Recyclable and Stable Porphyrin‐Based Self‐Assemblies by Electrostatic Force for Efficient Photocatalytic Organic Transformation

• Published in: Advanced science Vol. 11; no. 21; pp. e2308469 - n/a
• Main Authors: Cai, Bin, Huang, Ping, Fang, Yuan, Tian, Haining
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.06.2024; John Wiley and Sons Inc; Wiley
• Subjects: electrostatic assemblies; Light; Oxidation; Photocatalysis; photoredox catalysis; porphyrin; Recycling; Scanning electron microscopy; Spectrum analysis; superoxide; thioanisole; electrostatic assemblies; photoredox catalysis; porphyrin; superoxide; thioanisole
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202308469

Development of efficient, stable, and recyclable photocatalysts for organic synthesis is vital for transformation of traditional thermal organic chemistry into green sustainable organic chemistry. In this work, the study reports an electrostatic approach to assemble meso‐tetra (4‐sulfonate phenyl) porphyrin (TPPS)tetra (4‐sulfonate phenyl) porphyrin (TPPS) as a donor and benzyl viologen (BV) as an acceptor into stable and recyclable photocatalyst for an efficient organic transformation reaction – aryl sulfide oxidation. By use of the electrostatic TPPS‐BV photocatalysts, 0.1 mmol aryl sulfide with electron‐donating group can be completely transformed into aryl sulfoxide in 60 min without overoxidation into sulfone, rendering near 100% yield and selectivity. The photocatalyst can be recycled up to 95% when 10 mg amount is used. Mechanistic study reveals that efficient charge separation between TPPS and BV results in sufficient formation of superoxide which further reacts with the oxidized sulfide by the photocatalyst to produce the sulfoxide. This mechanistic pathway differs significantly from the previously proposed singlet oxygen‐dominated process in homogeneous TPPS photocatalysis. A kind of porphyrin‐viologen‐based self‐assembly by electrostatic force has been prepared. It is found that the efficient photo‐induced electron transfer from the excited tetra (4‐sulfonate) porphyrin (TPPS) donor to the benzyl viologen (BV) acceptor exists in the TPPS‐BV self‐assembly, which is beneficial to sulfide oxidation when acting as the photocatalyst. Correspondingly, TPPS‐BV exhibits a remarkable fourfold increase in catalytic efficiency compared to TPPS‐EDA when changing BV into ethylene diammonium (EDA).