Photocatalytic C–H Activation with Alcohol as a Hydrogen Atom Transfer Agent in a 9-Fluorenone Based Metal–Organic Framework

Abstract

Hydrogen atom transfer (HAT) has become an attractive strategy for the activation of hydrocarbon feedstocks. Alcohols, as inexpensive and efficient hydrogen transfer reagents, have limited application in C–H functionalization due to the difficulty in the alkoxy radical acquisition. 9-Fluorenone moieties were incorporated into the metal–organic framework (MOF) as a photocatalyst; through the formation of hydrogen bonds between the carbonyl group of a ligand and alcohol, alkoxy radicals could be obtained by the visible-light-driven oxidation of 2,2,2-trichloroethanol via proton-coupled electron transfer (PCET). Effectively photocatalyzed intermolecular coupling reactions between phenyl vinyl sulfone and aldehyde or cyclic ether were realized through the HAT pathway. Compared to homogeneous catalysts, the heterogeneous MOF photocatalyst improved the catalytic efficiency and could be recycled at least five times. The microenvironment of the Zn-OFDC channel was beneficial for the formation of hydrogen bonds and stability of alkoxy radicals.

Application of Copper(II)–Organic Frameworks Bearing Dilophine Derivatives in Photocatalysis and Guest Separation

“…Principally, the low resistance and small arc radius in the EIS-Nyquist plot imply fast charge transfer in the semiconductor, and the experimental results showed that the resistance of Cu-MOF was greatly reduced under light illumination conditions (Figure c). Furthermore, the transient photoluminescence spectra demonstrate the stronger separation efficiency of Cu-MOF for photogenerated electron and hole pairs (Figure d), which further explains the properties of Cu-MOF as a well-performing photocatalyst. , …”

“…Furthermore, the transient photoluminescence spectra demonstrate the stronger separation efficiency of Cu-MOF for photogenerated electron and hole pairs (Figure 7d), which further explains the properties of Cu-MOF as a well-performing photocatalyst. 50,51 According to the above experimental results, we attempted to propose a mechanism for the photodegradation of methylene blue by Cu-MOF (Figure 8). When the photon energy irradiated onto Cu-MOF exceeded or equaled to E g (3.29 eV), electron−hole pairs are generated and the excess photoinduced electrons are separated from the valence band and migrate to the conduction band (CB).…”

2D Metal–Organic Frameworks as Competent Electrocatalysts for Water Splitting

“…Except for conductive materials, some electrocatalytically active materials, such as metal sulfides and transition metal hydroxide, are widely used to fabricate MOF‐based composites. [ 180,181 ] The synergistic interaction between the additional species and 2D MOF may lead to further enhancement of catalytic properties. The poor HER performances of MoS 2 in basic environment stem from the improper hydroxyl adsorption.…”

Ligand-regulated metal–organic frameworks for synergistic photoredox and nickel catalysis

“…26,27 Furthermore, metal-organic frameworks with ordered organic bridging linkers and inorganic metal nodes promote the well-regulated immobilization of functional organic dye-based ligands into their networks to prevent the aggregation and polymerization of organic dyes. [28][29][30][31] Importantly, the crystalline metal-organic frameworks immobilize photosensitizers and metal ions in high local concentrations to regulate the twisted conjugative junction between the electron-donating and accepting sections, which enable MOFs to markedly heighten the charge-transfer resistance to hamper the futile intramolecular fluorescence quenching. 32,33 Our group has developed a series of triphenylamine-based photoactive metal-organic frameworks to generate radicals by photoreduction.…”