Electron paramagnetic resonance solution

Nuclear magnetic resonance spectroscopy of the solutes in clathrates and low temperature specific heat measurements are thought to be particularly promising methods for providing more detailed information on the rotational freedom of the solute molecules and their interaction with the host lattice. The absence of electron paramagnetic resonance of the oxygen molecule in a hydroquinone clathrate has already been explained on the basis of weak orientational effects by Meyer, O Brien, and van Vleck.18... 

Fig. 6. The electron-paramagnetic resonance spectrum of Kpl in frozen solution at 10 K.

Since cupric ions are paramagnetic, it is possible by electron paramagnetic resonance (EPR) to obtain information on the status and the environment of the Cu ions adsorbed on uronic acids [4, 5]. Nitella cell walls with uronate charges compensated to 9 or 100% with copper in equilibrium with mixed copper and zinc chloride solutions had their EPR spectra recorded at two different temperatures, 93 and 293 °K (Fig. 3.a, b). 

Lagerstedt, J.O., Budamagunta, M.S., Oda, M.N., and Voss, J.C. 2007. Electron paramagnetic resonance spectroscopy of site-directed spin labels reveals the structural heterogeneity in the N-terminal domain of ApoA-I in solution. The Journal of Biological Chemistry 282 9143-9149. 

The description theoretical study of defects frequently refers to some computation of defect electronic structure i.e., a solution of the Schrodin-ger equation (Pantelides, 1978 Bachelet, 1986). The goal of such calculations is normally to complement or guide the corresponding experimental study so that the defect is either properly identified or otherwise better understood. Frequently, the experimental study suffices to identify the basic structure of the defect this is particularly true when the system is EPR (electron paramagnetic resonance) active. However, if the computational method properly simulates the defect, we are provided with a wealth of additional information that can be used to reveal some of the more basic and general features of many-electron defect systems and defect reactions. 

Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR), has rightly been called the NMR of unpaired electrons . A sample of a radical (generally in solution) is irradiated with a beam of microwave radiation and the proportion of the radiation that is absorbed is then determined. 

Before the availability of a high-resolution structure of P. aeruginosa CCP, the properties and environments of the two hemes had been probed using a range of solution spectroscopies. These include electron paramagnetic resonance (EPR) (51, 57, 58, 61), resonance Raman (59), circular dichroism (CD) 71, 72), MCD 58, 61, 73, 74). Until the demonstration by Ellfolk and colleagues that it is the mixed-valence form of the... 

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) studies on frozen solutions of TDTA in tetrahydrofuran (THE) allowed estimates of its spin density distribution <2005JCD3838>. A comparison with that of TTTA <2001JMC1992> determined by similar methods shows that replacement of N of TTTA by isoelectronic C-H groups results in greater localization of spin density on the dithiazolyl ring. 

Analysis of antioxidant properties relative to the DPPH" radical involves observation of colour disappearance in the radical solution in the presence of the solution under analysis which contains antioxidants. A solution of extract under analysis is introduced to the environment containing the DPPH radical at a specific concentration. A methanol solution of the DPPH radical is purple, while a reaction with antioxidants turns its colour into yellow. Colorimetric comparison of the absorbance of the radical solution and a solution containing an analysed sample enables one to make calculations and to express activity as the percent of inhibition (IP) or the number of moles of a radical that can be neutralised by a specific amount of the analysed substance (mmol/g). In another approach, a range of assays are conducted with different concentrations of the analysed substance to determine its amount which inactivates half of the radical in the test solution (ECso). The duration of such a test depends on the reaction rate and observations are carried out until the absorbance of the test solution does not change [4]. If the solution contains substances whose absorbance disturbs the measurement, the concentration of DPPH radical is measured directly with the use of electron paramagnetic resonance (EPR) spectroscopy. 

Electron paramagnetic resonance studies have shown that the biacetyl ketyl radical (3) and the radical derived from dioxane are formed when biacetyl is irradiated in dioxane solution.51 Nonphotochemically generated radicals derived from dioxane and cyclohexane add to biacetyl to yield acylated product.56 If cleavage were occurring in addition to or instead of hydrogen abstraction, one would expect to find at least moderate yields of acylated products in all solvents instead of just those which produce the least stable solvent radical. 

The reaction of cobalt(II) porphyrins with CO has been studied by Wayland et al. (153-156) in some detail by electron paramagnetic resonance (EPR) in frozen solutions. They conclude that Co(II)TPP forms an axially symmetric weakly bonded 1 1 adduct with CO (153-156). To the best of our knowledge, there are no other studies on CoP-CO complexes, neither experimental nor theoretical. 

The blue solution is characterized by (I) its color, which is independent of the metal involved (2) its density, which is very similar to that of pure ammonia (3) its conductivity, which is in the range of electrolytes dissolved in ammonia and (4) its paramagnetism, indicating unpaired electrons, and its electron paramagnetic resonance g-factor, which is very close to that of the free electron. This has been interpreted as indicating that in dilute solution, alkali metals dissociate to form alkali metal cations and solvated electrons ... 

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