Glycal-ruthenium carbonyl clusters: Syntheses, characterization, and anticancer activity

Four new chiral ruthenium carbonyl cluster complexes Ru-3(mu-H)(2)(CO)(9)(L- 2H)(1), Ru-3(mu-H)(2)(CO)(7)( L-2H)(dppm)(2), Ru-3(mu-H)(2)(CO)(7)(L-2H)(PPh3)(2) (3), Ru-3(mu-H)(2)(CO)(7)(L-2H)(dppe)(4)containing a dehydrogenated form (L-2H)of 3,4,6-tri-O-benzyl-D-galactal (L)as a chiral ligand have been prepared and characterized. The anticancer activity of five compounds 1-4 and Ru-3(mu-H)(2)(CO)(9)(L-2H) 5 (L=tribenzyl glucal)against six types of human cancer cell lines was studied and compared to cisplatin. Compound 1 was chosen to produce more detailed growth curves based on overall highest activity profile. The structure of compound 2 was established by a single-crystal X-ray diffraction analysis. The structure based on triangular metal framework contains a bridging dehydrogenated tribenzyl galactal ligand bonded in a parallel mu(3)-eta(2)-bonding mode and a bridging dppm ligand. Variable-temperature NMR studies show that the two hydride ligands in compounds 1 and 2 are dynamically active on the NMR time scale at room temperature. (C) 2008 Elsevier B. V. All rights reserved.