New piperazine-hydrazone derivatives as potential antimicrobial agents: Synthesis, characterization, biological evaluation, and in silico investigations

•Antimicrobial activities of newly synthesized schiff base derivatives.•Docking studies were performed for the most active compounds.•DFT calculations FMO analysis, (NLO) properties and MEP surface were implemented. In this work, the synthesis and biological activity of a new series of piperazine-hydrazone derivatives have been reported. The titled compounds were prepared in good yields from 1-methylpiperazine and 2-chloro-5-nitropyridine as starting materials via a five-step process. The newly synthesized compounds were fully characterized using spectral analyses such as IR, 1H NMR, 13C NMR, and MS spectra. Furthermore, DFT (density functional theory) calculations were performed to better understand the molecular geometry and electronic properties of the synthesized compounds. The primary antimicrobial activity of all synthesized compounds was evaluated against four pathogenic microorganisms. As a result, compound 6 was identified as the best candidate for selectively inhibiting Candida krusei. Compound 7e was also found to be a good inhibitor of Bacillus subtilis and Candida krusei. Docking studies revealed that compounds 6 and 7e exhibit good affinity for the active site of sterol 14-alpha demethylase (CYP51) of Candida krusei, which may explain their promising antimicrobial activity. [Display omitted]