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In this work, the various biological activities of eight organoruthenium(II) complexes were evaluated to reveal correlations with their stability and reactivity in aqueous media. Complexes with general formula [Ru(η⁶-<i>p</i>-cymene)(X,Y)(Z)] were prepared, where (X,Y) represents either an <i>O</i>,<i>O</i>-ligand (<i>β</i>-diketone), <i>N</i>,<i>O</i>-ligand (8-hydroxyquinoline) or <i>O</i>,<i>S</i>-pyrithione-type ligands (pyrithione = 1-hydroxypyridine-2(1<i>H</i>)-thione) with Cl⁻ or 1,3,5-triaza-7-phosphaadamantane (PTA) as a co-ligand (Z). The tested complexes inhibit the chlamydial growth on HeLa cells, and one of the complexes inhibits the growth of the human herpes simplex virus-2. The chlorido complexes with <i>N</i>,<i>O</i>- and <i>O</i>,<i>S</i>-ligands displayed strong antibacterial activity on Gram-positive strains including the resistant <i>S. aureus</i> (MRSA) and were cytotoxic in adenocarcinoma cell lines. Effect of the structural variation on the biological properties and solution stability was clearly revealed. The decreased bioactivity of the <i>β</i>-diketone complexes can be related to their lower stability in solution. In contrast, the <i>O</i>,<i>S</i>-pyrithione-type complexes are highly stable in solution and the complexation prevents the oxidation of the <i>O</i>,<i>S</i>-ligands. Comparing the binding of PTA and the chlorido co-ligands, it can be concluded that PTA is generally more strongly coordinated to ruthenium, which at the same time decreased the reactivity of complexes with human serum albumin or 1-methylimidazole as well as diminished their bioactivity.