The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Goro Maruta - One of the best experts on this subject based on the ideXlab platform.
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Electron Spin Density distribution of a series of nitroxide radicals with five-member ring as studied by solid-state 1H, 2H and 13C NMR
Polyhedron, 2009Co-Authors: Yasuhiro Kawahashi, Goro Maruta, Sadamu TakedaAbstract:Abstract Stable nitroxide radicals are useful to construct molecular magnetic systems. Particularly, radicals substituted by –COOH and –CONH2 can be coordinated to magnetic metal ions and may be used as cladding reagents of gold nano-particles for modifying magnetism. Nitroxide molecules with unsaturated five-member ring have almost planner structure and Electron Spin delocalization may be expected. We determined the hyperfine coupling constants (hfcc) of 1H, 2H and 13C of a series of nitroxide radicals with five-member ring. Experimental values of hfcc were compared with those deduced from calculations based on Density functional theory. The Electron Spin Density distribution at β position of ring was sensitive to the ring structure, although the Electron Spin Density at β position is small compared with N–O site. Magnetic susceptibility and UV–Vis absorption spectra were also measured and discussed.
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Solid-State High-Resolution 1H and 2D NMR Study of the Electron Spin Density Distribution of the Hydrogen-Bonded Organic Ferromagnetic Compound 4-Hydroxyimino-TEMPO
Journal of the American Chemical Society, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Ron Imachi, Takayuki Ishida, Takashi Nogami, Kizashi YamaguchiAbstract:The Electron Spin Density distribution at hydrogen atoms of 4-hydroxyimino-2,2,6,6-tetramethylpiperidin-1-yloxyl (4-hydroxyimino-TEMPO), which has recently been shown to act as a molecular ferromagnet at low temperature, was determined in the crystalline phase on the basis of the temperature dependence of the Fermi contact shifts in the magic angle Spinning deuterium NMR spectrum to elucidate the mechanism of intermolecular magnetic interaction. There are two kinds of close contacts among neighboring radical molecules in the crystalline phase. An axial methyl hydrogen atom locates near a neighboring N−O radical group, and the hydroxyl group undergoes hydrogen bonding with another neighboring N−O radical group. The plus and minus signs of the observed hyperfine coupling constants AD of methyl deuteriums indicate that there are two different mechanisms for the Electron Spin Density distribution. Equatorial CD3 groups show negative coupling constants (AD = −0.24 MHz) induced by an intramolecular Spin polariz...
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Solid state high resolution nmr studies of Electron Spin densities in charge-transfer complex-based organic ferromagnets*
Synthetic Metals, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Kizashi Yamaguchi, Kazumasa Ueda, Toyonari SugimotoAbstract:Abstract Electron Spin Density distribution in the charge-transfer complexes of a series of 2-(4- N -alkylpyridinium)-4, 4,5,5-tetramethylimidazolin-1-oxyls with TCNQF 4 −· was investigated by the temperature dependence of the Fermi contact shifts in the solid state high resolution 1 H, 13 C and 19 F-NMR measurements.
Sadamu Takeda - One of the best experts on this subject based on the ideXlab platform.
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Electron Spin Density distribution of a series of nitroxide radicals with five-member ring as studied by solid-state 1H, 2H and 13C NMR
Polyhedron, 2009Co-Authors: Yasuhiro Kawahashi, Goro Maruta, Sadamu TakedaAbstract:Abstract Stable nitroxide radicals are useful to construct molecular magnetic systems. Particularly, radicals substituted by –COOH and –CONH2 can be coordinated to magnetic metal ions and may be used as cladding reagents of gold nano-particles for modifying magnetism. Nitroxide molecules with unsaturated five-member ring have almost planner structure and Electron Spin delocalization may be expected. We determined the hyperfine coupling constants (hfcc) of 1H, 2H and 13C of a series of nitroxide radicals with five-member ring. Experimental values of hfcc were compared with those deduced from calculations based on Density functional theory. The Electron Spin Density distribution at β position of ring was sensitive to the ring structure, although the Electron Spin Density at β position is small compared with N–O site. Magnetic susceptibility and UV–Vis absorption spectra were also measured and discussed.
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Solid-State High-Resolution 1H and 2D NMR Study of the Electron Spin Density Distribution of the Hydrogen-Bonded Organic Ferromagnetic Compound 4-Hydroxyimino-TEMPO
Journal of the American Chemical Society, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Ron Imachi, Takayuki Ishida, Takashi Nogami, Kizashi YamaguchiAbstract:The Electron Spin Density distribution at hydrogen atoms of 4-hydroxyimino-2,2,6,6-tetramethylpiperidin-1-yloxyl (4-hydroxyimino-TEMPO), which has recently been shown to act as a molecular ferromagnet at low temperature, was determined in the crystalline phase on the basis of the temperature dependence of the Fermi contact shifts in the magic angle Spinning deuterium NMR spectrum to elucidate the mechanism of intermolecular magnetic interaction. There are two kinds of close contacts among neighboring radical molecules in the crystalline phase. An axial methyl hydrogen atom locates near a neighboring N−O radical group, and the hydroxyl group undergoes hydrogen bonding with another neighboring N−O radical group. The plus and minus signs of the observed hyperfine coupling constants AD of methyl deuteriums indicate that there are two different mechanisms for the Electron Spin Density distribution. Equatorial CD3 groups show negative coupling constants (AD = −0.24 MHz) induced by an intramolecular Spin polariz...
