Intramolecular hydroxylation of a tetrabenzimidazole-based dicopper complex

The synthesis of bis(N-methylbenzimidazol-2-yl)methane serves as the entry point for the preparation of a tetrabenzimidazole-based binucleating ligand. A cupric complex of the former compound was prepared to compare its properties to those of the dicopper complexes of the tetrabenzimidazole derivative. In the latter case, the reaction of the binucleating ligand with cupric trifluoromethylsulfonate in air results in intramolecular C-H activation with concomitant hydroxylation, presumably by an in situ formed copper-oxygen reactive intermediate. This reactivity highlights the relevance of benzimidazole-based scaffolds in biologically inspired copper-oxygen systems. (C) 2017 Elsevier B.V. All rights reserved.