In Situ Generation of N -Heteroaromatic Polymers: Metal-Free Multicomponent Polymerization for Photopatterning, Morphological Imaging, and Cr(VI) Sensing

Abstract

The electron-deficient N-heteroaromatic polymers are crucial for the high-tech applications of organic materials, especially in the electronic and optoelectronic fields. Thus, the development of new polymerizations to afford adaptable electron donating-accepting scaffolds in N-heteroaromatic polymers is in high demand.Herein, metal-free multicomponent polymerizations of diynes, diamines and glyoxylates are successfully developed for in-situ generation of poly(quinoline)s with high molecular weights (M w up to 16 900) in nearly quantitative yields. By tuning the electron distributions of the polymer backbones, the resulting poly(quinoline)s show various aggregation-induced behaviors and photo-responsive abilities. The thin films of poly(quinoline)s can be readily fabricated into well-resolved photopatterns by photolithography techniques.They can be utilized as fluorescent probes to directly visualize the morphologies of polymer materials including spherulites and microphase separation of polymer blends. Their nanoparticles demonstrate sensitive and highly selective fluorescence quenching to hexavalent chromium ion Cr(VI), which provides access for the biological imaging of Cr(VI) in unicellular algae.

Fused Heterocyclic Polymers with Aggregation-Induced Emission: Synthesis and Applications

“…In addition to MCPs based on C–H activation chemistry, other kinds of MCPs were reported to afford AIE-active polymers with a fused heterocycle at the same time. For example, our group developed a MCP of terminal diynes, diamines, and glyoxylates to synthesize poly­(quinoline)­s (PQ)­s in a metal-free manner in high yields at ambient temperature (Figure E) . These quinoline-containing polymeric materials with donor–acceptor scaffolds can be used for highly selective fluorescent detection of chromium ion in unicellular algae .…”

“…Recently, Hu et al applied an AIE-active quinoline-containing polymer in the visualization of mesoscale morphological structures of polymer blends . As illustrated in Figure , polymer P1 was sensitive to the variation of structural rigidity.…”

“…(H) Chemical structure of the poly­(quinoline) P1 . This figure has been published in CCS Chemistry [2021]; In Situ Generation of N-Heteroaromatic Polymers: Metal-Free Multicomponent Polymerization for Photopatterning, Morphological Imaging, and Cr­(VI) Sensing is available online at DOI: 10.31635/ccschem.021.202101137 . CCS Chemistry is an Open Access journal.…”

Multicomponent Polymerizations of Isocyanides, Aldehydes, and 2-Aminopyridine toward Imidazo[1,2-a]pyridine-Containing Fused Heterocyclic Polymers

“…They could not only proceed smoothly to afford polymer products with high efficiency and specificity but also construct the newly formed fused heterocycle functional units in situ from polymerization, demonstrating great synthetic efficiency and simplicity. For example, we have reported MCPs of alkynes, sulfonylazides, and 2-hydroxybenzonitrile or 2-aminobenzonitrile to directly construct iminocoumarin or quinoline in the polymer mainchain from the simple monomers, affording polymer products with high molecular weights and high yields . Conjugated polymers with imidazo­[2,1- b ]­thiazole units were also synthesized through the MCPs of heterocyclic diazoles, dialdehydes, and terminal alkyne or alkynecarboxylic acids; poly­(quinoline)­s with nearly quantitative yields could also be afforded from metal-free MCPs of diynes, diamines, and glyoxylates .…”

“…For example, we have reported MCPs of alkynes, sulfonylazides, and 2-hydroxybenzonitrile monomers, affording polymer products with high molecular weights and high yields. 20 Conjugated polymers with imidazo-[2,1-b]thiazole units were also synthesized through the MCPs of heterocyclic diazoles, dialdehydes, and terminal alkyne or alkynecarboxylic acids; 21 poly(quinoline)s with nearly quantitative yields could also be afforded from metal-free MCPs of diynes, diamines, and glyoxylates. 22 MCPs were hence proved to be powerful tools for the construction of fused heterocyclic polymers.…”