Papers - Yoshioka, Naoki

Poly[(p-ethynylphenyl)hydrogalvinoxyl]　and its Polyradical Derivative with High Spin Concentration

YOSHIOKA NAOKI, NISHIDE HIROYUKI, KANEKO TAKASHI, YOSHIKI HAJIME, TSUCHIDA EISHUN

Macromolecules 25 ( 15 ) 3838 - 3442 1992.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

[4-[(3,5-Di-tert-butyl-4-hydroxyphenyl) (3,5-di-tert-butyl -4-oxocyclohexa-2,5-dien-1-ylidene) -methyl]pheny l ]acetylene (6), was synthesized and polymerized to yield a solvent-soluble polyacetylene poly-[[4-[3,5-di-tert -butyl-4-hydroxyphenyl) (3,5-di-tert-butyl-4 -oxocyclohexa-2,5-dien-1-ylidene) methyl]phenyl ] acetylene] (5a). The polymer gave its polyradical derivative 5b through the chemical oxidation with active PbO2. 5b was stable, whose spin concentration could be increased up to 4.8 × 1023 spins per molar monomer unit. ESR analysis indicated localization of unpaired electrons in the galvinoxyl residue. ESR analysis also suggested an exchange-narrowing and interpolymer dipole-dipole interaction.

• Access to Document (DOI)

歯科用高分子中でのラジカル生成量と硬化特性

藤森行雄、加来恭彦、吉岡直樹、西出宏之、土田英俊

高分子論文集 49 ( 6 ) 509 - 512 1992.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

光硬化型歯科用コンポジットレジン中のアクリレートモノマーの重合挙動を, 硬化体中に残存するラジカル濃度とモノマー二重結合のESR及びIR定量から考察した. 光照射により硬化体中にはメタクリル生長ラジカルが検出され, その濃度は光到達度に対応した. 生長ラジカルは極めて安定に硬化体中に残存したが, 温度が高く換気十分な口腔内では速やかに減少した. 一方, モノマー二重結合消費率は硬化体表面では酸素により, また深部では低い光透過により減少した. 重合率の経時変化から, 残存ラジカル種の後反応によって硬化体深部で重合が進行し, 硬度が維持されていることが示された.

• Access to Document (DOI)

Effect of Ultrasonic Irradiation on　Luminescence Properties of Lanthanide-Polyelectrolyte Complexes

KIDO JUNJI, OKAMOTO YOSHIO, YOSHIOKA NAOKI, NISHIDE HIROYUKI, TSUCHIDA EISHUN

Polymer 33 ( 11 ) 2273 - 2276 1992.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Luminescence properties of Tb3+ - or Eu3+-polycarboxylate complexes in aqueous solution were investigated. The excitation bands near 300 nm for terbium- or europium-polyacrylate solutions were drastically enhanced by the addition of hydroxyl-radical generating reagents as well as ultrasonic irradiation. These spectral changes were attributed to the energy transfer from chromophore molecules formed by the hydroxyl radicals generated in both systems.

• Access to Document (DOI)

Poly[(3,5-di-tert-butyl-4-hydroxyphenyl)acetylene] and Its Polyradical Derivative

NISHIDE HIROYUKI, YOSHIOKA NAOKI, INAGAKI KATSUNARI, KAKU TAKAHIKO, TSUCHIDA EISHUN

Macromolecules 25 ( 2 ) 569 - 575 1992.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

(3,5-Di-tert-butyl-4-hydroxyphenyl)acetylene (8) was synthesized and polymerized with WCIs and MoCl5, giving a novel and solvent-soluble conjugated polymer, poly[(3,5-di-tert-butyl-4-hydroxyphenyl)acetylene] (3). Visible absorption of the polymer indicated a fairly long π-conjugated system along the main chain. The polymer yielded its polyanion 10 and polyradical derivative 4 after the treatment of its solution with an alkali and oxidizing reagent, respectively. The polyradical 4 was surprisingly stable, and spin concentration was increased up to 2.3 × 1023 spins/molar (hydroxyphenyl)acetylene residue. ESR spectra of the polyradical 4 in solution suggested that the formed unpaired electrons were delocalized along the polyacetylene main chain. 4 was also very stable even in solid state. Spin-exchange interaction observed in 4 strongly depended on its spin concentration. Antiferromagnetic interaction between the unpaired electrons was suggested from the temperature dependency of the ESR signal intensity.

