Of carbonyl bands

Table 7.20 Absorption Frequencies of Single Bonds to Hydrogen Table 7.21 Absorption Frequencies of Triple Bonds Table 7.22 Absorption Frequencies of Cumulated Double Bonds Table 7.23 Absorption Frequencies of Carbonyl Bands...

TABLE 7.23 Absorption Frequencies of Carbonyl Bands All bands quoted are strong. 

TABLE 7.33 Raman Frequencies of Carbonyl Bands Continued)... 

The reactivity of seven resin-bound thiophenol esters toward n.-butylamine (41) varied depending on their structures. The reaction of aromatic thiophenol esters (resins (34-36) took about 24 h to complete as indicated by the complete disappearance of carbonyl band in single bead FTIR spectra. On the other hand, the same reaction with alkyl thiophenol esters (resins 38-40) went to completion in less than 8 hours. The reaction with benzimidazolecarboxylic thiophenol ester (resin (37) was the fastest, finished in 3 h. 

The IR spectrum of dihydroarcyriarubin B (352) showed the presence of carbonyl bands at v ax 1710 and 1770 cm , indicating the presence of a dihydromaleimide function. The H-NMR spectrum showed the presence of an AB quartet at 5 4.48 and 4.53 assignable to the methylene protons of the dihydromaleimide ring. 

TABLE 6.14 Absorption Frequencies of Carbonyl Bands (continued)... 

Figure 10.9 Polycyclooctene irradiated in the photoDSC system at 35°C under air. Left ordinate ( ) IR kinetic evolution of carbonyl band (1721 cm-1). Right ordinate ( ) change in crystallization heat. Reproduced from reference [59], 2005 with permission from Elsevier.

Another type of sample for surface analysis is one where some kind of reaction has taken place on the surface. A common example of this is the appearance of carbonyl bands from the surface oxidation of PE. A spectrum of ozone treated PE film is shown in Figure 2.14. 

The number of carbonyl bands increases as the overall symmetry of the molecule decreases. Only one IR-active carbonyl stretching vibration is normally observed for species of high symmetry, such as octahedral (O/,) or tetrahedral (Td) complexes (see the examples given above the data for the negatively charged species refer to media with a strong solvating power for the cation). 

Complexes containing three or more carbonyls. Here, (he predictions are not quite so simple. The exact number of carbonyl bands can be determined according to (he symmetry approach of Chapter 4. For convenient reference, the numbers of bands expected for a variety of CO complexes are given in Table 13-7. 

Fig. 20. IR spectra of carbonyl bands and Ru—H—Ru bands ol Ru ketenylidene clusters on SiOj (a), SiOj/AIjO, (b), and MgO (c), along with proposed structures ol the surface-graRed Ru ketenylidene clusters on the diflerent oxides.

A recent literature report has shown that changes in the stability of the different stable oxidation states of copper can be produced upon interaction with CO-Oj mixtures [12]. Thus, in order to examine the changes produced in the copper species characteristics upon interaction of the calcined samples with a CO-O2 mixture, the evolution of carbonyl bands has been monitored for CuA and CulOCA, as shown in Figure 6. Two different temperatures were selected for these experiments at 373 and 573 K. The samples were heated using a 10 K min ramp until the corresponding temperature is reached, and subsequently cooled to RT, in a stoichiometric flow similar to that used for the catalytic reactivity tests shown above. Then, after prolonged outgassing at RT, a known CO pressure is admitted in the cell. 

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