Vapor-phase infrared spectra

Nyquist, R. A. "The Interpretation of Vapor-Phase Infrared Spectra", vol. 1 Sadtler Research Labs Philadelphia, PA, 1984. Socrates, G. "Infrared Characteristic Group Frequencies" ... 

Nyquist, R.A. (1984). Interpretation of Vapor-Phase Infrared Spectra. Philadelphia Sadtler-Heyden. 

Dirinck et al., " successfully apphed GC/FTIR to the analysis of amphetamine-like compounds in judiciary exhibits. With fight-pipe GC/FTIR, unique vapor-phase infrared spectra were generated, allowing the unambiguous differentiation between closely related amphetamines. The obtained vapor-phase spectra were submitted to a spectral search on a laboratory-made vapor-phase FTIR library. Several amphetamine analogues have been identified in confiscated powders and tablets using this approach. 

Miyazawa, Shimanouchi and Mizushima9, Jones30 and Hallam and Jones31 examined the vapor phase infrared spectrum of NMA but it has not been possible to deduce the predominant conformation of the molecule from the available data (although N-methylformamide was concluded to exist primarily as the trans con-... 

The allene contains up to 3% of 2-chloropropene, determined by its vapor-phase infrared spectrum and by vapor-phase chromatography (cf. Note 5). 

Figure 10. Vapor-phase infrared spectrum of basic component Peak A (Figure 9). Component identified as 2,4-dimethyl-6-ethylpyridine. Helium flow rate 10.5 mL/min, 6-sec scan.

The most detailed investigation and the only one which combines both infrared and Raman spectra is mainly concerned with the dibenzene-chromium cation, [(CgH6)2Cr]+ (38). However, the infrared spectra of uncharged complexes were also given. Due to the dark color and low solubility of dibenzenechromium(O), as well as the similarity of solvent absorptions, only the inner vibrations of the complex framework were observable in the Raman spectrum of its benzene solution. While in this work (38) the partial vapor phase infrared spectrum of (CgH6)2Cr was also reported, another study described the infrared spectrum of the uncharged complex at — 180° C. The main purpose of this paper (115) was the comparison of the infrared spectrum of dibenzenechromium and benzene with that of ferrocene. 

The vapor pressure of /i-[(CH3)2N]B2H5 obeys the relationship log P = 2158.56/T + 1.75 log T - 0.008061T + 7.518831 (101 torr at 0°). The gas-phase infrared spectrum has been reported in detail.5 The compound is a useful intermediate in the synthesis of other boron nitrogen compounds, including those containing NBNB6 and PBNB7 chains, and Na[(CH3)2-N(BH3)2].8 The compound can be stored at 25° for months in sealed, evacuated Pyrex tubes. It is soluble in ethers and aromatic hydrocarbons, but is attacked by protic solvents. 

Fig. 14.7 shows the vapor-phase infrared absorption spectrum of HCl, which involves rotational transitions occurring simultaneously with the fundamental vibrational transition u = 1 <— v = 0. 

The vapor-phase Raman spectrum of SF5CI (17), the argon-matrix Raman and infrared spectra of SF5CI and SFsBr (18), and the vapor-phase infrared and liquid-phase Raman spectra of SFsBr 19), as well as photoelectron diffraction 20) and microwave spectra of SF5CI 21) and SFjBr 22) have been reported. The ionization potential of SF5 (9.65 eV) has been measured by photoionization mass spectrometry of SF5CI (23). 

Sigrist, Manzardo, and Amado investigated the behavior of 3-methyl-2,4-non-anedione under photooxida-tive conditions. The structure of main oxidation product, 3-hydroxy-3-methyl-2,4-non-anedione, was tentatively assigned based on mass (GC/MS) and vapor-phase infrared (GC/FTIR). The infrared spectrum showed the status of the OH group, and the structure was easily assigned to a-hydroxy- (3-diketones. 

Infrared spectra of polymers are also obtained in a rapid screening mode by pulse pyrolysis-FTIR using solid samples (ca. 0.1-0.5 mg) that are placed "as is" into the Pyroprobe-Pyroscan-FTIR system for semi-quantitative, qualitative information. The vapor phase IR spectrum in Figure 3a is that from a pulse pyrolysis (750 C for 10 sec) of a 100 mg sample of solid poly(styrene). The thermal decomposition of poly(styrene) to its slyrene... 

Valence Vibrations. pCH and pCD. In the 3100 cm region the infrared spectrum of thiazole shows only two absorptions at 3126 and 3092 cm F with the same frequencies as the corresponding Raman lines (201-4) (Fig. I-IO and Table 1-23). In the vapor-phase spectrum of... 

Figure 15-2 Infrared spectrum of ethanol (a) in the vapor phase and (b) as a 10% solution in carbon tetrachloride...

I. Spectroscopic Determinations. Gas-phase infrared spectra provide a useful adjunct to vapor pressure measurements in the identification of volatile materials. The cell illustrated in Fig. 9.15 allows the sample to be quantitatively returned to the vacuum line after the spectrum has been obtained, so the process is completely nondestructive. The primary problem with a gas cell is to obtain a vacuum-tight seal between the window material and the cell body this may be accomplished with Glyptal paint or with wax- If the latter is used, it is necessary to warm and cool the alkali halide windows slowly to avoid cracking them due to thermal stress. For this purpose an infrared lamp is handy. The most satisfactory method of attaching windows is O-rings because this allows the easy removal of the windows for cleaning and polishing. 

Phosphine prepared by this method exhibits a vapor pressure of 170 1 mm. at —111.6°C. (CS2 slush). The literature value is 171 mm.8 Infrared9 and mass spectral10 data have been reported. The infrared spectrum shows t pH at 2327 cm.-1 and also peaks at 1121 and 900 cm.-1. In the gas phase, all these bands show complex fine structure. 

Fluorination of partially oxidized Re with fluorine in a Knudsen cell at 350°C results in the vapor phase oxide fluorides, Re03F, Re02F3 and ReOF4 which have been proposed on the basis of the cations detected in the mass spectrum [325], The oxide fluorides, Re03F, Re02F3, ReOF5 and ReOF4 have been studied by infrared and UV/VIS spectroscopy in inert-gas matrices [340],... 

As noted, various simple carbonyls have molecular structures in solution diiferent from those in the solid state. The structure of the molecules in the vapor state may be different again. It has been found that the infrared spectrum in the CO-stretching region of [C5H5Ni(CO)]2 in solution contains two bands, but there is only one band in the gas-phase spectrum (142, 235). Furthermore, mass spectroscopic studies have shown various anomalies between structures of certain compounds in the gas phase and in solution. Infrared spectroscopic studies are now in progress to ascertain the structure of the compounds [C6H5M(CO)3]2 (M = Cr, Mo, or W), [C5HbM (CO)2]2 (M = Fe, Ru, or Os), M"3(CO)i2 (M" = Fe, Ru, Os), and M" 4(CO)i2 (M " = Co, Rh, or Ir) in the vapor state (159). 

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