Ingold-Robinson acid-base

The discussion and classification of reagents is masterful in identifying Ingold s new nomenclature and principles with more widely known oxidation-reduction and acid-base theory. The 1953 lectures at Cornell University, published as Structure and Mechanism in Organic Chemistry, follow this same strategy, showing how old classification schemes overlap with each other and how apparent inconsistencies disappear as old schemes are incorporated into the new one. Nineteenth-century Berzelian electrochemical dualism, revived by Lapworth and Robinson in the cationic/anionic schema, disappears into the electrophilic/nucleophilic language. 

The classification of chemical substances as electrophilic and electrodotic according to their behavior in their reactions with other substances can be extended to radicals in a molecule. When this is done, a flood of light is thrown upon the nature of acid-base catalysis. Ingold,Robinson, and others have already done much to clarify many organic reaction mechanisms, but the electronic theory of acids and bases provides a measure of correlation and insight which so far is unobtainable by any other method. Generalized acid-base catalysis will be considered later. In this chapter we shall deal primarily with the effect of acidic and basic radicals in the benzene ring. 

The conversion experience is found in Ingold s response to a paper presented by Robinson at the Chemical Society in the summer of 1925 and sent to Ingold before its publication in 1926. Robinson s paper, written with J. Allen, A. E. Oxford, and John C. Smith, classified conjugated systems into nine categories of reactants, two of them "anionoid" and the rest "cationoid." "Crotonoid" and "crotenoid" were two of the nine types. This was a detailed and cumbersome classification, based on studies of crotonic acid, amino acids, and their salts, in which crotenoid was an instance of anionoid (electron donor) reaction and crotonoid of cationoid (or electron acceptor) reaction. 

Electrophiles (i.e., electron-deficient species) are of fundamental importance to chemistry. The concept of nucleophiles (lit. nucleus seeking ) and electrophiles (lit. electron seeking ) was suggested by Ingold following similar views implied by Lapworth s description of anionoid and cationoid reagents, Robinson s concepts, and Lewis s theory of bases (electron donors) and acids (electron acceptors).1... 

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