Laboratoire des IMRCP, UMR CNRS 5623, Université Toulouse III (Paul Sabatier, UPS) , 118 route de Narbonne F-31062 Toulouse Cedex 9, France.
ACS Appl Mater Interfaces. 2014 Jan 8;6(1):275-88. doi: 10.1021/am404175y. Epub 2013 Dec 16.
The photophysical properties of several photosensitizers (PSs) included or grafted in silica monoliths were compared to their properties in solution. The effects of the solid support on their steady-state and transient absorption spectra, on their quantum yields of singlet oxygen ((1)O2) production, and on their ability to photoinduce the oxidation of dimethylsulfide (DMS) were investigated. Two cyanoanthracene derivatives (9,14-dicyanobenzo[b]triphenylene, DBTP, and 9,10-dicyanoanthracene, DCA), as well as three phenothiazine dyes (methylene blue, MB(+), new methylene blue, NMB(+), methylene violet, MV), were encapsulated in silica, analyzed and compared to two reference PSs (perinaphthenone, PN and rose bengal, RB). A DBTP derivative (3-[N-(N″-triethoxysilylpropyl-N'-hexylurea)]carboxamido-9,14-dicyanobenzo[b]triphenylene, 3) was also prepared and grafted onto silica. Thanks to the transparency and the free-standing shape of the monoliths, the complete spectroscopic characterization of the supported PSs was carried out directly at the gas-solid interface. The influence of the silica network, the PS, and the adsorption/grafting link between the PS and silica was investigated. The effects of PS concentration, gaseous atmosphere, humidity, and hydrophobicity on the production of (1)O2 were analyzed. With all PSs, (1)O2 production was very efficient (quantum yields of (1)O2 production, relative to PN, between 0.6 and 1), and this species was the only one involved in the pollutant photooxidation. The influence of the matrix on the PSs' photophysics could be considered as negligible. In contrast, the matrix effect on DMS photooxidation was extremely important: the gas diffusion inside the porous structure, and thus, the photoactivity of the materials, strictly depended on silica's surface area and porosity. Our results highlight the suitability of these silica structures as inert supports for the study of the photosensitizing properties at the gas-solid interface. Moreover, thanks to the adsorption properties of the matrix, the synthesized materials can be used as microphotoreactor for the (1)O2-mediated oxidation of volatile pollutants.
几种被包裹或嫁接在二氧化硅整体中的光物理性质的敏化剂（PSs）与它们在溶液中的性质进行了比较。研究了固体支撑对它们的稳态和瞬态吸收光谱、单线态氧（1O2）产生的量子产率以及光诱导二甲基硫（DMS）氧化能力的影响。两种氰基蒽衍生物（9,14-二氰基苯并[b]三苯并，DBTP 和 9,10-二氰基蒽，DCA）以及三种吩噻嗪染料（亚甲蓝，MB(+)，新亚甲蓝，NMB(+)，甲紫，MV）被包裹在二氧化硅中进行分析，并与两种参考 PS（邻二氮杂菲酮，PN 和玫瑰红，RB）进行了比较。还制备了一种 DBTP 衍生物（3-[N-（N''-三乙氧基硅丙基-N'-己基脲）]羧酰胺-9,14-二氰基苯并[b]三苯并，3）并将其嫁接到二氧化硅上。由于整体的透明性和独立式形状，可以直接在气固界面上对负载 PS 的完整光谱特性进行表征。研究了二氧化硅网络、PS 和 PS 与二氧化硅之间的吸附/嫁接连接对其的影响。分析了 PS 浓度、气态气氛、湿度和疏水性对 1O2 产生的影响。对于所有 PS，1O2 的产生都非常有效（相对于 PN 的 1O2 产生量子产率在 0.6 到 1 之间），并且这种物质是唯一参与污染物光氧化的物质。基质对 PS 光物理性质的影响可以忽略不计。相反，基质对 DMS 光氧化的影响非常重要：气体在多孔结构内的扩散，以及因此，材料的光活性，严格取决于二氧化硅的表面积和孔隙率。我们的结果强调了这些二氧化硅结构作为在气固界面研究光敏性质的惰性支持的适用性。此外，由于基质的吸附特性，合成材料可以用作挥发性污染物 1O2 介导氧化的微光反应器。
