Synthesis, structure, redox properties and DNA interaction studies on mononuclear iron(III) complexes with amidate ligand

• [Fe(Pamp)(MeOH)Cl2], [Fe(Pamp)2](ClO4) complexes were synthesized and characterized.
• Crystal structures of [Fe(Pamp)2](ClO4) was resolved by X-ray diffraction.
• DNA interactions as well as nuclease study were investigated.
• Participation of reactive oxygen species (ROS) was confirmed by rhodamine B dye.
• DNA cleavage initiated in an oxidative pattern by [Fe(Pamp)(MeOH)Cl2] complex.

A new family of mononuclear Fe(III) complexes [Fe(Pamp)(MeOH)Cl2], 1 and [Fe(Pamp)2](ClO4), 2 were synthesized using designed tridentate ligand PampH having pyridine and amide nitrogen donors (PampH is N′-phenyl-N′-(pyridin-2-yl)picolinohydrazide) and H stands for dissociable proton). Both the complexes (1 and 2) were characterized by different spectroscopic studies and molecular structure of [Fe(Pamp)2](ClO4), 2 was determined by single crystal X-ray diffraction. Geometry around metal centre was described as distorted octahedral with two meridionally oriented Pamp− ligands. Electrochemical studies afforded E1/2 values of Fe(III)/Fe(II) couple +0.065 V (for 1) and −0.077 V (for 2) versus Ag/AgCl electrode. DNA binding properties of these complexes were investigated and complex 1 exhibited nuclease activity. Mechanistic investigation revealed the possible participation of hydroxyl radical in nuclease activity which was supported by rhodamine B assay.

Novel mononuclear complexes, [Fe(Pamp)(MeOH)Cl2], 1 and [Fe(Pamp)2](ClO4), 2 were synthesized and characterized. Molecular structure of [Fe(Pamp)2](ClO4), 2 was determined by single crystal X-ray diffraction. DNA interaction studies of both complexes showed, complex 1 only exhibited nuclease activity. Mechanism of DNA cleavage confirmed the involvement of reactive hydroxyl radical (OH) species which was indicated by rhodamine B assay. Hence, complex 1 plays significant role in the nuclease, initiated in an oxidative pattern.Figure optionsDownload as PowerPoint slide