New formamidine ligands and their mixed ligand palladium(II) oxalate complexes: Synthesis, characterization, DFT calculations and in vitro cytotoxicity

• New formamidine ligands were synthesized and characterized.
• Their mixed oxalate Pd(II) complexes were also synthesized and characterized.
• The structures are geometrically optimized and the computed vibrations and transition are compared with the experimental.
• The cytotoxicity of the ligands and complexes were tested with promising IC50 values.

A series of new ternary palladium(II) complexes of the type [Pd(L1–4)ox]·xH2O where L = formamidine ligands and ox = oxalate, were synthesized and characterized by elemental analyses, magnetic susceptibility, UV–Vis, infrared (IR) and mass spectroscopy and thermal analysis. The spectroscopic data indicated that the formamidine ligands act as bidentate N2 donors and the oxalate as O2 ligand. The complexes (1–4) are diamagnetic and the optimization of their structures indicated that the geometry is distorted square planer with O–Pd–O and N–Pd–N bond angles ranged 82.70–83.87° and 88.21–95.02°; respectively which is acceptable for the heteroleptic complexes. The dipole moment of the complexes (13.97–18.77 Debye) indicating that the complexes are more polarized than the ligands (1.93–4.96 Debye). The complexes are thermally stable as shown from their relatively higher overall activation energies (441–688 kJ mol−1). The ligands and the complexes are proved to have good cytotoxicity with IC50 (μM) in the range of (0.011–0.168) against MCF-7, (0.012–0.150) against HCT-116, (0.042–0.094) against PC-3 and (0.006–0.222) against HepG-2 cell lines, which open the field for further application as antitumor compounds.

A series of new ternary palladium(II) complexes of the type [Pd(L1–4)ox]·xH2O where L = formamidine ligands and ox = oxalate, were synthesized and characterized by elemental analyses, magnetic susceptibility, UV–Vis, infrared (IR) and mass spectroscopy and thermal analysis. The spectroscopic data indicated that the formamidine ligands act as bidentate N2 donors and the oxalate as O2 ligand.Figure optionsDownload as PowerPoint slide