A theoretical study of the complexes formed by monosubstituted phosphines (XH2P) and the methyl radical (CH3) has been carried out by means of MP2 and CCSD(T) computational methods. Two minima configurations have been obtained for each XH2P:CH3 complex. The first one shows small P-C distances and, in general, large interaction energies. It is the most stable one except in the case of the H3P:CH3 complex. The second minimum where the P-C distance is large and resembles a typical weak pnicogen bond interaction shows interaction energies between -9.8 and -3.7 kJ mol(-1). A charge transfer from the unpaired electron of the methyl radical to the P-X σ* orbital is responsible for the interaction in the second minima complexes. The transition state (TS) structures that connect the two minima for each XH2P:CH3 complex have been localized and characterized.
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http://dx.doi.org/10.1021/jp412144r | DOI Listing |
J Am Chem Soc
December 2024
Department of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States.
Donor-acceptor dyads are promising materials for improving triplet-sensitized photon upconversion due to faster intramolecular energy transfer (ET), which unfortunately competes with charge transfer (CT) dynamics. To circumvent the issue associated with CT, we propose a novel purely organic donor-acceptor dyad, where the CT character is confined within the donor moiety. In this work, we report the synthesis and characterization of a stable organic radical donor-triplet acceptor dyad () consisting of the acceptor perylene () linked to the donor (4--carbazolyl-2,6-dichlorophenyl)-bis(2,4,6-trichlorophenyl)methyl radical ().
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal Quebec H3A 2K6 Canada
Methyl groups rank among the most abundant carbon fragments found in natural products and small-molecule pharmaceuticals. The late-stage and environmentally friendly installation of these groups onto biologically active molecules has attracted widespread attention in both industry and academia. In 2008, we published the first use of a methyl radical derived from a peroxide toward a directed transition-metal catalysed C-H methylation.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
Research Center for Structural Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Ibaraki, Japan.
Methane photolysis is a very important initiation reaction from the perspective of hydrogen production for alternative energy applications. In our recent work, we demonstrated using our recently developed novel method, non-adiabatic excited-state time-dependent GW (TDGW) molecular dynamics (MD), how the decomposition reaction of methane into a methyl radical and a hydrogen atom was captured accurately via the time-tracing of all quasiparticle levels. However, this process requires a large amount of photoabsorption energy (PAE ∼10.
View Article and Find Full Text PDFJ Phys Chem Lett
November 2024
Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
Stable triarylmethyl radicals are the most common carbon radical building blocks and have recently attracted much attention for their luminescent properties. However, magnetic circular dichroism (MCD) discovered by Michael Faraday and magnetic circularly polarized luminescence (MCPL) have not been observed for simple triarylmethyl radicals, probably due to their photodegradability. Here we report the first observation of MCD and MCPL of triarylmethyl radicals in solution using racemic mixtures of (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM) and (3,5-difluoro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (FPyBTM), which are much more photostable than simple triphenylmethyl radical derivatives.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
State Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, China.
An anatase/TiO(B) homojunction loaded with Au nanoparticles was synthesized, achieving a CH yield rate of 170 μmol g h in a flow photoreactor. The homojunction reduces TiO(B)'s strong oxidative ability, offering a more moderate environment for methane dehydrogenation, while Au aids in charge mitigation and methyl radical coupling. The catalyst highlights homojunction engineering and a ternary synergistic effect in photocatalytic CH coupling.
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