Impact of pyrazine doping on the electrical conductance and antimicrobial behaviour of novel one-pot synthesized polyaniline-<i>co</i>-pyrazine: DFT and molecular docking

The present investigation employs the chemical oxidative polymerization approach to synthesize co-doped polyaniline (PANI) and polyaniline-<i>co</i>-pyrazine (PANI-<i>co</i>-Pyr) in a single pot. UV-visible spectroscopy, FTIR spectroscopy, TGA, viscosity, BET, and conductivity analyses were conducted to characterize the structural, thermal, and electrical properties of the synthesised compounds. The conductivities of the fabricated PANI and PANI-<i>co</i>-Pyr were depicted in a range of semiconductors due to their smaller band gaps. The stability and reactivity of PANI and PANI-<i>co</i>-Pyr are supported by DFT calculations, providing essential insights into their structural and energetic characteristics. Furthermore, the antibacterial properties of PANI-<i>co</i>-Pyr were tested against <i>S. aureus</i>, <i>E. coli</i>, <i>B. subtilis</i>, and <i>P. aeruginosa</i>, and their antifungal activity against <i>A. niger</i> and <i>P. chrysogenum</i> was measured in terms of IC₅₀ and minimum inhibitory concentration (MIC). Molecular docking was used to investigate the bonding interactions of the Pyr ring with the surrounding residues of 1IX1 and 1UKC. PANI-<i>co</i>-Pyr shows higher binding affinity towards bacterial and fungal strains and exhibits significant antibacterial and antifungal activity.