Hyperbranched Poly(aroxycarbonyltriazole)s: Metal-Free Click Polymerization, Light Refraction, Aggregation-Induced Emission, Explosive Detection, and Fluorescent Patterning

Abstract

The metal-free click polymerization (MFCP) of azide and alkyne has become a powerful tool for the synthesis of functional polytriazoles. Among which, the MFCP of propiolate and azide has been used to prepare functional linear poly(aroxycarbonyltriazole)s (PACTs). Their hyperbranched analogues, however, have been rarely prepared. In this paper, hyperbranched PACTs with satisfactory molecular weights and high regioregularities were synthesized in high yields by the MFCP of tripropiolates (1) and tetraphenylethene (TPE)-containing diazide (2) under the optimized reaction conditions without protection from oxygen and moisture. The resultant polymers are soluble in common organic solvents and thermally stable, with 5% loss of their weights at temperatures higher than 330 °C. The polymers exhibit high refractive indices with low chromatic dispersion. Thanks to their contained TPE units, the polymers show the unique feature of aggregation-induced emission, and their aggregates can function as fluorescent sensors for the detection of explosives with the superamplification quenching effect. Furthermore, the polymers can be readily photo-cross-linked, yielding two-dimensional fluorescent patterns with high resolution.

Progress on Catalytic Systems Used in Click Polymerization

“…This work not only establishes a new kind of metal‐free click polymerization but also provides a facile tool for the preparation of functional polyesters. In terms of the universality of this robust polymerization, the linear and hyperbranched PACTs with multiple functions were generated successively, such as degradability, magnetic ceramic precursors and high refractivity …”

Click Chemistry: A Powerful and Versatile Methodology for Preparation of Ferrocene-Containing Polymers

“…The removal of the copper residues after Cu(I)-catalyzed AACP is, however, difficult. To surmount this difficulty, we have successfully established the metal-free AACPs of activated alkynes and azides [67][68][69][70][71][72][73]. Recently, we employed the metal-free AACP of propiolates and azide to prepare Fc-containing poly(aroxycarbonyltriazole)s (PACTs) [74].…”

High sensitivity sensing of nitroaromatic explosive vapors based on polytriphenylamines with AIE‐active tetraphenylethylene side groups

“…The main reason for the AIE behavior is the restriction of intramolecular rotations (RIR) of peripheral phenyl (or heteroaryl) rotors in the aggregated state as has been concluded from experimental and theoretical studies . Recently, AIE luminogens have been used as active component of PL sensors . Tang et al reported a series of linear and hyperbranched polymers based on the AIE‐active tetraphenylethylene (TPE) unit made by metal‐free click polymerization for explosive detection .…”

“…Recently, AIE luminogens have been used as active component of PL sensors . Tang et al reported a series of linear and hyperbranched polymers based on the AIE‐active tetraphenylethylene (TPE) unit made by metal‐free click polymerization for explosive detection . We also fabricated explosive sensors for nitroaromatic compounds based on PCz with AIE‐active TPE side groups, that showed amplified PL quenching during exposure to trinitrobenzene (TNB) in THF/water mixtures, as well as high solid state sensitivity .…”