Nanocomposite Dendrimers Based on Cyclic Phosphazene Cores: Amorphous Materials for Electroluminescent Devices

A new family of solution-processable, photoluminescent, nanocomposite dendrimers based on cyclic phosphazene (CP) cores have been prepared and characterized. The synthetic approach is based on the preparation of bromoaromatic-functionalized CP cores by reacting selected bromophenolic compounds with the commercially available hexachlorocyclotriphosphazene in yields >90%. The bromophenyl-functionalized CP cores are then reacted with N-p-tolylpyren-1-amine using Buchwald-Hartwig amination chemistry to give the dendrimers of interest in yields >90%. The resultant dendrimers have high glass transition (>165°C) and decomposition temperatures (>465°C), are monodisperse (PDI < 1.05), have high purity via common chromatographic techniques, have high photoluminescent quantum efficiencies (83%), and form defect-free amorphous films via spin/dip coating. A comparison to their molecular analogues is also provided to demonstrate the superior properties of the new nanocomposite dendrimers.