Organic chemistry articles within Polymer Journal

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  • Original Article |

    The depolymerization of super engineering plastics such as polysulfone (PSU) smoothly proceeded in the presence of methanol mediated by sodium hydroxide in 1,3-dimethyl-2-imidazolidinone (DMI) at 80 °C to form bis(4-methoxyphenyl)sulfone and 4,4’-(propane-2,2-diyl)diphenol (bisphenol A) in high yields. These products were readily isolated by simple filtration. The DMI solvent effectively promoted depolymerization and allowed insoluble resins such as polyetheretherketone (PEEK) to undergo the reaction. This method was applicable to other alcohols, such as ethanol and isopropyl alcohol.

    • Yasunori Minami
    • , Rena Honobe
    •  & Masaru Yoshida

  • Rapid Communication |

    We designed multiblock amphiphilic cyclophanes that possess twisted aromatic units with axial chirality. Electronic absorption and emission spectroscopy revealed that these cyclophanes are molecularly dispersed in organic solvents, while they form aggregates in aqueous environments. We also found that under aqueous conditions, the chiral aromatic units within homochiral cyclophanes adopt a more planar conformation compared to their diastereomer, demonstrating the possibility of stereoselective recognition. Furthermore, by comparing the corresponding multiblock amphiphiles that are linear and chiral, we found that the macrocyclic structure might be essential for recognition.

    • Ryoto Matsuda
    • , Haruki Otake
    •  & Kazushi Kinbara

  • Focus Review
    | Open Access

    We have developed innovative new phosgenation reactions and their special reaction systems with the key objective of “safe application” to organic synthesis. This focus review summarizes our recent studies on in situ photo-on-demand phosgenation reactions of alcohols and amines for synthesizing polycarbonates, polyurethanes, and their precursors such as chloroformates, carbonate esters, and diisocyanates, in batch reaction systems, which are preferable for laboratory or small-scale industrial syntheses.

    • Akihiko Tsuda

  • Original Article |

    We performed cationic ring-opening polycondensation of a galactose-based cyclic sulfite monomer to give (1 → 2)-galactan. Treatment of the cyclic sulfite with 10-(+)-camphorsulfonic acid (CSA) in the presence of water initiated ring-opening polycondensation to give benzylated (1 → 2)-galactan. The MALDI-TOF mass spectrum of the obtained polymer showed a simple pattern with even intervals, indicating the formation of benzylated (1 → 2)-galactan with OH termini. When we used 4-penten-1-ol as the alcohol initiator for cationic polycondensation, we obtained a pentenoyl group-terminated polymer and/or cyclic oligosaccharides. The mechanism for the polycondensation reaction was determine through systematic investigations of the polymerization and DOSY spectral measurements of the polymer. The present method may be useful with graft polymerizations designed to give oligogalactan-containing glycosides in one pot.

    • Ryo Miyazaki
    • , Misaki Suzuki
    •  & Yasuhito Koyama

  • Original Article |

    Transition metal-free aldol condensation was applied to synthesize n-type conjugated polyelectrolyte (CPE), PIIGBDV-N. The quaternary ammonium groups with Br- ions on the side chain enabled in situ n-doping during polymerization, which resulted in strong polaron absorption in the near infrared region and increased conductivity of the obtained CPE. PIIGBDV-N exhibited good electron transport capability and can be utilized as thickness-insensitive electron transporting layer in high-performance organic solar cell devices.

    • Haoran Tang
    • , Yuejia Dou
    •  & Yong Cao

  • Original Article |

    Multiarmed cyclosiloxanes bearing terminal amine groups (DnA, n = 4, 5) were obtained via a photocatalytic thiol-ene reaction, with regioselectivities of β-adducts as high as 93% irrespective of the repeating unit number in the cyclosiloxane rings. Ketoenamine-linked hybrid networks using D4A and D5A as the starting monomers were successfully synthesized via a mild Schiff base reaction with 2,4,6-triformylphloroglucinol and demonstrated high thermal stability and the formation of nanoparticle assemblies.

