8 - The electron density of delocalized bonds (EDDBs) as a measure of local and global aromaticity

Abstract

Many of the commonly used aromaticity descriptors suffer from serious issues such as the arbitrariness of choice of a reference system and parameterization, ring-size extensivity problems, limited applicability, computational inefficiency, as well as methodological shortcomings and interpretative mistiness. Thus, introducing new aromaticity measures makes sense nowadays only if their performance provides an advantage over the already existing descriptors or they offer similar quality but at a significantly lower computational cost. In this chapter, the recently proposed electron density of delocalized bonds method will be described, which may fulfill these conditions by a wide margin providing a uniform approach not only to quantify but also to visualize electrons delocalized through the system of all (global) or selected (local) conjugated bonds in a wide range of aromatic species regardless of their size and topology.