Electronic Structure of Aromatic π-Electron Systems as Reflected in their MCD Spectra

Abstract

The physical origin of the MCD effect in aromatic Molecules is described in simple terms, and the rules for the effect of substituents and heteroatoms on their MCD signs are reviewed. Three examples of their application are presented: the effect of -E substituents in a subdominant position of an even-soft chromophore (y-substituted pyridinium), the effect of +I, +E, and -E substitution in different positions of an odd-soft chromophore (the three positions of pyrene), and the effect of the introduction of heteroatoms into a single-soft chromophore (conversion of the indenide anion into indole and similar heterocycles). © IUPAC