Ligand effect on Ru-centered species toward methane activation

Abstract

Ligands have been known to profoundly affect the chemical transformations of methane, yet significant challenges remain in shedding light on the underlying mechanisms. Here, we demonstrate that the conversion of methane can be regulated by Ru centered cations with a series of ligands (C, CH, CNH, CHCNH). Gas-phase experiments complemented by theoretical dynamic analysis were performed to explore the essences and principles governing the ligand effect. In contrast to the inert Ru⁺, [RuC]⁺, and [RuCNH]⁺ toward CH₄, the dehydrogenation dominates the reaction of ligand-regulated systems [RuCH]⁺/CH₄ and [RuCHCNH]⁺/CH₄. In active cases, CH acts as active sites, and regulates the activation of CH₄ assisted by the “seemingly inert” CNH ligand.