Photocatalytic C–H Carboxylation of 1,3-Dicarbonyl Compounds with Carbon Dioxide Promoted by Nickel(II)-Sensitized α-Fe₂O₃ Nanoparticles

Abstract

Insertion of carbon dioxide into C–H bonds under mild conditions is an industrially important yet highly challenging task. In the present study, we report the synthesis of an efficient photocatalyst consisting of a Ni­(bpy)3Cl2 sensitizer supported on α-Fe2O3 nanoparticles for the CO2 insertion into C–H bonds, particularly carboxylation of 1,3-dicarbonyl compounds like acetyl acetone, methyl acetoacetate, and ethyl acetoacetate with CO2 under visible light irradiation using carbon tetrachloride as a solvent. The carboxylation of these compounds afforded the predominant formation of a single isomeric acid as confirmed by 13C NMR spectroscopy. Based on the computational studies, a possible reaction mechanism suggested the generation of CO2 radical anions at the conduction band of α-Fe2O3 through single electron transfer mediated by the nickel­(II) complex that coupled with acetyl acetone cation radicals at the valence band of α-Fe2O3 to give the corresponding carboxylic acid. The protocol described in the present study presents a light-assisted approach and a low-cost material for the synthesis of carboxylic acids utilizing CO2 under mild reaction conditions.

Visible Light-Driven C(sp3)-H Carboxylation of Diverse Amines with CO2 into α-Amino Acids Using an Eco-Friendly and Reusable Covalent Organic Framework

“…The direct transformation of the starting substrate into the corresponding carboxylated product in the presence of a catalytic amount of a NiO NPs/COF composite was supported in terms of activation energy (Δ E ). The lower activation energy of the NiO NPs/COF composite (1.56 eV) as compared to its parent materials [ PI-COF (1.66 eV) and Ni 13 O 14 nanocluster (2.30 eV)] confirmed a mild and high-yielding visible-light-driven conversion of the starting substrate into the corresponding α-amino acid. , As for an experimental proof in a visible-light-driven C­(sp 3 )-H α-carboxylation reaction, the intermediacy of te amine radical cation was supported by a radical-trapping experiment (i.e., detection of the radical intermediate by TEMPO trapping). TEMPO • serves as a promising radical scavenger, and the corresponding adduct was confirmed by high resolution electrospray ionization mass spectrometry (ESI-HRMS).…”

“…27 Recently, Jain and co-workers demonstrated Ni(bpy) 3 Cl 2 sensitizer decorated over α-Fe 2 O 3 NPs as a potential photocatalytic system for visible-light-driven photocatalytic CO 2 incorporation into C(sp 3 )−H bonds, particularly, photochemical carboxylation of C(sp 3 )−H bonds of 1,3-dicarbonyl systems such as ethyl acetoacetate, methyl acetoacetate, and acetylacetone with CO 2 employing CCl 4 as a solvent at atmospheric CO 2 pressure and room temperature (Scheme 1, eq 5). 28 Furthermore, Jain and co-workers reported a facile methodology for photocatalytic thiocarboxylation of olefin systems with CO 2 using a metal− organic framework (MOF). 29 On the other hand, a series of inorganic semiconductors was tested as photocatalytic systems for the reduction of CO 2 , like ZrO 2 , 30 TiO 2 , 31 In 2 O 3 , 32 ZnGa 2 O 4 , 33 or CdS.…”

“…König and co-workers reported a visible-light-triggered C­(sp 3 )-H carboxylation at the benzylic position with CO 2 into 2-arylpropionic acid derivatives in the absence of any metal-based systems (Scheme , eq 4) . Recently, Jain and co-workers demonstrated Ni­(bpy) 3 Cl 2 sensitizer decorated over α-Fe 2 O 3 NPs as a potential photocatalytic system for visible-light-driven photocatalytic CO 2 incorporation into C­(sp 3 )–H bonds, particularly, photochemical carboxylation of C­(sp 3 )–H bonds of 1,3-dicarbonyl systems such as ethyl acetoacetate, methyl acetoacetate, and acetylacetone with CO 2 employing CCl 4 as a solvent at atmospheric CO 2 pressure and room temperature (Scheme , eq 5) . Furthermore, Jain and co-workers reported a facile methodology for photocatalytic thiocarboxylation of olefin systems with CO 2 using a metal–organic framework (MOF) .…”

Recyclable ferroferric oxide@titanium dioxide@molybdenum disulfide with enhanced enzyme-like activity under visible light for effectively inhibiting the growth of drug-resistant bacteria in sewage

“…[29][30][31][32][33][34] The binding energies of Fe 2+ 2p 1/2 and Fe 3+ 2p 1/2 in Fe 3 O 4 @TiO 2 @ MoS 2 are 721.1 eV and 726.01 eV, Fe 3+ 2p 3/2 is 711.26 eV and Fe 2+ 2p 3/2 is 708.07 eV, where the peaks at 733.06 eV and 716.3 eV should be satellite peaks. [35][36][37][38][39][40] As shown in Fig. 1g, the binding energies of Ti 2p 3/2 and Ti 2p 1/2 are located at 458.54 eV and 464.24 eV, respectively, while in Fe 3 O 4 @TiO 2 @ MoS 2 , the binding energies move to 459.3 eV and 464.7 eV, respectively.…”

Light-assisted coupling of phenols with CO2 to 2-hydroxybenzaldehydes catalyzed by a g-C3N4/NH2-MIL-101(Fe) composite

“…Molecular simulation studies were carried out to determine the interaction between two or more molecules, various physicochemical parameters, and the efficiency of the migration of electrons from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). 31,32 In this study, an iron-based metal-organic framework (MOF) combined with graphitic carbon nitride photocatalyst was synthesized and used to transform phenol to 2-hydroxybenzaldehyde with the help of CO 2 in the presence of visible light irradiation. Molecular simulation studies support the possible mechanism for the conversion of phenol to 2-hydroxybenzaldehyde.…”