KINETIC ACIDITY FUNCTION HCNOT-EQUAL .1. DEFINITION OF THE FUNCTION IN AQUEOUS SULFURIC-ACID AND ITS APPLICABILITY TO ACID-CATALYZED HYDROGEN-EXCHANGE OF THE RING PROTONS OF AROMATIC-MOLECULES, AND PROTONATION OF CARBON-CARBON DOUBLE AND TRIPLE BONDS

The acid-catalyzed hydrogen exchange of 4-nitro-N, N-dimethylaniline in the 2, 6 positions has been measured over a wide range of acidities in D2O-D2SO4. This enables the extension of the Hc acidity function, which describes the equilibrium protonation of carbon bases into the high acidity region, and also the definition of a kinetic acidity function Hcǂ. which is shown to correlate the selectivity of proton-transfer reactions to carbon over a wide range of reactivity for a large variety of aromatic bases, as well as for carbon-carbon double and triple bonds. The implications of this with regard to substituent effects and Marcus theory are examined. © 1979, American Chemical Society. All rights reserved.