Synthesis, characterization and aggregation-induced emission of alternating copolymers containing cyclophanes and tetraphenylethenes

Abstract

The alternating copolymers containing tetraphenylethenes bonded to pseudo-para or pseudo-meta [2.2]paracyclophanes were synthesized by palladium catalyzed Suzuki-Miyaura cross-coupling reaction. Relatively high molecular weights of polymers were obtained by the reaction of their corresponding comonomers using Pd(OAc)₂ as a catalyst with S-Phos as a ligand and K₃PO₄ as a base under a high base to monomer ratio. The maximum emission intensity of polymer in THF increases gradually as the addition of water fraction increases. The polymers exhibited aggregation-induced emission in aggregated state. In particular, the photoluminescence quantum yield of those tetraphenylethenes bonded to pseudo-meta [2.2]paracyclophanes is up to 0.334 when the water fraction reaches to 90%. The polymers used in the detection of 2,6-dinitrotoluene are more sensitive than that of small molecule containing the same conjugated segment of the polymers. They are promising candidates for potential uses in the optoelectronic applications.