IR spectroscopic investigations

Our studies also included IR spectroscopic investigation of the observed ions (Fig. 6.2). John Evans, who was at the time a spectroscopist at the Midland Dow laboratories, offered his cooperation and was able to obtain and analyze the vibrational spectra of our alkyl cations. It is rewarding that, some 30 years later, FT-IR spectra obtained by Denis Sunko and his colleagues in Zagreb with low-temperature matrix-deposition techniques and Schleyer s calculations of the spectra showed good agreement with our early work, considering that our work was... 

It has been shown by IR-spectroscopic investigations which evidence on the appearance of new absorption bands after chitosan introducing, elementary analyses data. (N, occurrence in the samples, which quantity depends on chitosan nature and isolation conditions) It leads to significant increase of sorption capacity and specific surface of sorbents, which contain chitosan from silk waren chrysalises. Where as these parameters decrease for sorbents with chitosan from crabs. Evidently it is connected to more dense structure of the last one. It has been shown, that yield of sorbent on the base of PES and chitosan obtained by sol-gel method has depended significantly on such factors as components ratio, temperature, catalyst quantity etc. 

Hi. Pentacoordinated complexes. The structures of tris(stannyl)amines could not be determined exactly. On the one hand, IR spectroscopic investigations indicate a pyramidal... 

A 1 2 mixture of l-methyl-3-ethylimidazolium chloride and aluminum trichloride, an ionic liquid that melts below room temperature, has been recommended recently as solvent and catalyst for Friedel-Crafts alkylation and acylation reactions of aromatics (Boon et al., 1986), and as solvent for UV/Vis- and IR-spectroscopic investigations of transition metal halide complexes (Appleby et al., 1986). The corresponding 1-methyl-3-ethylimidazolium tetrachloroborate (as well as -butylpyridinium tetrachlo-roborate) represent new molten salt solvent systems, stable and liquid at room temperature (Williams et al., 1986). 

This species was proposed to play an important role in the catalytic activation of H202 on TS-1. IR spectroscopic investigations showed that a Ti(t 2-OOH) moiety oxidized small alkenes at room temperature in the dark (propene) or upon photoexcitation (ethene). These data appear to be the first direct detection of the active oxidation site in H202-loaded titanium silicalite (Lin and Frei, 2002). 

Special problems arise in quantitative IR spectroscopic investigations of pure fluids at high pressure. In this case, the optical path length should usually be as short as several pm. These distances are of about the same size as the changes of path length induced by applying pressure and temperature in cells of the type shown in Figures 6.7-4 and 6.7-5. Moreover, it is extremely difficult to join the parts of such a cell in a way which affords a... 

Kuhlmaim U, Jantoljak H, Pfander N, Bernier P et al (1998) Infrared active phonons in single-walled carbon nanotubes. Chem Phys Lett 294(l-3) 237-240 Zawadzki J (1980) Ir spectroscopic investigations of the mechanism of oxidation of carbonaceous films with HNO3 solution. Carbon 18(4) 281-285... 

Gasheva, L.M. Kalinkova, G. Minkov, E. Krestev, V. IR spectroscopic investigations of amoxicillin trihydrate included in the technological models sirup granules in ethylcellulose. J. Mol. Struct. 1984, 115, 323-326. 

Kalinkova, G. Krasteva, S. IR-Spectroscopic investigation of interactions in the drug preparation nystatin-plaque. In Recent Developments in Molecular Spectroscopy, Jordanov, B., Kirov, N., Simova, P., Eds. World Scientific Singapore, 1989 705-709. 

IR spectroscopic investigation of intermolecnlar interactions with phenols has a long history. Phenols are freqnently nsed as convenient model proton donors in the study of intermolecularly hydrogen bonded systems. Differently snbstitnted phenols are characterized by a range of different acidities, and complexes can be stndied with a wide variety of proton acceptors. The most commonly adopted acceptors are O and N bases. A special case is carbon monoxide that in complexes with phenols apparently forms ArOH- CO contacts (rather than ArOH- OC). Here we mention some recent investigations with typical proton acceptors like water, alcohols and amines. 

Ruggiero, P., Interesse, F. S., Cassidei, L., and Sciacovelli, O. (1981). H NMR and IR spectroscopic investigations on soil organic fractions obtained by gel chromatography. Soil Biol. Biochem. 13, 361-366. 

According to IR spectroscopic investigations with compounds of type 192 a solvent dependent equilibrium between the sesquiacetylenic structure 192a and the allenic structure 192b was formulated. The result that sesquiacetylenes can be IR spectroscopically detected only in the presence of HMPT or TMEDA and partly in THF as the solvent, however, is not in agreement with the earlier report of the same author where those species had been detected by NMR spectroscopy also in diethyl ether as the solvent. 

Upon dissolution of physical mixtiues (blends) of PTFE micropowders (without carboxylic acid groups) and PA-6 in formic acid, pure PTFE separates very fast from the solution. If the new melt-modified PTFE polyamide materials (PTFE irradiated 2,000 kGy) are dissolved in formic acid, the separation is very difficult. After separation of the insoluble content by centrifugation and ehmination of the soluble pure polyamide, the presence of an amide bond R1-CF2-CO-NH-CH2-PA between the PTFE and e.g. PA-6 was proved by IR spectroscopic investigations. The 1,708-cm band in the IR difference spectrum (Fig. 8 blue line) deriving from the direct PTFE polyamide linkage was in agreement with the IR spectra of low molecular model substances. 

Compared with NMR spectroscopy, vibrational spectroscopy plays a much less deeisive role in the characterization of boron-containing heterocycles because of the lack of vibrations which could give characteristic information about structure and bonding in most cases. Best suited for IR spectroscopic investigations are unsaturated rings with <2=C double bonds. For instance, 2,2,3-triethyl-1,1,4-trimethyl- l/f-2,5-dihydro-l,2-azoniaboratole and 2,2,3,4-tetraethyl-l-methyl-2,5-dihydro-l,2-oxoniaboratole display easily determined v (C=C) vibrations at 1636 cm <75CB395) and 1640 cm <74S350), respectively. 

In order to characterize the supported metal catalysts, various techniques have been applied. The infrared (IR) spectroscopic investigation of adsorbed CO is one such effective method and has been applied to various supported metal catalysts [2-5]. The states of adsorbed CO can be observed directly by IR examination, and reflect the state of supported metal dispersed over the support. Therefore, the information obtained from the examination also reflects the properties of the supports as the dispersion media for metal catalysts. 

Grossmann HP, Arnold R, Burkle KR (19M1) IR spectroscopic investigations of cycloalkanes. Polymer Bulletin, 5 135... 

Complementary IR-spectroscopic investigations revealed that this transition involves an orientation change of TMA molecules from planar to perpendicular, accompanied by the deprotonation of one COOH-group that is chemically bound to the positively charged electrode [68]. 

Electron Optical and IR Spectroscopic Investigation of Coal Carbonization... 

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