Fig. 5. Activation strain diagrams (ASD) for the oxidative addition of: (a) CH3–X bonds (X = H, Cl, CH3: black, green, red) to singlet Fe(CO)4; (b) CH3–H bonds to singlet and triplet Fe(CO)4 (black and blue); and (c) CH3–H bonds to neutral and dianionic Fe(CO)4 (black and red); and (d) decomposition of the total strain energy into catalyst and substrate strain. Energy barriers relative to reactants for the TSs are also included (see upper left corner panel) and the positions of TSs are marked by dots.
