Herein, we described a cooperative catalyst system consisting of an acridinium photoredox catalyst and a cobalt-based proton-reduction catalyst that is effective for the C-H amination of arenes with concomitant generation of hydrogen. This oxidant-free method allows a variety of amines with diverse functional groups to be converted to aromatic amines. Additionally, this protocol can also be extended to hydrolytically unstable benzophenone imines.
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http://dx.doi.org/10.1021/acs.orglett.8b03089 | DOI Listing |
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August 2024
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Science, Nanjing Forestry University, Nanjing, 210037, China.
The high crystalline covalent triazine framework-1 (CTF-1), composed of alternating triazine and phenylene, has emerged as an efficient photocatalyst for solar-driven hydrogen evolution reaction (HER). However, it is of great challenge to further improve photocatalytic HER performance via increasing crystallinity due to its near-perfect crystallization. Herein, an alternative strategy of scaffold functionalization is employed to optimize the energy band structure of crystalline CTF-1 for boosting hydrogen-evolving activity.
View Article and Find Full Text PDFJ Chem Phys
February 2024
Division of Computational Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden.
Photoredox properties of several earth-abundant light-harvesting transition metal complexes in combination with cobalt-based proton reduction catalysts have been investigated computationally to assess the fundamental viability of different photocatalytic systems of current experimental interest. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations using several GGA (BP86, BLYP), hybrid-GGA (B3LYP, B3LYP*), hybrid meta-GGA (M06, TPSSh), and range-separated hybrid (ωB97X, CAM-B3LYP) functionals were used to calculate relevant ground and excited state reduction potentials for photosensitizers, catalysts, and sacrificial electron donors. Linear energy correction factors for the DFT/TD-DFT results that provide the best agreement with available experimental reference results were determined in order to provide more accurate predictions.
View Article and Find Full Text PDFInt J Mol Sci
May 2023
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy.
The extraordinary potential of hydrogen as a clean and sustainable fuel has sparked the interest of the scientific community to find environmentally friendly methods for its production. Biological catalysts are the most attractive solution, as they usually operate under mild conditions and do not produce carbon-containing byproducts. Hydrogenases promote reversible proton reduction to hydrogen in a variety of anoxic bacteria and algae, displaying unparallel catalytic performances.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2023
NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK.
Hollow-core photonic crystal fibers (HC-PCFs) provide a novel approach for in situ UV/Vis spectroscopy with enhanced detection sensitivity. Here, we demonstrate that longer optical path lengths than afforded by conventional cuvette-based UV/Vis spectroscopy can be used to detect and identify the Co and Co states in hydrogen-evolving cobaloxime catalysts, with spectral identification aided by comparison with DFT-simulated spectra. Our findings show that there are two types of signals observed for these molecular catalysts; a transient signal and a steady-state signal, with the former being assigned to the Co state and the latter being assigned to the Co state.
View Article and Find Full Text PDFJ Colloid Interface Sci
September 2022
Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing, College of Materials Science and Engineering, Huaqiao University, Xiamen 361021, Fujian, China. Electronic address:
Polymeric carbon nitride (CN) has evoked considerable attention in photocatalysis, however, its π-deficiency conjugated frameworks engendering weak visible-light absorption and rapid charge recombination hinder the practical utilizations. Herein, a novel donor-acceptor (D-A) conjugated polymer based on triptycene incorporated carbon nitride (T-CN) has been facilely prepared by thermal copolymerization of melamine and 2,6,14-triaminotriptycene. Combined with the density functional theory (DFT) calculations, it is found that the formation of intramolecular charge transfer and the extended π-conjugative effect in the D-A structure contribute to a broadened light-harvesting spectral range, a higher charge separation/transfer efficiency and more active sites of T-CN for photoredox reactions.
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