Comparison with mechanical spectroscopy

Macrocycles and other concave structures, acid-base behaviour in, 30,63 Macromolecular systems in biochemical interest, 13C NMR spectroscopy in, 13,279 Magnetic field and magnetic isotope effects on the products of organic reactions, 20,1 Mass spectrometry, mechanisms and structure in a comparison with other chemical processes, 8, 152... 

The limitation in all of these flash experiments is that only broad featureless UV/vis bands are observed and hence assignment has to rely on comparison with matrix data and/or kinetic consistency. How much more informative vibrational spectroscopy would be There is good reason to be optimistic as in the recent work of Schaffner (8), where, incidentally, it is shown how important a role is played by traces of H2O in the detailed mechanism of the photochemistry of Cr(C0)6 ... 

The detailed mechanism of P aeruginosa CCP has been studied by a combination of stopped-flow spectroscopy (64, 65, 84, 85) and paramagnetic spectroscopies (51, 74). These data have been combined by Foote and colleagues (62) to yield a quantitative scheme that describes the activation process and reaction cycle. A version of this scheme, which involves four spectroscopically distinct intermediates, is shown in Fig. 10. In this scheme the resting oxidized enzyme (structure in Section III,B) reacts with 1 equiv of an electron donor (Cu(I) azurin) to yield the active mixed-valence (half-reduced) state. The active MV form reacts productively with substrate, hydrogen peroxide, to yield compound I. Compound I reacts sequentially with two further equivalents of Cu(I) azurin to complete the reduction of peroxide (compound II) before returning the enzyme to the MV state. A further state, compound 0, that has not been shown experimentally but would precede compound I formation is proposed in order to facilitate comparison with other peroxidases. 

In the preceding decade, solid-state NMR spectroscopy has provided important and novel information about the nature and properties of surface sites on working solid catalysts and the mechanisms of these surface reactions. This spectroscopic method offers the advantages of operation close to the conditions of industrial catalysis. A number of new techniques have been introduced and applied that allow investigations of surface reactions by solid-state NMR spectroscopy under both batch and flow conditions. Depending on the problems to be solved, both of these experimental approaches are useful for the investigation of calcined solid catalysts and surface compounds formed on these materials under reaction conditions. Problems with the time scale of NMR spectroscopy in comparison with the time scale of the catalytic reactions can be overcome by sophisticated experimental... 

Despite its importance, our knowledge about GO is still limited [27, 28], For example, due to its amorphous and nonstoichiometric character, the atomic structure of GO is not very clear. Many experimental studies on GO structure have been reported. However, structure characterization of systems as complicated as GO requires a combination of both experimental and theoretical efforts. Recently, there are significant progresses on the theoretical sides. First-principles calculations have been used to compare stabilities of different GO structure models. More importantly, computational spectroscopy strategy has also been used to make a direct comparison with experimental data and thus obtain deeper insights for GO structure. At the same time, electronic structure and other properties of GO can also be predicted by computational studies. The most difficult part is the understanding of the mechanisms of oxidation and reduction, which also requires an intense theoretical study. In this review, we will focus on recent progresses in theoretical studies on GO. Structure characterization based on computational spectroscopy is specially emphasized. 

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