Electron Spectroscopic Studies

2 and 533.6 eV, assigned to acidic, respectively, basic OH groups. This assignment, however, does not take into account the presence at the rutile surface of chemisorbed molecular water. 

On the basis of these observations, Lo et al. have postulated that the T ions, present on the surface of a Ti02 photoanode, play an essential role in the process of photo-oxidation of water and that, on the other hand, the stoichiometric Ti02 should be 

3 Nuclear Magnetic Resonance Spectroscopy of the Ti02 Surface 

The analysis of the NMR spectra of the samples with different extents of hydration, according to the above model, enabled to calculate the coverages of the hydroxyl groups and of the molecular water. For the less dehydrated sample, approximately half of the total amount of 9 equivalent water molecules per square nanometer of the surface was found to be present in the form of the OH groups. The resulting concentration of ca. 

On the basis of the results obtained for the samples with varying extents of hydration, the dehydration appears to proceed through the simultaneous removal of molecular water and of a restricted number of hydroxyl groups. In addition, the final loss of water was associated with the broadening of the NMR spectra, observed for the relatively dehydrated samples, explained by the appearance of the paramagnetic sites. 

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A"-Ray structure determinations (see Chapter 11 for details) have been reported for triphenylphosphine oxide, tri-o-tolylphosphine oxide, sulphide, and selenide, and for cw-2,2,3,4,4-pentamethyl-l-phenylphos-phetan-1-oxide (5). Electron spectroscopic studies of phosphorus oxychloride and thiophosphoryl chloride in the gaseous state, and n.m.r., i.r., and u.v. spectra of phosphine sulphides have appeared. Dipole moments have been used to define the stereochemistry of 2-cyanoethylphosphine oxides, such as (6), which is shown in its preferred conformation. 

Rao, C.N.R., Kamath, P.V. andYashonath, S. (1982) Molecularly adsorbed oxygen on metals electron spectroscopic studies. Chemical Physics Letters, 88, 13—16. 

The first electron spectroscopic study of adsorbed hydrocarbons was that reported by Eastman and Demuth (78) who used He radiation to probe the valence electrons of benzene, acetylene, and ethylene. Figure 17 shows the difference spectrum of C2H4 adsorbed on Ni(lll) at 100 and 230 K compared with the results of Clarke et al. (79) for ethylene adsorption on Pt(lOO) at 290 K, propylene adsorption on Pt(lOO), and ethylene adsorption on Pt(lll). 

NMR, microwave and He(I) photo-electron spectroscopic studies on this compound have been reported (.12, 13.) ... 

The metal polymer interface can be studied in a variety of ways using surface science methods. Recently, much emphasis has been placed on the understanding of the initial stages of metallization of polymers. In particular, the role of metal-organic interactions as they relate to the fundamentals of adhesion mechanisms are of interest. One experimental approach is to examine the first monolayers of metal as they are deposited on a polymer surface (1), i.e the polymer is the substrate. However, the organic polymer-metal interface may be studied in the opposite perspective, via understanding the roles of organic molecular or macromolecular structure and chemistry of the metal surface qua substrate (2). In the present paper, recent ion and electron spectroscopic studies of the... 

The second term is temperature-independent paramagnetism and can be verified independently if A, is known from spectral studies. This is an excellent example of the complementary data that may be obtained from magnetic susceptibility and electronic spectroscopic studies. 

Henrich, V. E. (1987). Electron spectroscopic studies of perfect and defect metal oxide surfaces. Phys. Chem. Mineral. 14, 396-400. 

The general conclusion to be drawn from electronic spectroscopic studies is that the model considering only the -d interactions is satisfactory. The absence of reliable data for many transition metals does not allow us to study the effects of variation of metal d-orbital energy by this technique. 

Electron spectroscopic studies have been undertaken early on by Zhang and Henrich and by the Horn group [167-171]. The latter group, however, has been more interested in bulk than in surface properties. Fig. 36 shows a photoemission spectrum of 205(00 ) at the top of the lower panel taken in the authors laboratory. It may be interpreted on the basis of calculations by Klaus Hermann and his group [172]. Briefly, the spectrum is dominated by 02p/02s emissions and there is a minor admixture of the V3d wave functions in the panel showing the results of the calculations. There are no features near the Fermi energy which would, if they were present, be characteristic for defects leaving V atoms in lower oxidation states. 

We begin with a brief overview of the findings from the limited number of theoretical calculations, photoelectron and electronic-spectroscopic studies, and other physical measurements on terminal metal-alkynyl complexes in order to provide a context for discussing the results of X-ray... 

Evans S. and Raftery E. (1982) Electron spectroscopic studies of galena and its oxidation by microwave-generated oxygen species and by air. Chem. Soc. Faraday Trans. 78, 3545-3560. 

