Benzimidazole-based N-heterocyclic carbene ruthenium(II) complexes: Synthesis and C-H bond activation properties

The transition-metal-promoted C-H activation has become an efficient as well as an atom-economic methodology for the synthesis of a wide array of organic molecules. Herein, the reaction of RuCl2(p-cymene)](2) with 1,3-dialkylbenzimidazolium salts ( 1a-c ) in the presence of a small excess of cesium carbonate yields chelated eta(6)-arene, eta(1)-carbene ruthenium complexes ( 2a-c ). All synthesized compounds were characterized by elemental analysis and NMR spectroscopy. The catalytic activity of [Cl2Ru(eta(6)-arene, eta(1)-carbene)] complexes ( 2a-c ) were evaluated in the direct arylation of 2-phenylpyridine and 1-phenylpyrazole with (hetero)aryl chlorides derivative. (C) 2022 Published by Elsevier B.V.