We synthesized four diphenylquinoxaline derivatives（SQs） with phenyl-thioether units, which combine photo-cleavable and hydrogen-abstracting groups in one molecule. The photochemistry and photopolymerization of SQs ...We synthesized four diphenylquinoxaline derivatives（SQs） with phenyl-thioether units, which combine photo-cleavable and hydrogen-abstracting groups in one molecule. The photochemistry and photopolymerization of SQs were investigated. SQs possess suitable UV-vis absorption in the range of 350-400 nm with high extinction coefficients. UV-vis and HPLC-MS spectra revealed that C–S bond in phenyl-thioether group of SQs can be broken by irradiation of UV-light. Photolysis and photopolymerization experiments showed that SQs can be used as photo-cleavable photointiators,their photoinitiating efficiency can be enhanced by hydrogen donor. As photo-cleavable photoinitiators,SQs could initiate hexamethylene diacrylate（HDDA） very efficiently with the double bond conversion（DBC） of 80%. In the presence of ethyl-4-（dimethylamino） benzoate（EDB） as coinitiator, photoinitiator systems initiated photopolymerization of commercial acrylate monomers with higher double bond conversion than 90%. These characteristics make SQs potential photoinitiators in photo-curing field.展开更多
The photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles in aqueous solution was comprehensively investigated using various selected wavelength light in the UV-Vis-NIR r...The photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles in aqueous solution was comprehensively investigated using various selected wavelength light in the UV-Vis-NIR region. The time-dependent photo-dimerization degree （PD） changes in the photo-dimerization experiments showed saturating behaviors with intensity-independent of PDmax values at 28%, 44%, 92%, 85%, 36%, 35%, 32% and 31% for 254, 288, 320, 360, 400, 500, 650 and 900 nm irradiations, respectively. The irradiation experiments at 254 and 288 nm announced the occurring of an asymmetric equilibrium of photo-dimerization and photo-cleavage at the used conditions. Both the alternative irradiation cycles of 360 and 254 nm, 650 and 254 nm showed a partially, but evidently reversible photo-dimerization tendency.展开更多
基金the National Basic Research Program (No. 2013CB834506)National Nature Science Foundation of China (Nos. 51373098 and 21522403)
文摘We synthesized four diphenylquinoxaline derivatives（SQs） with phenyl-thioether units, which combine photo-cleavable and hydrogen-abstracting groups in one molecule. The photochemistry and photopolymerization of SQs were investigated. SQs possess suitable UV-vis absorption in the range of 350-400 nm with high extinction coefficients. UV-vis and HPLC-MS spectra revealed that C–S bond in phenyl-thioether group of SQs can be broken by irradiation of UV-light. Photolysis and photopolymerization experiments showed that SQs can be used as photo-cleavable photointiators,their photoinitiating efficiency can be enhanced by hydrogen donor. As photo-cleavable photoinitiators,SQs could initiate hexamethylene diacrylate（HDDA） very efficiently with the double bond conversion（DBC） of 80%. In the presence of ethyl-4-（dimethylamino） benzoate（EDB） as coinitiator, photoinitiator systems initiated photopolymerization of commercial acrylate monomers with higher double bond conversion than 90%. These characteristics make SQs potential photoinitiators in photo-curing field.
基金financially supported by the National Natural Science Foundation of China(No.21374056)the Natural Science Basic Research Plan in Shaanxi Province of China(NSBRP-SPC 2014JM2051)+2 种基金the Fundamental Research Funds for the Central Universities(GK201302045)Shaanxi Innovative Research Team for Key Science and Technology(2012KCT-21,2013KCT-17)the One Hundred Plan of Shaanxi Province
文摘The photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles in aqueous solution was comprehensively investigated using various selected wavelength light in the UV-Vis-NIR region. The time-dependent photo-dimerization degree （PD） changes in the photo-dimerization experiments showed saturating behaviors with intensity-independent of PDmax values at 28%, 44%, 92%, 85%, 36%, 35%, 32% and 31% for 254, 288, 320, 360, 400, 500, 650 and 900 nm irradiations, respectively. The irradiation experiments at 254 and 288 nm announced the occurring of an asymmetric equilibrium of photo-dimerization and photo-cleavage at the used conditions. Both the alternative irradiation cycles of 360 and 254 nm, 650 and 254 nm showed a partially, but evidently reversible photo-dimerization tendency.