Pratt A. R., Muir I. J., and Nesbitt H. W. (1994a) X-ray photoelectron and Auger electron spectroscopic studies of pyrrhotite and mechanisms of air oxidation. Geochim. Cosmochim. Acta 58, 827-841. 

Electron spectroscopic studies by Coughlan show that in 27% Ni " L the nickel is located in the main tunnels of the hydrated zeolite, but on dehydration Ni + migrates to less accessible sites as indicated by increasing inaccessibility to both water and ammonia. In contrast to this, migration of Ni " into hexagonal prisms in Y zeolite could be reversed by admitting ammonia to the system. ... 

McDowell and coworkers (15J studied the high resolution infrared spectrum of UF5 at ambient and low temperatures. This work was followed by a series of vibrational and electronic spectroscopic studies of matrix isolated UFg (16,17,18,19,20). In the first experiments, UFg deposited in Ar or CO matrices was vibrationally characterized by infrared spectroscopy and then exposed to broadband UV radiation at 10°K. In argon, photoreduction proceeded rapidly the 619 cirri UF5 infrared peak decreased in intensity while two new peaks grew in at 584 cirri anc 561 cirri. The new peaks were assigned to the expected UF5 photolysis product and a tentative C4V structure assignment was made. The wavelength dependence of the photoreduction was studied using a monochroma-tized UV source (1 kw Hg-Xe lamp, Schoeffel 6M-250 monochromator). The relative quantum efficiency of the UF5 dissociation per unit absorbance of UFg was found to be relatively constant in the allowed B-X absorption band (250-300 nm) (T7). Radiation in the... 

Miscellaneous. - Photo-electron spectroscopic studies on (17a) afford evidence for a transannular n-rr interaction and this is firmly supported by the rapid reaction of (17a) with acids to give (17b).27 PE speotra and MINDO/3 calculations on 2-azabicyclo[2.2. l]hept-5-ene (and its N-OH derivative) have... 

K. Hashimoto, K. Asami, K. Teramoto, An X-ray photo-electron spectroscopic study on the role of molybdenum in increasing the corrosion resistance of ferritic stainless steels in HCl, Corros. Sci. 19 (1979) 3-14. 

The photochemical activation of hydrocarbons by 430 was the first such report for any group 9 Tp complex,and has subsequently been the subject of numerous independent mechanistic studies. The earliest of these involved matrix isolation (Ar, CH4, N2, CO) infrared and electronic spectroscopic studies of 430, and its analogue Bp Rh(CO)2 (262). On this basis it was established that the initial photoreaction results in loss of CO and mono-dechelation of the, initially ic, Tp ligand to afford (K -Tp )Rh(CO), which in N2 and CO matrices was rapidly trapped. It was also noted that at 12K no evidence of C-H activation was observed in either the methane matrix, or in Nujol muUs. However, at 77 K activation of Nujol was observed, thus establishing a thermal requisite for the C-H activation step, i.e. while photolysis generates the active species , subsequent C H oxidative addition is a thermal process. 

In acetonitrile 18S6 fails to coordinate to ]anthanide(III) perchlorates, but it does so in CH2CI2 to yield complexes of stoichiometry Ln[C104]3 18S6-HjO (Ln = Sm, Eu, Yb) [158]. Although no structural data are available, electronic spectroscopic studies of these complexes establish interaction between Ln(III) and 18S6. 

Sundgren, J. E., Bodo, P., Lunstrom, I., et al., "Auger Electron Spectroscopic Studies of Stainless-Steel Implants, Journal of Biomedical Materials Research, Vol. 19, 1985, pp. 663-671. 

Eberhardt MA, Houalla M, Hercules DM (1993) Ion scattering and electron spectroscopic study of the surface coverage of V/AI2O3 catalysts. Surf Interface Anal 20 (9) 766-770... 

H20. Mass spectrometry confirmed that the product was [ 0]-hydroxyatrazine and thus the reaction was hydrolytic. More recendy, further mechanistic studies have revealed that atrazine chlorohydrolase coordinates ferrous iron, which is essential for its catalytic activity (29). Incubating atrazine chlorohydrolase with the chelators 1,10-phenanthroline or oxalic acid removed the required metal with concomitant loss of activity. Chlorohydrolase activity was restored by the addition of Fe(II), Mn(II), or Co(II) salts. Electron paramagnetic resonance (EPR) and electronic spectroscopic studies provided data consistent with a 1 1 metal to subunit stoichiometry. In total, the data indicate that atrazine chlorohydrolase is a metalloenzyme, making this the first report of a metal-dependent hydrolytic dehalogenase. 

An electron spectroscopic study was recently performed on the y-a transition (CeTh and not on Ce because of certain practical reasons). 

Cu Cl. Condensation reactions of iV-sulphinylarenesulphonamides with diaryl selenones afforded iminoselenones of type (134) in excellent yields, the structures of which were confirmed by i.r. and electron spectroscopic studies. ... 

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