Protein staining agents from low toxic platinum(ii) complexes with bidentate ligands.

Three new luminescent platinum(ii) complexes with bidentate C^N and O^O ligands have been designed and synthesized in this work. Along with the changing of C^N ligands, the emission peaks of these complexes range from 489 to 629 nm and the photoluminescence quantum efficiencies are up to 55% at room temperature. DFT and TD-DFT calculations have also been employed to investigate the ground and excited states of these platinum(ii) complexes. Most importantly, these platinum(ii) complexes with bidentate ligands have almost no cytotoxicity towards HeLa cells and their applications in living cell imaging and protein staining are focused on in this work.