• Access to Document (DOI)

Synthesis and Magnetic Properties of Conjugated Stable Polyradicals

NISHIDE HIROYUKI, YOSHIOKA NAOKI, KAKU TAKAHIKO, YAMAZAKI MASANORI, TSUCHIDA EISHUN

Journal of Macromolecular Science-Chemistry 28 ( 11-12 ) 1177 - 1187 1991.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

ynthesis and magnetic properties of π-conjugated stable polyradicals bearing a polyacetylene backbone are described. 2,6-Di-tert-butyl-4-ethynylphenol (8) and 4-ethynylphenylhydrogalvinoxyl (9) are polymerized with W, Mo chloride or Rh complex to yield their polyacetylene derivatives with molecular weight of ca. 10^4, while 2-ethynylphenalenone (10) gives only its oligomer. The polymers are soluble in common solvents and converted to the corresponding conjugated polyradicals via heterogeneous chemical oxidation using PbO2 or alkaline K3Fe(CN)6. The polyradicals with extremely high spin concentration (up to 4.8 × 10^23 spins/monomer mol) are obtained by regulating the oxidative conditions. The polyradicals are quite stable in solution and even in the solid state because of resonance stabilization and/or a steric effect of the substituents. Magnetic interactions between the unpaired spins in the conjugated stable polyradicals are discussed.

• Access to Document (DOI)

UPS Spectra of the Polyacetylene Derivatives Carrying Stable Radical Substituents

YOSHIOKA NAOKI, NISHIDE HIROYUKI, KAKU TAKAHIKO, KANEKO TAKASHI, TSUCHIDA EISHUN, NARIOKA SATORU, SEKI KAZUHIKO

Polymer Journal 23 ( 7 ) 921 - 924 1991.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

側鎖に安定有機ラジカルを有するポリアセチレンの光電子スペクトルの解析結果について報告した。

• Access to Document (DOI)

Magnetic Properties of Conjugated Phenoxy Polyradicals

NISHIDE HIROYUKI, YOSHIOKA NAOKI, TSUCHIDA EISHUN

Journal of Macromolecular Science-Chemistry 27 ( 9-11 ) 1261 - 1273 1990.11

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Formation and magnetic properties of ?r-conjugated phenoxy radicals bearing a porphyrin macrocycle or a polyacetylenic backbone are described. Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphinatometals (7-M) [M = Zn(II), VO(II), and Cu(II)] were oxidized to give the corresponding stable monoradical and biradical. Magnetic properties of the radical species depend on the magnetic orbital of the central metal ion. ESR hfs structure reveals that the biradical for 7-Zn and -VO are in the triplet (S = 1) and quartet state (S = 3/2), respectively. Poly(3,5-di-t-butyl-4-hydroxyphenylacetylene) (8) and poly(pethynylphenylhydrogalvinoxy1) (9) with molecular weights of %lo4 are characterized. ESR spectra with hyperfine structure for 8 indicate that the phenoxy radicals are conjugated with the polyacetylenic main chain over ~7 monomer units as a“neutral soliton.” Formed polyradicals for 8 and 9 are surprisingly stable, even in the solid state, due to resonance stabilization and/or steric effect of the conjugated main chain. An antiferromagnetic interaction is observed for oxidized 8 with a spin concentration above 10 mol%.

• Access to Document (DOI)

Poly(p-ethynylphenyl)galvinoxyl: Formation of a New Conjugated Polyradical with an Extraordinarily High Spin Concentration

NISHIDE HIROYUKI, YOSHIOKA NAOKI, KANEKO TAKASHI, TSUCHIDA EISHUN

Macromolecules 23 ( 20 ) 4487 - 4488 1990.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

This paper describes the synthesis of poly-[4-[(3,5-di-tert-butyl-4-hydroxyphenyl) (3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-yldene) methyl]phenylacetylene] (abbreviated as poly[(p-ethylphenyl)hydrogalvinoxyl]) (4) and also the formation of its polyradical macromolecule, 5, through chemical oxidation. 5 is one of the model polymers with an indirect magnetic interaction; the unpaired electron is mainly localized at the phenylgalvinoxyl side chain, whose spin density is distributed mainly over the galvinoxyl substituent, but also over the phenyl ring to some extent by a spin polarization mechanism.

