfonium)diction guest G2.The formation mechanism of the supramolecular polymer network has been explored by the intensive study.With the addition of the competitive molecules and heating,the supramolecular polymer network could be dissociated and lead to clear changes in NMR spectroscopy and viscosity property.
文摘The photochemical and photophysical behaviors of tri(4-tert-butoxycarbonyl oxyphenyl) sulphonium salts have been investigated. In argon-satureted acetonitrile, the quantum yields of Bronsted acid formed during photolysis of these compounds was abount 0.5. In the transient absorption spectrum excited by 266nm in mathanol and dioxane an evident absorption peak at 360 nm decayed in accordance with pseudo-first-order reac tion was observed. In the presence of poly-p-hydroxystyrene or diphenyl sulphide, the apparent second-order reaction decay rate constants were 107 and 108 L·mol-1 ’s-1 t re spectively. Results indicated that the transient absorption peak at 360nm was attributed to the diphenyl sulphide radicaJ cations formed in photolysis of sulphonium salts, which were proposed by abstraction of hydrogen from solvent or polymer to yield the protonic acid and diphenyl sulphide as listed in eqns. (1) and (2). The influence of non-nucleophilic anions of title compounds on their photochemical behavior was just less important.
