Synthesis and Characterization of Neutral Cyclometalated Platinum(II) Complexes and their Antibacterial and Cytotoxic Evaluations

Abstract A series of neutral cyclometalated platinum(II) complexes bearing 2,6‐bis(2‐naphthyl)pyridine as a C^N^C tridentate chelating ligand with monodentate pyridyl ligands with different substituents 1 – 3 have been synthesized via double cyclometalation and ligand displacement reaction. The structural, photophysical, electrochemical and aggregation induced emission (AIE) properties of these neutral platinum(II) complexes were systematically studied. Complexes 1 – 3 exhibited AIE effects with different emission intensities and colors, in which 1 showed the highest quantum efficiency of 8.6 % under aggregated state, and the aggregates were assembled to ordered spheres. Among the Pt(II) complexes, 1 showed a bactericidal activity against both Staphylococcus aureus ( S. aureus ) (MIC and MBC=3.13 μg/mL) and methicillin‐resistant S. aureus (MRSA) (MIC and MBC=6.25 μg/mL). Complex 1 did not possess noticeable cytotoxicity to human skin HaCaT keratinocytes. The non‐cytotoxic complex 1 would have a good potential to be used for the antibacterial therapy to combat with S. aureus and MRSA‐infected skin diseases.