Magnetic Properties of Organic Stable Radicals. I. 2,2,6,6-Tetramethyl-4-Hydroxypiperidine-1-Oxyl

Yamauchi, Jun; Fujito, Teruaki; Ando, Eiji; Nishiguchi, Hiroaki; Deguchi, Yasuo

doi:10.1143/jpsj.25.1558

Cited by 24 publications

(4 citation statements)

References 6 publications

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“…As shown in Figure S5 (Supporting Information), the 4HTB reagents show monotonous Curie–Weiss behavior above 1.8 K. On the other hand, the two TEMPOL reagents and DPPH-B show magnetic behavior due to the spin–spin interaction, and then, it may cause narrower analytical temperature ranges. These low-temperature magnetic behaviors were similar to those reported by Yamauchi et al or Fujito et al , DPPH-C (containing benzene molecules) shows monotonous Curie–Weiss behavior above 1.8 K and the 4HTB reagents; however, much larger Θ value of the DPPH-C reagent might cause a narrower analytical temperature region. Θ is the intrinsic property of each compound.…”

Section: Resultssupporting

confidence: 89%

“…One of the major methods for synthesis of TEMPOL is oxidation of the triacetone amine in the presence of a metallic catalyst and hydrogen peroxide . The possible solvent used for purification is ethereal alcohol, acetone, ethyl acetate, ether, methanol, or ethanol. ,− The traces of the solvent for purification of the TEMPOL reagents and the additional peak on the Q-band EPR of TEMPOL-A could not be observed from the NMR measurements. However, there were differences between the spectra of two TEMPOL reagents, as shown in Figure S11a (Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

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Absolute Quantification of Pure Free Radical Reagents by Combination of the Effective Magnetic Moment Method and Quantitative Electron Paramagnetic Resonance Method

2022

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An absolute quantitative analysis of free radicals by combining the effective magnetic moment method and the quantitative electron paramagnetic resonance [qEPR] method is proposed. This combined method utilizes the advantages of both the analytical methods and compensates for their disadvantages. In the effective magnetic moment method, the magnetic moment under a constant magnetic field is measured accurately using a superconducting quantum interference device. The qEPR method compares a "primary standard sample" and "secondary standard sample". The effective magnetic moment method was used to determine the purity of the primary standard sample. The qEPR method realizes a simple purity analysis of free-radical reagents with traceability to the International System of Units (SI). The purity of the free radicals by the qEPR method for pure 4-hydroxy-2,2,6,6tetramethylpiperidine 1-oxyl benzoate [4HTB], 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine [TEMPOL], and di(phenyl)-(2,4,6trinitrophenyl)iminoazanium [DPPH] reagents was obtained with a relative expanded uncertainty of 0.7% for 4HTB to 1.5% for the DPPH. These small uncertainties were almost equal to those of the purity of the primary standard samples and were achieved by adopting in-plane positioning of the measured sample perpendicular to the cylindrical axis of the sample space of the superconducting quantum interference device. Some purity values of the free radicals for these reagents differed from those stated by the manufacturers. This combined method enables short-time quality control of pure radical reagents, instead of quality control by separation analytical methods or titrations.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Absolute Quantification of Pure Free Radical Reagents by Combination of the Effective Magnetic Moment Method and Quantitative Electron Paramagnetic Resonance Method

2022

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“…The ESR-active molecules belonging to the uppermost spectrum are situated in small clusters attached to the first temperatures in the solid phase (26)(27)(28), but the retention of ESR inactivity up to the desorption temperature of 170 layer of inactive clusters, and the exchange rate is low. After preadsorption of xenon, the number of ESR-active molecules K (see Fig.…”

Section: Resultsmentioning

confidence: 99%

ESR and TPD Investigations of the Adsorption of Di-tert-butyl Nitroxide on Au(111) and NiO(111). Evidence for Long-Range Interactions

Katter

Risse

Schlienz

et al. 1997

Journal of Magnetic Resonance

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“…22 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) is a typical radical molecule used as a spin probe. 23 Since TEMPOL shows a magnetic transition to antiferromagnetism from paramagnetism around 6 K, 24 if this is confined in nanospaces, magnetic anomalies are expected to be observed as for oxygen molecules confined in nanospaces.…”

Section: Introductionmentioning

confidence: 99%

Magnetism of Organic Radical Molecules Confined in Nanospace of Single-Wall Carbon Nanohorn

et al. 2007

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The temperature and magnetic field dependences of magnetic characteristics of an organic radical (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL)) adsorbed on oxidized single-wall carbon nanohorn (ox-NH) were studied with a SQUID magnetometer and an electron spin resonance (ESR) spectrometer. TEMPOL molecules adsorbed on ox-NH do not form any ordered structures, but the formation of disordered clusters was suggested because of intensive restriction by nanoconfinement. Exchange interaction of TEMPOL adsorbed on ox-NH was weaker than that of bulk TEMPOL. Slow relaxation phenomena of magnetization and paramagnetic behaviors were observed by confinement of TEMPOL in nanospace.

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Magnetic Properties of Organic Stable Radicals. I. 2,2,6,6-Tetramethyl-4-Hydroxypiperidine-1-Oxyl

Cited by 24 publications

References 6 publications

Absolute Quantification of Pure Free Radical Reagents by Combination of the Effective Magnetic Moment Method and Quantitative Electron Paramagnetic Resonance Method

Absolute Quantification of Pure Free Radical Reagents by Combination of the Effective Magnetic Moment Method and Quantitative Electron Paramagnetic Resonance Method

ESR and TPD Investigations of the Adsorption of Di-tert-butyl Nitroxide on Au(111) and NiO(111). Evidence for Long-Range Interactions

Magnetism of Organic Radical Molecules Confined in Nanospace of Single-Wall Carbon Nanohorn

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