Cleavage of Carbon Monoxide Promoted by a Dinuclear Tantalum Tetrahydride Complex

The reaction of one equivalent of carbon monoxide with the dinuclear tetrahydride complex ([NPN]­Ta)₂(μ-H)₄ (where NPN = PhP­(CH₂SiMe₂NPh)₂) results in the cleavage of the CO triple bond and formation of ([NPN]­Ta)­(μ-O)­(μ-H)­(Ta­[NPN′]) (where NPN′ = PhP­(CH₂SiMe₂NPh)­(CH₂SiMe₂NC₆H₄)) via extrusion of CH₄. The identity of the ditantalum complex was confirmed by single-crystal X-ray analysis, isotopic labeling studies, and GC-MS analysis of the methane released. DFT calculations were performed to provide information on the initial adduct formed and likely transition states for the process.