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 , where 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 ), where ADC is an acyclic diaminocarbene installed by amine nucleophilic addition to one of the isocyanides. All of the complexes exhibit deep blue phosphorescence with λ max ~430 nm in poly(methyl methacrylate) (PMMA) thin films. Whereas isocyanide complexes 1 - 3 exhibit modest photoluminescence quantum yields ( Φ PL ), incorporation of one acyclic diaminocarbene ligand results in a three-fold to 16-fold increase in Φ PL while still maintaining an identical deep blue color profile.