Preparation of 9,10-diarylphenanthrene derivative and its application in full color emitters synthesis

Abstract

As a building block with high photo- and thermo-stability, phenanthrene plays an important role in the preparation of blue(or deep-blue) and full color fluorescence materials. However, some critical issues must be addressed before its full potential can be realised, such as its tedious and low-yield modification processes and the red-shift effect in its aggregated state. In this work, the inexpensive raw material 9,10-phenanthrenequinone(PQ) was chosen as the preparatory functional phenanthrene block. After modifying PQ via halo-substituted, nucleophilic and rearrangement reactions with high yields, the corresponding monomers featured high reactivity and solubility. Compared with classical synthetic approaches for similar phenanthrene-based derivatives, the low efficiency ring-closed reaction and hazardous lithium-injection operation can be omitted using this approach. This new building block demonstrates a clear steric effect following the introduction of peripheral phenyl and alkoxy groups; moreover, stacking in the aggregated state is avoided, which benefits controlling the bandgap and maintaining blue emission as either an emitter or a donor. By changing the central building block in three oligomers, emission of the three primary colors was achieved in solution and film via the conjugated increment and charge-transform effect. This work provides a method of modifying phenanthrene by a simple and efficient synthesis route with inhibition of solid-state aggregation and offers an effective strategy to further develop functional phenanthrene-based building blocks.