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

  • Biswajit Sinha
  • Malay Bhattacharya
  • Sanjoy SahaEmail author
Regular Article


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, \(^{ 1}\hbox {H NMR}\) and \(^{13}\hbox {C-NMR}\)) 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 in vitro 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.


Ionic liquid Schiff base transition metal complexes antimicrobial studies 



The authors are grateful to the Departmental Special Assistance Scheme under the University Grants Commission, New Delhi (SAP-DRS-III, NO.540/12/DRS/2013) for financial support and SAIF, NEHU, Guwahati, India for \(^{13}\hbox {CNMR}\), \(^{1}\hbox {H NMR}\), ESI-MS and elemental analysis. We are thankful to USIC, NBU, West Bengal, India and Department of Chemistry, Sikkim University, Sikkim, India for SEM and PXRD spectra respectively.

Supplementary material

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Supplementary material 1 (pdf 1282 KB)


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Copyright information

© Indian Academy of Sciences 2019

Authors and Affiliations

  • Biswajit Sinha
    • 1
    • 3
  • Malay Bhattacharya
    • 2
  • Sanjoy Saha
    • 1
    • 3
    Email author
  1. 1.Department of ChemistryUniversity of North BengalDarjeelingIndia
  2. 2.Department of Tea ScienceUniversity of North BengalDarjeelingIndia
  3. 3.Department of ChemistryKalimpong CollegeKalimpongIndia

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