Details of a Researcher - Yoshioka, Naoki

Papers - Yoshioka, Naoki

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Synthesis and magnetic properties of 2,2,4-and 2,2,6-triphenyl-1,2-dihydroquinoline-N-oxyl derivatives

Yao Masaru, Shibuya Hideki, Kato Takashi, Inoue Hidenari, Yoshioka Naoki

Polyhedron (PERGAMON-ELSEVIER SCIENCE LTD) 24 ( 16-17 ) 2828 - 2834 2005.11

Research paper (scientific journal), Joint Work, Accepted, ISSN 0277-5387

The synthesis and magnetic properties of two novel aromatic Ar-oxyl radicals based on the quinoline skeleton, 2,2,4-triphenyl-1,2-dihydroquinoline-N-oxyl (1) and 2,2,6-triphenyl-1,2-dihydroquinoline-N-oxyl (2) are described. ESR measurements and DFT calculations for 1 and 2 revealed that their spins were delocalized over the pi-systems. Based on the SQUID measurement, 1 exhibited a weak antiferromagnetic interaction in its crystal. For 2, two crystalline phases were obtained, and the alpha-phase of 2
exhibited a paramagnetic behavior; however, the beta-phase of 2 showed a weak ferromagnetic interaction. The observed ferromagnetic interaction was analyzed by a dimer model, and the singlet-triplet gap was estimated to be 2J = +2.5 cm(-1).

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Synthesis of Cationic Water-Soluble Esters of Chlorin e(6)

Taima Hidetoshi, Okubo Akihiro,Yoshioka Naoki, Inoue Hidenari

Tetrahedron Letters (PERGAMON-ELSEVIER SCIENCE LTD) 46 ( 24 ) 4161 - 4164 2005.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 0040-4039

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Formation of a One-Dimensional Stacking Structure of pi-Conjugated Nitroxyl Radical Bearing a 1,2,5-Thiadiazole Ring and its Magnetic Property

Yao Masaru, Asakura Satoshi, Abe Masahiro, Inoue Hidenari, Yoshioka Naoki

Crystal Growth & Design (AMER CHEMICAL SOC) 5 ( 2 ) 413 - 417 2005.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 1528-7483

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Novel Aromatic N-oxyl Radical Based on the Benzo[g]quinoline Skeleton: Synthesis and Intermolecular Ferromagnetic Interaction

Yao Masaru, Inoue Hidenari, Yoshioka Naoki

Chemical Physics Letters (ELSEVIER SCIENCE BV) 402 ( 1-3 ) 11 - 16 2005.01

Research paper (scientific journal), Single Work, Accepted, ISSN 0009-2614

A novel stable organic radical,2,2-diphenyl-1,2-dihydrobenzo[g]quinoline-N-oxyl (2), has been synthesized and structurally characterized in order to examine the ring
extension effect on the known derivative, 2,2-diphenyl-1,2-dihydroquinoline-N-oxyl (1). Based on SQUID measurement, 2 exhibited a ferromagnetic interaction obeying the Bleaney-Bowers equation with 2J = +4.6 cm(-1). The X-ray analysis revealed an intermolecular edge-edge association of the aryl ring and N-oxyl moiety in the crystal of 2. The bifurcated edge-edge contacts between the alpha-spin site (nitroxyl O atom) and the beta-spin site (aryl-H atoms) are responsible for the ferromagnetic interaction of 2.

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Amphiphilic meso-Disubstituted Porphyrins: Synthesis and the Effect of the Hydrophilic Group on Absorption Spectra at the Air-Water Interface

Yao Masaru, Iwamura Yuko,Inoue Hidenari, Yoshioka Naoki

Langmuir (AMER CHEMICAL SOC) 21 ( 2 ) 595 - 601 2005.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 0743-7463

Five amphiphilic meso-disubstituted porphyrins bearing one polar group were synthesized. and their monolayer films were prepared. Their limiting molecular areas obtained from pi-A isotherms were 0.5-0.6nm(2), which were smaller than those of the corresponding meso-tetrasubstituted porphyrins. At the air-water interface, the disubstituted porphyrins showed a broad band in visible absorption spectra compared with the solution state, and the red shift of the Soret band exhibited a significant dependence on the kind of hydrophilic groups at the meso positions. Interestingly, the monolayer of the disubstituted porphyrin bearing a carboxyphenyl group (1-CO2H) showed a blue shift of the Soret band by adding cadmium chloride to the subphase, and the spectra varied upon multilayer deposition. The observed phenomena were interpreted by using the exciton theory. The effect of hydrophilic substituents on the absorption Spectra of disubstituted porphyrin monolayers is discussed.

