Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110-fold enhancement compared to the oleylamine-coated AuNP in current density for electrochemical reduction of CO to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93 %. These catalysts also show excellent stability without deactivation (<5 % productivity loss) within 72 hours of electrolysis. DFT calculation results further confirm the chelation effect in stabilizing molecule/NP interface and tailoring catalytic activity. This general approach is thus anticipated to be complementary to current NP catalyst design approaches.
We report herein a highly efficient Cucatalyzed protocol for the conversion of aliphatic carboxylic acids to the corresponding difluoromethylated analogues. This robust, operationally simple and scalable protocol tolerates a variety of functional groups and can convert a diverse array of acid-containing complex molecules to the alkyl-CF 2 H products. Mechanistic studies support the involvement of alkyl radicals.
We report herein the first catalytic strategy to harness
amidyl
radicals derived from N-chloroamides for C–C
bond formation, allowing for the discovery of the first catalytic
benzylic C–H difluoromethylation. Under copper-catalyzed conditions,
a wide variety of N-chlorocarboxamides and N-chlorocarbamates direct selective benzylic C–H
difluoromethylation with a nucleophilic difluoromethyl source at room
temperature. This scalable protocol exhibits a broad substrate scope
and functional group tolerance, enabling late-stage difluoromethylation
of bioactive molecules. This copper-catalyzed, chloroamide-directed
strategy has also been extended to benzylic C–H pentafluoroethylation
and trifluoromethylation. Mechanistic studies on the difluoromethylation
reactions support that the reactions involve the formation of benzylic
radicals via intramolecular C–H activation, followed by the
copper-mediated transfer of difluoromethyl groups to the benzylic
radicals.
Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110‐fold enhancement compared to the oleylamine‐coated AuNP in current density for electrochemical reduction of CO2 to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93 %. These catalysts also show excellent stability without deactivation (<5 % productivity loss) within 72 hours of electrolysis. DFT calculation results further confirm the chelation effect in stabilizing molecule/NP interface and tailoring catalytic activity. This general approach is thus anticipated to be complementary to current NP catalyst design approaches.
The difluoromethyl group (CF2H) is considered to be a lipophilic and metabolically stable bioisostere of an amino (NH2) group. Therefore, methods that can rapidly convert an NH2 group into a CF2H group would be of great value to medicinal chemistry. We report herein an efficient Cu‐catalyzed approach for the conversion of alkyl pyridinium salts, which can be readily synthesized from the corresponding alkyl amines, to their alkyl difluoromethane analogues. This method tolerates a broad range of functional groups and can be applied to the late‐stage modification of complex amino‐containing pharmaceuticals.
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