[H2CZrH2]: The Simplest Carbene Hydride Complex, Agostic Bonding, and CH Activation of CH4 to Form [(CH3)2ZrH2]

Spectrum of zirconium methylidene: Reaction of laser-ablated zirconium with CH4 in excess neon at 5 K forms [H2CZrH2], the simplest carbene complex. Density functional theory calculations predict a C1 symmetry structure (see picture) with agostic CH⋅⋅⋅Zr bonding. This structure is confirmed by the match between calculated and observed IR frequencies. Methane activation by [H2CZrH2] gives [(CH3)2ZrH2].