Spectroelectrochemical Investigation of Nuclease Active Pt(II) Complexes Containing Pyrrole Oxime†

• Spectroelectrochemistry of [Pt(NH3)Cl(L)] (1), [Pt(L)2] (2), and K[PtCl2(L)] (3) (HL = 1H-pyrrole-2-carbaldehyde oxime) are studied.
• The electrochemical oxidation mechanism of the complexes is elucidated.
• Oxidation of the HL produces an iminoxy radical, which then dimerizes to L2.
• Oxidative electrolysis of each complex solutions yields similar type of Pt(IV) compounds.
• The DFT calculations are performed to support the electrochemical results.

ABSTRACTIn this paper, the electrochemical oxidation of three Pt(II) complexes containing pyrrole oxime (HL) having a general formula of [Pt(NH3)Cl(L)] (1), [Pt(L)2] (2), and K[PtCl2(L)] (3) has been investigated by in-situ spectroelectrochemistry in dimethylformamide (DMF). An irreversible metal-based oxidation process occurs during the anodic scan for each of the three complexes. The electronic absorption spectral changes indicate that all the three complexes generate similar Pt(IV) compounds and free ligand. Our experimental data is supported by quantum chemistry calculations utilizing density functional theory. In addition, the frontier orbital energy distributions indicate that electron densities are localized on mainly platinum atom.