Synthesis, spectral characterization and antimicrobial evaluation of Schiff base Cr (III), Mn (III) and Fe (III) macrocyclic complexes

A Schiff base ligand was synthesized by reacting 1,4-dicarbonyl-phenyl-dihydrazide and chromene-2,3-dione (2:2) and a series of metal complexes with this new ligand were synthesized by reaction with Cr (III), Mn (III), and Fe (III) metal salt in methanolic medium. The Schiff base ligand and its metal complexes have been characterized with the help of elemental analysis, conductance measurements, magnetic measurements and their structure configuration has been determined by various spectroscopic (electronic, IR, 1H NMR, 13C NMR, GCMS) techniques. Electronic spectra of the complexes indicate that the geometry of the metal center was five coordinate square pyramidal. These metal complexes were also tested for their antimicrobial activities to assess their inhibiting potential.

Graphical abstractSchiff base M (III) complexes were synthesized and evaluated for antimicrobial activity. Complex 3 [Cr(C34H24N8O6)OAc]OAc2 exhibited best antimicrobial activity.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The analytical data suggested a mononuclear structure for the complexes. ► The spectral data is in favor of a five coordinate square pyramidal geometry. ► Antimicrobial study reveals that, metal complexes have more biological activity. ► Complex [Cr(C34H24N8O6)OAc]OAc2 shows best antimicrobial activity.