Spin-lattice relaxation time, measurement

Maryott A. A., Farrar T. C., Malmberg M. S. 35C1 and 19F NMR spin-lattice relaxation time measurements and rotational diffusion in liquid CIO3F. J. Chem. Phys. 54, 64-71 (1971). 

Bicyclo[3,l,l]heptanes.—Spin-lattice relaxation time measurements have facilitated the n.m.r. spectral assignments of paeoniflorin and albiflorin (Vol. 3, p. 71). trans-Pinocarveol (223) has been synthesized from /3-pinene in t-butyl alcohol with hydrogen peroxide in the presence of a catalytic amount of selenium... 

Two-proton transfer in crystals of carboxylic acids has been studied thoroughly by the 7 -NMR and IINS methods. The proton spin-lattice relaxation time, measured by T,-NMR, is associated with the potential asymmetry A, induced by the crystalline field. The rate constant of thermally activated hopping between the acid monomers can be found from Tj using the theory of spin exchange [Look and Lowe, 1966] ... 

C spin-lattice relaxation time measurements (Table VIII) have been used in the assignment of quaternary, 3C signals in brucine [419] (121) (for details see discussion on codeine in Section V). 

Variable-temperature 13C NMR spin-lattice relaxation time measurements have been used to probe the motional behavior of 2,3 5,6-di-O-isopropylidene-a-D-mannofuranose (22) in dimethyl sulfoxide solution.67 This carbohydrate deriva-... 

B. D. Sykes, W. E. Hull, and G.H. Snyder, Biophys. /, 21, 137 (1978). Experimental Evidence for the Role of Cross-relaxation in Proton Nuclear Magnetic Resonance Spin Lattice Relaxation Time Measurements in Proteins. 

The temperature dependence of the quadrupole echo 2H NMR lineshape and 2H NMR spin-lattice relaxation time measurements demonstrated that the hydrogen bonding arrangement is dynamic. 

Computational methods have been applied to study the conformations of free and metal-complexed oxathiacrown ethers 1-4 shown in Figure 6. The results were compared to variable temperature NMR and i spin-lattice relaxation time measurements <2001JP2988>. Theoretical studies included simulated 111 NMR spectra using PERCH and molecular modeling with PM3 semi-empirical quantum-chemical calculations. The NMR and the computational data both show that Ag+ coordinates equally well to S and O atoms, Bi3+ and Sb3+ prefer O atoms, and that Ptz+ and Pdz+ prefer exo-cyclic coordination only to the S atoms in this maleonitrile macrocycle. 

Wide-line and F NMR spectra were obtained at frequencies of 13 MHz and 35 MHz, respectively, using a Varian WL-112 spectrometer. The ESR data were accumulated on a Varian Century Series (E-12) spectrometer operating at 9.5 GHz. A Bruker SXP spectrometer operating from 10 to 80 MHz was used for F spin lattice relaxation time measurements. Measurements reported here were at 300K. 

Muller and coworkers have recently reported the molecular behavior of 1,3,5-trioxane in a cyclophosphazene inclusion compound using H-2 NMR [68]. The experimental data were obtained by variable-temperature line shape analysis, spin-spin and spin-lattice relaxation time measurements and by 2D exchange between 30 and 370 K. At room temperature, highly mobile trioxane guests were observed. They undergo various overall and conformational motions which give rise to substantial orientational disorder within the hexagonal cyclophosphazene channels. 

Self-diffilsion and spin-lattice-relaxation-time measurements... 

The Carbon-13 spin-lattice relaxation-time measurements are related to the reorientation time of a C—H bond axis. For mesitylene the C—H bond axis observed was that of the ring carbons (not the methyl carbon). For symmetric top molecules such as benzene and mesitylene the tnmr is related to both r and r by (Huntress, 1968)... 

Alms, et al. (1973,1974) have performed depolarized Rayleigh scattering and Carbon-13 spin-lattice relaxation-time measurements on solutions of benzene and mesitylene as a function of solvent viscosity. The solvents used were isopentane, cyclooctane,... 

The block diagram in the last section shows the spectrometer with the CAMAC modules identified. Several different experiments requiring different pulse sequences can be performed easily with such a system. A moderately complicated example is a spin-lattice relaxation time measurement in the time domain on a poly crystalline intermetallic sample containing 1=3/2 nuclei. Since a non-cubic 1=3/2 system has unequally spaced levels, special techniques must be used for relaxation time measurements (see III.C.3.) and we adopt the procedure of Avogadro and Rigamonti (1973) to initialize the populations before the magnetization recovery. 

Pearson, H., Gust, D., Armitage, I. M., Huber, H., Roberts, J. D., Stark, R. E., Void, R. R., and Void, R. L. (1975). Proc. Nat. Acad. Sci. U.S.A. 72, 1599. Nuclear Magnetic Resonance Spectroscopy Reinvestigation of Carbon-13 Spin-Lattice Relaxation Time Measurements of Amino Acids. 

Some of the earliest spin-lattice relaxation time measurements were carried out using superheterodyne detection by partial saturation of the magnetic resonance by a microwave pulse, and subsequent monitoring of the transient recovery on an oscilloscope [147], which is essentially a type of saturation recovery measurement... 

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