Long-range proton hyperfine coupling

King, Frederick W.

doi:10.1021/cr60300a001

Cited by 74 publications

(21 citation statements)

References 79 publications

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“…Further protonic weaker interactions generating minor splitting in the spectral trace are observed and according to Kira's [29] and King's [30] work can be assigned to H in γ position. In both these papers, the symmetry of the crystal has been deeply analysed and an extensive study on spin delocalisation and spin polarisation has been proposed.…”

Section: Ch 2 Ch Ch 2 Radical Amentioning

confidence: 74%

Electron beam radiation effects on UHMWPE: an EPR study

Brunella¹,

Paganini²

2011

Magnetic Reson in Chemistry

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Electron paramagnetic resonance (EPR) technique has been employed to detect and characterise a series of different radical species generated in ultra-high molecular weight polyethylene (UHMWPE) via electron beam irradiation. Three different radical species have been found and assigned on the basis of their EPR spectra and of the related computer simulations. A secondary alkyl species, the prevalent one, is present immediately after irradiation, an allyl species appears only 24 h after irradiation when the alkyl species disappears.The third species, clearly visible at high microwave power only, has been observed for the first time and assigned to a tertiary alkyl carbon radical, whose formation is strictly connected with a Y-shape crosslink and a migration of the unpaired electron on a carbon atom localised in an adjacent position.

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Section: Ch 2 Ch Ch 2 Radical Amentioning

confidence: 74%

Electron beam radiation effects on UHMWPE: an EPR study

Brunella¹,

Paganini²

2011

Magnetic Reson in Chemistry

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“…Since this extra splitting is absent in comparable oxygen-centered adducts of M,PO (76) (e.g., tert-butoxyl, Fig. 2) it is expected that this y-hydrogen splitting originates from one of the hydrogen nuclei attached to the 3-position of the pyrrolidine ring (which may form a favourable geometric "W-type" arrangement with the arninoxyl p, orbital) (77). It is noteworthy that of the oxyl family of DMPO spin adducts the hydroxyl adduct is anomalous in that it does not exhibit the characteristic small doublet splitting in organic (or aqueous) solvents (9).…”

Section: Resultsmentioning

confidence: 97%

The first ¹H and ¹⁴N ENDOR spectra of an oxygen-centered radical adduct of DMPO-type nitrones

Haire¹,

Oehler²,

Goldman³

et al. 1988

Can. J. Chem.

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. Can. J. Chem. 66, 2395 (1988). ~, We report the first 'H and ' 4~ electron nuclear double resonance (ENDOR) spectra of oxygen-centered radical adducts (i.e.,derived from the addition of tert-butoxyl radicals) of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as well as the related cyclic nitrones: 4-phenyl-5,5-dimethyl-1-pyrroline-N-oxide (4-Ph-DMPO) and 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO).Features of the electron paramagnetic resonance (EPR) and ENDOR spectra of these cyclic (pyrrolidine) aminoxyl (nitroxide) species along with some deuterated analogues in liquid toluene solutions are highlighted. For instance, we found several long-range y-H hyperfine splittings (HFS's) detectable by ENDOR that provide unique spectral signatures for these radical adducts. Conformational assignments of the pyrrolidine aminoxyl structures based upon the EPR and ENDOR findings are also discussed. Signs of the various hyperfine splittings (i.e., aN, a;, a : ) investigated by cross-relaxation intensity sequence patterns (CRISP) in the ENDOR spectra are also presented. [Traduit par la revue]

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“…Elemental analyses were performed on a Perkin-Elmer 240C analyzer. 1 H NMR spectra were recorded on a Bruker AV 400 instrument, while IR spectra were recorded as KBr discs on a Nicolet 560 ESP FT-IR spectrometer. X-ray measurements were taken on a Bruker Smart 1000 CCD diffractometer using graphite monochromated Mo Ka (k = 0.71073 Å ) radiation.…”

Section: Methodsmentioning

confidence: 99%

“…Replacement of the hydrogen atoms by other substituents alters both the steric and electric influences of the g 5 -cyclopentadienyl ring, resulting in differing reactivity and stability of the substituted cyclopentadienyl transition metal complexes [1][2][3][4][5][6][7]. We report herein the reaction of a series of substituted tetramethylcyclopentadiene with Fe(CO) 5 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structures of substituted tetramethylcyclopentadienyl dinuclear metal carbonyl compounds

Zhao

et al. 2010

Transition Met Chem

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Cyclopentadienes (C 5 Me 4 R) [R = Allyl (1), n-Butyl (2), Benzyl (3), and PhMe-2 (4)] reacted with Fe(CO) 5 in refluxing xylene to give new substituted tetramethylcyclopentadienyl dinuclear iron carbonyl complexes [(g 5 -C 5 Me 4 R)Fe(CO)(l-CO)] 2 [R = Allyl (5), n-Butyl (6), Benzyl (7), and PhMe-2 (8)], respectively. The four new complexes 5-8 were characterized by elemental analysis, IR, and 1 H NMR spectra. The crystal structures of complexes 5-7 were determined using single crystal X-ray diffraction. The crystal structure of complex 5 showed that allyl underwent isomerization to give the corresponding methyl-vinyl. A possible mechanism is discussed. The X-ray crystal structures of complexes 5, 6, and 7 confirm the structure with bridging and terminal CO groups. They show that the steric effects of substituents influence the Fe-Fe bond distances of the complexes.

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Long-range proton hyperfine coupling

Cited by 74 publications

References 79 publications

Electron beam radiation effects on UHMWPE: an EPR study

Electron beam radiation effects on UHMWPE: an EPR study

The first ¹H and ¹⁴N ENDOR spectra of an oxygen-centered radical adduct of DMPO-type nitrones

Synthesis and structures of substituted tetramethylcyclopentadienyl dinuclear metal carbonyl compounds

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Long-range proton hyperfine coupling

Cited by 74 publications

References 79 publications

Electron beam radiation effects on UHMWPE: an EPR study

Electron beam radiation effects on UHMWPE: an EPR study

The first 1H and 14N ENDOR spectra of an oxygen-centered radical adduct of DMPO-type nitrones

Synthesis and structures of substituted tetramethylcyclopentadienyl dinuclear metal carbonyl compounds

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The first ¹H and ¹⁴N ENDOR spectra of an oxygen-centered radical adduct of DMPO-type nitrones