Hyperbranched Polyynes: Syntheses, Photoluminescence, Light Refraction, Thermal Curing, Metal Complexation, Pyrolytic Ceramization, and Soft Magnetization

An overview of the synthetic strategies of C3-symmetric polymeric materials containing benzene and triazine cores and their biomedical applications

C3-symmetric star-shaped materials are an emerging category of porous organic polymers with distinctive properties such as permanent porosity, good thermal and chemical stability, high surface area, and appropriate functionalization that promote outstanding potential in various applications. This review is mostly about constructing benzene or s-triazine rings as the center of C3-symmetric molecules and using side-arm reactions to add functions to these molecules. Over and above this, the performance of various polymerization processes has been additionally investigated in detail, including the trimerization of alkynes or aromatic nitriles, polycondensation of monomers with specific functional groups, and cross-coupling building blocks with benzene or triazine cores. Finally, the most recent progress in biomedical applications for C3-symmetric materials based on benzene or s-triazine have been summarized.

Advances in the application of named reactions in polymer synthesis

With the development of polymer science, more and more named reactions have been applied to synthesizing polymers. Introducing new reactions into polymer synthesis is undoubtedly an excellent expansion for monomer and polymer libraries. In this review, the named reactions employed in polymer-chain synthesis were divided into seven types: electrophilic reactions, nucleophilic reactions, transition metal-mediated cross-coupling reactions, free radical reactions, pericyclic reactions, multi-component reactions and rearrangement reactions. The discussion was mainly focused on the progress in the utilization of these named reactions in polymer synthesis, which could be a valuable reference for researchers in the polymer field.

Synthesis of Polydiynes via an Unexpected Dimerization/Polymerization Sequence of C3 Propargylic Electrophiles

Here, we describe the unexpected discovery of a Cu-catalyzed condensation polymerization reaction of propargylic electrophiles (CPPE) that transforms simple C3 building blocks into polydiynes of C6 repeating units. This reaction was achieved by a simple system composed of a copper acetylide initiator and an electron-rich phosphine ligand. Alkyne polymers (up to 33.8 kg/mol) were produced in good yields and exclusive regioselectivity with high functional group compatibility. Hydrogenation of the product afforded a new polyolefin-type backbone, while base-mediated isomerization led to a new type of dienyne-based electron-deficient conjugated polymer. Mechanistic studies revealed a new α-α selective Cu-catalyzed dimerization pathway of the C3 unit, followed by in situ organocopper-mediated chain-growth propagation. These insights not only provide an important understanding of the Cu-catalyzed CPPE of C3, C4, and C6 monomers in general but also lead to a significantly improved synthesis of polydiynes from simpler starting materials with handles for the incorporation of an α-end functional group.

Helix Induction and Inversion of Polymeric Foldamer Regulated by the Single Enantiomers

In general, a single enantiomer can induce a foldamer into a preferred-handed helix, while another condition is required for the helical inversion. In this work, it is found that the helix induction and subsequent inversion of the poly(m-phenylene diethynylene)-based foldamer bearing aza-18-crown-6 pendants (Poly-1) can be realized by increasing the concentration of sterically hindered L-amino acid perchlorate salts. When the amount of chiral enantiomers is small, one enantiomer tends to complex with two non-adjacent aza-18-crown-6 rings via three N⁺ -H···O hydrogen bonds in a sandwich mode. Notably, the transition dipole moment is perpendicular to aza-18-crown-6 ring, so that the induced helical chirality in Poly-1 main chain is opposite to the chirality of enantiomers. When the amount of chiral enantiomers is large enough, each aza-18-crown-6 is occupied by one enantiomer, which causes the transition dipole moment in a parallel direction to aza-18-crown-6 ring. In this case, the increased steric hindrance can facilitate the inversion of screw sense of Poly-1 main chain, which is directed by chiral center of enantiomers. As a result, a helix inversion has been achieved successfully. This work not only provides a novel strategy for regulating the two-stage folded helical conformations by the single enantiomers, but opens a window to develop chiral recognition materials. This article is protected by copyright. All rights reserved.