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An Ideal One-Dimensional Antiferromagnetic Spin System Observed in Hydrogen-Bonded Naphth[2,3-d]imidazol-2-yl Nitronyl Nitroxide Crystal:The Role of the Hydrogen Bond

NAGASHIMA HIDEAKI, INOUE HIDENARI, YOSHIOKA NAOKI

Journal of Physical Chemistry B 108 ( 20 ) 6144 - 6151 2004.05

Research paper (scientific journal), Joint Work, Accepted

A novel stable organic radical, 2-(naphth[2,3-d]imidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide (4), has been designed, synthesized, and structurally characterized to examine the effects of ring extension on 2-(benzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide (2). 4 forms four-centered intramolecular and intermolecular hydrogen bonds, and the hydrogen bonds are repeated along the c-axis to form a one-dimensional chain structure. This hydrogen-bonding motif contrasts that of 2, which forms three-centered intramolecular and intermolecular hydrogen bonds. The magnetic susceptibility measurement of 4 reveals that an antiferromagnetic interaction is dominant between spins, and the magnetic behavior is reproduced by the Bonner-Fisher model with J = −14 cm-1. Because each hydrogen-bonded chain is well isolated, a magnetic interaction pathway was thought to exist along the chain direction. Two interaction pathways have been assumed: (i) through-space interaction between the O atoms of the nitroxide and (ii) through the NH···ON intermolecular hydrogen bond. We have concluded that pathway (i) is predominant, by considering the identical magnetic data between the NH nondeuterated and deuterated samples. The hydrogen bond mainly has a role in crystal scaffolding.

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DNA-Binding Properties of Iron(II) Mixed-Ligand Complexes Containing 1,10-Phenanthroline and Dipyrido[3,2-a : 2 ',3 '-c]phenazine

MUDASIR, WIJAYA, Karna, YOSHIOKA NAOKI, INOUE HIDENARI

Zeitschrift für Naturforschung B (VERLAG Z NATURFORSCH) 59 ( 3 ) 310 - 318 2004.03

Research paper (scientific journal), Joint Work, Accepted

An iron(II) mixed-ligand complex with 1,10-phenanthroline (phen) and dipyrido[3,2-a:2’,3’- c]phenazine (dppz), [Fe(phen)2(dppz)]2+, has been synthesized. The DNA-binding properties of the mixed-ligand complex have been studied in terms of equilibrium binding constant, thermodynamic parameter, thermal denaturation as well as Pfeiffer effect upon binding to DNA. The spectrophotometric titration of [Fe(phen)2(dppz)]2+ with calf thymus DNA (ct-DNA) has shown that the iron(II) mixed-ligand complex binds effectively to ct-DNA in an intercalation mode as indicated by remarkable hypochromicity (ca. 36%) and moderate bathochromic shift (8 nm) of the absorption spectra. This intercalative mode is supported by a significant increase (Δ Tm = 21 °C) in the melting temperature (Tm) of ct-DNA at R([complex]/[ct-DNA]) = 1.5. The binding of [Fe(phen)2(dppz)]2+ to ct-DNA is entropically driven as characterized by a positive enthalpy change and a large negative TΔ S term. An intense CD signal in the UV and visible region develops upon addition of ct-DNA to the racemate solution of [Fe(phen)2(dppz)]2+. This has revealed that a shift in diastereomeric inversion equilibrium takes place in the solution to yield an excess of one enantiomer of the DNA-iron(II) complex (Pfeiffer effect). The striking resemblance of the CD spectral profiles to those of the corresponding Δ -enantiomer indicates that Δ -[Fe(phen)2(dppz)]2+ is preferentially bound to ct-DNA

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Metamagnetic Behavior Observed in Purely Organic 5-Azaindol-2-yl Nitronyl Nitroxide Brick-Wall Architecture

NAGASHIMA HIDEAKI, FUJITA SHIN'YA, INOUE HIDENARI, YOSHIOKA NAOKI

Crystal Growth & Design 4 ( 1 ) 19 - 21 2004.01

Research paper (scientific journal), Joint Work, Accepted

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Interaction of Dicationic Bis(imidazoliumyl)porphyrinatometals with DNA

