ENDOR resonance spectroscopy

We refer to a textbook dealing with ENDOR resonance spectroscopy of radicals in solution [15] for a review of measurements on radicals showing hyperfine structure... 

B1.15.5.1 ELECTRON-NUCLEAR DOUBLE RESONANCE SPECTROSCOPY (ENDOR)... 

Mdbius K, Plato M and Lubitz W 1982 Radicals in solution studied by ENDOR and TRIPLE resonance spectroscopy P/rys. Rep. 87 171-208... 

Double-resonance spectroscopy involves the use of two different sources of radiation. In the context of EPR, these usually are a microwave and a radiowave or (less common) a microwave and another microwave. The two combinations were originally called ENDOR (electron nuclear double resonance) and ELDOR (electron electron double resonance), but the development of many variations on this theme has led to a wide spectrum of derived techniques and associated acronyms, such as ESEEM (electron spin echo envelope modulation), which is a pulsed variant of ENDOR, or DEER (double electron electron spin resonance), which is a pulsed variant of ELDOR. The basic principle involves the saturation (partially or wholly) of an EPR absorption and the subsequent transfer of spin energy to a different absorption by means of the second radiation, leading to the detection of the difference signal. The requirement of saturability implies operation at close to liquid helium, or even lower, temperatures, which, combined with long experimentation times, produces a... 

The experimental methods in ENDOR spectroscopy have been extensively described by Kevan and Kispert4) in their monograph, Electron spin double resonance spectroscopy, and by Leniart18 in a recent paper. In this section we shall briefly review the instrumentation used in solid state ENDOR and describe the technical details of some new experimental methods. 

The new techniques of phosphorescence-microwave multiplet resonance spectroscopy with optical detection have been reviewed by El-Sayed and Kwiram Such exciting experiments as the optical detection on electron-nuclear double resonance (ENDOR) and of electron-electron double resonance (EEDOR) in zero magnetic field have been achieved, and it is certain that much detailed knowledge concerning the phosphorescent states will evolve from this field. 

In collaboration with Fabian Gerson at the University of Basel, the radical anion of 72 was also studied by ESR, ENDOR, and triple-resonance spectroscopy. The results obtained thus far indicated that the odd electron of the radical anion of 72 was delocalized exclusively between the para-linked benzene rings, and was consistent with the result procured from a similar study on the parent [2.2]paracy-clophane. " ... 

Upon treatment of 2,5-dihydro-1,2,3,5-thiatriazole 1-oxides with sodium or potassium (4.20.5.1) in 1,2-dimethoxyethane 2,5-dihydro-l,2,3,5-thiatriazol-5-yl radicals are formed which have been studied by means of ESR, ENDOR, and general triple resonance spectroscopy <90JCS(P2)1619>. 

Dihydro-l, 2,3,5-thiatriazole 1-oxide radicals were generated from the thiatriazole oxides upon hydrogen abstraction in the reaction with thermally formed bis(4-methylphenyl)aminyl (4.20.5.1). Only radicals with aryl substituents in positions two and four are persistent, radicals with alkyl groups in these positions could not be detected. The radicals were investigated by ESR, ENDOR, and general triple resonance spectroscopy <92MRC84>. 

Magnetic resonance spectroscopy Nuclear magnetic resonance Electron paramagnetic resonance ENDOR... 

The data on electron spin resonance (ESR), electron-nuclear double resonance (ENDOR), and general triple resonance spectroscopy for 2,5-dihydro-l,2,3,5-thiatriazole-5-yl radicals was reviewed by Holm and Larsen <1996CHEC-II(4)733>. There are no new data on this subject. 

Hertel, MM, Denysenkov, VP, Bennati M, Prisner TP. Pulsed 180-GHz EPR/ENDOR/PELDOR spectroscopy. Mag. Reson. Chem. 2005 43 S248-S255. 

The radical cations from several substituted A V -diphenyl viologens (PV) have also been investigated by means of EPR spectroscopy as well as electron nuclear double resonance (ENDOR) and triple resonance spectroscopies. 

Figure 2 gives a scheme illustrating some applications in geochemistry and technology where surface reactivity (kinetics of dissolution, catalytic activity, photochemical activity) depends on surface structure, expecially on surface coordination. It has been shown by various spectroscopic techniques [electron-spin resonance (ESR), electron double-resonance spectroscopy (ENDOR), electron-spin echo modulation (e.g., see Motschi, 1987), Fourier transform infrared spectroscopy (Zeltner et al., 1986), and in situ X-ray absorption studies of surface complexes (EXAFS) (Hayes et al., 1987 Brown, 1989)] that inner-sphere... 

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