Figure 5. Geometries and energetics of mechanisms.

(left) More O'Ferrall-Jencks plot illustrating the concurrent reaction coordinate geometry changes of proposed mechanisms. (right) Comparative reaction profile diagrams for dissociative (S_N1, S_Ni) and orthogonal pathways. The relative energetics and rate-limiting transition state locations of the three pathways are speculative and are offset for clarity, but both S_N1 and S_Ni displacement would certainly involve an intermediate in anenergy well whereas the orthogonal mechanism does not.