Yamamoto Tomoko, Tjahjono Hadi Daryono, Yoshioka Naoki, Inoue Hidenari

Bulletin of the Chemical Society of Japan 76 ( 10 ) 1947-1955 - 1955 2003.10

Research paper (scientific journal), Joint Work, Accepted

A pair of dicationic metalloporphyrins with only two meso-substituents, i.e. copper(II) and zinc(II) complexes of 5,15-bis(1,3-dimethylimidazolium-2-yl)porphyrin (H2-1), have been synthesized by insertion reaction of the metal ions. Interactions of [5,15-bis(1,3-dimethylimidazolium-2-yl)porphyrinato]copper(II) (Cu-I) and [5,15-bis(1,3-dimethylimidazolium-2-yl)porphyrinato]zinc(II) (Zn-1) with calf thymus DNA (CT-DNA) and double-helical synthetic polynucleotides ([poly(dA-dT)]2 and [poly(dG-dC)]2) have been studied by melting temperature, viscometric, visible absorption, CD and MCD spectroscopic measurements. The copper(II) complex, Cu-1, intercalates into the base pairs of DNA such as CT-DNA, [poly(dA-dT)]2 and [poly(dG-dC)]2 to stabilize the DNA duplex due to its high affinity for them. In contrast, the zinc(II) complex, Zn-1, binds edge-on to CT-DNA, [poly(dA-dT)]2 and [poly(dG-dC)]2 as an outside binder. The binding constant of Cu-1 to DNA is in the order of 106 M-1 in a phosphate buffer (pH 6.8) at 25 °C, while that of Zn-1 ranges from 104 to 10 5 M-1 under the same experimental conditions. The binding of Cu-1 and Zn-1 to DNA is entropically driven, although that of H 2-1 is enthalpically driven. As a result, it has been revealed that the kind of central metal ions in dicationic metalloporphyrins influences the binding properties of the dicationic porphyrin to DNA.

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Synthesis, Solution ESR Spectra, and Solid-State Magnetic Property of Thieno[3,4-d]imidazol-2-yl Nitronyl Nitroxide

NAGASHIMA HIDEAKI, INOUE HIDENARI, YOSHIOKA NAOKI

Polyhedron 22 ( 14-17 ) 1823 - 1827 2003.07

Research paper (scientific journal), Joint Work, Accepted

2-(Thieno[3,4-d]imidazol-2-yl)-1,3-dihydro-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (2) was designed and synthesized. Compound 2 was stable in a solid state but unstable in organic solvents. Solution ESR spectra showed that small spin densities locate on the four methyl groups and the thieno[3,4-d]imidazole ring, though most of spin densities localized on the ONCNO moiety. Magnetic susceptibility measurement showed that antiferromagnetic interaction is dominant which could be fitted to the Bonner–Fisher model with J=−8.8 cm−1.

A new nitronyl nitroxide derivative carrying thieno[3,4-d]imidazole ring was designed and synthesized. It was stable in a solid state but unstable in organic solvents. Solution ESR spectra showed that small spin densities locate on the four methyl groups and the thieno[3,4-d]imidazole ring. Magnetic susceptibility measurement showed that antiferromagnetic interaction is dominant which could be fitted to the Bonner–Fisher model with J=−8.8 cm−1.

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Synthesis and Physicochemical Properties of Some 5,15-Diarylporphyrin Derivatives

YAO MASARU, KAMISHIRO MASAFUMI, INOUE HIDENARI, YOSHIOKA NAOKI

Polyhedron 22 ( 14-17 ) 2281 - 2285 2003.07

Research paper (scientific journal), Joint Work, Accepted

Several derivatives of meso-5,15-diarylporpyrins (1–4) and their metal complexes were prepared and their physicochemical properties were studied. Their magnetic properties were characterized by SQUID magnetometer. The temperature dependence of the molar magnetic susceptibility of the copper and vanadyl complex of 5,15-diphenylporphyrin (1-Cu, 1-VO) obeyed the Curie law and were almost identical with those of corresponding meso-tetraphenyl derivatives. In addition to the magnetic properties of disubstituted porphyrins, the properties of Langmuir film of meso-disubstituted porphyrins 2-H2 were investigated by π–A isotherms and visible absorption spectra.

meso-Diphenylmetalloporpyrins (M=Cu, VO) were prepared and their magnetic properties were characterized. These derivatives obeyed the Curie law and were almost identical with those of corresponding meso-tetraphenyl derivatives. Prepared amphiphilic diarylporphyrin showed a large red shift pattern in the visible absorption spectrum at air–water interface, compared with in the solution.