Ring Opening of Triflates Derived from Benzophospholan-3-one Oxides by Aryl Grignard Reagents as a Route to 2-Ethynylphenyl(diaryl)phosphine Oxides

A new simple method for the synthesis of 2-ethynylphenyl(diaryl)phosphine oxides via ring opening of benzophosphol-3-yl triflates has been developed. This process occurs via nucleophilic attack of a Grignard reagent at the phosphorus center, which results in ring opening and cleavage of a leaving group. The reaction proceeds under mild conditions and, within 15-60 min, leads to a library of previously unavailable 2-ethynylphenylphosphine oxides in yields up to 98%.

Recent progress of magnetic nanomaterials from cobalt-containing organometallic polymer precursors

This review summarizes the recent progress in the syntheses and materials applications of Co-containing organometallic polymers, and mainly focuses on the preparation of magnetic nanostructures from Co-containing organometallic polymer precursors.

A molecular approach to magnetic metallic nanostructures from metallopolymer precursors

This tutorial review summarizes the strategies of using metallopolymers as precursors for generating functional magnetic metal/metal alloy NPs and other metal nanostructures.

Synthesis, thin-film self-assembly, and pyrolysis of ruthenium-containing polyferrocenylsilane block copolymers

The self-assembly of a ruthenium-containing polyferrocenylsilane in bulk and thin films yielded spherical or cylindrical domains in a PS matrix; pyrolysis provided a route to bimetallic Fe/Ru NPs for potential catalytic applications.

Tunable room-temperature soft ferromagnetism in magnetoceramics of organometallic dendrimers

This article represents an introduction of new dendrimeric precursors to magnetic ceramics, and homometallic and heterometallic dendrimers with tunable magnetic properties.

Development of a transition metal-free polymerization route to functional conjugated polydiynes from a haloalkyne-based organic reaction

Construction of functional polydiynes by transition metal-free homo-polycoupling of bis(iodoalkyne)s.

Functional hyperbranched polymers with advanced optical, electrical and magnetic properties

This review summarizes the recent progress in functional HBPs and their application in optics, electronics and magnetics, including light-emitting devices, aggregation-induced emission materials, nonlinear optical materials, chemosensors, solar cells, magnetic materials, etc., and provides outlooks for further exploration in the field.

Room temperature magnetic materials from nanostructured diblock copolymers

Nanostructured magnetic materials are important for many advanced applications. Consequently, new methods for their fabrication are critical. However, coupling self-assembly to the generation of magnetic materials in a simple, straight-forward manner has remained elusive. Although several approaches have been considered, most have multiple processing steps, thus diminishing their use of self-assembly to influence magnetic properties. Here we develop novel block copolymers that are preprogrammed with the necessary chemical information to microphase separate and deliver room temperature ferromagnetic properties following a simple heat treatment. The importance of the nanostructured confinement is demonstrated by comparison with the parent homopolymer, which provides only paramagnetic materials, even though it is chemically identical and has a higher loading of the magnetic precursor. In addition to the room temperature ferromagnetic properties originating from the block copolymer, the in situ generation densely functionalizes the surface of the magnetic elements, rendering them oxidatively stable.

Conjugated oligoyne-bridged [60]fullerene molecular dumbbells: syntheses and thermal and morphological properties

A series of linear and star-shaped pi-conjugated oligomer hybrids (2-5) composed of an oligoyne core, ranging from 1,3-butadiyne to 1,3,5,7,9,11-dodecahexayne, and fullerenyl end-capping groups has been synthesized and studied. The molecular structures of these fullerene-oligoyne hybrids were assembled through three key reactions: Pd-catalyzed cross-coupling, Cu-catalyzed oxidative homocoupling, and an in situ alkynylation reaction on [60]fullerene. The properties of these compounds were investigated by UV-vis spectroscopy, differential scanning calorimetry (DSC), and atomic force microscopy (AFM) with the purpose of understanding the thermal reactivity arising from the oligoyne moieties as well as the morphological properties on surface. Our study shows that these fullerene-oligoyne hybrids tend to aggregate in different morphologies, including nanospheres, nanoflakes, and continuous thin films, while the morphological properties appear to be subject to the influence of molecular factors such as oligomer chain length, solubilizing alkylphenyl groups, and the thermal reactivity of the oligoyne unit. The correlation between molecular property and interfacial aggregation behavior evinced by these fullerene-oligoyne hybrids suggests a viable approach to exert bottom-up control over the structures and properties of fullerene based nanomaterials.