Pd/NHC complexes containing fluorine atoms were synthesized at the Zelinsky Institute

Complexes metal/N-heterocyclic carbene (NHC) have been actively used in recent years in various catalytic reaction. They managed to prove themselves excellently in the processes of C-H-activation, Mizoroki-Hek, Suzuki-Miyaura, Negishi, Buchwald-Hartwig cross-couplings. Their key feature is the ability to tune the catalytic properties of such systems through changes in ligand exclusion, which opens a convenient path to highly efficient and selective catalytic systems. The introduction of fluorine into the metal/NHC system seems especially promising. Presumably, this modification affects the breaking of the metal-carbon bond and the rate of the catalytic process. However, to date, only several M/NHC complexes containing fluorine atoms have been obtained, and there are no general methods for the synthesis of such structures.

Scientists from the Laboratories of Metal Complex and Nanoscale Catalysts of the ZIOC have developed a method for obtaining Pd/NHC-fluorinated complexes under mild conditions. The molecular structure of one of them was confirmed by X-ray diffraction analysis. Based on experimental and calculated data, it was shown that fluoro-substituted NHCs are similar to alkyl-substituted NHCs. Electronic effects are not inherent in the properties of molecules, fluorine atoms have an impact only on their steric load. The fluorine atom slightly affects the NHC core, while the fluorine-containing substituents in the ligand decrease the contribution of the σ-interaction and increase the contribution the π-interaction of the Pd–NHC bond. Thus, fluorine-substituted complexes are of interest for research in the field of catalysis.

Source:

Darya O. Prima, Roman O. Pankov, Alexander Yu. Kostyukovich, Mikhail E. Minyaev, Julia V. Burykina, Valentine P. Ananikov Synthesis and characterization of Pd/NHCF complexes with fluorinated aryl groups. Dalton Trans., 2022, 51, 9843-9856. DOI: 10.1039/d2dt00892k.