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Franceschi P, Rossin E, Goti G, Scopano A, Vega-Peñaloza A, Natali M, Singh D, Sartorel A, Dell'Amico L. A Proton-Coupled Electron Transfer Strategy to the Redox-Neutral Photocatalytic CO 2 Fixation. J Org Chem 2023; 88:6454-6464. [PMID: 36760023 DOI: 10.1021/acs.joc.2c02952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Herein, we report our study on the design and development of a novel photocarboxylation method. We have used an organic photoredox catalyst (PC, 4CzIPN) and differently substituted dihydropyridines (DHPs) in combination with an organic base (1,5,7-triazabicyclodec-5-ene, TBD) to access a proton-coupled electron transfer (PCET) based manifold. In depth mechanistic investigations merging experimental analysis (NMR, IR, cyclic voltammetry) and density-functional theory (DFT) calculations reveal the key activity of a H-bonding complex between the DHP and the base. The thermodynamic and kinetic benefits of the PCET mechanism allowed the implementation of a redox-neutral fixation process leading to synthetically relevant carboxylic acids (18 examples with isolated yields up to 75%) under very mild reaction conditions. Finally, diverse product manipulations were performed to demonstrate the synthetic versatility of the obtained products.
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Affiliation(s)
- Pietro Franceschi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Elena Rossin
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Giulio Goti
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Angelo Scopano
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Alberto Vega-Peñaloza
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Mirco Natali
- Department of Chemical, Pharmaceutical, and Agricultural Sciences, University of Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy
| | - Deepak Singh
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Andrea Sartorel
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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Fu Y, Suo X, Yang Z, Dai S, Jiang DE. Computational Insights into Malononitrile-Based Carbanions for CO 2 Capture. J Phys Chem B 2022; 126:6979-6984. [PMID: 36047943 DOI: 10.1021/acs.jpcb.2c03082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although anionic N and O sites have been widely used in chemisorption of CO2, carbanions are much less explored for CO2 capture. Here we employ ab initio calculations and quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations to examine the interaction between CO2 and the malononitrile carbanion, [CH(CN)2]-. We have explored the potential energy surface of CO2 binding by scanning the C-C distance between CO2 and the central C site of the carbanion. We find that CO2 prefers to bind to the nitrile group physically rather than to form a C-C bond via the carboxylation reaction at the sp2 C site. Moreover, the two -CN groups can attract two CO2 molecules at equal strength. The presence of an alkali metal ion enhances both physical and chemical interactions of CO2 with the malononitrile carbanion. QM/MM MD simulations further confirm the preference of physical interaction in the condensed ionic liquid phase with a phosphonium cation. Our findings suggest that ionic liquids based on the malononitrile carbanion may have a high CO2 solubility for carbon capture.
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Affiliation(s)
- Yuqing Fu
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Xian Suo
- Department of Chemistry, Joint Institute for Advanced Materials, The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Zhenzhen Yang
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sheng Dai
- Department of Chemistry, Joint Institute for Advanced Materials, The University of Tennessee, Knoxville, Tennessee 37996, United States.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - De-En Jiang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
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