Biological Investigations of Ru(II) Complexes With Diverse β-diketone Ligands.

The β-diketone scaffold is a commonly used synthetic intermediate, and is a functional group found in natural products such as curcuminoids. This core structure can also act as a chelating ligand for a variety of metals. In order to assess the potential of this scaffold for medicinal inorganic chemistry, seven different κ-O,O'-chelating ligands were used to construct Ru(II) complexes with polypyridyl co-ligands, and their biological activity was evaluated.

Avobenzone incorporation in a diverse range of Ru(II) scaffolds produces potent potential antineoplastic agents.

Four structurally distinct classes of polypyridyl ruthenium complexes containing avobenzone exhibited low micromolar and submicromolar potencies in cancer cells, and were up to 273-fold more active than the parent ligand. Visible light irradiation enhanced the cytotoxicity of some complexes, making them promising candidates for combined chemo-photodynamic therapy.

Bis-tridentate N-Heterocyclic Carbene Ru(II) Complexes are Promising New Agents for Photodynamic Therapy.

Ruthenium(II) complexes developed for photodynamic therapy (PDT) are almost exclusively tris-bidentate systems with C or D symmetry. This is due to the fact that this structural framework commonly produces long-lived excited states, which, in turn, allow for the generation of large amounts of singlet oxygen (O) and other reactive oxygen species. Complexes containing tridentate ligands would be advantageous for biological applications as they are generally achiral (D or C symmetry), which eliminates the possibility of multiple isomers which could exhibit potentially different interactions with chiral biological entities.