Enhancement of cytotoxicity by combining pyrenyl-dendrimers and arene ruthenium metallacages.

Three generations of pyrenyl bis-MPA dendrimers with two different end-groups, acetonide (pyr(Gn)) or alcohol (pyr(Gn-OH)) (n = 1-3), were synthesized, and the pyrenyl group of the dendritic molecules was encapsulated in the arene ruthenium metallacages, Ru(6)(p-cymene)(6)(OO∩OO)(3)(tpt)(2) (OO∩OO = 5,8-dioxydo-1,4-naphtaquinonato (donq) 1 and 6,11-dioxydo-5,12-naphtacenedionato (dotq) 2; tpt =2,4,6-tri(pyridin-4-yl)-1,3,5-triazine). The host-guest properties of guest⊂1 and guest⊂2 were studied in solution by NMR and UV-vis spectroscopic methods, thus allowing the determination of the affinity constants. Moreover, the cytotoxicity of these water-soluble host-guest systems and the pyrenyl-dendrimers was evaluated on human ovarian cancer cells.