Structure-dependent emission of polytriazoles

Aggregation-induced emission (AIE) and aggregation-enhanced emission (AEE) have recently been a hot research topic. Currently, efforts have been mostly made on low mass molecules. Their structure-property relationship has been well-established but no work on polymers has been reported, probably due to the harsh reaction conditions for most of the polymerization processes. We used the powerful and facile Cu(i)-catalysed click polymerization in this paper to synthesize four polytriazoles with small variation in either the backbones or the linking manner of the triazole. The results show that changing the hydrogen groups of the stilbene units of P3b and P6b to the phenyl rings of the tetraphenylethene moieties of P3a and P6a readily leads to distinctive differences in their photophysical properties. P3a and P6a are AEE-active, while P3b and P6b display a typical aggregation-caused quenching effect. Meanwhile, investigation on the linking manner of 1,4-positions of the triazole ring indicates that this variation exerts little influence on the emission properties. This work could thus serve as a guideline for the further design of luminogenic polymers for high-tech applications.