The resonance of cation and anion radicals with multiple conjugated bonds

This work describes a computational study of the electronic structure of anion and cation radicals of some conjugated systems-buta-1,3-diyne, hexa-1,3,5-triyne, buta-1,3-diene, and hexa-1,3,5-triene. The main purpose was to investigate how the gain or loss of one electron affected the geometry and, electron and spin densities. The NBO, QTAIM, ELF, and LMO-EDA methods helped to study the electronic structure of the target compounds and their radicals. Several methods indicate an increased electronic delocalization upon ionization. The unpaired electron is preferentially localized at the terminal carbon atoms in radicals. The calculated isodesmic and homodesmotic bond separation reactions indicated that disruption of the conjugation system prompted higher energy at the radicals as compared with neutral molecules.