Arene C–H Functionalization by p-Block Metal Tl(III) Occurs at the Borderline of C–H Activation and Electron Transfer
| Autor: | Michael M. Konnick, Brian M. Hashiguchi, Benjamin R. Black, Daniel H. Ess, Clinton R. King, Samantha J. Gustafson, Steven Kay Butler, Roy A. Periana |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Stereochemistry Organic Chemistry Regioselectivity 010402 general chemistry Photochemistry 01 natural sciences Toluene 0104 chemical sciences Inorganic Chemistry Metal Electron transfer chemistry.chemical_compound Hydrocarbon chemistry visual_art Kinetic isotope effect visual_art.visual_art_medium Density functional theory Physical and Theoretical Chemistry Benzene |
| Zdroj: | Organometallics. 36:109-113 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/acs.organomet.6b00475 |
| Popis: | M06 density functional theory calculations reveal that arene C–H functionalization by the p-block main-group-metal complex TlIII(TFA)3 (TFA = trifluoroacetate) occurs by a C–H activation mechanism akin to transition-metal-mediated C–H activation. For benzene, toluene, and xylenes a one-step C–H activation is preferred over electron transfer or proton-coupled electron transfer. The proposed C–H activation mechanism is consistent with calculation and comparison to experiment, of arene thallation rates, regioselectivity, and H/D kinetic isotope effects. For tetramethyl- and pentamethyl-substituted arenes, electron transfer becomes a competitive pathway and thermodynamic and kinetic calculations correctly predict the experimentally reported electron transfer crossover region. These calculations show that p-block metals activate strong hydrocarbon C–H bonds through organometallic intermediates and changes in arene functional groups can result in a shift from C–H activation to electron transfer. |
| Databáze: | OpenAIRE |
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