Oxidation magnetic field effects

A2. Alderman, D. W., Improvement of signal-to-noise ratio in continuous-wave nuclear magnetic resonance at liquid-helium temperature by using a metal oxide semiconductor field-effect-transistor radio-frequency amplifier. Rev. Set. Instrum. 41, 192-197 (1970). 

The proposed reaction mechanism of phenols with O2 catalyzed by Co-amine complexes is shown in Scheme 47. On oxidation of 2,6-dimethylphenol (206) to 2,6-dimethyl-p-benzoquinone (223), magnetic field effects in the cobalt(II)-catalyzed oxidations were examined by using two different high- and low-spin cobalt(II) complexes. The former complex, Co bis(3-(salicylideneamino)propyl)methylamine, Co SMDPT (S = 3/2), displays a maximum increase in the initial rate of ca 1000 G, while the low-spin cobalt complex, Co iV,iV -bis(salicylidene)ethylenediamine, Co salen (S = 1/2), in a 1 10 ratio with pyridine displays a maximum decrease in the initial rate at ca 800 G. The difference in the magnetokinetics of both complexes is explained by magnetic field effects on the singlet-triplet (S-T) radical pair and triplet-triplet (T-T) annihilation reactions... 

Magnetic field effects on the oxidation rate of 2,6-DTBP catalyzed by Co(NMesalpr) and Mn(NMesalpr) have been revealed [44,45]. 

Afanasyeva, M. A., Taraban, M. B., Purtov, P. A., Leshina, T. V., Grissom, C. B. (2006). Magnetic field effects in enzymatic reactions Radical oxidation of NADH by horseradish peroxidase. Journal of the American Chemical Society, 128, 8651. 

The magnet current can be controlled with the aid of gate-turn-on thyristors (GTOs), metal-oxide semiconductor field-effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs). The latter are most powerful with respect to maximum current... 

On the other hand, internal magnetic fields at the iron nucleus arising from the magnetic moments of unpaired valence electrons can be much stronger than any applied field and their effect can easily exceed the quadrupole interaction. For instance, Mossbauer nuclei in magnetic materials such as metals or oxides may experience fields of 30-50 T even without applied field. Similarly, the typical... 

Mossbauer spectroscopy is one of the techniques that is relatively little used in catalysis. Nevertheless, it has yielded very useful information on a number of important catalysts, such as the iron catalyst for Fischer-Tropsch and ammonia synthesis, and the cobalt-molybdenum catalyst for hydrodesulfurization reactions. The technique is limited to those elements that exhibit the Mossbauer effect. Iron, tin, iridium, ruthenium, antimony, platinum and gold are the ones relevant for catalysis. Through the Mossbauer effect in iron, one can also obtain information on the state of cobalt. Mossbauer spectroscopy provides valuable information on oxidation states, magnetic fields, lattice symmetry and lattice vibrations. Several books on Mossbauer spectroscopy [1-3] and reviews on the application of the technique on catalysts [4—8] are available. 

IR spectra, 27 283, 284 magnetic measurements, 27 280 oxidized state, 27 289 Raman spectra, 27 284 reduced state, 27 291 reflectance spectroscopy, 27 279 X-ray diffraction, 27 272, 273 support interactions, 27 290 Cobalt monoxide, field effect, 27 44, 45 Cobalt(nickel)-molybdenum-sulfide catalysts, 42 417... 

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