Towards Ruthenium(II)-Rhenium(I) Binuclear Complexes as Photosensitizers for Photodynamic Therapy.

The search for new metal-based photosensitizers (PSs) for anticancer photodynamic therapy (PDT) is a fast-developing field of research. Knowing that polymetallic complexes bear a high potential as PDT PSs, in this study, we aimed at combining the known photophysical properties of a rhenium(I) tricarbonyl complex and a ruthenium(II) polypyridyl complex to prepare a ruthenium-rhenium binuclear complex that could act as a PS for anticancer PDT. Herein, we present the synthesis and characterization of such a system and discuss its stability in aqueous solution.

A ruthenium-oligonucleotide bioconjugated photosensitizing aptamer for cancer cell specific photodynamic therapy.

Ruthenium complexes have emerged as a promising class of compounds for use as photosensitizers (PSs) in photodynamic therapy (PDT) due to their attractive photophysical properties and relative ease of chemical alteration. While promising, they generally are not inherently targeting to disease sites and may therefore be prone to side effects and require higher doses. Aptamers are short oligonucleotides that bind specific targets with high affinity.

Increasing the Cytotoxicity of Ru(II) Polypyridyl Complexes by Tuning the Electronic Structure of Dioxo Ligands.

Due to the great potential expressed by an anticancer drug candidate previously reported by our group, namely, Ru-sq ([Ru(DIP)(sq)](PF) (DIP, 4,7-diphenyl-1,10-phenanthroline; sq, semiquinonate ligand), we describe in this work a structure-activity relationship (SAR) study that involves a broader range of derivatives resulting from the coordination of different catecholate-type dioxo ligands to the same Ru(DIP) core. In more detail, we chose catechols carrying either an electron-donating group (EDG) or an electron-withdrawing group (EWG) and investigated the physicochemical and biological properties of their complexes. Several pieces of experimental evidences demonstrated that the coordination of catechols bearing EDGs led to deep-red positively charged complexes - in which the preferred oxidation state of the dioxo ligand is the uninegatively charged semiquinonate.