Near-infrared luminescence from platinum(II) diimine compounds

Square-planar Pt( II) complexes of the bis( mesitylimino) acenaphthene ( mesBIAN) ligand are emissive from a MMLL'CT excited state in a dichloromethane solution at room temperature. Investigation of the nature of the frontier orbitals in these near-IR emitters by a combination of emission spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations suggests that emission is enabled by the presence of low-lying ligand pi* orbitals on the mesBIAN.