Sawhorse-type diruthenium tetracarbonyl complexes containing biologically relevant acids

Article abstract of DOI:10.1016/j.ica.2012.09.034

The reaction between the biologically active acids probenecid (HO ₂CC₁₂H₁₈NO₂S), indomethacin (HO ₂CC₁₈H₁₅ClNO₂) and sulindac (HO ₂CC₁₉H₁₆FOS) with Ru₃(CO) ₁₂, followed by addition of axial ligands (L), such as pyridine, triphenylphosphine, or 5-(4-pyridyl)-10,15,20-triphenylporphyrin, generates a series of stable diruthenium tetracarbonyl complexes of the formula Ru ₂(CO)₄(μ₂-η²-O ₂CC₁₂H₁₈NO₂S)₂L ₂, Ru₂(CO)₄(μ₂-η²- O₂CC₁₈H₁₅ClNO₂)₂L ₂ and Ru₂(CO)₄(μ₂- η²-O₂CC₁₉H₁₆FOS) ₂L₂, respectively. The molecular structure of 1a · C₆H₆ was solved by single-crystal X-ray structure analysis and a typical diruthenium tetracarbonyl backbone bridged by the carboxylato ligands and two axial triphenylphosphine ligands was revealed. The benzene molecule sits between two probenecid units, and is involved in π-stacking interactions with the aromatic part of probenecid. Despite the presence of biologically relevant derivatives and carbonyl groups within the sawhorse-type dinuclear complexes, all systems show no cytotoxicity towards human cancer cells, presumably due to the high lipophilicity of these neutral complexes.