New palladium(II) formamidine complexes: preparation, characterization, theoretical calculations and cytotoxic activity

Abstract

Binary Pd(II) formamidine complexes formulated as [Pd(L1-4)Cl2] where L=formamidine ligands, were synthesized and characterized using different tools, such as; elemental analyses, mass, infrared spectroscopy, magnetic susceptibility, thermal analysis and DFT calculations. The complexes are diamagnetic and the electronic spectral data showed the peaks due to square planar Pd(II) complexes. The optimized structures of complexes (1-4) indicate a distorted square planar geometry with Cl-Pd-Cl and N-Pd-N bond angles in the range 83.89º-94.27º. The electronic energies (a.u.) (-553.79 to -763.92) and the highest occupied molecular orbital (-0.223 to -0.250) and lowest unoccupied molecular orbital energies (-0.091 to -0.127) of the complexes were negative in their values indicated the stability of the complexes. The complexes are polarized as indicated from dipole moment values (6.50-15.71 Debye). All complexes are neutral, stable and nonhygroscopic. The complexes have noticeable cytotoxicity with IC50 (M): 0.0740 (MCF-7), 0.0074-0.0082 (HEP-2), and 0.0119-0.0144 (HepG-2).