Synthesis, structural characterization, and antimicrobial evaluation of new mononuclear mixed ligand complexes based on furfural-type imine ligand, and 2,2 '-bipyridine

The present investigation goal was to investigate the chemistry of four new mononuclear mixed ligand Fe(III), Co(II), Cu(II), and Cd(II) complexes constructed from furfural-type imine ligand (L), and the co ligand 2,2 '-bipyridine in addition to assessing their antimicrobial activity against some bacterial, and fungi strains. The structure of the complexes was interpreted by different spectroscopic techniques such as MS, IR, H-1 NMR, UV-Vis, elemental analysis, TG-DTG, conductivity, and magnetic susceptibility measurements. The correlation of all results revealed that ligand (L) acts as a neutral ONNO tetradentate whereas the co ligand acts as a neutral NN bidentate. The coordination of the ligands with the metal ions in a molar ratio of 1:1:1 leads to formation of an octahedral geometry around the metal ions. The octahedral geometry has been validated and optimized by DFT analysis. Conductivity data showed the electrolytic nature of all complexes. The thermal stability of all complexes was deduced in addition to evaluating some thermodynamic, and kinetic parameters using Coats-Redfern method. Furthermore, all complexes in comparison to their parent ligands were tested for their biological potency against some pathogenic bacterial, and fungi strains using the paper disk diffusion method. [CdL(bpy)](NO3)(2) complex revealed the highest antimicrobial activity.

Automated summary

The study investigated the chemistry and antimicrobial activity of four new mononuclear mixed ligand Fe(III), Co(II), Cu(II), and Cd(II) complexes constructed from furfural-type imine ligand (L) and 2,2'-bipyridine as a co-ligand. Various spectroscopic techniques were used to determine the structure of the complexes. The results showed that the ligand (L) acted as a neutral ONNO tetradentate and the co-ligand acted as a neutral NN bidentate. The complexes exhibited octahedral geometry around the metal ions. Conductivity data showed electrolytic nature of the complexes. The [CdL(bpy)](NO3)(2) complex exhibited the highest antimicrobial activity compared to the parent ligands.