Cytotoxicity of cyclometallated ruthenium complexes: the role of ligand exchange on the activity. Academic Article uri icon


  • The cyclometallated Ru(II) complexes cis-[Ru(phpy)(phen)(CH3CN)2](PF6) (1; phpy(-)=deprotonated 2-phenylpyridine, phen=1,10-phenanthroline) and cis-[Ru(phpy)(bpy)(CH3CN)2](PF6) (2; bpy=2,2'-bipyridine) were investigated as potential agents for photodynamic therapy. The presence of phpy(-) in the coordination sphere results in a red-shift of the Ruphen and Rubpy metal-to-ligand charge transfer of 1 and 2, respectively, thus improving the tissue penetration of light while maintaining the efficient photo-induced ligand exchange required for DNA binding. The 14-fold enhancement of OVCAR-5 cell death that occurs upon irradiation with 690nm light can be attributed to photo-aquation. The role of glutathione (GSH) on the toxicity of the complex was also explored. Complexes 1 and 2 undergo ligand substitution in the presence of GSH in the dark, such that the metal may covalently bind to biomolecules. The combination of photo-induced ligand exchange and GSH-facilitated ligand exchange may explain the observed cytotoxicity.

published proceedings

  • Philos Trans A Math Phys Eng Sci

author list (cited authors)

  • Palmer, A. M., Pea, B., Sears, R. B., Chen, O., El Ojaimi, M., Thummel, R. P., Dunbar, K. R., & Turro, C.

citation count

  • 31

complete list of authors

  • Palmer, Alycia M||Peña, Bruno||Sears, R Bryan||Chen, Olivia||El Ojaimi, Maya||Thummel, Randolph P||Dunbar, Kim R||Turro, Claudia

publication date

  • July 2013