Solvation effects on the rate of protolytic cleavage of a 9-nitroanthracene Meisenheimer sigma complex

The kinetics of protolytic cleavage of the Meisenheimer sigma complex of 9- nitroanthracene with methoxide ion in alcohols and their mixtures with DMSO were studied by spectrophotometry. The reaction rate increases with decrea sing inductive and increasing steric constants of the alkyl radicals in the alcohols. In DMSO-alcohol mixtures, the effect of sigma* constants is the opposite, which is explained by formation of poorly active heteroassociates between the aprotic and protic molecules.