Aromatic C–H bond activation revealed by infrared multiphoton dissociation spectroscopy

Metal‐oxide cations are models of catalyst mediating the C–H bond activation of organic substrates. One of the most powerful reagents suggested in the gas phase is based on CuO⁺. Here, we describe the activation of the aromatic C–H bonds of phenanthroline in its complex with CuO⁺. The reaction sequence starts with a hydrogen atom abstraction by the oxygen atom from the 2‐position of the phenanthroline ring, followed by OH migration to the ring. Using infrared multiphoton spectroscopy, it is shown that the reaction can be energetically facilitated by additional coordination of a water ligand to the copper ion. As the reaction is intramolecular, a spectroscopic characterization of the product is mandatory in order to unambiguously address the reaction mechanism. Copyright © 2012 John Wiley & Sons, Ltd.