Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions

2011 ◽  
Vol 89 (7) ◽  
pp. 870-884 ◽  
Author(s):  
Klaus Eichele ◽  
Arnd-Rüdiger Grimmer
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Chemical Shift Anisotropy ◽  
Lattice Relaxation ◽  
Nuclear Quadrupole Interaction ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Nmr Studies

Field-dependent 31P solid-state NMR studies demonstrate that the line shape in spectra of β-VOPO4 depends on 51V–31P direct and indirect spin-spin interactions (M2 (51V, 31P) = 101(23) × 106 rad2 s–2, 2Jiso (51V, 31P) = 48(5) Hz) and, to a lesser extent, on 31P chemical shift anisotropy (δiso = –10.4(2), Ω = δ11 – δ33 = 22(2) ppm) and 31P–31P interactions (M2 (31P, 31P) = 6.7(1) × 106 rad2 s–2). In contrast, homonuclear dipolar interactions play an important role for the field and spinning rate dependent 31P spin-lattice relaxation via paramagnetic impurities (T1 = 20–60 s). Vanadium-51 magic-angle spinning NMR spectra indicate a sizeable chemical shift anisotropy (δiso = –754(1), δ11 = –336(10), δ22 = –344(6), δ33 = –1581(8) ppm) and nuclear quadrupole interaction (χ = 1.5(1) MHz, η = 0.35(5)); the principal axis systems of both interactions are clearly not coincident, with an angle of 35(5)° between the greatest component of the electric field gradient tensor and δ33.

Solid-state CP/MAS 13C NMR analysis of particle size and density fractions of a soil incubated with uniformly labeled 13C-glucose

Soil Research ◽  
1990 ◽  
Vol 28 (2) ◽  
pp. 193 ◽  
Author(s):  
JA Baldock ◽  
JM Oades ◽  
AM Vassallo ◽  
MA Wilson
Keyword(s):  
Solid State ◽  
Relaxation Times ◽  
Clay Fraction ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Ultrasonic Probe ◽  
13C Nuclear Magnetic Resonance

A soil incubated for 34 days in the absence (control) and presence (treated) of uniformly labelled 13C-glucose was dispersed using an ultrasonic probe and fractionated by sedimentation in water and a polytungstate solution of density 2.0 Mg m3 . The residual substrate carbon was concentrated in the clay and light fractions. Solid state CP/MAS 13C n.m.r. (cross polarization/magic angle spinning 13c nuclear magnetic resonance) spectroscopy was used to characterize the chemical structure of the native soil organic carbon and the residual substrate carbon in the fractions of the control and treated soils. To obtain quantitative results it was essential to determine the spin lattice relaxation times in the rotating frame, T1pH, of the individual carbon types in the spectra as the relaxation behaviour of the native organic materials in the clay fraction was substantially different from that of the residual substrate carbon. After correcting for T1pH effects, a significant linear relationship existed between the signal intensity and 13C content of the samples. This enabled the content, expressed in �mol 13C g-1 fraction, of each type of carbon in the fractions to be calculated. The residual substrate carbon was found to accumulate in predominantly alkyl and O-alkyl structures in both fractions. However, significant amounts of acetal and carboxyl carbon were also observed in the clay fraction. Little if any aromatic or phenolic carbon was synthesized by the soil microorganisms utilizing substrate carbon. Dipolar dephasing CP/MAS 13C n.m.r. experiments were also performed and allowed the proportion of each type of carbon which was protonated and nonprotonated to be estimated. Essentially all of the O-alkyl and acetal carbon, 25-40% of the aromatic carbon and 66-80% of the alkyl carbon was protonated in the fractions isolated from the treated soil

Tin-119 NMR of 1,3,2-dioxastannolanes and a 1,3,2-dioxastannane in the solid state

1992 ◽  
Vol 70 (1) ◽  
pp. 205-217 ◽  
Author(s):  
T. Bruce Grindley ◽  
Roderick E. Wasylishen ◽  
Rasiah Thangarasa ◽  
William P. Power ◽  
Ronald D. Curtis
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Chemical Shift ◽  
Variable Temperature ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
X Ray ◽  
Spin Lattice

The cross-polarized static and high-resolution magic angle spinning 119Sn NMR spectra of a number of 2,2-dialkyl-1,3,2-dioxastannolanes and one 1,3,2-dioxastannane have been measured in the solid state. For the four compounds on which X-ray studies had been performed, the numbers and positions of the isotropic peaks in the high-resolution spectra were related to the number of tin sites present and the state of oligomerization of the compounds. The chemical shifts of hexacoordinate Sn nuclei are 35–80 ppm larger in polymeric solids than for the same compounds in solution where the compounds exist as trimers and tetramers. States of oligomerization for solids that had not been previously studied by X-ray crystallography were determined using CP/MAS 119Sn NMR spectroscopy. The principal components of the 119Sn chemical shift tensors were obtained from the static spectra and used to calculate chemical shift anisotropies and asymmetry parameters. The values of the chemical shift anisotropies ranged from 600 to 800 ppm for 1,3,2-dioxastannolanes but the value for a 1,3,2-dioxastannane was larger, 919 ppm. The chemical shift anisotropies measured directly from the solid-state powder patterns are in excellent agreement with the values derived from previous variable temperature spin-lattice relaxation measurements in solution when the same oligomer was present in both states. Our results support our previous conclusion that the antisymmetric terms of the chemical shift tensor make a small or negligible contribution to the rate of 119Sn spin-lattice relaxation in these compounds. Keywords: 1,3,2-dioxastannolanes, stannylene acetals, 119Sn NMR, 119Sn NMR of solids, 119Sn chemical shift an-isotropy.

scholarly journals Physicochemical properties and structural dynamics of organic–inorganic hybrid [NH3(CH2)3NH3]ZnX4 (X = Cl and Br) crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ae Ran Lim ◽  
Sun Ha Kim ◽  
Yong Lak Joo
Keyword(s):  
Structural Dynamics ◽  
Chemical Shifts ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Scanning Calorimetry ◽  
Inorganic Hybrid ◽  
Halogen Atoms

AbstractThe physical properties of the organic–inorganic hybrid crystals having the formula [NH3(CH2)3NH3]ZnX4 (X = Cl, Br) were investigated. The phase transition temperatures (TC; 268K for Cl and 272K for Br) of the two crystals bearing different halogen atoms in their skeletons were determined through differential scanning calorimetry. The thermodynamic properties of the two crystals were investigated through thermogravimetric analysis. The structural dynamics, particularly the role of the [NH3(CH2)3NH3] cation, were probed through 1H and 13C magic-angle spinning nuclear magnetic resonance spectroscopy as a function of temperature. The 1H and 13C NMR chemical shifts did not show any changes near TC. In addition, the 1H spin–lattice relaxation time (T1ρ) varied with temperature, whereas the 13C T1ρ values remained nearly constant at different temperatures. The T1ρ values of the atoms in [NH3(CH2)3NH3]ZnCl4 were higher than those in [NH3(CH2)3NH3]ZnBr4. The observed differences in the structural dynamics obtained from the chemical shifts and T1ρ values of the two compounds can be attributed to the differences in the bond lengths and halogen atoms. These findings can provide important insights or potential applications of these crystals.

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.

Sign in / Sign up

Export Citation Format

Share Document