Synthesis, characterization and antimicrobial properties of some mixed ligand complexes of Zn(II) dithiocarbamate with different N-donor ligands

• Zn(II) adducts containing different N-donor ligands were synthesized and characterized.
• Structure of the bpy adducts show the methyl and ethyl groups are alternatively disordered.
• The antimicrobial activities of the complexes were evaluated.
• The highest antimicrobial property was exhibited by the precursor complex.

In this study, adducts of Zn(II) dithiocarbamates containing different N-donor ligands (pyridine, 2,2′-bipyridine and 1,10-phenanthroline) have been synthesized. The parent dithiocarbamate complex comprise N-methyl-N-phenyl dithiocarbamate (L1) and N-ethyl-N-phenyl dithiocarbamate (L2), and the adducts are represented as [ZnL1L2py], [ZnL1L2bpy], and [ZnL1L2phen] (where py = pyridine, bpy = 2,2′-bipyridine, and phen = 1,10-phenanthroline). All the compounds have been characterized by elemental analysis and spectroscopic techniques (IR and NMR). In addition, the crystal structure of [ZnL1L2bpy] complex is also reported. The structure indicates that the two dithiocarbamate ligands are disordered in 0.67:0.33 ratio and alternatively bond as monodentate and bidentate ligands. The bipyridine acts as a bidentate ligand, and gives the structure around the Zn atom a distorted square pyramidal geometry. In order to evaluate their antimicrobial properties, the precursor complex and the adducts were screened against six pathogenic bacteria strains and two fungi organisms. The antimicrobial activities of the complexes were in the order [ZnL1L2] > [ZnL1L2py] > [ZnL1L2bpy] > [ZnL1L2phen]. The precursor complex, ZnL1L2, showed the lowest MIC and is considered as the complex with most antimicrobial activity against the selected microorganisms.

Ortep diagram of [ZnL1L2bpy] with only the major disordered components shown. Thermal ellipsoids are drawn at 50% probability level. A histogram representation of the antimicrobial data of the synthesised complexes.Figure optionsDownload as PowerPoint slide