Nuclear magnetic resonance temperature control

Nuclear Magnetic Resonance (NMR) Spectroscopy. Longitudinal and transverse relaxation times (Ti and T2) of 1H and 23Na in the water-polyelectrolytes systems were measured using a Nicolet FT-NMR, model NT-200WB. T2 was measured by the Meiboom-Gill variant of the Carr-Purcell method (5). However, in the case of very rapid relaxation, the free induction decay (FID) method was applied. The sample temperature was changed from 30 to —70°C with the assistance of the 1180 system. The accuracy of the temperature control was 0.5°C. 

Crystal reaction study mechanistic tools, 296 computer simulation, 297 electronic spectroscopy, 298 electron microscopy, 298 electron paramagnetic resonance (EPR), 299 nuclear magnetic resonance (NMR), 298 Raman spectroscopy, 299 Crystal reaction study techniques crystal mounting, 308 decomposition limiting, 309 polarized IR spectroscopy, 309 temperature control, 308 Cycloreversions, adiabatic photochemical involving anthracenes, 203 excited state properties of lepidopterenes, 206... 

The diffusion coefficient can also be determined from measurements of other phenomena that are controlled by the activated motion of atoms. These indirect methods include internal friction measurements, nuclear magnetic resonance spectra, and some magnetic relaxation phenomena (in ferromagnetic substances). These techniques are advantageous in allowing the measurement of D at lower temperatures than are practicable by the conventional methods. 

For instance, UV and nuclear magnetic resonance (NMR) studies of the reaction between A-methylacridinium ion and primary aromatic amines have revealed the formation of unstable N-adducts under kinetically controlled conditions (—50°C). Their formation is especially favored in case of anilines bearing in the /jara-position an electron-donating substituent R. At temperatures above 0°C, these N-adducts are gradually converted into thermodynamically more favored C-adducts. Also it has been shown that when no oxidant is added, the A-methylacridinium cation acts as oxidant of both N- and C-adducts, thus giving the corresponding products and 10-methyl-9,10-dihydroacridine (Scheme 36) [11, 136]. 

TEMPERATURE-CONTROLLED PICK-UP UNIT FOR SPIN-ECHO NUCLEAR MAGNETIC RESONANCE SPECTROMETER. //ENGLISH TRANSLATION OF ZH. FIZ. KHIM. 42 /6/ 1547-9,1968.// PANCHENKOVGM BORISENKO N N ERCHENKOVVV RUSS J PHYSCHEM... 

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