Recent Progress in the Development of New Acetylenic Polymers

Isoxazole group directed Rh(III)-catalyzed alkynylation using TIPS-EBX

A highly effective isoxazole directed ortho C-H alkynylation has been developed. Rhodium(III) catalyzed direct di-(and/or mono) alkynylation using a hypervalent iodine reagent (TIPS-EBX) is reported. The reaction proceeds with a wide substrate scope under benign conditions. Preliminary mechanistic studies support this chelation assisted C-H alkynylation.

Introducing a sulfone-embedded anhydride to the anhydride-imine reaction for the modular synthesis of N-heterocyclic sulfones bearing vicinal stereocenters

N-heterocyclic sulfones constitute the core of several pharmaceuticals, including the antityrpanosomal drug Nifurtimox. Their biological relevance and architectural complexity makes them valued targets and inspires the development of more selective and atom-economical strategies for their construction and post-modification. In this embodiment, we describe a flexible approach to sp³-rich N-heterocyclic sulfones, which hinges on the efficient annulation of a novel sulfone-embedded anhydride with 1,3-azadienes and aryl aldimines. Further elaboration of the lactam esters has facilitated the construction of a library of vicinally functionalized sulfone-embedded N-heterocycles.

Copper-Catalyzed Formal Dehydration Polymerization of Propargylic Alcohols via Cumulene Intermediates

Here we report a copper-catalyzed formal dehydration polymerization of propargylic alcohols. Copper catalysis allows for efficient in situ generation of [n]cumulenes (n = 3, 5) by a soft deprotonation/β-elimination pathway and subsequent polymerization via organocopper species. Alkyne polymers (M_n up to 36.2 kg/mol) were produced with high efficiency (up to 95% yield) and excellent functional group tolerance. One-pot synthesis of semiconducting head-to-head poly(phenylacetylene) was demonstrated through a polymerization-isomerization sequence.

A Simple Approach to Bioconjugation at Diverse Levels: Metal-Free Click Reactions of Activated Alkynes with Native Groups of Biotargets without Prefunctionalization

The efficient bioconjugation of functional groups/molecules to targeted matrix and bio-related species drives the great development of material science and biomedicine, while the dilemma of metal catalysis, uneasy premodification, and limited reaction efficiency in traditional bioconjugation has restricted the booming development to some extent. Here, we provide a strategy for metal-free click bioconjugation at diverse levels based on activated alkynes. As a proof-of-concept, the abundant native groups including amine, thiol, and hydroxyl groups can directly react with activated alkynes without any modification in the absence of metal catalysis. Through this strategy, high-efficient modification and potential functionalization can be achieved for natural polysaccharide, biocompatible polyethylene glycol (PEG), synthetic polymers, cell penetrating peptide, protein, fast whole-cell mapping, and even quick differentiation and staining of Gram-positive bacteria, etc. Therefore, current metal-free click bioconjugation strategy based on activated alkynes is promising for the development of quick fluorescence labeling and functional modification of many targets and can be widely applied towards the fabrication of complex biomaterials and future in vivo labeling and detection.

Direct ortho-Selective C-H Functionalization of Carboxybenzyl-Protected Arylalkylamines via Ir(III)-Catalyzed C-H Activation

A convenient and practical approach to synthesize ortho-alkynylated arylalkylamines through ortho-selective C-H functionalization has been developed using Cbz-amide as the directing group and Ir(III) as the catalyst. Various substrates were well tolerated, affording the corresponding products in moderate to good yields. Moreover, preliminary mechanistic study revealed the role of the amide as the coordination center to cooperate with the Ir(III) complex during C-H activation. Development of this Cbz-amide-promoted C_Ar-H functionalization offers a practical approach with potential applications in organic synthesis.

Rh(iii)-Catalyzedortho-C–H alkynylation ofN-phenoxyacetamides with hypervalent iodine-alkyne reagents at room temperature

Directing group ONHR preservedortho-alkynylation under mild conditions catalyzed by rhodium is reported.

Ultrafast and efficient aza- and thiol-Michael reactions on a polyester scaffold with internal electron deficient triple bonds

A polyester scaffold possessing electron deficient triple bonds in the main chain was prepared and utilized as a precursor for aza- and thiol-Michael addition reactions.

Palladium-catalyzed direct ortho-alkynylation of arylalkylacid derivatives at γ and δ positions via an N,O-bidentate directing group

A new N,O-bidentate directing group: first example of the ortho-alkynylation of arylalkylacid derivatives at γ and δ positions.

