Cyclometallated platinum(II) complexes featuring an unusual, C^N‐coordinating pyridyl‐pyridylidene ligand and L^X coligands: synthesis, structures and dual luminescence behaviour

A series of cyclometallated platinum(II) complexes incorporating a rare, N^C‐chelating, pyridyl‐pyridylidene ligand are described, in which the coordination sphere is completed by two chlorides or an L^X co‐ligand, namely O^O‐coordinating acetylacetonate (acac), or N^O‐coordinating 2‐picolinate (pic) or 8‐hydroxyquinolinate. The acac and pic complexes have been structurally characterized in the solid state by single‐crystal X‐Ray diffraction. These two complexes display red phosphorescence in the solid state at room temperature. In a frozen glass at 77K, all four complexes show two broad emission bands that span much of the visible spectrum, apparently from two unequilibrated excited states.