Synthetic Strategies Towards Pi-Extended Dithienophospholes Available for Click Chemistry

Abstract

A series of highly luminescent P-acetylenyl functionalized dithieno[3,2-b:2’,3’-d]phospholes were attempted to be synthesized following the previously studied P-phenyl phosphole as a guide. The original synthesis pathway of forming the dithienophosphole scaffold first, then cross-coupling onto the 2,6-positions, then modifying the acetylene to be able to perform click chemistry saw many difficulties. An alternative route was explored where the cross-coupling reaction with a brominated bithiophene was performed first, then a ring closure reaction to form the phosphole was done. Finally, the emissive materials were able to be clicked onto benzyl azide as a proof-of-concept for an organic light-emitting polymer material for the potential application of solid-state lighting.