Photophysical and biological characterization of new cationic cyclometalated M(III) complexes of rhodium and iridium

•New cyclometalated complexes [M(ptpy)2(ddmp)]PF6 (M = Rh, 1; Ir, 2) were prepared.•Both molecular structures were confirmed by single-crystal X-ray diffraction.•2 phosphoresces yellow in a polymer matrix and in solution at ambient temperature.•1 and 2 show significant cytotoxicity against human cancer cell lines.

Synthesis and characterization of new cyclometalated complex salts [M(ptpy)2(ddmp)]PF6 (M = Rh, 1; M = Ir, 2; ptpy = 2-(p-tolyl)pyridinato; ddmp = 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline) is described. Compounds 1 and 2 were obtained by the reaction of ddmp with the complexes [{M(μ-Cl)(ptpy)2}2] (M = Rh, Ir) in a mixture of CH2Cl2/MeOH/H2O under reflux conditions. The compounds 1 and 2 crystallized from dichloromethane/chloroform/hexane in the triclinic space group P  1¯ and their molecular structures were confirmed by single-crystal X-ray diffraction. Compound 2 exhibits strong yellow phosphorescence in a polymer matrix and in solution at ambient temperature. Both compounds display significant cytotoxicity against human cancer cell lines with the IC50 values in the high nanomolar range.

Graphical abstractSynthesis and characterization of [M(ptpy)2(ddmp)]PF6 (M = Rh, 1; M = Ir, 2; ptpy = 2-(p-tolyl)pyridinato; ddmp = 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline) is described. Compound 2 exhibits strong yellow phosphorescence in a polymer matrix and in solution at ambient temperature. Both compounds display significant cytotoxicity against human cancer cell lines.Figure optionsDownload full-size imageDownload as PowerPoint slide