Temperature Dependence of Molecular Conformation, Dynamics, and Chemical Shift Anisotropy of α,α-Trehalose in D2O by NMR Relaxation

1997 ◽  
Vol 119 (6) ◽  
pp. 1336-1345 ◽  
Author(s):  
Gyula Batta ◽  
Katalin E. Kövér ◽  
Jacquelyn Gervay ◽  
Miklós Hornyák ◽  
Gareth M. Roberts
Keyword(s):  
Chemical Shift ◽  
Temperature Dependence ◽  
Molecular Conformation ◽  
Chemical Shift Anisotropy ◽  
Nmr Relaxation

Selenium-77 and phosphorus-31 nuclear spin relaxation in tri-(tert-butyl) phosphine selenide

1991 ◽  
Vol 69 (7) ◽  
pp. 1054-1056 ◽  
Author(s):  
Glenn H. Penner
Keyword(s):  
Chemical Shift ◽  
Nuclear Spin ◽  
Chemical Shift Anisotropy ◽  
Relaxation Times ◽  
Nmr Relaxation ◽  
Lattice Relaxation ◽  
Spin Rotation ◽  
Spin Lattice Relaxation ◽  
Phosphine Selenide ◽  
High Fields

Selenium-77 and phosphorus-31 spin-lattice relaxation times are reported for tri-tert-butylphosphine selenide in chloroform-d, at 303 K and at several different magnetic field strengths. At moderate fields the 31P–1H dipole–dipole, spin-rotation, and chemical shift anisotropy mechanisms contribute significantly towards the 31P T1. At high fields chemical shift anisotropy dominates. The selenium-77 nuclear spin relaxes almost exclusively by spin rotation at low to moderate fields and the chemical shift anisotropy contribution only becomes significant at very high fields. This is due to an unusually small 77Se CSA. The contribution due to 31P–77Se dipole–dipole interactions is small but significant. Key words: 77Se NMR, NMR relaxation, phosphine selenide.

13C NMR Relaxation Rates:  Separation of Dipolar and Chemical Shift Anisotropy Effects

2004 ◽  
Vol 108 (29) ◽  
pp. 6096-6099 ◽  
Author(s):  
W. Robert Carper ◽  
Phillip G. Wahlbeck ◽  
Andreas Dölle
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Chemical Shift Anisotropy ◽  
Nmr Relaxation ◽  
Relaxation Rates

NMR relaxation of tin-119 in pentacoordinate and hexacoordinate environments

1990 ◽  
Vol 68 (11) ◽  
pp. 2102-2110 ◽  
Author(s):  
T. Bruce Grindley ◽  
Ronald D. Curtis ◽  
Rasiah Thangarasa ◽  
Roderick E. Wasylishen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Chemical Shift Anisotropy ◽  
Relaxation Times ◽  
Nmr Relaxation ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Powdered Sample ◽  
Axially Symmetric ◽  
Resonance Spin

Carbon-13 and 119Sn nuclear magnetic resonance spin-lattice relaxation times at 8.48 T and at 4.70 T have been measured at several temperatures for a number of 2,2-di-n-butyl-1,3,2-dioxastannolane derivatives, most of which were prepared from monosaccharide derived diols. The tin nuclei in these compounds, which are at either pentacoordinate or hexacoordinate sites, have 119Sn T1values that are relatively short, between 13 ms and 300 ms. At 8.48 T, chemical shift anisotropy is the only important mechanism for relaxation of the 119Sn nuclei in these compounds. However, at 4.70 T, the 1H,119Sn dipole–dipole mechanism also contributes slightly. The principal components of the 119Sn chemical shift tensor for the pentacoordinate site in the dimeric structure of methyl 4,6-O-benzylidene-2,3-dibutylstannylene-α-D-glucopyranoside (1) were determined directly from the static 119Sn spectrum of a powdered sample and indirectly from slow spinning CP/MAS spectra using both the Herzfeld–Berger procedure and computer simulation. The tin shift tensor for 1 in the solid state is non-axially symmetric with η = 0.49 ± 0.03. The chemical shift anisotropy determined from the solid state experiments, 748 ± 20 ppm, was in good agreement with the value obtained from the solution T1data, 720 ± 50 ppm. For compounds containing both pentacoordinate and hexacoordinate tin atoms, the 119Sn relaxation data indicate that the tin chemical shift anisotropies for the hexacoordinate sites are approximately 1.6 times those of the pentacoordinate sites. Keywords: 119Sn NMR, NMR relaxation, stannylene acetals, 1,3,2-dioxastannolanes.

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