Facile C≡O Triple Bond Cleavage of Carbon Monoxide by a Mononuclear Uranium Borohydride Complex.

Complete scission of the C≡O triple bond in carbon monoxide by an actinide complex has so far been restricted to multimetallic nitride-bridged systems, where the reaction proceeds via formation of strong C─N multiple bonds. Here we report an alternative mode of complete CO cleavage mediated by a mononuclear uranium(IV) borohydride complex supported by a double layer N-P ligand at room temperature. Single-crystal x-ray diffraction reveals that the oxygen atom becomes bonded to both uranium and boron (U-O-B), while the carbon atom is inserted into a new hydrocarbyl framework, forming U─C, C─C, and C─Si bonds. Computational studies elucidate a cooperative mechanism involving CO insertion into the U-H-B linkage followed by low-barrier rearrangements. This work demonstrates complete CO cleavage by a mononuclear actinide complex operating through a U-H-B cooperative pathway, thereby establishing an alternative, nitride-free route for this transformation at a single uranium center.