Yamaguchi Masahiro, Shioya Kaito, Li Chifeng, Yonesato Kentaro, Murata Kei, Ishii Kazuyuki, Yamaguchi Kazuya, Suzuki Kosuke
Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
J Am Chem Soc. 2024 Feb 21;146(7):4549-4556. doi: 10.1021/jacs.3c11394. Epub 2024 Jan 29.
Organic-polyoxometalate (POM) hybrids have recently attracted considerable interest because of their distinctive properties and wide-ranging applications. For the construction of organic-POM hybrids, porphyrins are promising building units owing to their optical properties and reactivity, including strong visible-light absorption and subsequent singlet-oxygen (O*) generation. However, the practical utilization of porphyrins as photocatalysts and photosensitizers is often hindered by their own degradation by O*. Therefore, there is a substantial demand for the development of porphyrin-derived photocatalysts with both high efficiency and durability. Herein, we present a porphyrin-polyoxotungstate molecular hybrid featuring a face-to-face stacked porphyrin dimer () fastened by four lacunary polyoxotungstates. Hybrid exhibited remarkable efficiency and durability in photocatalytic aerobic oxidation reactions, and the selective oxidation of various dienes, alkenes, sulfides, and amines proceeded using just 0.003 mol % of the catalyst. Mechanistic investigations suggested that the high activity of stems from the efficient generation of O*, resulting from the heavy-atom effect of POMs. Furthermore, despite its high efficiency in O* generation compared to free porphyrins, exhibited superior durability against O*-induced degradation under photoirradiation.
有机-多金属氧酸盐（POM）杂化物因其独特的性质和广泛的应用，近年来引起了人们的极大兴趣。对于有机-POM杂化物的构建，卟啉因其光学性质和反应活性，包括强烈的可见光吸收以及随后的单线态氧（O*）生成，是很有前景的构建单元。然而，卟啉作为光催化剂和光敏剂的实际应用常常受到其自身被O降解的阻碍。因此，迫切需要开发兼具高效性和耐久性的卟啉衍生光催化剂。在此，我们展示了一种卟啉-多金属氧钨酸盐分子杂化物，其具有由四个缺位多金属氧钨酸盐固定的面对面堆叠的卟啉二聚体（）。杂化物在光催化需氧氧化反应中表现出显著的效率和耐久性，仅使用0.003 mol%的催化剂就能实现各种二烯烃、烯烃、硫化物和胺的选择性氧化。机理研究表明，的高活性源于POMs的重原子效应导致的O的高效生成。此外，尽管与游离卟啉相比，在O生成方面效率很高，但在光照射下，对O诱导的降解表现出卓越的耐久性。
