A Selective Determination of the Proton Nuclear Relaxation Times of the Alkaloid Vindoline

1972 ◽  
Vol 50 (4) ◽  
pp. 497-503 ◽  
Author(s):  
R. Burton ◽  
C. W. M. Grant ◽  
L. D. Hall
Keyword(s):  
Relaxation Time ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Nuclear Relaxation ◽  
Methyl Group ◽  
Selective Determination ◽  
Spin Lattice

An audiofrequency-pulse n.m.r. spectrometer has been used to measure the nuclear relaxation times of individual protons of the alkaloid, vindoline. For this substance in deuterochloroform solution the spin–lattice relaxation times (T1) vary between 1.15 and 1.50 s and the spin–spin relaxation times (T2) are between 0.90 and 1.40 s. The N-methyl group has the shortest relaxation time of those resonances which were measured. A discussion of the apparatus and methodology is given.

A Selective Determination of the Proton Nuclear Relaxation Times of the Alkaloid Vindoline: An Extension via Fourier Transform Measurements

1974 ◽  
Vol 52 (5) ◽  
pp. 829-832 ◽  
Author(s):  
L. D. Hall ◽  
Caroline M. Preston
Keyword(s):  
Fourier Transform ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Nuclear Relaxation ◽  
Transform Method ◽  
Fourier Transform Method ◽  
Selective Determination ◽  
Spin Lattice

A Fourier Transform method has been used to measure the spin–lattice relaxation times of essentially all the protons of the alkaloid, vindoline. It is shown that even for a molecule of this size substantial and potentially useful differences exist in the experimental relaxation times which reflect the degree of crowding of each proton by other protons.

Relaxationszeiten des Elektronenspins von Radikalen in einigen bestrahlten Aminosäuren bei 4,2 °K

1966 ◽  
Vol 21 (3) ◽  
pp. 296-300 ◽  
Author(s):  
G. Bürk ◽  
G. Schoffa
Keyword(s):  
Amino Acids ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Electron Spin Relaxation ◽  
Spin Lattice ◽  
Saturation Method ◽  
Rapid Adjustment ◽  
Inhomogeneous Line Broadening

Electron spin relaxation times of the irradiated amino acids acetyl valine, sarcosine, betaine, and glycine have been measured at 4.2 °K with two different methods. From the exponential decrease of signals due to saturation after rapid adjustment of the ESR spectrometer on resonance, the following spin-lattice relaxation times have been measured: acetyl valine T1= 0.2 sec, sarcosine T1=0.14 sec, betaine T1=0.07 sec, glycine T1 ∼ 0.3 sec. By the PORTIS saturation method the product T1 T2 was measured, and, T1 being known, the following spin-spin relaxation times T2 have been obtained: acetyl valine 2.1.10-9sec, sarcosine 1.10-9sec, betaine 9.10-10sec. All measured amino acids show the saturation behaviour of substances with “inhomogeneous” line broadening.

SPIN LATTICE RELAXATION IN NEODYMIUM ETHYLSULPHATE AT LIQUID HELIUM TEMPERATURES

1960 ◽  
Vol 38 (5) ◽  
pp. 604-615 ◽  
Author(s):  
J. M. Daniels ◽  
K. E. Rieckhoff
Keyword(s):  
Relaxation Time ◽  
Faraday Effect ◽  
Pulse Length ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Approach To Equilibrium ◽  
Spin Lattice ◽  
Spin Populations ◽  
Adiabatic Magnetization

The optical Faraday effect was used to measure instantaneous magnetization in neodymium ethylsulphate. The spin populations were disturbed by pulses of microwave power, and by adiabatic magnetization and demagnetization, and the approach to equilibrium was studied. The relaxation was found to be exponential and spin lattice relaxation times were measured, for temperatures between 1.3° K and 4.2° K, and for magnetic fields between 80 and 6000 oersted. The relaxation time was found to decrease with increasing magnetic field, and to vary with temperature approximately as 1/T3. No dependence of relaxation time on pulse length was found.

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