(189ck) Electrophilic Aromatic Substitution and Intrinsic Nature of Aromaticity

Aromatic
compounds are essential in the functioning of modern society and greatly affect
the quality of everyday life. Aromatics-derived products are key to meeting the
demands of pharmaceutical industry, transportation and packing industry,
textile industry, electronics, and construction. Any fundamental breakthrough
in the perception of the concept of aromaticity and
the intrinsic nature of these compounds paves the way toward better
understanding and more efficient utilization of this diverse class of molecules.
Explaining the electronic structure of aromatic compounds, together with
rational predictions regarding the reactivity and spectroscopic variables,
provides a mean to define this venerable concept in a more
strict manner. This will help us to understand the nature of these
compounds, their reactivity and behavior to a higher extent. One of the
interesting issues is the conceptual question whether the aromaticity
represents the local or global property. In order to tackle this problem, we
have examined the behavior of various aromatic compounds during the
electrophilic aromatic substitution (EAS). In this work we considered how EAS
affects the aromaticity in polycyclic aromatic
compounds, conjugated systems (with the linkers of the variable length) and
selected metallocenes. In order to fully understand
these effects, we have used density functional theory, NICS value and other
important aromaticity criterions. Finally, we have
reproduced literature results regarding effects of benzene substitution on the
system aromaticity, so we could more easily
distinguish between effect originating from a different substituent and
local/global aromaticity considerations. The obtained
results and rationalizations establish a deeper insight into the nature of aromaticity and relate this understanding to their
reactivity, thus providing a connection to their various applications.