Efficient Deep Blue Platinum Acetylide Phosphors with Acyclic Diaminocarbene Ligands.

Here we report five blue-phosphorescent platinum bis-phenylacetylide complexes with an investigation of their photophysical and electrochemical attributes. Three of the complexes (1-3) are of the general formula cis-Pt(CNR)2 (C≡CPh)2 , in which CNR is a variably substituted isocyanide and C≡CPh is phenylacetylide. These isocyanide complexes serve as precursors for complexes of the general formula cis-Pt(CNR)(ADC)(C≡CPh)2 (4 and 5), in which ADC is an acyclic diaminocarbene installed by amine nucleophilic addition to one of the isocyanides. All of the complexes exhibit deep blue phosphorescence with λmax ∼430 nm in poly(methyl methacrylate) (PMMA) thin films. Whereas isocyanide complexes 1-3 exhibit modest photoluminescence quantum yields (ΦPL ), incorporation of one acyclic diaminocarbene ligand results in a three-fold to 16-fold increase in ΦPL while still maintaining an identical deep blue color profile.