Novel bioactive copper and nickel polymeric complexes: Synthesis,characterization, antimicrobial activity,and DFT calculations

Polymeric complexes, especially metal-containing polymers, possess aggregated medical applications, especially as antibacterial and antifungal agents. This work describes a facile procedure for producing a series of novel copper and nickel complexes of poly(2-hydroxyphenyl methacrylamide) and poly(2-carboxyphenyl methacrylamide). The polymeric ligands were synthesized through a multistep procedure. Firstly, 4-formylphenyl methacrylate was constructed by acylating 4-hydroxybenzaldehyde with methacryloyl chloride. Then, polymerization of the as-prepared monomer to obtain poly(4-formylphenyl methacrylate) using benzoyl peroxide as an initiator. Thirdly, the polymeric ligands PL1 and PL2 were achieved via exchange reactions between poly(4-formylphenyl methacrylate) and o-aminophenol and anthranilic acid, respectively. Consequently, the two ligands were reacted with copper and nickel acetates to afford four target complexes (Cu-PL1, Ni-PL1, Cu-PL2, and Ni-PL2). By FT-IR, ¹HNMR, UV-visible, and TGA analyses, the structures of PL1, PL2, and their complexes were investigated. Furthermore, the geometries of PL1, PL2, and their complexes were reported through a molecular modeling to investigate some interesting parameters such as the bond length, bond angle, charge on the atoms, the HOMO and LUMO using the Material Studio program. The calculation results illustrated that octahedral geometries are proposed for the synthesized metal complexes. The reported antimicrobial efficiency showed a strong potency for most synthesized compounds against the selected microbes, especially compounds Cu-PL1 and Cu-PL2 which are more effective than the standard against Candida albicans.