Deuterated, electron spin resonance

The use of selective deuteration is a powerful tool in electron spin resonance (ESR) experiments, in order to establish unequivocal assignments of experimental spectra of radicals. The reason for this is, as is well known, the difference in magnetic properties between the deuteron and the proton, which can be exploited to distinguish chemically inequivalent hydrogens in the molecule. 

Experimental techniques that are frequently used in physicochemical studies should be applied to reactive plasmas. These techniques are, for example, the use of deuterated compounds, the analysis of stable products in the gas phase, and the use of matrix isolation or trapping of reactive species at low temperatures combined with electron-spin resonance (ESR) or optical spectroscopy. 

Deuterium Orgemisms in Esr. The availcibility of fully deuterated algae has permitted some significant biological problems to be attacked in new and effective ways. Deuterium had been used as a tool to aid in the simplification and interpretation of electron spin resonance (esr) and nuclear magnetic resonance (nmr) spectra of relatively simple organic molecules for many... 

The presence of radicals was demonstrated (De Groot et al., 1973) using the radical trap, 2-methyl-2-nitrosopropanol. By studying the hyperfine splitting constants of the electron spin resonance (esr) spectra of a series of adduct radicals formed when linoleic acid or different deuterated analogues were used as the substrate, it was shown that the radical scavenger reacted at position 9 or 13 on linoleic acid. This is evidence that the linoleyl radical... 

The NH2 radical trapped in various matrices was extensively studied by electron spin resonance (ESR) spectroscopy see Table 13, p. 196. The ESR spectrum of NH2 in an Ar matrix at 4.2 K consists of the expected nine lines [1, 2] assigned to the threefold hyperfine splittings of 67 and 29 MHz due to the two protons and "" N, respectively. The peak Intensities within each triplet are roughly 1 1 1 instead of the expected 1 2 1. An Interpretation is given In [3]. Spectral lines of deuterated NH2 in Ar formerly assigned to ND2 [1] were reassigned to NHD [2]. 

The hydrocarbon chains of the lipid bilayer are in a liquid-like state as evidenced by X-ray diffraction, electron spin resonance spectroscopy, and differential scanning calorimetry studies. A quantitative characterization of the hydrocarbon chain order in lipid bilayers by means of H-NMR became possible by selectively deuterating both fatty acyl chains in a lipid molecule. Measurement of the deuterium quadrupole splittings, Avq, allowed calculation of the order parameter of the C—D bond vector at each labeled carbon atom. The variation of the order parameter ScdI with the position of the labeled carbon atom in the membrane is the so-called order profile. An... 

A persistent question concerning the Wolff rearrangement is whether or not an alternate intermediate, such as an excited state of the diazo precursor " or an oxirene, is involved. Carbonylcarbenes have been detected in low-temperature matrices by electron spin resonance (ESR) and FTIR " spectroscopies. Evidence for the participation of oxirenes - comes from experiments " in which diazoketones labeled at the carbonyl carbon rearrange to form ketenes that possess a label at both carbon atoms (Scheme 3). Similar results were obtained in studies of unsymmetricaUy substituted diazoketones. "- The direct observation of oxirene intermediates, however, has been more elusive. Initial reports of oxirene detection - were later called into question. - Bodot and co-workers have advanced evidence for the existence of dimethyloxirene and its deuterated analogue by low-temperature FTIR methods. - ... 

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