Temperature dependence of the reorientation of the ND3+ group in α-glycine

Müller-Rowat, Carmen; Haeberlen, Ulrich; Rowat, J.; Colpa, J.P.

doi:10.1016/0301-0104(85)85095-3

Cited by 8 publications

(1 citation statement)

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“…Ulrich Haeberlen's group contributed significantly to the progress in this field [4]. Starting with an investigation of an ND3 group in an amino acid [5] some experimental and theoretical work on the deuteron nuclear magnetic resonance (NMR) spectra of single crystals containing CD3 groups followed [6][7][8][9][10]. Also relaxation phenomena were treated in the group [11].…”

Section: Introductionmentioning

confidence: 99%

Spin-lattice relaxation of deuterated methyl groups: Implications of the pauli principle

Diezemann

1999

Appl. Magn. Reson.

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The high-field spin-lattice relaxation of deuterated methyl groups undergoing rotational tunneling is investigated theoretically. It is found that for systems showing a tunneling frequency comparable to accessible Larmor frequencies the relaxation to equilibrium of the Zeeman energy does not follow a simple exponential time dependence even in powdered samples due to a finite coupling to the relaxation of the tunneling system. This finding contrasts to the high-temperature behavior of reorienting methyl groups which undergo simple exponential relaxation. The nonexponentiality has its origin in the statistical coupling of the three deuteron spins due to the Pauli principle.

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Section: Introductionmentioning

confidence: 99%

Spin-lattice relaxation of deuterated methyl groups: Implications of the pauli principle

Diezemann

1999

Appl. Magn. Reson.

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The static and Dynamic NMR spectra of 4,4′‐bis(N‐isopropyl‐N‐nitrosoamino)biphenyl, a four‐site exchange problem

Grindley¹,

Lu²,

Colpa³

et al. 1986

Magnetic Reson in Chemistry

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The 'H and 'jC NMR spectra of 4,4'-bis(N-isopropyl-N-nitrosoamino)biphenyl at 22 "C were consistent with the presence of three isomers due to slow rotation about the N-N bonds of the two N-nitroso groups. The structures of the three isomers were assigned by means of their symmetries and from the known effects of the two orientations of the N-nitroso group on ' H and "CNMR chemical shifts. Each conversion of an N-nitroso group from anti to syn to an aryl group was associated with the same free energy ditference (0.26 kcal mol-') after symmetry corrections were made. The changes in the "C NMR spectra recorded from 95 to 150 "C were simulated using a program for classical four-site exchange. The potential barrier to rotation was calculated to be 20.76 It 0.06 kcal mo1-l at 400 K.

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