Tsuyoshi Nishikawa

Random poly(quinoxaline-2,3-diyl) copolymers, containing achiral 5,8-diarylquinoxaline units and chiral units bearing (<i>S</i>)-2-butoxymethyl groups, exhibited circularly polarized luminescence (CPL). The emission color was fully tunable by changing the aryl substituents on the 5,8-diarylquinoxaline units. An energy transfer from the quinoxaline main chain to the 5,8-diarylquinoxaline units was observed. The handedness of the CPL was dependent on the helical chirality of the polymer main chain

The ability of isopropenyl boronate pinacol ester to serve as a monomer in radical polymerizations was established and exploited for the synthesis of polymers that are difficult to access using other polymerization techniques. Although the monomer exhibits an α-methyl-substituted unconjugated structure, which is usually unfavorable for radical propagation, both free and controlled radical polymerizations smoothly afford the corresponding polymers. A density-functional-theory-based investigation

Alkenylboronate units were incorporated into poly(methyl methacrylate) as trigger sites for backbone degradation. The complexation of a fluoride anion to the boron pendant and subsequent activation by a manganese salt triggered the degradation through the generation of a main-chain carbon radical and β-scission in an adjacent methacrylate unit. The addition of catechol was required, and presumably the chelate coordination to the Mn center was crucial for the degradation.

Isopropenyl boronic acid pinacol ester (IPBpin) was used as a comonomer in radical polymerization with a wide range of common vinyl monomers for elucidation of the monomer character and syntheses of conventionally inaccessible copolymers via the replacement of the boron pendant. The study revealed that the boron-containing monomer is categorized into an electron-rich conjugated monomer, which was well consistent with the results of density functional theory (DFT)-based investigation. One of the

Correction for 'Vinylboronic acid pinacol ester as a vinyl alcohol-precursor monomer in radical copolymerization with styrene' by Hiroshi Makino et al., Chem. Commun., 2021, DOI: 10.1039/D1CC02603H.

Metal-free photoinitiated controlled cationic polymerization of isopropyl vinyl ether proceeded <italic>via</italic> the spontaneous cleavage of the carbon–iodine bonds at the propagating ends.

We have studied several protecting groups for vinylboronic-acid derivatives as monomers in radical polymerizations with the objective to improve the polymerization ability and C-B bond-cleaving post-transformation performance. Anthranilamide (aam)-protected vinylboronic acid (VBaam) exhibited experimentally a relatively high polymerization activity, which was theoretically corroborated by density functional theory (DFT) calculations that revealed a peculiar effect of the interaction between the

We used the carbon–boron (C–B) bond of a vinyl boronate unit as a trigger site to achieve the main-chain degradation of the copolymer through radical generation from the C–B trigger by the addition of a base (e.g., sodium methoxide) for interaction with Lewis acidic boron and subsequent photocatalysis with an organic photocatalyst. The C–B bond in the side chain and the carbon–carbon (C–C) bond in the main chain of the copolymers are thermally stable, but the copolymer underwent main-chain degra

A planar-chiral pillar[5]arene with cyclohexylmethoxy side chains and a pendant diphenylphosphine was prepared and used as a chiral ligand in asymmetric reactions. Chirality transfer from the planar-chiral pillar[5]arene scaffold to the chiral biaryl moiety was demonstrated by circular dichroism (CD) spectroscopy, single-crystal X-ray diffraction analysis, and asymmetric catalysis.

Conventionally inaccessible end-functionalized vinyl polymers were synthesized via orthogonal side-chain replacement for terminal and repeating units of poly(alkenyl boronate)s. A terminal-defined polymer of isopropenyl boronic acid pinacol ester (IPBpin) was synthesized via RAFT polymerization, and subsequent cobalt (Co)-catalyzed end olefination afforded the polymer carrying the C(sp²)-B bond at the terminal and the C(sp³)-B bond in repeating units. Herein, the terminal C

In chain-growth polymerization, the polymerization behaviors are governed by the nature of monomer depending on the side-chain structure (e.g. conjugated/non-conjugated, electron-rich/deficient), leading to limitations in (co)polymers we can synthesize. This highlight review summarizes recent development in polymer reactions to overcome such limitations. The key is the design of transformable monomers as well as the utilization of novel organic transformations. In chain-growth polymerization, th

Abstract Vinyl polymers are typically synthesized through the addition polymerization of corresponding vinyl compounds. However, the polymerization ability significantly depends on the substituent on the vinyl moiety, resulting in various synthetic limitations in the molecular structure of vinyl polymers. Given the increasing societal demand for enhanced properties and functions of polymer materials, innovative synthetic technologies are required for developing next-generation polymers through f

We found that radical polymerization of vinyl boronic acid pinacol ester (VBpin) was accompanied by a backbiting chain transfer reaction to the polymer backbone, and thus, branched chains were generated via the propagation from the midchain radical. The subsequent oxidation for the boron pendant afforded a branched poly(vinyl alcohol) (PVA), which was certainly supported by NMR structural analyses. The synthesis of the branched PVA is inaccessible via radical polymerization of vinyl acetate (VAc

Abstract The ability of isopropenyl boronate pinacol ester to serve as a monomer in radical polymerizations was established and exploited for the synthesis of polymers that are difficult to access using other polymerization techniques. Although the monomer exhibits an α‐methyl‐substituted unconjugated structure, which is usually unfavorable for radical propagation, both free and controlled radical polymerizations smoothly afford the corresponding polymers. A density‐functional‐theory‐based inves

Abstract Vacant p-orbital of boron is often utilized for design of unique organic reactions based on its stabilization of adjacent carbon radical and Lewis acidity for interactions with internal or external base. In this study, these unique properties of boron were utilized to design vinyl monomers for chain-growth polymerization. The author found that alkenylboronic acid derivatives, where boron is connected to a vinyl moiety, exhibit radical (co)polymerization abilities due to the stabilizatio