Soluble ruthenium(II) with 3,4-diaminobenzoic acid complexes

Abstract

New four water-soluble Ru(II) with 3,4-diaminobenzoic acid complexes were synthesized. The complexes have been characterized using different tools such as: elemental analysis, mass, infrared, UV–Vis spectroscopy, magnetic susceptibility, thermal analysis and theoretical calculations. The complexes are diamagnetic and the electronic spectral data showed the peaks due to low-spin octahedral Ru(II) complexes. The thermal studies of complexes were investigated by the thermogravimetric analysis. The derivative thermogravimetric analysis has been also used to describe the steps ranges for better precision. The data showed that all complexes have been decomposed in three steps, and the decomposition data are consistent with the proposed formulae of the complexes. The thermal stability of the complexes (1–4) is confirmed by their relatively high overall activation energy ranged (96–207 kJ mol−1). The optimized structures of complexes (1–4) indicate that the complexes have distorted octahedral geometries with bond angles around the ruthenium atom ranged 78.37°–99.08°. The negative values of the electronic energies (− 807 to − 1319 a.u.), the highest occupied molecular orbital energies (− 0.176 to − 0.215 a.u.) and the lowest unoccupied molecular orbital energies (− 0.094 to − 0.138 a.u.) of the complexes indicate the stability of the complexes. The complexes are polarized as indicated from dipole moment values (5.18–13.33 Debye). All complexes are water soluble, neutral, stable and non-hygroscopic. The complexes have noticeable cytotoxicity with IC50 (µM): 0.017–0.083 (MCF-7), 0.014–0.123 (HCT-116), 0.024–0.126 (PC-3) and 0.013–0.056 (HepG-2). New soluble Ru(II) complexes with 3,4-diaminobenzoic acid (DABA) ligand and different secondary ligands have been synthesized and characterized. The complexes are diamagnetic with distorted low-spin octahedral geometries. The thermal decomposition of complexes was studied and the thermodynamic parameters were evaluated. The IC50 values are in the range (0.013–0.089) μΜ.