Mixed Ligand Metal (II) Complexes from a Functionalized Ionic Liquid Tagged Schiff Base and N-Methyl Imidazole: Synthesis, Spectroscopic Studies and Antibacterial Effects On Rhizosphere Bacteria

Mononuclear Cobalt (II), Nickel (II) and Copper (II) mixed ligand complexes were derived from a primary ligand, 1-{2-(5-bromo-2-hydroxybenzylideneamino)ethyl}-3-methyl-imidazolium[BF₄] and a secondary ligand, N-methyl imidazole. The synthesized mixed ligand complexes along with the Schiff base were characterized and established by different analytical as well as spectral methods like elemental analysis, ESI–MS, SEM, EDX, PXRD, FT-IR, 1H-NMR, 13C-NMR, UV–visible and magnetic susceptibility measurements. The analytical data suggested octahedral coordination of the two ligands around the metal centre. The synthesized complexes and Schiff base were screened on twelve different bacterial strains isolated from the rhizospheric soil which plays pivotal role in plants growth, yield improvement, nutrient acquisition, pest prevention and overall development even any changes in rhizospheric microbial community, will affect material and energy circulation of the soil system, the release of plant root exudates as well as soil fertility. Among the synthesized mixed ligands complexes, Cu (II) was seen to pose no negative impact on the viability of the 12 bacterial cultures, though Ni (II) and Co (II) exhibited significant inhibitory effect. The Gram-positive bacteria were seen to be comparatively more vulnerable to the metal complex except for Cu.