Spectroscopic Studies and Antimicrobial Evaluation of New Mixed Ligand Mn(II), Ni(II), Cu(II) Complexes Synthesized from an Ionic Liquid-Supported Schiff Base and 1-Methyl Imidazole

Abstract

Mn(II), Ni(II), Cu(II) complexes with the ionic liquid-supported Schiff base 1-{2-(2-hydroxy-5-chlorobenzylamine)ethyl}-3-methylimidazolium tetrafluoroborate (primary ligand) and 1-methyl imidazole (secondary ligand) and were synthesized and characterized by PXRD, SEM, ESI-MS, UV-Visible, FT-IR, ¹H NMR, ¹³CNMR spectroscopic and various analytical (elemental analysis and magnetic susceptibility measurements) methods. Based on these spectra and spectral data hexa coordinated geometries were assigned for the synthesized mixed ligand metal (II) complexes. Antimicrobial activity of the mixed ligand Mn(II), Ni(II), Cu(II) complexes with respect to the Schiff base against two gram positive (Staphylococcus aureus and Bacillus cereus) and two were gram negative (Escherichia coli and Klebsiella pneumoniae) were conducted to assess their antibacterial activities. The Schiff base along with the mixed ligand complexes exhibited very significant responses for gram positive and negative bacterial samples though maximum inhibition zone was produced by Ni(II) complex while the minimum inhibition zone was produced by Cu(II) complex in plates of Staphylococcus aureus.

Graphical Abstract

Keywords:

• Mixed ligand complexes
• imidazole
• ionic liquid supported Schiff base
• antimicrobial studies

Acknowledgements

The authors are grateful to the SAIF, NEHU, Guwahati, India for ¹³CNMR, ¹H NMR and SAIF, CDRI, Lucknow, India for ESI-MS and elemental analysis. We indebted to USIC, University of North Bengal, Darjeeling, India and Sikkim University, Sikkim, India for SEM and PXRD spectra, respectively.

Disclosure statement

No potential conflict of interest was reported by the authors.