A nuclear magnetic resonance study of pyridoxal phosphate – metal ion interactions. II. Binding of manganese(II)

1979 ◽  
Vol 57 (9) ◽  
pp. 1050-1055 ◽  
Author(s):  
Tenkasi S. Viswanathan ◽  
Terrence J. Swift
Keyword(s):  
Metal Ion ◽  
Pyridoxal Phosphate ◽  
Lattice Relaxation ◽  
Dipolar Interaction ◽  
Rotational Correlation Time ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nmr Methods

The line width and spin–lattice relaxation rates of phosphorus and proton nuclei in PLP have been measured as a function of temperature in the presence of Mn(II) using pulsed nmr methods. The T1M of 31P in PLP-Mn(II) is very close to the T1M values of β- and γ-phosphorus atoms in ATP–Mn(II) at ∼40 °C. The T1 data of 31P and 1H have been interpreted in terms of the dipolar interaction between the electron and nuclear spins. With the assumption that the Mn(II) interacts directly with the phosphate of PLP the rotational correlation time τc at 38 °C was calculated to be 7.6 × 10−10 s from phosphorus T1 data. This τc value was subsequently used to calculate metal–proton distances from proton T1 and T2 data. The results lead to the conclusion that the phosphate-bound metal interacts directly with the aldehyde oxygen in a 1:1 PLP–Mn(II) complex. The linewidth of the 13C resonances of PLP in the presence of Mn(II) supports this conclusion. The structure assigned for PLP–Mn(II) complex is in conformity with the structure for PLP-Co(II) complex.

A multinuclear nuclear magnetic resonance study of t-butylthiol

1985 ◽  
Vol 63 (11) ◽  
pp. 2926-2932 ◽  
Author(s):  
Sandra Mooibroek ◽  
Roderick E. Wasylishen
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Rotational Correlation Time ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Isotropic Reorientation ◽  
Line Narrowing ◽  
Abrupt Changes ◽  
Order Of Magnitude

Deuterium nmr lineshapes for polycrystalline samples of (CD3)3CSH and (CH3)3CSD have been investigated between 110 and 200 K. Unlike t-butylchloride-d9 which undergoes line narrowing in three distinctive stages, t-butylthiol-d9 undergoes almost complete motional line narrowing at 120 ± 5 K. Above the solid II ↔ solid I phase transition no quadrupolar splitting is observed, consistent with rapid "isotropic" reorientation in the solid I phase.An analysis of the 2H and 13C spin–lattice relaxation times of (CD3)3CSH, (CH3)3CSD and unlabelled t-butylthiol in both liquid and solid phases is also reported. The rotational correlation time is observed to decrease by an order of magnitude at the solid II ↔ solid I transition and to increase slightly at the melting point. Deuterium T1s in solids III and IV of the labelled species indicate abrupt changes at the phase transitions and motion slower than ω0−1 in solid IV.

Interaction of divalent metal ions with pyridoxal phosphate. I. Nuclear magnetic resonance studies of cobalt(II) binding

1980 ◽  
Vol 58 (11) ◽  
pp. 1118-1124 ◽  
Author(s):  
Tenkasi S. Viswanathan ◽  
Terrence J. Swift
Keyword(s):  
Metal Ion ◽  
Pyridoxal Phosphate ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Methylene Proton ◽  
Divalent Metal Ions ◽  
Spin Lattice ◽  
Neutral Ph

The binding of Co(II) to pyridoxal phosphate (PLP)at neutral pH was investigated with 31P, 1H, and 13C nmr spectroscopy. The proton and phosphorus spin–lattice relaxation times of PLP were measured in the absence of Co(II) and with increasing amounts of the metal ion. The shifting and the relaxation enhancement of the phosphorus resonance in the presence of Co(II) have indicated the binding of the metal ion to the phosphate of PLP. The addition of metal ion also shifted and broadened the proton and carbon resonances. The shifting and broadening was the largest for the 4-CHO proton with other protons following the order 4-CHO [Formula: see text] 2-methyl > 5-methylene > 6-H. At neutral pH Co(II) shifted only the 5-methylene proton resonance of pyridoxamine phosphate (PMP) indicating binding of Co(II) only to the 5′-phosphate of PMP at this pH. Comparison of the shifting and broadening of the proton resonances of PLP with similar shifts in model compounds has indicated a structure for the 1:1 PLP:Co(II) complex in which the metal ion is simultaneously bound to the phosphate and the aldehyde oxygen. The proton spin–lattice relaxation times and the isotropic shifts of the 13C resonances in the 1:1 PLP:Co(II) complex support this conclusion.