    • Huie Zhu
    • , Yuhi Watanabe
    •  & Masaya Mitsuishi

  • Original Article |

    The first main-chain type triphenylarsine (AsPh3) polymers were synthesized by Suzuki-Miyaura polycondensation. The electronic and photophysical properties of the AsPh3 polymers were comparison with model compounds by experimental and computational methods. As a result, it was found that the conjugated systems were expanded through the arsenic atoms. The present AsPh3 polymers are promising as luminescent materials.

    • Hyota Kihara
    • , Hiroaki Imoto
    •  & Kensuke Naka

  • Original Article |

    The role of alcohol in the Yb(OTf)3- and Y(OTf)3-catalyzed stereoselective radical polymerization of acrylamides is clarified. The coordination of two equivalents of alcohol to the metal triflate generates a complex, which increases both the polymerization rate and stereocontrol compared to those without an alcohol. The importance of hydroxyl groups of the alcohol is suggested by the observed secondary isotope effect for the rate enhancement. The conditions are highly compatible with those for organotellurium-mediated radical polymerization, and the dual control of molecular weight and tacticity is successfully achieved.

    • Beomsu Park
    • , Yuji Imamura
    •  & Shigeru Yamago

  • Rapid Communication |

    When the radical polymerization inhibitor 1,4-naphthoquinone (NQ) acts on styrene, the radical capture reaction greatly contributes carbon atoms. In this study, the 1-phenethyl radical, which is a model for the growth radicals of polystyrene, was reacted with NQ using four radical sources, and we identified the reaction product. We confirmed that the same compound was formed upon addition of a small amount of NQ to heated styrene. The frontier orbital energy levels and reaction path energy diagrams were calculated, which provided numerical values to support our experimental results.

    • Takuji Takahashi
    • , Yujirou Ikejiri
    •  & Hiroaki Gotoh

  • Original Article |

    The reactive groups (–OH or –NH2) of natural melanin nanoparticles from cuttlefishes react with isocyanate groups in pre-polyurethane (pre-PU) to form cross-links, further strengthening the self-healing of PU based on the reversible acylhydrazone bond. The self-healing efficiency was improved from 91.73% to 99.58% due to the strong interactions between the MNs and PU.

    • Xiaoyue Ma
    • , Chuanying Shi
    •  & Yanyan Wei

  • Focus Review |

    In this focus review, our recent progress on hybrid polymers and supramolecules utilizing silicon and arsenic is overviewed. Novel materials design based on polyhedral oligomeric silsesquioxane (POSS) has been realized by focusing on the symmetry. Practical synthetic methods have opened new avenue to experimental studies on organoarsenic compounds.

    • Hiroaki Imoto

  • Original Article |

    To synthesize CO2-derived polycarbonates with high Tg values, epoxides having rigid and bulky 2-norbornyl or 1-adamantyl substituents were selected as comonomers. The alternating copolymer obtained from 1-adamantylethylene oxide showed a Tg above 150 °C. This is the highest Tg among those observed for alternating copolymers obtained from CO2 and a terminal epoxide.

    • Rie Arai
    • , Keitaro Seto
    •  & Hiroshi Sugimoto

  • Original Article |

    The Michael addition of N-heterocyclic carbenes (NHCs) to the unsaturated polyesters, polymaleates and a polyfumarate, produced the polymers bearing the NHCs as side chains in good-to-high yields. The glass transition temperatures of the obtained polymers were widely tunable and increased linearly with the increasing NHC content. The stiff and bulky structures of the NHCs can reduce the mobility of the polymer main chain. The simultaneous Michael addition and transfer hydrogenation of the unsaturated polyesters have also been performed by the reaction with an NHC in the presence of water.

    • Shin-ichi Matsuoka
    • , Yuya Kamijo
    •  & Masato Suzuki

  • Original Article |

    π-Conjugated polymers capped with a boronic acid end-functional group were synthesized by chain-growth Suzuki–Miyaura polycondensation. The obtained polymers were reacted with a π-stacked-polymer scaffold to synthesize graft polymers. The spectroscopic and optical characterization of the obtained graft polymers in the solid state revealed that the original π-conjugated polymers were stacked in a single polymer chain. Direct observations of the obtained graft polymers showed that they self-assembled into spherical or fiber structures depending on the introduced polymers, whereas no ordered structures were formed by the same polymers before the polymer reaction.

