Triphenylamine-Appended Half-Sandwich Iridium(III) Complexes and Their Biological Applications

Organometallic half-sandwich Ir-III complexes of the type [((5)-Cp-x)Ir((NN)-N-boolean AND)Cl]PF6 (Cp-x: Cp* or its phenyl Cp-xph or biphenyl Cp-xbiph derivatives; (NN)-N-boolean AND: triphenylamine (TPA)-substituted bipyridyl ligand groups) were synthesized and characterized. The complexes showed excellent bovine serum albumin (BSA) and DNA binding properties and were able to oxidize NADH to NAD(+) (NAD=nicotinamide adenine dinucleotide) efficiently. The complexes induced apoptosis effectively and led to the emergence of reactive oxygen species (ROS) in cells. All complexes showed potent cytotoxicity with IC50 values ranging from 1.5 to 7.1m toward A549 human lung cancer cells after 24hours of drug exposure, which is up to 14times more potent than cisplatin under the same conditions.