Mechano-Responsive, Thermo-Reversible, Luminescent Organogels Derived from a Long-Chained, Naturally Occurring Fatty Acid

The gelating ability of an α-diketo derivative of oleic acid, 9,10-dioxooctadecanoic acid (DODA), is investigated. DODA can gelate aromatic liquids and many other organic liquids. By contrast, none of the liquids examined can be gelated by the methyl ester of DODA. DODA is a more efficient gelator than stearic acid and the monoketo derivative due to its more extensive intermolecular dipole-dipole interactions. Formation of organogels of DODA can be induced by both thermal and mechanical stimuli, during which the luminescent and mechanical properties can be modulated significantly. The emission from DODA in 1-octanol exhibits a large, reversible, hypsochromic shift (≈25 nm) between its thermally cycled gel and sol states. The emission changes have been exploited to probe the kinetics of the aggregation and deaggregation processes. DODA is the simplest gelator of which we are aware that exhibits a reversible shift in the emission. Although the self-assembled fibrillar networks of the DODA gels in 1-octanol, benzonitrile, or silicone oil are crystalline, isothermal mechanical cycling between the gel and the sol states is rapid and can be repeated several times (i.e., they are thixotropic). The single-crystal structure of DODA indicates that extended intermolecular dipole-dipole interactions are crucial to the thermal and mechanical formation of DODA gels and the consequential changes in emissive and mechanical properties. From analyses of structural information, gelator packing, and morphology differences, we hypothesize that the mechanical destruction and reformation of the gel networks involves interconversion between the 3D networks and 1D fiber bundles. The thermal processes allow the fibrillar 3D networks and their 0D components (i.e., isolated molecules or small aggregates of DODA) to be interconverted. These results describe a facile approach to the design of mechano-responsive, thermo-reversible gels with control over their emission wavelengths.

Ir(III)-catalyzed C-H alkynylation of arenes under chelation assistance

An efficient and mild Ir(III)-catalyzed, chelation assisted C-H alkynylation of arenes has been developed using hypervalent iodine alkynes as alkynylating reagents. A broad scope of N-phenyl-2-aminopyridines and 2-phenoxypyridines has been established as effective substrates for this C-H functionalization and the desired alkynylated products were isolated in moderate to high yields.

Palladium-catalyzed alkyne polyannulation of diphenols and unactivated internal diynes: a new synthetic route to functional heterocyclic polymers

A new polymerization route for the preparation of functional heterocyclic polymers was developed from diphenol derivatives and unactivated internal diynes.

Synthesis of platinum-containing poly(phenyleneethynylene)s having various chromophores: aggregation and optical properties

Various platinum-containing phenylene–ethynylene–arylene polymers were synthesized, and the relationships between the optical properties and aggregation behaviour were examined.

Alpha and beta diimine cobalt complexes in isoprene polymerization: a comparative study

Isoprene was polymerized by diimine cobalt catalyst in the presence of DEAC to produce cis-1,4 and 3,4 polyisoprene.

Intriguingly tuning the fluorescence of AIEgen using responsive polyelectrolyte microspheres

We successfully synthesized counterion-sensitive TPE–METAC polyelectrolyte microspheres and tuned its fluorescence and size by ClO₄⁻, PF₆⁻ and TFSI⁻.

Conjugated polymers developed from alkynes

The numerous merits of conjugated polymers (CPs) have encouraged scientists to develop a variety of synthetic routes to CPs with diverse structures and functionalities. Among the large scope of substrates, alkyne plays an important role in constructing polymers with conjugated backbones. In addition to some well-developed reactions including Glaser–Hay and Sonogashira coupling, azide/thiol-yne click reaction and cyclotrimerization, some novel alkyne-based reactions have also been explored such as oxidative polycoupling, decarbonylative polycoupling and multicomponent tandem polymerizations. This review focuses on the recent progress on the synthetic methodology of CPs in the last five years using monomers with two or more triple bonds and some of their high-technological applications. Selected examples of materials properties of these CPs are given in this review, such as fluorescence response to chemical or physical stimuli, magnetism, white light emission, cell imaging and bioprobing. Finally, a short perspective is raised in regard to the outlook of the preparation methodologies, functionalities as well as potential applications of CPs in the future.

Regio- and stereoselective construction of stimuli-responsive macromolecules by a sequential coupling-hydroamination polymerization route

Sequential coupling-hydroamination polymerization towards stimuli-responsive polymers.

Palladium-catalyzed oxalyl amide assisted direct ortho-alkynylation of arylalkylamine derivatives at δ and ε positions

Palladium-catalyzed oxalyl amide directed ortho-alkynylation of arylalkylamine derivatives via rare six- and seven-membered palladacycles has been reported.

A dual-mode fluorescence “turn-on” biosensor based on an aggregation-induced emission luminogen

A dual-mode fluorescent biosensor based on TPE-TEG-PA is developed for protamine quantification and alkaline phosphatase activity assay.

Indium-catalyzed polycyclotrimerization of diynes: a facile route to prepare regioregular hyperbranched polyarylenes

The facile and efficient InCl₃/2-iodophenol-catalyzed polycyclotrimerization of diynes to generate regioregular hyperbranched polyarylenes was successfully established.

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene

Cobalt II ions ligated byfac-κ³-β-triketimine ligands form bromide-bridged square-based pyramidal dimers which upon activation with MAO and fed with a constant supply of butadiene produce high-cis-1,4-polybutadiene with activities and molecular weights surpassing all previously seen for this metal.

AIE macromolecules: syntheses, structures and functionalities

A comprehensive review of macromolecules with aggregation-induced emission attributes is presented, covering the frontiers of syntheses, structures, functionalities and applications.