• Access to Document (DOI)

Magnetic Interaction Observed in the Polyacetylenic Derivatives with High Spin Concentration

YOSHIOKA NAOKI, NISHIDE HIROYUKI, TSUCHIDA EISHUN

Molecular Crystals and Liquid Crystals 190 ( 1 ) 45 - 53 1990.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Electronic state and magnetic interaction of π-conjugated phenoxy radicals bearing a polyacetylenic backborn are described. Poly(3,5-di-t-butyl-4-hydroxyphenylacetylene) (7a) and poly(p-ethynyl-phenylhydrogalvinoxyl) (8a) with molecular weight ca. 10^4 are characterized. ESR spectra with hyperfine structure for the chemically oxidized 7b indicate that the phenoxy radical conjugates through the polyacetylenic main chain over ca. 7 monomer units as a “neutral soliton.” Polyradicals 7b and 8b are surprisingly stable even in the solid state, because of a resonance stabilization and/or a steric effect of the conjugated main chain. An antiferromagnetic interaction is observed for 7b with spin concentration above 10 mol%. Mechanism of the magnetic interaction is discussed.

• Access to Document (DOI)

Electrical Conductive and Magnetic Properties of Conjugated Tetrathiolate Nickel Polymers

YOSHIOKA NAOKI, NISHIDE HIROYUKI, INAGAKI KATSUNARI, TSUCHIDA EISHUN

Polymer Bulletin (Springer)  23 ( 6 ) 631 - 636 1990.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Three tetrathiolate (tetrathiafulvalenetetrathiolate, ethylenetetrathiolate, and butadienetetrathiolate) nickel polymers are prepared. The polymers contain mixed valence Ni ions and are ESR active based on low-spin d8 Ni (III) species. Magnetic susceptibility measurement in the range of 30–60 K suggests and antiferromagnetic interaction between the Ni ions in the polymers. Below 30K a weak ferromagnetic interaction is observed. Chemically oxidized polymers are ESR inactive, while electrical conductivity is greatly enhanced.

• Access to Document (DOI)

UV Curing of Acrylate Monomers Activated with Resol Resin

YOSHIOKA NAOKI, Dwi Wahini Nurhajati, NISHIDE HIROYUKI, TSUCHIDA EISHUN, KASAI MASANORI

Journal of Photopolymer Science and Technology 2 ( 2 ) 231 - 236 1989.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

UV Curing behavior of acrylate monomers in the presence of resol is described. A thin layer consist of resol, monofunctional acrylate (ECA), and hexafunctional acrylate (DPCA-60) gives the crosslinked polymer under UV irradiation. IR spectra of the crosslinked polymer show characteristic absorptions due to both resol and acrylate with a decrease of v C=C′ which indicates the additional polymerization takes place in this system. The curing is accelerated by addition of alkali, which suggests the phenol structure is active site for the polymerization. Among several kinds of alkali investigated, Ba(OH)2 is most effective for the reaction from the point of insoluble polymer yield. Consumption of acrylate double bond in the insoluble polymer ranges above 60% which decreases slowly with an increase in the DPCA-60 content due to steric hindrance. The synergic effect of Ba(OH)2 appears when it is added 0.1mol% for hydroxy group in the resol. UV irradiation leads to color change of the cured layer from pale yellow to reddish violet (λmax =570nm) with an appearance of ESR signal at g =2.004, which indicates the formation of phenoxy radical. The phenoxy radical formed in the resol should be an active site for UV polymerization of this system.

• Access to Document (DOI)

Coordination Structure and Magnetic Property of Poly(pyridilenemethylidenen nitriloiron)s

NISHIDE HIROYUKI, YOSHIOKA NAOKI, TSUCHIDA EISHUN, INOUE HIDENARI

Journal of Polymer Science, Part A, Polymer Chemistry Edition 27 ( 2 ) 497 - 505 1989.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Poly[bis(2,6‐pyridinediylmethylidenenitrilohexamethylenenitrilomethylidene)iron sulfate] was said to be a ferromagnetic compound by earlier investigators. This polymer and its derivatives are carefully reprepared and their unusual magnetic property is reinvestigated spectroscopically. The counter anion species and spacer length of the polymers affect their coordination structure and magnetism. Mössbauer spectroscopy and x‐ray diffractometry on the polymers indicate that their unusual magnetic property is caused by the ferromagnetic iron oxide slightly formed in the polymers.

