Transition metal complexes obtained from an ionic liquid-supported Schiff base: synthesis, physicochemical characterization and exploration of antimicrobial activities

An ionic liquid-supported Schiff base 1-{2-(2-hydroxy-5-chlorobenzylamine) ethyl}-3-methylimidazolium tetrafluoroborate and its Co(II), Ni(II), Cu(II), Mn(III), Fe(III) and Cr(III) complexes were synthesized and characterized by various analytical (elemental analysis, molar conductance and magnetic susceptibility measurements) and spectroscopic (PXRD, SEM, ESI-MS, UV-Visible, FT-IR, ${}^1\text{H NMR}$ and ${}^{13}\text{C-NMR}$) methods. Based on these spectral data and spectra, tetra coordinated and hexacoordinated geometries were assigned for the synthesized metal complexes. Molar conductance of the complexes showed their (1:2) electrolytic nature. The Schiff base ligand and its complexes were screened for invitro antimicrobial activities against some naturally available gram positive and gram negative bacteria to assess their inhibition potentials. Maximum inhibition zone was produced by the Cu(II) complex (5a) in plates of Klebsiella pneumoniae while the minimum inhibition zone was produced by in plates of Bacillus cereus.

Graphical abstract

Transition metal complexes synthesized from an ionic liquid-supported Schiff base have been characterized by various spectroscopic and analytical techniques. Based on the experimental data, it was suggested that the metal ions be coordinated by the ligand in 1:2 ratio. The complexes were explored against Gram-positive and Gram-negative bacteria. .