Thiazolothiazole-linked solid-state emissive linear and porous organic polymers utilizing tetraphenyl-buta-1,3-diene-based AIE-active building blocks

Constructing linear or porous organic polymers with aggregation-induced emission (AIE)-active building blocks has garnered abundant attention owing to their successful manifestation of solid-state emissive properties, which are usually absent in traditional luminophores. Herein, three newly designed and synthesized aldehyde (-CHO)-containing tetraphenyl-buta-1,3-diene (TPB)-based AIEgens have been utilized to construct a series of thiazolothiazole-linked linear polymers and branched porous organic polymers (POPs), following a metal-free one-step synthesis. The newly synthesised monomers, linear polymers and POPs have been characterized thoroughly with 1H, 13C and 13C MAS NMR, FTIR and MALDI-ToF studies. The AIE properties of the monomers and the linear polymers have been studied in a THF : water mixture, whereas temperature-dependent emission studies have been carried out in solution to understand the AIE behaviour of the insoluble porous polymers. The results suggest that the molecular dynamics in the excited states are distinctly different in the linear and the porous polymers. Nevertheless, all the newly synthesized polymers exhibit solid-state emission, with excellent luminescence (PLQY = 17.7%) in the yellow region being obtained for the porous polymer POP-1. This result for the first time demonstrates that TPB derivatives can act as a backbone for POPs with high luminescence efficiency in the solid state, creating immense scope for different applications in optoelectronics. Three newly designed and synthesized -CHO-containing tetraphenyl-buta-1,3-diene-based AIEgens have been used to construct a series of thiazolothiazole-linked linear polymers and branched porous organic polymers, via a metal-free one-step synthesis.