Anticancer Activity of Half-Sandwich RhIII and IrIII Metalla-Prisms Containing Lipophilic Side Chains.

Two hexacationic pentamethylcyclopentadienyl rhodium(III) and iridium(III) metalla-prisms, [(η5 -C5 Me5 )6 M6 (μ3 -tpt-κN)2 (μ4 -C6 HRO4 -κO)3 ]6+ (tpt=2,4,6-tri-(pyridin-4-yl)-1,3,5-triazine; R=(CH2 )10 CH3 ; M=Rh, [3]6+ ; M=Ir, [4]6+ ) isolated as their triflate salts, have been synthesised from the dinuclear complexes (η5 -C5 Me5 )2 M2 (μ4 -C6 HRO4 -κO)Cl2 (M=Rh, 1; M=Ir, 2) and AgCF3 SO3 . The antiproliferative activity of the neutral and cationic complexes has been evaluated in vitro in human cancer cell lines. The positively charged metalla-prisms appear to target mitochondria, which ultimately induce apoptosis in cancer cells. All biological studies suggest that the rhodium derivative [3][CF3 SO3 ]6 possesses excellent activities, not only in vitro but also in vivo in tumour-induced C57L6/J mice.