    • Yuichi Tsuji
    • , Yasuhiro Morisaki
    •  & Yoshiki Chujo

  • Original Article |

    Many molecules of normal tricosane in the rotator phases belong to any one of three types of rows of molecules as shown in the figure. In the three stable conformations, they are making the translational motion along and the rotational oscillation around the molecular axes. The estimation of disorder parameters relevant to the thermal motions shows that the translational motion and the rotational oscillation are fairly restricted in the rotator phases.

    • Kazuo Kato

  • Focus Review |

    This review describes the N-heterocyclic carbene-catalyzed transformations of Michael acceptors that were developed by our research group, including (1) tail-to-tail dimerization of a wide variety of substrates, such as vinyl pyridines, acrylates, methacrylates and methacrylonitrile, (2) cyclotetramerization of acrylates to form trisubstituted cyclopentenones, (3) tandem oxa-Michael addition and head-to-tail dimerization of methacrolein and (4) oxa-Michael addition polymerization of hydroxyl-functionalized acrylates.

    • Shin-ichi Matsuoka

  • Original Article |

    Chitosan phenylcarbamate (CtsPC) samples were synthesized and their lyotropic liquid crystallinity in ionic liquids was investigated. 1-Ethyl-3-methylimidazolium dicyanamide ([C2Mim][N(CN)2]) was found to be a novel solvent for CtsPC, and the lyotropic system formed a cholesteric liquid-crystalline phase and exhibited vivid colorations owing to selective light reflection. The cholesteric helical pitch was controllable by polymer concentration, temperature or the degree of phenylcarbamoyl substitution. Although the helical sense of CtsPC/[C2Mim][N(CN)2] cholesterics remained right-handed under the adopted measurement conditions, an inversion of cholesteric sense was achieved by using a mixed solvent of [C2Mim][N(CN)2]/N,N-dimethylformamide.

    • Junichi Sato
    • , Nobuhiro Morioka
    •  & Yoshiyuki Nishio

  • Original Article |

    Novel amphiphilic graft copolymers composed of poly(γ-glutamic acid) (γ-PGA) as a hydrophilic backbone and enantiomeric PLA as hydrophobic side chains were successfully synthesized by using carbodiimide as the coupling agent. The enantiomeric γ-PGA-graft-PLLA (γ-PGA-g-PLLA) and γ-PGA-graft-PDLA (γ-PGA-g-PDLA) copolymers could form NPs, and stereocomplex crystallites were formed in the case of the mixture of γ-PGA-g-PLLA and γ-PGA-g-PDLA copolymers. These NPs with reactive functional groups would have great potential to be used as stable delivery vehicles for pharmaceutical and biomedical applications.

    • Ye Zhu
    • , Takami Akagi
    •  & Mitsuru Akashi

  • Original Article |

    This paper reports multivariate analyses such as principal component analysis and partial least-squares regression of NMR spectra of poly(N-isopropylacrylamide)s [poly(NIPAAm)s]. Principal component analysis successfully interpreted the assignments of 1H and 13C NMR spectra of methylene protons and methine carbons, respectively, of poly(NIPAAm)s in terms of stereostructures. Furthermore, triad tacticity was successfully predicted by partial least-squares regression of 1H NMR spectra of the methine and methylene groups. Consequently, it is assumed that chemometric analysis of NMR spectra is a promising method for the characterization of synthetic polymers.

    • Tomohiro Hirano
    • , Takuya Anmoto
    •  & Koichi Ute

  • Original Article |

    Would the chain-scission mechanism of the polymer depolymerizations be changed by the non-thermal effects of microwave irradiation? and how are the chain-scission mechanism and its kinetic behaviors? In this paper, the kinetic processes and mechanisms of poly(ethylene terephthalate) (PET) hydrolytic depolymerization of microwave were investigated, and the chain-scission mechanism was further discussed to give effective support to the non-thermal effects of microwave irradiation for which chemical reactions of small molecules could not give effective evidences.

