Carbazole Functionalized Silole: Synthesis, Aggregation‐induced Emission, and Electrochemical Polymerization

Abstract

A carbazole‐functionalized silole, 9,9′‐(4,4′‐(2,3,4,5‐tetraphenyl‐1H‐silole‐1,1‐diyl)bis(4,1‐phenylene))bis(9H‐carbazole) ( BPCTPS ), was prepared through the reaction of dilithium diene with tetrachlorosilane followed by a direct substitution reaction with (4‐(9H‐carbazol‐9‐yl)phenyl)lithium. Combining the carbazole donor with the silole acceptor resulted in a new type of donor–acceptor (D–A) dyad. Density function theory (DFT) calculations showed that the highest occupied molecular orbital was localized on the carbazole group whereas the lowest unoccupied molecular orbital was localized on the silole group. BPCTPS exhibited very weak emission properties in dilute solution but emitted intensely in the aggregated state, revealing that it was an aggregation‐induced emission (AIE)‐active species. Furthermore, addition of electron donating groups to the silole ring resulted in a slight red shift of both the absorption and emission spectra compared with those of the reference compound hexaphenylsilole ( HTS ). The electrochemical properties of BPCTPS were also studied by cyclic voltammetry (CV), which indicated that the compound formed a cross‐linked film on the Pt electrode via electropolymerization.