Vibrational spectroscopic studies

Vibrational spectroscopic studies of heterogeneously catalyzed reactions refer to experiments with low area metals in ultra high vacuum (UHV) as well as experiments with high area, supported metal oxides over wide ranges of pressure, temperature and composition [1]. There is clearly a need for this experimental diversity. UHV studies lead to a better understanding of the fundamental structure and chemistry of the surface-adsorbate system. Supported metals and metal oxides are utilized in a variety of reactions. Their study leads to a better understanding of the chemistry, kinetics and mechanisms in the reaction. Unfortunately, the most widely used technique for determining adsorbate molecular structure in UHV,... 

Bowmaker, G. A. Kennedy, B. J. Reid, J. C. Crystal structures of AuCN and AgCN and vibrational spectroscopic studies of AuCN, AgCN, and CuCN. Inorg. Chem. 1998, 37, 3968-3974. 

Vibrational Spectroscopic Studies of Adsorbate Competition During Carbon Monoxide Adsorption on Platinum Electrodes... 

M. Baranska, H. Schulz, S. Reitzenstein, et al.. Vibrational spectroscopic studies to acquire a quality control method of Eucalyptus essential oils. Biopolymers, 78, 237-248 (2005). 

The results of a vibrational spectroscopic study of the SO2 complexes [RuX(S02)(NH3)4]" (X = Cl, Br) and [Ru(H20)(S02)NH3)4] + have been reported the j/(sym) and j/(asym) modes of the 5 -bound SO2 ligand come at lower frequencies than those of the free molecule. The ammonium salt of the sulfito complex tra 5-[Ru(S03-5)2(NH3)4] 4H20 has been structurally characterized. Although the crystals are stable when retained in the mother liquor, the isolated compound is only stable at 298 K for several days. Relationships between the structural and vibrational spectroscopic data are discussed. ... 

Due to limitations in signal-to-noise ratio available for the then common dispersive IR instruments, peptide and protein vibrational spectroscopic studies shifted to emphasize Raman measurements in the 1970s 29-32 Qualitatively the same sorts of empirical correlations as discussed above have been found between frequencies of amide bands in the Raman and secondary structure. However, due to the complementary selection rules for Raman as compared to IR and to the multi-component nature of these polymeric spectral bands, the... 

ML c(2 x 2) ordered phase corresponds to the coverage beyond which this transition occurs, but photoelectron and vibrational spectroscopic studies show that there is typically co-occupation of both states when the well-ordered c(2 x 2) LEED pattern is seen. The use of the photoelectron binding energy shifts in the PhD... 

Teplyakov, A. V., Kong, M. J. and Bent, S. F. Vibrational spectroscopic studies of Diels-Alder reactions with the Si(100)—2 x 1 surface as a dienophile. Journal of the American Chemical Society 119, 11100 (1997). 

Comparisons with the vibrational spectroscopic studies of the adsorption and dehydrogenation of ethene on single-crystal Pt surfaces (Section X.B.l) show that the di-cr-C2H4 to ethylidyne conversion occurs on (111) facets of the Pt crystallites of the catalysts. It is considered that the di-cr -C2H4 species occur on metal sites on which this conversion is not allowed, perhaps on (100), (110), or (210) facets. It is not clear whether the labile it-C2H4 species is formed on amorphous areas of the clean Pt particles or whether it occurs on sites which are affected by proximity of the metal oxide support (408) we favor the former possibility. 

Vibrational, spectroscopic studies of water and carbohydrate solutions have been performed, in order to provide information on the nature and variety of hydrogen bonding between molecules (see Sections 11,3 and V,2). It is generally accepted208,209 that i.r.- and Raman-spectral results concerning... 

Although we have presented here only two examples of pressure tuning vibrational spectroscopic studies with aqueous surfactants, we hope that they are sufficient to demonstrate the uniqueness of pressure as a physical parameter in the investigation of the structural and dynamic properties of aqueous surfactants. For many systems, the vibrational spectra at atmospheric pressure are very similar. Yet, the pressure tuning of these spectra will be able to provide additional information about the structure of the surfactant molecules and about their aggregation in water. 

Johnston, C.T. Stone, D.A. Applewhite, L.A. Vibrational spectroscopic study of tire kaolinite-hydrazine intercalation complex. The Third Conference on the Environmental Chemistry of Hydrazine Fuels, Panama City, FL 15-17 Sept. 1987 1987, ESL-TR-87-74,118. 

As outlined above, vibrational spectroscopic studies have been used largely in order to elucidate the nature of the bonding between boron and nitrogen in 1,3,2-diazaboracycloalkanes by relating BN stretching modes with the bond order. It is worth noting, however, that the frequency of the antisymmetrical BN valence vibration appears to be relatively independent of the electronic nature of exocyclic substituents at either the nitrogen or the boron atom 28>. 

---