A comprehensive theoretical study was conducted on benzimidazole and several of its derivatives in the gas phase to evaluate the effect of heat transfer on their thermodynamic properties, including enthalpy, entropy, heat capacity, and correlation properties.

Benzimidazole and its various derivatives, such as Proquazone, are flexible nitrogen-containing heterocyclic compounds. These compounds are recognized as promising biologically active molecules, exhibiting a wide range of biological and pharmacological activities, including antibacterial, anti-inflammatory, anti-ulcer, and anti-diabetic effects.

Benzimidazole is a cyclic compound formed by the fusion of a benzene ring with an imidazole ring, providing a stable and favorable molecular structure.

The theoretical study of benzimidazole and its derivatives was carried out to calculate thermodynamic properties, including entropy, enthalpy, and heat capacity, over a temperature range of 200 K to 1000 K. Density Functional Theory (DFT) calculations were employed to examine the energy behavior and molecular moments of the compounds in the gas phase at the B3LYP/6-311++G(d,p) level.

Additionally, electronic properties such as the energy gap between HOMO and LUMO, total energy for various orbital transitions, chemical hardness, softness, electrophilicity index, and electronegativity were calculated using the B3LYP/6-311G(d,p) level of theory.