Solvent nucleophilicity quantitative scales

Various scales of nucleophilic reactivity for anions have been in use for several years (Swain and Scott, 1953 Edwards, 1956 Pearson et al., 1968 Ritchie, 1972 see also Bunnett, 1963 Ibne-Rasa, 1967 Hartshorn, 1973b), but quantitative scales of solvent nucleophilicity have only recently been developed. Peterson and Waller (1972) derived a scale of solvent nucleophilicity (APW) based on the... 

The development of quantitative scales of solvent nucleophilicity based on solvolysis reactions is reviewed. Effects of solvent nucleophilicity are illustrated by product studies, by correlations of kinetic data, and by quantitative estimates of competing nucleophilic pathways, including competing solvent-assisted and anchimerically assisted pathways. The problem of separating quantitatively the nucleophilic and electrophilic solvent contributions to reactivity is discussed. Recent results on the nucleophilicities of aqueous sulfuric acid mixtures are presented. 

Quantitative Scales of Solvent Nucleophilicity. Solvolytic studies in solvents of low nucleophilicity led to renewed interest in quantitative measures of solvent nucleophilicity. Peterson and Waller (44) derived a scale of solvent nucleophilicity (Npw) from the rates of displacement by solvent of tetramethylenehalonium ions (VI) in liquid sulfur dioxide. The reaction is approximately half-order in carboxylic acid, possibly because dimer-monomer preequilibrium occurs (44). More recently, hydrolysis of the iodonium salt (VIII) in competition with anionic or solvent nucleophiles was studied. A scale of nucleophilicity relative to water was obtained by quan-... 

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