Synthesis, characterization, and anticancer activity of some mononuclear ruthenium(II) compounds

Mononuclear Ru-based compounds cis-Ru-II(dppm)(2)Cl-2 (1) and trans-Ru-II(dppe)(2)Cl-2 (4) were synthesized by treatment of (RuCl2)-Cl-II(DMSO)(4) with dppm or dppe, respectively (dppm = bis(diphenylphosphino) methane, dppe = 1,2-bis(diphenylphosphino) ethane, DMSO = dimethyl sulfoxide). Mononuclear Ru-based compounds trans-Ru-II(dppm)(2)Cl-2 (2) and cis-Ru-II(dppe)(2)Cl-2 (3) were obtained by reaction of (RuCl2)-Cl-II(PPh3)(3) with dppm or dppe, separately. These two pair of cis-trans isomers, cis/trans-Ru-II(dppm)(2)Cl-2 and cis/trans-Ru-II(dppe)(2)Cl-2, were characterized by electronic absorption spectra, infrared, elemental analysis, H-1 NMR, C-13 NMR, P-31 NMR, and single-crystal X-ray diffraction analysis. Both the crystal structure data and electronic absorption spectra indicate that the cis-isomer is a more thermodynamically stable structure and has lower energy than the trans-isomer. The luminescence spectroscopic study and relative cell viability of 1-4 on HeLa cancer cells has been investigated.