More O’Ferrall

Fig. 11.8. More O Ferrall representation of Claisen rearrangement. Adapted from J. J. Gajewski, Acc Chem. Res. 30, 219 (1997).

Energy surfaces of this type appear to have been described first by Hughes et al. in 1936. Their current popularity and utility are a consequence of developments by Albery, More O Ferrall, and Jencks, and they are sometimes called More O Ferrall plots or More O Ferrall-Jencks plots. We will refer to them as RIP diagrams, this designation arising from the symbolism in Fig. 5-19. 

They were able to infer p for the identity reaction in which Ar = Ar, and interpreted the results in terms of a More O Ferrall-Jencks diagram of the type described in Section 5.3. 

The BEP/Hammond/Marcus treatment only considers changes due to energy differences between the reactant and product, i.e. changes in the TS position along the reaction coordinate. It is often useful also to include changes that may occur in a direction perpendicular to the reaction coordinate. Such two-dimensional diagrams are associated with the names of More O Ferrall and Jenks (MOJ diagrams). 

More O Ferrall diagram for base-promoted, imine forming 1,2-elimination reactions. 

R.A. More O Ferrall, in The Chemistry of the Carbon-Halogen Bond, S. Patai, Ed. Wiley-Interscience, Part 2, Chapter 9,609-675, (1973). 

On the basis of the preceding discussion, the systematic trend in AV observed for water exchange on [M(H20)6]2+ may be rationalized through a More-O Ferral type of diagram (4, 7) as shown in Fig. 4. The bond-making and bond-breaking contributions to AV are plotted on the two axes, which are scaled to AVt for a D mechanism being... 

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