Infrared spectroscopy halides

Infrared spectroscopy is not as inherently informative with regard to metal interactions in highly symmetrical metal-metal bound dimers as is Raman spectroscopy, since the totally symmetric metal-metal stretch is a forbidden absorption in the infrared experiment. Oldham and Ketteringham have prepared mixed-halide dimers of the type Re2ClxBr 2xto lower the symmetry and hence introduce some infrared allowedness into the Re-Re stretching mode (206). Indeed, the appearance of a medium-intensity band at 274 cm 1 in the infrared spectrum of the mixed-halo species was considered to be the result of absorption by the metal—metal stretching vibration, which was also observed in the Raman spectrum at 274 cm ". ... 

The compression of a solid to transparency is really not new. A standard technique in infrared spectroscopy is the use of mulls made of the heavier alkali halides. These materials are squeezed transparent at relatively low pressures. However, when these low pressures are used, evacuation of the sample is essential. In our work, evacuation is not necessary. A reasonable review of the alkali halide work is given by Ford, Wilkinson, and Price (4). 

The halide ions are strong hydrogen-bond acceptors. The infrared spectroscopy data for halides show clearly the characteristic shifts associated with hydrogen-bond acceptors, in the sequence... 

The arena of mononuclear carbonyl complexes of iridium is dominated by Vaska s compound, [IrCl(CO)(PPh3)2] (29), and its variants. The most conunon variation found in the literature comes from replacement of the chloride ligand with other monoanionic hgands such as halides and pseudohalides. Infrared spectroscopy has been used (by examining... 

Zeng, Y. R, Sharpe, S. W., Shin, S. K., Wittig, C., and Beaudet, R. A., Infrared spectroscopy of C02 D(H)Br Molecular structure and its reliability, J. Chem. Phys. 97, 5392-5402 (1992). Muenter, J. S., Potential functions for carbon dioxide-hydrogen halide and hydrogen halide dimer van der Waals complexes, J. Chem. Phys. 103, 1263-1273 (1995). 

Because the reflectivity at energies near the TO mode is strongly frequency-dependent, this effect has been used with alkali halides in infrared spectroscopy... 

D.E.H. Jones and J.L. Wood (ref. 7) used infrared spectroscopy to study the chloride complexes of acidic A1C13. The study of the complexation of acetyl chloride by the various metal halides (Table 1) was performed by measuring the variation of the vibration intensity (CO) at 1808 cm. ... 

Zaera F, Hoffmann H and Griffiths P R 1990 Determination of molecular chemisorption geometries using reflection-absorption infrared spectroscopy alkyl halides on Pt(1 )J. Electron. Spectrosc. Relat. Phenom. 54/55 705-15... 

There are three general methods available for examining solid samples in transmission infrared spectroscopy, i.e, the use of alkali halide discs, mulls or films. Your choice of method depends very much on the nature of the sample to be examined. 

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