In
this study, we delve into the electronic structure, spectroscopic,
and optical properties of five benzo derivatives of pyridine, namely,
5-(4-chlorophenyl)-2-fluoropyridine (1), 2-fluoro-5-(4-fluorophenyl)pyridine
(2), 4-(2-fluoropyridin-5-yl)phenol (3),
5-(2,3-dichlorophenyl)-2-fluoropyridine (4), and 5-(5-bromo-2-methoxyphenyl)-2-fluoropyridine
(5). Utilizing quantum chemical density functional theory
calculations at the B3LYP and Perdew–Burke–Ernzerhof
levels of theory combined with the 6-311G(d,p) and 6-311++G(d,p) basis
sets, we investigated the electronic and optical characteristics of
these compounds. Band structure calculations were conducted for their
crystalline structures, revealing a direct band gap varying from 3.018
to 3.558 eV, with the valence band maximum and conduction band minimum
located at the G point in the Brillouin zone. The
optical properties were analyzed, including the dielectric functions,
reflectivity, and refractive index. Notably, reflectivity was found
to be minimal in the photon energy range of 0.0–3.0 eV, and
the static refractive index, n(0), ranged from 1.55
to 1.70. The research also involved assessing the reactivity of the
compounds through calculation of the frontier orbital energy gaps
(ΔE), indicating a significant charge transfer
and high reactivity. Additionally, we performed frequency analysis
to unveil the Fourier-transform infrared spectra of compounds 1–5 at room temperature. Molecular electrostatic
potential surfaces of the optimized structures were employed to map
the electrophilic and nucleophilic regions of the compounds. This
investigation provides a comprehensive understanding of the electronic
and optical properties of these pyridine derivatives, shedding light
on their potential applications in optoelectronics.