Institute of Applied and Physical Chemistry and Center for Environmental Research and Sustainable Technology, University Bremen, Leobener Str. 6, 28359, Bremen, Germany.
MAPEX Center for Materials and Processes, University Bremen, Bibliothekstr. 1, 28359, Bremen, Germany.
Photochem Photobiol Sci. 2021 Apr;20(4):547-558. doi: 10.1007/s43630-021-00037-7. Epub 2021 Apr 19.
Nanoporous gold was functionalized with a photosensitizer, a zinc(II) phthalocyanine derivative. Such systems are active for the generation of reactive singlet oxygen which can be used for photocatalytic oxidation reactions. This study aims to demonstrate the versatility of such an approach, in terms of substrates and the employed solvent, only possible for a truly heterogeneous catalytic system. The activity of the hybrid system was studied for [4 + 2] cycloadditions of three different types of dienes and a total of eight substrates in two organic solvents and once in water. The highest activity was measured for 1,3-diphenylisobenzofuran, which is also highest in terms of sensitivity for the reaction with O. Trends in conversion could be anticipated based on reported values for the rate constant for the reaction of O. In almost all cases, an amplification of the conversion by immobilization of the sensitizer onto nanoporous gold was observed. The limiting case was ergosterol, which was the largest of all substrates with a van-der-Waals radius of about 2.1 nm. Additional factors such as the limited lifetime of O in different solvents as well as the hampered diffusion of the substrates were identified.
纳米多孔金用一种光敏剂（一种锌（II）酞菁衍生物）功能化。此类系统可有效生成活性单重态氧，可用于光催化氧化反应。本研究旨在展示此类方法在底物和所用溶剂方面的多功能性，这在真正的多相催化体系中才有可能。在两种有机溶剂和一种水中，对三种不同类型二烯和总共 8 种底物的[4+2]环加成反应，研究了混合体系的活性。在所有情况下，都观察到通过将敏化剂固定在纳米多孔金上来提高转化率。在两种有机溶剂和一种水中，对三种不同类型二烯和总共 8 种底物的[4+2]环加成反应，研究了混合体系的活性。在所有情况下，都观察到通过将敏化剂固定在纳米多孔金上来提高转化率。在所有情况下，都观察到通过将敏化剂固定在纳米多孔金上来提高转化率。