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Theoretical study on magnetic properties of imidazolyl nitronyl nitroxide derivatives

NAGASHIMA HIDEAKI, INOUE HIDENARI, YOSHIOKA NAOKI

Synthetic Metals 137 ( 1-3 ) 1257 - 1258 2003.04

Research paper (scientific journal), Joint Work, Accepted

imidazol-2-yl nitronyl nitroxideとbenzimidazol-2-yl nitronyl nitroxideは、水素結合により連鎖構造を形成し、前者は強い反強磁性、後者は強磁性相互作用が存在する。構造－磁性相関より、磁気的相互作用として水素結合を介する経路と、空間を介した磁気軌道の接近による経路が考えられる。DFT計算を活用してこれら２つのラジカル分子では、磁気軌道の直積的な接近が主要な経路であることを明らかにした。

Coexistence of an Antiferromagnetically Coupled Dimer and Isolated Paramagnetic Spin in 4-Azaindol-2-yl Nitronyl Nitroxide Crystal

NAGASHIMA HIDEAKI, HASHIMOTO NORIKO, INOUE HIDENARI, YOSHIOKA NAOKI

New Journal of Chemistry (Royal Society of Chemistry) 27 ( 5 ) 805 - 810 2003.04

Research paper (scientific journal), Joint Work, Accepted

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Effect of Hydrophilic Group on Absorption Spectra of meso-Disubstituted Porphyrin LB Films

YAO MASARU, ISHIDA NAOMI, INOUE HIDENARI, YOSHIOKA NAOKI

Synthetic Metals 137 ( 1-3 ) 917 - 918 2003.04

Research paper (scientific journal), Joint Work, Accepted

ESR Study and Deuteration Effect on the Magnetic Property of Hydrogen-Bonded Benzimidazole Nitronyl Nitroxide

NAGASHIMA HIDEAKI, IRISAWA MUNETOSHI, YOSHIOKA NAOKI, INOUE HIDENARI

Molecular Crystals and Liquid Crystals 376 ( 1 ) 371 - 376 2002.03

Research paper (scientific journal), Joint Work, Accepted

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Self-Assembly of a Porphyrin Array via the Molecular Recognition Approach: Synthesis and Properties of a Cyclic Zinc(II) Porphyrin Trimer Based on Coordination and Hydrogen Bonding

IKEDA CHUSAKU, TANAKA YUICHI, FUJIHARA TAKESHI, ISHII YOKO, USHIYAMA TAKESHI, YAMAMOTO KIMIHISA, YOSHIOKA NAOKI, INOUE HIDENARI

Inorganic Chemistry 40 ( 14 ) 3395 - 3405 2001.08

Research paper (scientific journal), Joint Work, Accepted

Self-assembly of [5-(pyrazol-4-yl)-10,20-bis(p-tolyl)-15- (2-ethoxycarbonylphenyl)porphyrinato]-zinc(II) (1), designed to have both a coordination site and a hydrogen bonding site, leads to a stable cyclic trimer array where coordination of the pyrazole nitrogen to the zinc(II) ion as well as hydrogen bonding between carbonyl oxygen and pyrazole NH holds each zinc(II) porphyrin. The recognition event for pyrazole has been confirmed preliminarily in the model studies using [5-(2-ethoxycarbonylphenyl)tris(p-tolyl)porphyrinato]-zinc(II) (3). The zinc(II) porphyrin 3 has large affinity for pyrazole due to the hydrogen bond between pyrazole and the 2-ethoxycarbonyl group in addition to the coordination bonding accompanied by the conformational change of the ethoxycarbonyl group in the coordination process. The 1H NMR, IR, and UV−vis spectra of 1 and its ESI-MS and VPO measurements have revealed the cyclic trimer structure with an overall association constant of 6.0 × 1013 M-2 at 22 °C. The contribution of the hydrogen bond to the total free energy change in trimer formation is estimated to be 7.5 kcal/mol based on a reference trimer system without a hydrogen bonding site. The trimer geometry causes characteristic exitonic interaction between porphyrin units to yield a broad Soret band which is deconvoluted into four components by UV−vis and MCD spectral analyses. Electrochemical measurements have shown that only the first ring-oxidation process proceeds stepwise in the trimer.

