C–CN Bond Activation of Acetonitrile using Cobalt(I)

A cobalt(I) methyl species, (PMe3)4CoCH3, was found to promote C–CN bond oxidative addition of acetonitrile at ambient temperature. The isolated product of acetonitrile activation, cis,mer-(PMe3)3Co(CH3)2CN, was characterized by NMR, IR, and single-crystal X-ray diffraction studies and presents a higher valent metal in comparison to those previously observed for base-metal-mediated nitrile activations. A short-lived reaction intermediate was detected during nitrile cleavage and identified as fac-(PMe3)3Co(CH3)2CN, the kinetic product of C–CN oxidative addition. Conversion of the kinetic product to cis,mer-(PMe3)3Co(CH3)2CN proceeds with a rate constant of [1.0(1)] × 10–3 s–1 at 27 °C.