Impact of various lipophilic substituents on ruthenium(II), rhodium(III) and iridium(III) salicylaldimine-based complexes: synthesis, in vitro cytotoxicity studies and DNA interactions
- 358 Downloads
A series of bidentate salicylaldimine ligands was prepared and reacted with either [RuCl(µ-Cl)(p-cymene)]2, [RhCl(µ-Cl)(Cp*)]2 or [IrCl(µ-Cl)(Cp*)]2. All of the compounds were characterised using an array of spectroscopic and analytical techniques, namely, nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and mass spectrometry. Single crystal X-ray diffraction (XRD) was used to confirm the bidentate coordination mode of the salicylaldimine ligand to the metal centre. The platinum group metal (PGM) complexes were screened against the MCF7 breast cancer cell line. The ruthenium and iridium salicylaldimine complexes showed comparable or greater cytotoxicity than cisplatin against the MCF7 cancer cells, as well as greater cytotoxicity than their rhodium counterparts. Three of the salicylaldimine complexes showed potent activity in the range 18–21 µM. Two of these complexes had a greater affinity for cancerous cells than for CHO non-cancerous cells (SI > 4). Preliminary mechanistic studies suggest that the ruthenium complexes undergo solvation prior to 5′-GMP binding, whereas the iridium complexes were inert to the solvation process.
KeywordsSalicylaldimine Ruthenium–arene Rhodium Iridium Anticancer activity
Financial support from the University of Cape Town (UCT) and the National Research Foundation (NRF) of South Africa and the Medical Research Council (MRC) of South Africa is gratefully acknowledged. Dr Serah Kimani and Ms Sandra Jordaan are thanked for their contributions.
- 28.Bennett MA, Huang TN, Matheson TW, Smith AK, Ittel S, Nickerson W (2007) 16. (η6-Hexamethylbenzene)ruthenium complexes. In: Inorganic Syntheses, Wiley, Hoboken, pp 74–78Google Scholar
- 29.White C, Yates A, Maitlis PM, Heinekey DM (2007) (η5-Pentamethylcyclopentadienyl)rhodium and -iridium compounds. In: Inorganic Syntheses, Wiley, Hoboken, pp 228–234Google Scholar
- 31.SAINT Version 7.60a (2006) Bruker AXS Inc., MadisonGoogle Scholar
- 32.Sheldrick GM (2004) SHELXS-97, SHELXL-2014 and SADABS version 2.05, University of Göttingen, GermanyGoogle Scholar
- 36.Srisawat T, Chumkaew P, Heed-Chim W, Sukpondma Y, Kanokwiroon K (2013) Trop J Pharm Res 12:71–76Google Scholar