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Stress-Induced Ligand Field Distortion and Consequent Multi-Mode Spin Crossover Behavior in Fe(phen)2(NCS)2 and Fe[HB(pz)3]2

TSUCHIYA NAOKO, TSUKAMOTO ATSUSHI, OHSHITA TADASHI, ISOBE TETSUHIKO, SENNA MAMORU, YOSHIOKA NAOKI, INOUE HIDENARI

Solid State Sciences 3 ( 6 ) 705 - 714 2001.08

Joint Work, Accepted

Changes in the nature of spin crossover caused by mechanical stressing exerted on the crystalline powders were studied for FeII(phen)2(NCS)2 (phen = 1,10-phenanthroline) and FeII[HB(pz)3]2 (pz = pyrazol-1-yl) by means of a multi-component fitting of the temperature dependence of magnetic susceptibility. The analysis revealed the development and broadening of the ligand field distribution as a consequence of mechanical stressing. This was confirmed by the broadening of Mössbauer and far-infrared spectra.

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Ligand-Exchange Reaction between Tris(1,10-phenanthroline)metal(II) and　Tris(4,7-diphenyl-　1,10-phenanthroline)metal(II) Ions

MUDASIR, YOSHIOKA NAOKI, INOUE HIDENARI

Journal of Coordination Chemistry 52 ( 4 ) 333 - 344 2001.07

Research paper (scientific journal), Joint Work, Accepted

The ligand exchange reaction between [M(phen)3]2+ and [M(DIP)3]2+ (where M is the same and M = FeII or NiII, phen = 1,10-phenanthroline, DIP = 4,7-diphenyl-1,10-phenanthroline) has been investigated by reversed phase ion-paired chromatography (RP-IPC). The effect of pH and solvent on the ligand-exchange reaction is studied by monitoring the variation in chromatograms with time after mixing. The results have shown that the ligand exchange reaction between [M(phen)3]2+ and [M(DIP)3]2+ takes place in the pH range of 3–8 and the rate of reaction for nickel(II) complexes is about two times slower than that for iron(II) complexes. Experiments on the effect of various solvents on the ligand-exchange reaction have revealed that the rate of reaction is enhanced by the solvent in the following order: (CH3)2CO > CHCl3 ≥ CH2Cl2 > CH3CN > CH3OH. Elemental analysis and UV-visible spectroscopy confirmed that the products obtained from the ligand-exchange reaction are mixed-ligand complexes containing phen and DIP ligands, i.e., [M(phen)2(DIP)]2+ and [M(phen)(DIP)2]2+.

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Metallopyrazoliumylporphyrins with Calf Thymus DNA

TJAHJONO H. DARYONO, MIMA SHUNSUKE, AKUTSU TAKEHIRO, YOSHIOKA NAOKI, INOUE HIDENARI

Journal of Inorganic Biochemistry 85 ( 2-3 ) 219 - 228 2001.06

Research paper (scientific journal), Joint Work, Accepted

The interaction of transition metal complexes of cationic porphyrins bearing five membered rings, meso-tetrakis(1,2-dimethylpyrazolium-4-yl)porphyrin (MPzP, M=MnIII, NiII, CuII or ZnII), with calf thymus DNA (ctDNA) has been studied. Metalloporphyrins NiPzP and CuPzP are intercalated into the 5′GC3′ step of ctDNA. MnPzP is bound edge-on at the 5′TA3′ step of the minor groove of ctDNA, while ZnPzP is bound face-on at the 5′TA3′ step of the major groove of ctDNA. The binding constants of the metalloporphyrins to ctDNA range from 1.05×105 to 2.66×106 M−1 and are comparable to those of other reported cationic porphyrins. The binding process of the metallopyrazoliumylporphyrins to ctDNA is endothermic and entropically driven. These results have revealed that the kind of central metal ions of metalloporphyrins influences the binding characteristics of the porphyrin to DNA.

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Synthesis and Magnetic Properties of Nitronyl Nitroxide Radicals Carrying a Purine Ring

NAGASHIMA HIDEAKI, YOSHIOKA NAOKI, INOUE HIDENARI

Polyhedron 20 ( 11-14 ) 1151 - 1155 2001.05

Research paper (scientific journal), Joint Work, Accepted

2-(Purin-8-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide (Pu-NN) was designed and synthesized. Two crystalline phases (α- and β-phases) exhibiting different IR spectral patterns at the νNH region were obtained depending on the crystallizing condition. The temperature dependences of the magnetic susceptibility of these two phases followed Curie–Weiss law with θ=−5.7 K (α-phase) and θ=−0.3 K (β-phase) implying intermolecular antiferromagnetic interaction, which were quite different from that of parent benzimidazole derivative, 2-(benzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H- imidazolyl-1-oxyl-3-oxide that formed a 1-D ferromagnetic chain induced by an intermolecular hydrogen bonding.

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