The determination of the ring current and its relationship to the resonance energy in some aromatic compounds

Abstract

A critical evaluation is made of the determinations of the ring current in a number of aromatic molecules from observed proton chemical shifts and its relationship to the resonance energy and reactivity of the system. Recent developments in the theory of chemical shifts and the various methods of evaluating “aromaticity” are included. It is considered that the aromatic ring current, although possibly the most sensitive test for the detection of aromatic character, is not directly related to the resonance energy or reactivity of the molecule.