Hypoxia efficient and glutathione-resistant cytoselective ruthenium(II)- p-cymene-arylimidazophenanthroline complexes: biomolecular interaction and live cell imaging

Due to the side effects of marketed cancer drugs, we designed a series of ruthenium-based fluorescent anticancer drugs, which was demonstrated to be target specific, highly cytoselective, lipophilic, water soluble, hypoxia efficient and glutathione resistant. Herein, we developed novel ruthenium(ii)-p-cymene-2-aryl-imidazophenanthroline scaffolds as effective DNA-targeting agents. Specifically, the 2-aryl substituted imidazophenanthroline ligands make the Ru(ii) complex a decent DNA intercalator by affording planarity. Among the four Ru(ii) complexes (RuL1-RuL4), [(η6-p-cymene)RuIICl{K2-N,N-(2-(naphthalene-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline)}]PF6 (RuL4) exhibited the best cytoselectivity in two cancer cell lines (Caco-2 and HeLa), and [(η6-p-Cymene)RuIICl{K2-N,N-(2-(anthracen-9-yl)-1H-imidazo[4,5-f][1,10]phenanthroline)}]PF6 (RuL1) was established as a potent HeLa cell imaging probe.