:
A retrospective view of exaltation of refraction observed for many unsaturated
and aromatic compounds demonstrates that this physical phenomenon is undeservedly
considered only as a qualitative measure of conjugation. This mini-review discusses numerous
papers by the author that have been published earlier in inaccessible periodicals
and collections of scientific papers. Using a great number of illustrations, the author shows
that this parameter can be successfully used for quantitative estimate of resonance effects
in organic and polymer chemistry. The methods for derivation of strictly additive atomic
and group refraction constants are described; these constants were subsequently used as a
tool that allowed quantitative estimation of resonance effects in mono-, di-, tri- and polyalkylbenzenes,
alkylnaphthalenes, some alkyl derivatives of unsaturated hydrocarbons.
These effects cause strictly fixed increase in refraction of carbon atoms in different structural modifications
(graphene, fullerene, diamond) and in polycyclic aromatic hydrocarbons. The relevant results regarding quantitative
estimation of degree of steric inhibition of resonance in sterically hindered ortho-dialkylbenzenes, 1,2,3-
trialkyl-, 1,2,3,4-tetraalkyl-, and 1,2,3,4,5-polyalkylbenzenes accumulated by the author are summarized.