Analysis of Spin Polarisation Transients in Periodically Photo-excited Triplet States

1975 ◽  
Vol 30 (5) ◽  
pp. 571-582 ◽  
Author(s):  
C. J. Winscom
Keyword(s):  
Lattice Relaxation ◽  
Rectangular Pulse ◽  
Decay Rates ◽  
Spin Lattice Relaxation ◽  
Pulse Excitation ◽  
Triplet States ◽  
Relaxation Rates ◽  
Spin Sublevel ◽  
Spin Lattice ◽  
The Individual

Abstract The behaviour of spin sublevel populations with time following periodic photo-excitation is ex-amined. The treatment is limited to conditions of magnetic field strength and temperature for which the spin lattice relaxation rates dominate the individual spin sublevel decay rates. The response of the system to three modes of excitation is considered: (i) continuous excitation using a time-independent intensity (ii) periodic rectangular pulse excitation and (iii) periodic waveform excitation. A convenient correspondence between the various forms of solutions is pointed out. The requirements of an experiment to determine spin-lattice relaxation rates in organic triplets at 77 K are discussed.

Anion reorientations and cation diffusion in a carbon-substituted sodium nido-borate Na-7,9-C2B9H12: 1H and 23Na NMR studies

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander V. Skripov ◽  
Olga A. Babanova ◽  
Roman V. Skoryunov ◽  
Alexei V. Soloninin ◽  
Terrence J. Udovic
Keyword(s):  
Lattice Relaxation ◽  
Activation Energies ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Cation Diffusion ◽  
Relaxation Data ◽  
Nmr Studies ◽  
Spin Lattice ◽  
Jump Rate ◽  
Disordered Phase

Abstract Polyhydroborate-based salts of lithium and sodium have attracted much recent interest as promising solid-state electrolytes for energy-related applications. A member of this family, sodium dicarba-nido-undecahydroborate Na-7,9-C2B9H12 exhibits superionic conductivity above its order-disorder phase transition temperature, ∼360 K. To investigate the dynamics of the anions and cations in this compound at the microscopic level, we have measured the 1H and 23Na nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates over the temperature range of 148–384 K. It has been found that the transition from the low-T ordered to the high-T disordered phase is accompanied by an abrupt, several-orders-of-magnitude acceleration of both the reorientational jump rate of the complex anions and the diffusive jump rate of Na+ cations. These results support the idea that reorientations of large [C2B9H12]− anions can facilitate cation diffusion and, thus, the ionic conductivity. The apparent activation energies for anion reorientations obtained from the 1H spin-lattice relaxation data are 314 meV for the ordered phase and 272 meV for the disordered phase. The activation energies for Na+ diffusive jumps derived from the 23Na spin-lattice relaxation data are 350 and 268 meV for the ordered and disordered phases, respectively.

An experimental evaluation of simplified procedures for determining the proton spin–lattice relaxation rates of natural products

1980 ◽  
Vol 58 (19) ◽  
pp. 2016-2023 ◽  
Author(s):  
Lawrence D. Colebrook ◽  
Laurance D. Hall
Keyword(s):  
Natural Products ◽  
Lattice Relaxation ◽  
Null Point ◽  
Proton Spin ◽  
Computational Method ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Simplified Procedures

A general discussion is given of the determination of the proton spin–lattice relaxation rates of natural products, with particular emphasis on use of the null-point method which, for the systems studied here, gives identical results with those obtained via the conventional (and relatively time consuming) computational method.

Triplet spin-lattice relaxation rates from spin-echo saturation recovery

1981 ◽  
Vol 44 (2) ◽  
pp. 348-354 ◽  
Author(s):  
D.C Doetschman ◽  
B.J Botter
Keyword(s):  
Spin Echo ◽  
Lattice Relaxation ◽  
Saturation Recovery ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice

Application of a pseudo-one-dimensional kinetic Ising model to proton spin-lattice relaxation rates in squaric acid (H2C4O4)

1985 ◽  
Vol 31 (5) ◽  
pp. 3059-3063 ◽  
Author(s):  
U. Deininghaus ◽  
H. Fischer ◽  
P. K. Kahol ◽  
M. Mehring
Keyword(s):  
Ising Model ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Squaric Acid ◽  
Relaxation Rates ◽  
Kinetic Ising Model ◽  
One Dimensional ◽  
Spin Lattice
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