• Access to Document (DOI)

Poly[(3,5-di-tert-butyl-4-hydroxyphenyl)acetylene]: Formation of a Conjugated Stable Polyradical

NISHIDE HIROYUKI, YOSHIOKA NAOKI, INAGAKI KATSUNARI, TSUCHIDA EISHUN

Macromolecules 21 ( 10 ) 3119 - 3120 1988.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

description is given of the synthesis of poly[(3,5-di-tert-butyl-4-hydroxyphenyl)acetylene] (1) and the formation of its polyradical. Experimental data shows that the absorption intensity of the oxidized 1 solution suggests formation of the phenoxy radical of 1 in high concentration and stays constant upon standing at room temperature over a day. This radical formation of 1 is in contrast to the radical formation of the corresponding low molecular phenols, e.g. 3,5-di-tert-butyl-4-hydroxycinnamate; the latter had been reported to give bisquinone methides irreversibly. The sterically crowded structure of 1 probably suppresses bond formation between unpaired electrons.

• Access to Document (DOI)

Complexation of Gadolinium Ion with Poly(methacrylic acid)s and Magnetic Properties of the Complexes

YOSHIOKA NAOKI, NISHIDE HIROYUKI, TSUCHIDA EISHUN

Inorganica Chemica Acta 128 ( 1 ) 135 - 138 1987.04

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The complexation of gadolinium (Gd3+) ion with poly(methacrylic acid) and its copolymers was studied. Poly(methacrylic acid-co-acrylamide) formed the tris(carboxylate)-coordinate gadolinium complex with an extra large complex formation constant, while poly(methacrylic acid) formed the biscoordinate complex. Transparent and flexible film containing a high proportion of Gd ion was prepared by casting the complex solution of poly(methacrylic acid-co-methylacrylate). The complexed Gd ion was uniformly dispersed in the film and showed paramagnetism. The formation and magnetic properties of the polymer-Gd complexes are discussed in comparison with those of the corresponding iron complexes.

• Access to Document (DOI)

Complexation Constants of Lanthanide Ions with Poly (Methacrylic Acid) and Its Copolymers

NISHIDE HIROYUKI, IZUSHI TADAHIKO, ARAI AKEMI,TSUCHIDA EISHUN

Journal of Macromolecular Science-Chemistry (Taylor & Francis)  24 ( 3-4 ) 343 - 351 1987.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Complexation of some lanthanide ions with poly(methacry1ic acid) and its copolymers was studied by potentiometric titration. Poly [methacrylic acid-co-oligo(ethy1ene oxide)rnethacrylate] and poly(methacrylic acid-co-acrylamide) formed tris-carboxylate coordinate lanthanide complexes with large overall complexation constants, while poly(methacrylic acid)s and copolymer with higher content of the methacrylic acid residue formed bis-coordinate ones. It was concluded that the comonomer residues in the copolymer chains decreased the steric hindrance for the complexation and/or acted as co-coordinating groups of the carboxylic group to lanthanide ions. Very large positive and favorable entropy changes were observed for the complexation with poly(methacry1ic acid) and its copolymers. This contribution of thermodynamic parameters to the complexation was contrary to that for the analogous monomeric methacrylic acid complex and is assumed to be induced by dehydration of the polymers through the lanthanide ion complexation.

• Access to Document (DOI)

Complexation of Europium Ion with Poly(Methacrylic Acid)s and Fluorescent Property of the Complexes

NISHIDE HIROYUKI, IZUSHI TADAHIKO, YOSHIOKA NAOKI, TSUCHIDA EISHUN

Polymer Bulletin (Springer)  14 ( 5 ) 387 - 392 1985.11

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The complexation of europium ion(Eu3+) with poly(methacrylic acid) and its copolymers was studied. Poly(methacrylic acid-co-acrylamide) formed the tris(carboxylate)-coordinate Eu complex with extra large overall complexation constant while poly(methacrylic acid)s did the bis-coordinate ones. Transparent and flexible film containing much Eu ion was prepared by casting the complex solution of poly(methacrylic acid-co-methylacrylate). On exposure to ultraviolet light (393 nm), the film relatively strongly fluorescenced a red color based on the tris-coordinate and uniformly dispersed Eu complex.

• Access to Document (DOI)

ポリメタクリル酸－ガドリニウム錯体の合成と性質

吉岡直樹、出石忠彦、西出宏之、篠原　功、土田英俊、渡辺　強、近　桂一郎

高分子論文集 42 ( 5 ) 301 - 304 1985.05

Research paper (scientific journal), Joint Work, Accepted

　View Summary

メタクリル酸-メチルアクリラート共重合体 (モル組成比約1: 3) とガドリニウムの錯体は, 溶媒キャスト法によりGd3+含量が多く, かつ柔軟で透明な膜を与えた. 錯形成したGd3+は常磁性 (室温, 2.7×10-2emu mol-1) で, 膜中に均一に分散していることを確認した。

• Access to Document (DOI)