Encapsulation of hydrophobic pyrenyl-cycloplatinate complexes within a water-soluble arene ruthenium metalla-cage

Two hydrophobic pyrenyl-contg. cycloplatinate complexes {2-(1-pyrenyl)pyridine}Pt(acac) (Pt-1) and {2-(4-(1-pyrenyl)phenyl)pyridine}Pt(acac) (Pt-2) (acac = acetylacetonato) were encapsulated in the hexacationic water-sol. metalla-cage [(p-cymene)6Ru6(donq)3(tpt)2]6 + (donq = 5,8-dioxido-1,4-naphthoquinonato, tpt = 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine). The host-guest systems [(Pt-1)?cage]6 + and [(Pt-2)?cage]6 + were characterized by NMR and UV-visible spectroscopy, thus confirming the encapsulation of the Pt complexes in the hexa-Ru metalla-cage. The cytotoxicities of the complex-in-a-complex systems were established using human ovarian A2780 and A2780cisR cancer cell lines. This study shows IC50 values in the lower micromolar range for both compds. and on both cancer cell lines (IC50 ? 1 ?M), these values being higher than the empty metalla-cage which possesses an IC50 > 3 ?M. This amplified overall cytotoxicity for the complex-in-a-complex systems suggests an efficient delivery of the hydrophobic complexes by the water-sol. arene Ru metalla-cage. [on SciFinder(R)]