Addition of ethynylferrocene to transition-metal complexes containing a chelating 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolate ligand--in vitro cooperativity of a ruthenium compound on cellular uptake of an anticancer drug.

The addition reactions of the 16e half-sandwich complexes (p-cymene)M(S2C2B10H10) (, M=Ru; , M=Os) and CpIr(E2C2B10H10) (, E=S; , E=Se) with ethynylferrocene lead selectively to the 18e complexes (p-cymene)Ru(S2C2B10H9)(H2CCFc) (Fc=ferrocenyl) (), (p-cymene)Os(S2C2B10H9)(H2CCFc) (), CpIr(S2C2B10H9)(H2CCFc) () and Cp*Ir(Se2C2B10H9)(H2CCFc) (), in which the alkyne is regio- and stereoselectively inserted into one of the M-E bonds that may further lead to metal-induced B-H activation, hydrogen atom transfer from the carborane via the metal center to the inserted alkyne, and the generation of a M-B bond. In all complexes the S-eta2-(Fc)C-C and C-B(M) moieties occupy a cisoid position. The four new complexes are characterized by IR, MS, NMR spectroscopy and microanalysis, and the X-ray structural analysis of is performed. was observed to promote the uptake of anticancer drug daunorubicin in drug-resistant leukemia K562 cells.