Facile Route to Novel Diazaphosphinine-Based Polycyclic Aromatic Hydrocarbons

Doping main-group elements has become a unique strategy to fine-tune optoelectronic properties of organic pi-conjugated molecules. Herein, we report the first example of diazaphosphinine based polycyclic hydrocarbons (DP-PAHs) via facile synthetic protocols. Synthesis of diazaphosphinine heterocycles harnesses mild and efficient P-N chemistry. The heterocycles readily undergo photocyclizations by using only oxidants. The photocyclization protocol is applicable to the heterocycles with various P-centers. We successfully extended the protocols in extended DP-PAHs with 13-fused aromatic rings. Further adjusting P-chemistry allows to efficiently fine-tune the singlet and triplet emission characteristics. More importantly, single-molecule white-light-emitting character was achieved via the balanced singlet and triplet emission of DP-PAH. Therefore, this work opens up new horizons in the area of organic pi-conjugated materials.