    • Shuzhen Zhang
    • , Xiaofang Song
    •  & Yiguang Tian

  • Original Article |

    A clean post-functionalization of 7,7,8,8-tetracyanoquinodimethane polyester by a high-yielding addition reaction with electron-rich alkyne molecules provided highly colored polymer products with very stable charge-transfer bands in the visible to near-infrared region. Electrochemistry revealed elevated HOMO and LUMO levels after the post-functionalization.

    • Yusuke Washino
    • , Kimie Murata
    •  & Tsuyoshi Michinobu

  • Original Article |

    The cellulose derivatives bearing pyridyl and bipyridyl residues were synthesized, and their recognition abilities as chiral stationary phases for high-performance liquid chromatography were evaluated. Among them, the cellulose derivatives with regioselective substitution of bipyridyl residues exhibited a relatively high chiral recognition. The recognition ability of the derivatives was significantly influenced by the coordination of a Cu(II) ion to the bipyridyl residues. In addition, the derivatives were also used for the ligand-exchange chromatography with an eluent containing a copper salt in order to directly separate amino acids without derivatization.

    • Yasunaka Katoh
    • , Yasutaka Tsujimoto
    •  & Yoshio Okamoto

  • Original Article |

    Isotactic (it-) and syndiotactic (st-) uniform poly(methyl methacrylate)s (PMMAs) with hydroxyl end group, isolated by supercritical fluid chromatography (SFC), were reacted with benzene-1,3,5-tricarbonyl trichloride, and two types of uniform three-arm star-PMMAs with different stereoregular arms, [it/it/st]- and [it/st/st]-3-star-PMMAs, were isolated by SFC from the product mixture. The stereocomplex formation of these stereostar PMMAs was examined in acetone. Although both stereostar PMMAs formed intramolecular stereocomplexes, the [it/st/st]-3-star-PMMA, in particular, was found to form two types of intramolecular stereocomplexes with different hydrodynamic volumes because of different compositions of it- and st-PMMA arms involved in the stereocomplexes.

    • Takafumi Nishiura
    • , Yoshinori Abe
    •  & Tatsuki Kitayama

  • Original Article |

    Optical properties of thin films based on thermostable poly(oxadiazole-naphthylimide)s were investigated. The main absorption maxima of the films were centered at about 301–308 nm, their intensity and positions remaining almost unchanged up to 250 °C. The Kramers–Kronig analysis applied to the reflectance spectra yielded the extinction coefficient and refractive index values. The energy gaps obtained from the edge of the absorption coefficient, based on transmission and reflectivity measurements, were found in the range of 2.77–3.04 eV. In photoluminescence spectra, three maxima in the UV and blue spectral range were detected.

    • Mariana-Dana Damaceanu
    • , Radu-Dan Rusu
    •  & Bozena Jarzabek

  • Original Article |

    Model reactions of calix[4]resorcinarene (CRA), p-tert-butylcalix[n]arene (BCA[n], n=4, 6, 8) and their esterified derivatives with glycidyl phenyl ether (GPE) were examined using tetraphenylphosphonium chloride (TPPC) as the catalyst in chlorobenzene at 120 °C for 6 h. It was found that the degree of introduction of GPE (D.I.) to CRA series was higher than 95%, whereas for BCA[n] (n=4, 6, 8) series, D.I.s were lower than 81%. Therefore, CRA and its derivatives are good potential curing agents for preparing cured epoxy resins with excellent thermal properties.

    • Shengang Xu
    • , Hiroto Kudo
    •  & Shunichi Numata

  • Original Article |

    We report the direct synthesis of new functional novolacs having allyl ether in the side chain by the addition-condensation of allyl phenyl ether (1). In polymerization of 1 with formaldehyde using hydrated sulfuric acid as a catalyst, Claisen condensation did not occur with the polymerization; therefore, pure allylated novolac (4) without a phenol moiety was obtained. The obtained polymer (4) can be applicable for a latent curing system.

    • Gen-ichi Konishi
    • , Takatsugu Tajima
    •  & Yoshiaki Nakamoto

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