Papers - Yoshioka, Naoki

Magnetic Characterization and Computational Modeling of Poly (phenylacetylene)s Bearing Stable Radical Groups

NISHIDE HIROYUKI, KANEKO TAKASHI, IGARASHI MASAKAZU, TSUCHIDA EISHUN, YOSHIOKA NAOKI, LAHTI M. PAUL

Macromolecules 27 ( 11 ) 3082 - 3086 1994.05

Research paper (scientific journal), Joint Work, Accepted

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The magnetic properties of poly(phenylacetylene)s with radical groups at the paraposition, poly[(3,5-di-tert-butyl-4-oxyphenyl)acetylene] (l),poly[[4-[(3,5-di-tert-butyl-4-oxyphenyl)(3,5-di-tert-butyl4-oxocyclohexa-2,5-dien-l-ylidene)methyl]phenyl]acetylene](2) and poly[[4-(N-tert-butyl-N-oxyamino)-phenyl]acetylene](3), were studied with a SQUID magnetometer. The magnetization and magnetic susceptibility indicated unexpected antiferromagnetic interactions between the radical sites. The exchange interaction observed in these conjugated polyradicals was discussed in connection with their computationally modeled structures.

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Theory and Experiment of Investigation of Exchange Interactions in Organic Molecules and Materials

LAHTI M. PAUL, LING CHRIS, YOSHIOKA NAOKI, ROSSITTO C. FRANK, VAN WILLIGEN HANS

Molecular Crystals and Liquid Crystals Science and Technology. Section A. 233 ( 1 ) 17 - 32 1993.12

Research paper (scientific journal), Joint Work, Accepted

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Intramolecular and intermolecular exchange in molecules and polymers is investigated computationally and experimentally, in order to identify structure-property relationships.

Theory and Experiment of Investigation of Exchange Interactions in Organic Molecules and Materials.

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Poly (phenylvinylene) and Poly(phenylenevinylene) with Nitroxide Radicals

NISHIDE HIROYUKI, KANEKO TAKASHI, KUZUMAKI YOSHIHIRO, YOSHIOKA NAOKI, TSUCHIDA EISHUN

Molecular Crystals and Liquid Crystals, Section A. 232 ( 1 ) 143 - 150 1993.12

Research paper (scientific journal), Joint Work, Accepted

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Poly(phenylvinylene) and poly(phenylenevinylene) with tert-butyInitroxide as a built-in radical group were synthesized. Precursor polymers were obtained by the polymerization of the corresponding acetylene and styrene derivatives by Rh and Pd catalysts. They were soluble in common solvents and their chemical oxidation under moderate condition gave the corresponding polyradicals.

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Poly[[4-(N-tert-butyl-N-hydroxyamino)phenyl]acetylene] and the Magnetic Property of its Radical　Derivative

NISHIDE HIROYUKI, KANEKO TAKASHI, YOSHIOKA NAOKI, AKIYAMA HARUHISA, IGARASHI MASUKAZU, TSUCHIDA EISHUN

Macromolecules 26 ( 17 ) 4567 - 4571 1993.08

Research paper (scientific journal), Joint Work, Accepted

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[4-(N-tert-Butyl-N-hydroxyamino)phenyl]acetylene (7) was synthesized and polymerized to yield a solvent-soluble polyacetylene: poly [[4-(N-tert-butyl-N-hydroxyamino)phenyl] acetylene] (8). Oxidation of the polymer gave its radical derivative: the ESR spectrum showed a broad signal only in the delta ms = ±1 region, and magnetic measurement with a SQUID magnetometer revealed an antiferromagnetic through space interaction.

Polymerization and Photoinitiation Behavior in the Light-Cured Dental Composite Resins

FUJIMORI YUKIO, KANEKO TAKASHI, KAKU TAKAHIKO, YOSHIOKA NAOKI, NISHIDE HIROYUKI, TSUCHIDA EISHUN

Polymers for Advanced Technologies 3 ( 8 ) 437 - 441 1992.12

Research paper (scientific journal), Joint Work, Accepted

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The polymerization behavior and photoinitiation process in the visible light‐cured dental composite resins were studied using ESR and IR spectroscopies. The concentration of methacryl propagating radical corresponded to the transmittance of irradiated light. While the radical was stable and long‐lived in the cured resin, its concentration quickly decreased in the oral cavity due to the ventilation of atmospheric oxygen accompanied by respiration. Camphorquinone radical in the presence of tertiary amine easily initiated the radical polymerization. A decrease in monomer consumption was explained by the inhibition effect of oxygen in the photoinitiation process. Post‐curing by the residual radical proceeded effectively in the deeper part of the resin.

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Synthesis and Magnetic Property of Polyacetylene Bearing pi-Conjugated Bis (diphenylene) phenylallyl Radical

NISHIDE HIROYUKI, YOSHIOKA NAOKI, SAITOH YUKOH, GOTOH RITSUKO, MIYAKAWA TAKESHI, TSUCHIDA EISHUN

Journal of Macromolecular Science-Pure and Applied Chemistry A29 ( 9 ) 775 - 786 1992.07

Research paper (scientific journal), Joint Work, Accepted

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m- and p Bis(diphenylene)propenylphenylacetylene (m-, p-8) were synthesized and polymerized with WCI6, MoCl5, and Rh catalyst, yielding solvent-soluble poly(phenylacetylene)s bearing a π-conjugated bis(di-phenylene)propenyl groups (m-, p-7a). The polymers gave their polyanion derivatives, which were electrolytically and chemically oxidized to yield the corresponding polyradicals (m-, p-7b). The polyradicals were chemically very stable due to the resonance stabilization of an unpaired electron whose spin concentration could be increased up to ca. 2 × 1023 spins per molar monomer unit. ESR spectroscopy suggested an antiferro-magnetic interaction between unpaired electrons.

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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

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[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.

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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

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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.

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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

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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.

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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

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(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.

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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

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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.

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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

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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。

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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

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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%.

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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

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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.

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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

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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.

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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

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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.

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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

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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.

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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

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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.

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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

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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.

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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

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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.

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