Manganese(II) complexes of substituted salicylaldehydes and α-diimines: Synthesis, characterization and biological activity

J Inorg Biochem. 2022 Feb:227:111693. doi: 10.1016/j.jinorgbio.2021.111693. Epub 2021 Dec 10.

Abstract

The interaction of Mn+2 with substituted salicylaldehydes (X-saloH) led to the formation of five manganese(II) complexes formulated as [Μn(X-salo)2(MeOH)2]. When the reactions took place in the presence of an α-diimine such as 2,2'-bipyridine, 1,10-phenanthroline or 2,2'-bipyridylamine, five manganese(II) complexes of the formula [Mn(X-salo)2(α-diimine)] were isolated. The characterization of the complexes was accomplished by various spectroscopic techniques and single-crystal X-ray crystallography. The antioxidant activity of the compounds was evaluated via the scavenging of 1,1-diphenyl-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl free radicals. The antibacterial activity of the complexes was tested in vitro against Staphylococcus aureus and Xanthomonas campestris bacterial strains and was found moderate. Diverse techniques were employed to examine the interaction of the complexes with calf-thymus DNA which showed intercalation as the most possible interaction mode. The affinity of the complexes for bovine serum albumin was investigated by fluorescence emission spectroscopy and the binding constants were determined.

Keywords: Antimicrobial activity; Interaction with biomolecules; Manganese(II) complexes; Radical scavenging; Structure; Substituted salicylaldehydes.

MeSH terms

  • Aldehydes / chemistry*
  • Anti-Bacterial Agents* / chemical synthesis
  • Anti-Bacterial Agents* / chemistry
  • Anti-Bacterial Agents* / pharmacology
  • Coordination Complexes* / chemical synthesis
  • Coordination Complexes* / chemistry
  • Coordination Complexes* / pharmacology
  • Manganese / chemistry*
  • Staphylococcus aureus / growth & development*
  • Xanthomonas campestris / growth & development*

Substances

  • Aldehydes
  • Anti-Bacterial Agents
  • Coordination Complexes
  • salicylaldehyde
  • Manganese