Ternary palladium(II) complexes with N-benzyliminodiacetic acid derivatives and 2,2′-bipyridine: Preparation, thermogravimetric, vibrational spectroscopic, DFT, NMR studies and biological activity in vitro

Synthesis, thermal and spectroscopic (FTIR and NMR) studies, DFT molecular modelling, and antiproliferative activity against four cancer cell strands of the four new palladium(II) complexes with N-benzyliminodiacetic acid and its para-substituted (Cl, NO2, and MeO) derivatives. [Display omitted] •New Pd(II) complexes with N-benzyliminodiacetic acid and p-substituted derivatives.•Spectroscopical (FTIR, NMR) and thermogravimetric characterization.•Molecular geometry and IR spectra modelled using DFT calculation.•Antiproliferative activity tested on four cancer cell strands. The reactions of N-benzyliminodiacetic acid (BnidaH2) and its para-substituted derivatives, namely: N-(p-chlorobenzyl)iminodiacetic acid (p-ClBnidaH2), N-(p-nitrobenzyl)iminodiacetic acid (p-NO2BnidaH2) and N-(p-methoxybenzyl)iminodiacetic acid (p-MeOBnidaH2) with paladium(II) chloride and 2,2′-bipyridine, were performed in water-acetonitrile solutions. Four new prepared complexes [Pd(Bnida)(bipy)]∙2H2O (1), [Pd(p-ClBnida)(bipy)]∙4H2O (2), [Pd(p-NO2Bnida)(bipy)]∙2H2O (3) and [Pd(p-MeOBnida)(bipy)]∙3H2O (4) were identified by means of chemical analysis and mass spectrometry, and characterized by infrared spectroscopy and thermal analysis (TG/DTA). The molecular geometry and infrared spectra of these four complexes were modelled using DFT calculations at the BP86/def2-TZVP (Pd: ECP) level of theory. Extensive NMR studies have shown the presence of two isomers in solution (DMSO). The characterized palladium(II) complexes demonstrate valuable antiproliferative activity against Caco-2, SW620, NCI-H358 and MDCK I reducing cell growth from 71.7% to 79.9% (10−4 M) (1; 4). PANC-1 display mild sensitivity and slow reduction in cell growth (less than 50%) while BJ present higher viability range and proliferative status. BJ proliferation after exposure to palladium complexes at 10−4 M concentration ranged from 55.2% to 83.5% (1–4). In descending order, antiproliferative effect of tested palladium complexes is, as follows: 4 > 1 > 2 > 3.