Cyclometallated Platinum(II) Complexes Featuring an Unusual, C^N‐Coordinating Pyridyl‐pyridylidene Ligand and L X Coligands: Synthesis, Structures and Dual Luminescence Behavior

Abstract Thanks to an unusual protodemethylation reaction, a series of luminescent cyclometallated platinum(II) complexes can be prepared, which incorporate a rare NC‐chelating, pyridyl‐pyridylidene ligand, in combination with OO‐coordinating acetylacetonate (acac) or NO‐coordinating 2‐picolinate (pic) or 8‐hydroxyquinolate. The acac and pic complexes show unusual dual emission in a frozen glass. 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 77 K, all four complexes show two broad emission bands that span much of the visible spectrum, apparently from two unequilibrated excited states.