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Solid state high resolution nmr studies of Electron Spin densities in charge-transfer complex-based organic ferromagnets*
Synthetic Metals, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Kizashi Yamaguchi, Kazumasa Ueda, Toyonari SugimotoAbstract:Abstract Electron Spin Density distribution in the charge-transfer complexes of a series of 2-(4- N -alkylpyridinium)-4, 4,5,5-tetramethylimidazolin-1-oxyls with TCNQF 4 −· was investigated by the temperature dependence of the Fermi contact shifts in the solid state high resolution 1 H, 13 C and 19 F-NMR measurements.
Kizashi Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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Solid-State High-Resolution 1H and 2D NMR Study of the Electron Spin Density Distribution of the Hydrogen-Bonded Organic Ferromagnetic Compound 4-Hydroxyimino-TEMPO
Journal of the American Chemical Society, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Ron Imachi, Takayuki Ishida, Takashi Nogami, Kizashi YamaguchiAbstract:The Electron Spin Density distribution at hydrogen atoms of 4-hydroxyimino-2,2,6,6-tetramethylpiperidin-1-yloxyl (4-hydroxyimino-TEMPO), which has recently been shown to act as a molecular ferromagnet at low temperature, was determined in the crystalline phase on the basis of the temperature dependence of the Fermi contact shifts in the magic angle Spinning deuterium NMR spectrum to elucidate the mechanism of intermolecular magnetic interaction. There are two kinds of close contacts among neighboring radical molecules in the crystalline phase. An axial methyl hydrogen atom locates near a neighboring N−O radical group, and the hydroxyl group undergoes hydrogen bonding with another neighboring N−O radical group. The plus and minus signs of the observed hyperfine coupling constants AD of methyl deuteriums indicate that there are two different mechanisms for the Electron Spin Density distribution. Equatorial CD3 groups show negative coupling constants (AD = −0.24 MHz) induced by an intramolecular Spin polariz...
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Solid state high resolution nmr studies of Electron Spin densities in charge-transfer complex-based organic ferromagnets*
Synthetic Metals, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Kizashi Yamaguchi, Kazumasa Ueda, Toyonari SugimotoAbstract:Abstract Electron Spin Density distribution in the charge-transfer complexes of a series of 2-(4- N -alkylpyridinium)-4, 4,5,5-tetramethylimidazolin-1-oxyls with TCNQF 4 −· was investigated by the temperature dependence of the Fermi contact shifts in the solid state high resolution 1 H, 13 C and 19 F-NMR measurements.
Toyonari Sugimoto - One of the best experts on this subject based on the ideXlab platform.
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Solid state high resolution nmr studies of Electron Spin densities in charge-transfer complex-based organic ferromagnets*
Synthetic Metals, 1999Co-Authors: Goro Maruta, Sadamu Takeda, Kizashi Yamaguchi, Kazumasa Ueda, Toyonari SugimotoAbstract:Abstract Electron Spin Density distribution in the charge-transfer complexes of a series of 2-(4- N -alkylpyridinium)-4, 4,5,5-tetramethylimidazolin-1-oxyls with TCNQF 4 −· was investigated by the temperature dependence of the Fermi contact shifts in the solid state high resolution 1 H, 13 C and 19 F-NMR measurements.
R. Blinc - One of the best experts on this subject based on the ideXlab platform.
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Belt-like C60− Electron Spin Density distribution in the organic ferromagnet TDAE-C60
Journal of Magnetism and Magnetic Materials, 2004Co-Authors: Denis Arčon, Tomaz Apih, Peter Jeglič, Ales Omerzu, R. BlincAbstract:Abstract The measured 13C NMR spectra in the organic ferromagnet TDAE-C60 have been simulated in the temperature range between room temperature and 4 K. It is shown that the sudden increase in the inhomogeneous 13C NMR line width and the corresponding changes of the 13C NMR line shape deep in the ferromagnetic phase can be explained by the freezing out of the pseudo-rotations of the axes of the Jahn–Teller distortions of the C60− ions. A strong correlation between Spin ordering and orientational ordering has been found.
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Beltlike C(60)(-) Electron Spin Density distribution in the organic ferromagnet TDAE-C(60).
Physical review letters, 2002Co-Authors: R. Blinc, Peter Jeglič, Tomaz Apih, Janez Seliger, Denis Arčon, Ales OmerzuAbstract:The observed huge increase in the width of the 1 3 C NMR spectra of TDAE-C 6 0 in the middle of the ferromagnetic phase at 10 K is due to a Jahn-Teller distortion of the C - 6 0 ions which becomes visible in view of the resulting changes in the Fermi contact Electron- 1 3 C NMR shifts. The shape of the 1 3 C spectra allows for a direct determination of the beltlike redistribution of the unpaired Electron Spin Density on the C - 6 0 ions, which is responsible for the relatively high ferromagnetic transition temperature in this purely organic system.