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 formulacis-Pt(CNR)(2)(C equivalent to CPh)(2), in which CNR is a variably substituted isocyanide and C equivalent to CPh is phenylacetylide. These isocyanide complexes serve as precursors for complexes of the general formulacis-Pt(CNR)(ADC)(C equivalent to CPh)(2)(4and5), 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 lambda(max)similar to 430 nm in poly(methyl methacrylate) (PMMA) thin films. Whereas isocyanide complexes1-3exhibit modest photoluminescence quantum yields (phi(PL)), incorporation of one acyclic diaminocarbene ligand results in a three-fold to 16-fold increase in phi(PL)while still maintaining an identical deep blue color profile.