The role of ancillary ligand substituents in the biological activity of triruthenium-NO complexes

[Ru3(μ3-O)(μ-OOCCH3)6(NO)(L)2]PF6 (L = 4‑acetylpyridine, 1 or 4‑tert‑butylpyridine, 2) release NO. Vasodilation activity does not depend on ligand L structure; whereas methyl groups on the ancillary ligand of 2 modulate its cytotoxicity to B16F10 murine melanoma cells. Methylation also increases interaction of 2 with HSA (human serum albumin), through hydrophobic forces.140