Spin-lattice relaxation of 15N nuclei in organic compounds

Lippmaa, É.; Saluvere, T.; Laisaar, S.

doi:10.1016/0009-2614(71)80547-x

Cited by 40 publications

(26 citation statements)

References 8 publications

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“…one defined by the twofold axis through the nitrogen and the center of the molecule, and the other in the molecular plane perpendicular to the first one. The calculated moment of inertia around the first axis is lh = 1.436.10-38 g-cm 2 , around the other (}2 1.427 _10-38 gcm 2 (while the moment of inertia around the axis perpendicular to the molecular plane Independently, we can obtain values for CII and C 1. from our relaxation data by use of Eqs. [17] and [18].…”

Section: Resultsmentioning

confidence: 74%

“…Lippmaa et al (1,2) have shown that intramolecular dipole-dipole interaction (DDI) (e.g., C6HSNH2) and spin-rotation interaction (e.g., C 6 H s NO z ) are dominant relaxation processes for 15N. As long as the 15N nucleus is shielded by surrounding atoms of the same molecule, or 15N is attached to protons, as in the case of NH3 studied by Litchman and Alei (3), intermolecular DDI is not an important relaxation mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen-15 NMR of pyridine in high magnetic: Fields

Schweitzer

Spiess

1974

Journal of Magnetic Resonance (1969)

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The 15N NMR of pyridine was studied in the liquid and solid state. In the liquid the spin-lattice relaxation time Tl was studied from -60 to +55°C at 14 and 30 MHz. At low temperature, the two most important relaxation mechanisms are relaxation due to anisotropic chemical shift and intermolecular dipole-dipole interaction. The small contribution of intramolecular dipole-dipole interaction of 15N with protons was determined by making use of correlation times '!'c ohtained from 1 3 C relaxation rates, which were also measured. At higher temperatures, relaxation by spin-rotation interaction becomes important. Ana.lysis of the relaxation data shows that the anisotropy of the motion in liquid pyridine is rather small. The principal elements of the chemical shift tensor were obtained from powderspectraat-l05°CbyFTNMR:u xx =-313 ± 10ppm, Un =-94 ± 10 ppm, (Jzz = +469 ± 10 ppm relative to liquid pyridine. From these values the following spin-rotation components were calculated: C x ,. = 16.5 ± 1 kHz, Cyy = 11.5 ± 1 kHz, C zz = -0.6 ± 1 kHz. In both cases the z-axis is perpendicular to the molecular plane.

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Section: Resultsmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Nitrogen-15 NMR of pyridine in high magnetic: Fields

Schweitzer

Spiess

1974

Journal of Magnetic Resonance (1969)

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“…1300 s, [24] indole NH 3.5 s, heterocyclic tertiary N 25 s, NOE -5.0 [25] ), whereas nitro groups relax very slowly (e.g. T1 of nitrobenzene: 400 s [26] or 180 s [27] ) and display unfavourable NOE factors near -1 (e.g. (HOCH2)2CMeNO2 -1.0 [24] ).…”

Section: Resultsmentioning

confidence: 99%

Mononuclear Transition Metal Complexes of 7‐Nitro‐1,3,5‐Triazaadamantane

Wagner

Coles

2016

ChemistrySelect

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Abstract:Complexes of the type [MCl2(7-nitro-1,3,5-triaza-adamantane)2] (M = Zn(II), Pd(II), Pt(II)) and [MCl2(H2O)2(7-nitro-1,3,5-triazaadamantane)2] (M = Mn (II), Co(II), Ni(II)) have been prepared and their structures have been analysed by X-ray crystallography, elemental analysis, IR and solid state 13 C and 15 N NMR spectroscopy, supported by density functional theory/gauge independent atomic orbital (DFT/GIAO) calculations. In each case, 7-nitro-1,3,5-triazaadamantane acts as a mono-dentate ligand and binds to one metal centre only, in spite of the presence of three equivalent amino nitrogens. In the Co(II) and Ni(II) complexes, a two-dimensional intermolecular hydrogen bonding network between the aqua-and the chloro ligands is established. The uncoordinated amines of the 7-nitro-1,3,5-triaza-adamantane are not involved in any Hbonding, as a result of the exceptionally low basicity of this compound.

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“…Measurements of Tl for 15N in nitrobenzene at 4 MHz have been reported by Lippmaa et al (2) with which our data can be compared. Their studies were carried out in a temperature range of 1O-200°C, showing that relaxation due to spin rotation interaction (SRI) is the most important relaxation process under these conditions.…”

Section: Introductionmentioning

confidence: 94%

“…This is mainly due to the large value of the anisotropy of the chemical shift, Au = 672 ± 20 ppm (1). In liquid azoxybenzene, Lippmaa et al (2) observed a frequency dependence of the relaxation rate characteristic for relaxation through ACS even between 4 and 6 MHz and deduced a value of Au = 570 ± 100 ppm. In the linear molecule NNO, Au has recently been determined in a liquid crystal: Au = 512 ± 10 ppm for the central 15 N and Au = 368 ± 10 ppm for the end 1 5 N (3).…”

Section: Introductionmentioning

confidence: 99%

Anisotropic chemical shifts and spin rotation constants of 15N from liquid and solid state NMR: Nitrobenzene

Schweitzer¹,

Spiess²

1974

Journal of Magnetic Resonance (1969)

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The study of the 15N spin-lattice relaxation time Tl in nitrobenzene at 14 and 32 MHz from -10 to 60°C showed that at 32 MHz relaxation due to anisotropic chemical shift is predominant. At low frequencies, the relaxation is caused mainly by spin rotation and at low temperature also by intermolecular dipole-dipole interaction. From the powder spectrum in solid nitrobenzene, the principal elements of the shielding tensor a were obtained: 0' xx = -273 ± 10 ppm, 0'" = +94 ± 10 ppm, and O'zz = + 156 ± 10 ppm relative to liquid nitrobenzene,-398 ± 20 ppm. From the almost axially symmetric a-tensor, the spin rotation constants were calculated: CII = 11.4 ± 1.5 kHz and C.L = 1.35 ± 0.5 kHz, where ell is the component parallel to the twofold axis of the molecule. These values for Au and the spin rotation constants are in excellent agreement with those obtained by analysis of the relaxation data. A comparison of anisotropic chemical shifts and spin rotation constants for IsN and 13C in isoelectronic compounds is given.

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Spin-lattice relaxation of 15N nuclei in organic compounds

Cited by 40 publications

References 8 publications

Nitrogen-15 NMR of pyridine in high magnetic: Fields

Nitrogen-15 NMR of pyridine in high magnetic: Fields

Mononuclear Transition Metal Complexes of 7‐Nitro‐1,3,5‐Triazaadamantane

Anisotropic chemical shifts and spin rotation constants of 15N from liquid and solid state NMR: Nitrobenzene

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