A neutral σ 0 π 2 carbene enabling hydrogen activation via a σ -face pathway
Liu Leo Liu
Nature Chemistry, Published online: 11 May 2026; doi:10.1038/s41557-026-02147-0 Hydrogen activation by stable carbenes is rare and typically proceeds through π-face, non-least-motion pathways. Now, a neutral σ0π2 carbene has been synthesized and shown to cleave H2 at room temperature through a σ-face pathway, approaching the least-motion limit.