Tripodal Half-Sandwich Rhodium and Iridium Complexes Containing Sulfonate and Pyridinyl Entities as Antitumor Agents

In light of the widely used platinum anticancer drugs showing high toxicity and poor selectivity, the quest to develop new anticancer agents is increasing. This study investigated the synthesis of mononuclear and trinuclear Rh-III and Ir-III sulfonate-containing pyridinyl complexes that have been fully characterized using NMR and IR spectroscopy, HR-ESI-mass spectrometry and elemental analysis. The cytotoxicities of all sulfonated pyridinyl compounds were investigated against a WHCO1 oesophageal cancer cell line and the metal complexes showed moderate activity, while the uncomplexed ligands were inactive. Several of the trinuclear complexes are of comparable activity to that of the clinical cancer drug cisplatin. H-1 NMR model studies demonstrated the in vitro DNA binding ability of the most active complex.