Bond cleavage reactions including C−C and C−O bonds in the chemical industry and organic chemistry can be a valuable transformation. Especially, performing this chemical transformation under mild conditions (e.g., room temperature, solar light) is beneficial to enhance the selectivity of the targeted product or prevent the production of unwanted products. The work here reports a facile one-pot C−C/C−O σ-bonds cleavage reaction using the photocatalyst nanoparticles that affords the visible light-induced cleavage products in excellent yields under mild conditions. We synthesized carboxylic acid-functionalized RuII polypyridyl complexes (RuC) and then the photocatalyst RuC was immobilized onto TiO2 NPs (RuC-TiO2 NPs). This system allowed to perform photocatalytic cleavage reaction with lignin model compounds under the solar light illumination. Photophysical studies of RuC and TiO2 NPs reveal that the intermolecular energy/electron transfer from the photoexcited RuC to TiO2 NPs occurs in acetonitrile solution. Under ambient temperature and aerobic conditions, the photocatalytic reaction with RuC/TiO2 NPs afforded the Cα−Cβ/Cβ-O bonds cleavage products in excellent yields. This study successfully performed C-C/C-O bond cleavage reaction with the one-step process using a heterogeneous photocatalysis system at room temperature and under the solar light illumination without the need of the additional mediators or oxidizing/reducing agent. This system can be extended and served as a feasible method for lignin depolymerization under mild conditions.

Visible light-driven C-O/C-C bond cleavage reaction in lignin at room temperature using heterogeneous  photocatalysts

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.