Synthesis and functional assessment of a novel Mn(II)-based coordination polymer for antimicrobial and anticorrosion applications

The design and the synthesis of coordination polymers have become increasingly interesting because of their versatility in chemical and physical properties, making them suitable for antimicrobial and anticorrosion applications. This study reports the synthesis, structural characterization, and functional evaluation of a new manganese (II) coordination polymer incorporating a bis-pyridinyl aniline ligand. The ligand, N,N′-bis (pyridin-2-ylmethylene)-4-aminoaniline, was synthesized by condensation of benzene-1,4-diamine with pyridine-2-carboxaldehyde, followed by reduction with sodium borohydride to yield N , N ′-bis(pyridin-2-ylmethyl)-4-aminoaniline. Subsequent self-assembly with MnCl₂·4H₂O in methanol produced a one dimension (1D) zigzag coordination polymer of the formula [Mn(L1) 0.5 Cl]·CH 3 OH[Mn(L1) 0.5 Cl]·CH 3 OH_n. Detailed characterization was conducted using several spectroscopic techniques to confirm the identity and geometry of intermediates and the final polymer. The biological activity of both ligands and the complex was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), with results benchmarked to chloramphenicol. All compounds demonstrated significant antibacterial inhibition at 100 μg/mL. Additionally, the anticorrosion properties of the synthesized compounds were investigated on carbon steel substrates, demonstrating promising inhibition performance. Specifically, polarization measurements revealed that both ligands and the complex achieved an inhibition efficiency of 87–92 % at 0.1 mM concentration, substantially reducing the corrosion rate of carbon steel. These findings highlight the potential of manganese (II) coordination polymers for dual antimicrobial and anticorrosion applications.