Richardson’s rules

Richardson s rules, as enunciated by Richardson himself in updated form (in the MTP International Review of Science article that he wrote in 1973), are as follows ... 

SCHEME 42. The physical basis of Richardson s rules for nucleophilic displacement of carbohydrate sulfonic esters (1969). 

Finally, this obituary and retrospective survey could not close without a significant mention of Richardson s celebrated rules for nucleophilic replacement of tosylates, mesylates, and halo groups by charged nucleophiles in carbohydrate pyranoid derivatives. They emanated out of his early studies at Reading on the preparation of... 

A pictorial summary of Richardson s main rules is presented in Scheme 43. 

Standing back now from the detail, and placing Richardson s entire scientific work in perspective, he made enormous academic contributions as well as doing work having important societal impact. From the standpoint of organic chemistry, his rules for nucleophilic displacement linked together an extensive collection of his own... 

The net chirality of this complex ion is zero. The optical activity of the complex ion arises from the dissymmetric disposition of the methylene groups with respect to the coordination plane and the chiral arrangement of the two trans N-H bonds. Richardson s sector rule (60) was tested on the basis of the final atomic parameters. In his derivation the perturbation treatment... 

The phenomenon of compensation is not unique to heterogeneous catalysis it is also seen in homogeneous catalysts, in organic reactions where the solvent is varied and in numerous physical processes such as solid-state diffusion, semiconduction (where it is known as the Meyer-Neldel Rule), and thermionic emission (governed by Richardson s equation ). Indeed it appears that kinetic parameters of any activated process, physical or chemical, are quite liable to exhibit compensation it even applies to the mortality rates of bacteria, as these also obey the Arrhenius equation. It connects with parallel effects in thermodynamics, where entropy and enthalpy terms describing the temperature dependence of equilibrium constants also show compensation. This brings us the area of linear free-energy relationships (LFER), discussion of which is fully covered in the literature, but which need not detain us now. 

Hitchens, T.K., Zhan, Y, Richardson, L.V., Richardson, J.P., and Rule, G.S. 2006. Sequence-specific interactions in the RNA-binding domain of Escherichia coli transcription termination factor Rho. /. Biol. C/zem., 281, 33697-33703. 

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