Synthesis, characterization, and cytotoxicity studies of diimine derivatives and their ruthenium(II)-p-cymene complexes

The reaction of five di-imines obtained by condensation of etilendiamine with 4-hydroxybenzaldehyde (L1), 2,4dihydroxibenzaldehyde (L2) and 1-(2,4-dihydroxyphenyl)ethan-1-one (L3) or, condensations of glyoxal with 4aminophenol (L4) and 4-amino-3-fluorphenol (L5) with [Ru2(Cl)4(i6-p-cymene)2] was studied. In absence of silver salts, four cationic complexes of formula [RuCl(i6-p-cymene)(Ln)]X where n = 1, 3, 4 and X = Cl and, n = 5 and X = PF6 could be isolated as pure solid materials. The complexes were characterized by different spectroscopic techniques and the X-ray structures of the L1 hydrate and its complex [RuCl(i6-p-cymene)(L1)]Cl were also determined. These studies confirm the N,N'-bidentate nature of the ligand L1 and the pseudo-octahedral geometry of the ruthenium coordination environment in the complex. Furthermore, the complex derived from L3, shows a potent cytotoxic activity against tumor cell line A549.