Designing Multifunctional Biologically Active Poly(Azomethine-Ether) Containing Trimethylbenzene Moiety as New Antimicrobial Polymers

A novel series of thermally stable poly(azomethine-ether) polymers (PAZa-d) containing trimethylbenzene moiety were synthesized via polycondensation of a new monomer, with two aliphatic (C2 and C5) diamine and two aromatic (m-phenylene and o-phenylene) diamine. The structural characteristics of the polymers were elucidated using FT-IR, NMR, GPC, SEM, XRD, and TGA. The polymers exhibited high molecular weights (Mw) ranging from 32,600 to 41,600 g mol−1, with PAZc displaying the highest Mw. XRD analysis revealed the amorphous nature of PAZa-c and the crystalline phase of PAZd. SEM micrographs showed sponge-like porous structures for PAZa-c and semi-crystalline particles for PAZd. The polymers demonstrated high thermal stability, with final decomposition temperatures (FDT) ranging from 539.57 to 666.03°C. Antimicrobial screening revealed significant antibacterial activity against Gram-negative bacteria, with PAZc (m-phenylene derivative) exhibiting the highest efficacy. Further investigation of the polymers’ effect on E. coli O157:H7 showed 93–100% growth inhibition. Molecular docking studies using “1JIJ” and “1KNZ” proteins for S. aureus and E. coli, respectively, corroborated the experimental findings, with PAZb and PAZc demonstrating the highest docking scores. The synthesized poly(azomethine-ether) polymers, particularly PAZc, show promise as potential antimicrobial agents for combating Gram-negative bacteria.