1R spectroscopy

Assume that you are carrying out the base-induced dehydrobromination of 3-bromo-3-methylpentane (Section 11.7) to yield an alkene. How could you use 1R spectroscopy to tell which of two possible elimination products is formed ... 

Acid anhydride, amides from, 807 eleclrostatic potential map of, 791 esters from, 807 from acid chlorides, 806 from carboxylic acids, 795 1R spectroscopy of, 822-823 naming, 786... 

Wentrup et al. demonstrated the formation of imidoylketene (1214), methyleneketene (1215), and ethynamine (1216) during the flash vacuum pyrolysis (10-5 torr) of isopropylidene aminomethylenemalonate by collision activation mass spectroscopy and 1R spectroscopy (88JA1337). The imidoylketene (1214) appeared first at a pyrolysis temperature of 390°C. As the temperature was increased, the imidoylketene (1214) was rapidly converted into methyleneketene (1215). The formation of ethynamine (1216) was prominent in the temperature range 680-740°C, and it was accompanied by a sharp decrease in the signal of methyleneketene (1215), whereas the imidoylketene (1214) was less affected. Compounds 1214-1216 were stable at -196°C, but they polymerized on warm-up. 

Thermolysis (550-650°C/10 4-I0 Torr) of /m-butylaminomethylene-malonate (1707) gave a tautomeric equilibrium of (Z/ >3-hydroxypropene-nitrile and cyanoatetaldehyde (see Scheme 59). The products of thermolysis of 1707 were investigated by 1R spectroscopy at 77° K using a special apparatus. 

It should be noted that n-, is minimized at Ca/P = 1.6, where the intensity of the surface P-OH bands is maximum. This reveals that the surface P-OH interferes with the irreversible adsorption of C02, rather than acting as irreversible adsorption sites for C02. The adsorption mechanism of C02 on CaHAP was investigated by in situ 1R spectroscopy. It was found that the surface C032- and H20 resulted from the physisorbed C02. This fact suggests that C02 is irreversibly adsorbed by the reaction with the surface OH- ... 

Infrared Spectroscopy. Infrared (1R) spectroscopy is also used for understanding the structure of the bimetallic nanoparticles. Carbon monoxide can be adsorbed on the surface of metals, and the 1R spectra of the adsorbed CO depend on the kind of metal. These properties are used for analyzing the surface structure of metal nanoparticles. The inverted core/shell structure, constructed by sacrificial hydrogen reduction, was probed by this technique (44). 

Treatment of polymer films by reactive gases or reactive volatil compounds allows to easily modify polymers containing alcohols, hydroperoxides, carboxylic acids (or acids halides), double bonds or piperidine groups. New functional groups as organic nitrites, nitrates, iodides, acid halides (Cl, F), amides, esters, peresters and nitroxyl radicals can be generated by a single reaction or by combination of two consecutive treatments. The reactions are very efficient on thin films (ca 50-100 pm) and can be controlled by transmission and reflexion 1R spectroscopy. 

Thiazolidine-2,4-dione, 2-dialkylamino-bisimide synthesis, 5, 129 Thiazolidine-2,4-diones 1R spectroscopy, 6, 242 tautomerism, 6, 270 Thiazolidine-2,5-diones synthesis, 5, 138 Thiazolidine-4,5-diones synthesis, 5, 129 6, 316-317 Thiazolidine-2,4-dithiones tautomerism, 6, 270 Thiazolidines UC NMR, 6, 243 conformation, 6, 242, 247 dihydiothiazines from, 2, 93 hydrolysis, 6, 273 1R spectra, 6, 242 ring fission, S, 80 synthesis, 5, 118 6, 316-321 Thiazolidines, imino-tautomerism, 6, 273 Thiazolidines, methyl-conformation, 6, 242 Thiazolidine-2-thione, 3-acyl-reduction, 1, 469 Thiazolidine-2-thione, 4-alkyl-synthesis, 6, 318... 

Infrared (1R) spectroscopy (Section 13.4) A type of spectroscopy that employs infrared light. 1R spectroscopy uses transitions between vibrational energy levels to provide information about the functional groups that are present in a compound. 

Since the early 1950s, 1R spectroscopy has been a routine analytical tool for lignin chemists. In the past, spectra were recorded using the so-called dispersive technique, i.e., with grating-type or prism instruments. In the last decade, Fourier transform infrared (FT1R) spectrometers have become increasingly available for routine laboratory work. 

R spectroscopy is one of the most useful techniques for the characterization of zeolitie materials. It provides information on the nature of OH-groups in the materials and on the framework vibrations. Even more useful is the IR analysis of adsorbed species. Basic probe molecules, such as pyridine, ammonia, or benzene, allow the analysis of acidic sites. CO adsorbed at low temperature also helps to analyze acidic sites, but can also be used for the analysis of noble metal particles in zeolites. 

Problem 19.19 How might you use 1R spectroscopy to determine whether reaction between 2-cyclo-hexenone and lithium dimethylcopper gives the direct addition product or the conjugate addition product ... 

In 2D-1R spectroscopy, the sample is perturbed externally to induce time-dependent fluctuations of the IR signal. The external perturbation can be any perturbation source that can excite chemical species in the system, including mechanical, optical, electrical, magnetic, chemical, thermal and acoustic perturbations. The reorientation of each functional group in the sample with a unique rate, extent, and direction produces resolvable fluctuations in the dynamic IR intensities. The changes are recorded in the dynamic spectra in the form of variation in the intensities, shifts of spectral band positions and changes in the shape of peaks. 

Hunt, N.T. (2008) Ultrafast 2D-1R spectroscopy — method and applications. Spectrosc. Europe, 20, 7. 

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