Novel chemistry of carbon bound to cobalt in organocobalt complexes related to B12

The Co-C-N three-membered ring in organocobalt complexes related to B12 is formed when an equatorial nitrogen donor is added to a ligated axial carbon through a facile interligand nucleophilic addition. The Co-C-N ring angle is 43.7 degrees with Co-N and Co-C ring linkages having the greatest distortion of the coordination sphere. Phi-bending is a significant factor in the weakening of the Co-C bond, and causes Co-C bond cleavage along with theta-bending. Hypotheses regarding Co-C bond activation in B12 chemistry and calculations of the activation can be assessed using evidence from the highly distorted structure of the resulting complex.