Bond paper, electron spectroscopy

The paper presented by J. P. Wightman e aT, examines metal surface before and after bonding with polyimide resins. Again, as in the previous paper, the critical nature of the boundary layer between the adhesive and the metal surface becomes evident. By use of scanning electron microscopy, electron spectroscopy for chemical analyses, and reflectance infrared spectroscopy, the actual surface and boundary layers are examined. This paper develops experimental and theoretical criteria for evaluating new cured adhesives. 

Of special Interest as O2 reduction electrocatalysts are the transition metal macrocycles In the form of layers adsorptlvely attached, chemically bonded or simply physically deposited on an electrode substrate Some of these complexes catalyze the 4-electron reduction of O2 to H2O or 0H while others catalyze principally the 2-electron reduction to the peroxide and/or the peroxide elimination reactions. Various situ spectroscopic techniques have been used to examine the state of these transition metal macrocycle layers on carbon, graphite and metal substrates under various electrochemical conditions. These techniques have Included (a) visible reflectance spectroscopy (b) laser Raman spectroscopy, utilizing surface enhanced Raman scattering and resonant Raman and (c) Mossbauer spectroscopy. This paper will focus on principally the cobalt and Iron phthalocyanlnes and porphyrins. 

A study by Abu-Raqabah and Symons (Abu-Raqabah, A. Symons, M. C. R., J. Am. Chem. Soc., 1990, 112, 8614) has characterized the pyridine-chlorine atom three-electron bonded species Py <— Cl by ESR and UV spectroscopy. In an earlier paper, Breslow and co-workers (Breslow, R. Brandi, M. Hunger, J. Adams, A. D., J. Am. Chem. Soc., 1987,109, 3799) considered ring acylated pyridine-chlorine radicals to be n radicals and anticipated special stability for the 4-carboalkoxypyridine-chlorine radical. 

In this paper, we will report the electronic and catalytic reactivities of the model VC/V(110) surface, and our attempt to extend them to VC powder catalysts. By using high-resolution electron energy loss spectroscopy (HREELS) and NEXAFS techniques, we observed that the surface properties of V(110) could be significantly modified by the formation of vanadium carbide some of the experimental results on these model surfaces were published previously.3-5 We will discuss the selective activation of the C-H bond of isobutane and the C=C bond of isobutene on V(110) and on VC/V(110) model systems. These results will be compared to the catalytic performances of vanadium and vanadium carbide powder materials in the dehydrogenation of isobutane. 

O-H bond. Among such properties a prominent one is the ultraviolet absorption spectrum and the theory may therefore be used for the examination of some of the spectroscopic shifts which accompany the lactam-lactim tautomerization. Much caution must, however, be exercised in this respect. Thus, in a recent paper Kwiatkowski135,137 performed Pariser-Parr-Pople-type calculations on the electronic structure of hydroxypurines, essentially to interpret their ultraviolet spectra. In these calculations he assumed that these compounds exist predominantly in their lactim form, and the results of his calculations, at least for 6- and 8-hydroxypurine, did not seem to contradict this assumption. It is only in the case of the 2-hydroxy isomer that a particularly striking disagreement between theory and experiment led him to admit that this last compound may exist in the lactam form. Calculations carried out for this form gave, in fact, a more satisfactory agreement with experiment.138 As we have seen, unambiguous infrared spectroscopy evidence clearly show s that all three isomers exist essentially in the lactam form. This shows that ultraviolet absorption may provide only very uncertain evidence about the lactam-lactim tautomerism in hydroxypurines and related compounds. 

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