Environmentally friendly synthesis of 2D Co-MOF for transformation of isochromans to isochromanones by activating O2

• Published in: Journal of molecular structure 2025-01, Vol.1319, p.139503, Article 139503
• Main Authors: Lian, Jie, Chen, Baokuan, Guo, Yafei, Dai, Lingling, Tian, Hongrui, Bi, Yanfeng
• Format: Article
• Language: English
• Subjects: 2D MOF; Green synthesis; Heterogeneous catalysis; MOFs; Molecular oxygen
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.139503

•Two cobalt-based MOFs were synthesized in an environmentally friendly medium (ethanol as solvent), showing versatile structures with 2D and 3D frameworks, respectively.•Needing no additives, the 2D Co-MOF efficiently and selectively catalyzed the oxidation of isochromans to isochromanones under an oxygen atmosphere.•As a heterogeneous catalyst, the 2D Co-MOF can be recycled and reused at least five times with uncompromised performance.•A catalytic mechanism involving free radicals was proposed. From the perspective of green chemistry and sustainable development, it is highly desirable to produce catalysts in an environmentally friendly manner and utilize them to activate O2 for converting cheap chemicals into value-added chemicals. In this work, we have synthesized two cobalt-based metal-organic frameworks (Co-MOFs) in ethanol, a non-toxic reaction medium, and used them to convert isochromans to isochromanones with O2 as an oxidant and needing no additives. The experimental results indicate that the two Co-MOFs exhibit a favorable catalytic performance, in which the 2D Co-MOF (1) possesses a higher catalytic activity than the 3D Co-MOF (2). This may be due to the enhanced catalytic site exposure and rapid substance, electron, and proton transfer within the 2D Co-MOF. Furthermore, the reaction mechanism analysis indicates that the catalytic process may involve a radical reaction pathway. This work serves as an invaluable interpretation for advancing alternative 2D Co-MOF for activating O2 in organic catalytic transformation. A novel 2D cobalt-based MOF was rapidly prepared in a green medium (ethanol) and used as a recyclable catalyst for the additive-free selective oxidation of isochromans to isochromanones under an oxygen atmosphere, performing excellent catalytic activity and substrate tolerance. [Display omitted]