On the distinct reactivity of two isomers of [IrC4H2]+ toward methane and water

The gas-phase reactions of [IrC₄H₂]⁺ with methane and water have been explored by using mass spectrometry combined with quantum chemical calculations. Interestingly, under the employed conditions, two isomers of [IrC₄H₂]⁺ co-exist with different reactivity. One of them only activates methane while the other is solely reactive with water to produce CO. Apparently, upon varying the coordination patterns, the Ir center gains rather distinct capabilities of mediating the bond breaking and making processes. The reactivity toward methane mainly depends on the orbital orientation, while the π-aromaticity of the reaction complex matters for the conversion of water. The experimental and theoretical findings in this work do not only imply the promising role the Ir atom can play in the bulk-system methane conversion, but may also be instructive on how to construct a high-performance center for steam reforming of methane.