NH Deformation Vibrations

Fig. 2 DRIFT spectra of PVFA-co-PVAm modified ZnO particles where the degree of the PVFA-co-PVAm hydrolysis was varied a degree of hydrolysis = 0% b degree of hydrolysis = 10% c degree of hydrolysis = 30% d degree of hydrolysis = 50% and e degree of hydrolysis > 90%, desalted. The molar mass of the non-hydrolysed PVFA polymer was 340 000 g mol-1, during the adsorption the pH was pH = 8. The spectra show the overtone amide-II band at v = 3053 cm-1 (A), the amide-I band at v = 1675 cm-1 (71), the NH deformation vibration at v = 1590 cm-1 (C), the amide-H band at v = 1540 cm-1 (/.)). (v = wave number, a.u. = arbitrary units according to Kubelka and Munk)...

These NMR results are confirmed by the IR spectra of ammonium-exchanged Al-MCM-41. In the spectral range of NH deformation modes, a vibration band at ca. 1450 cm 1 is observed which is assigned to the deformation mode of ammonium ions (BS band). Its presence evidences the incorporation of A1 into tetrahedrally coordinated framework positions, because ammonium ion exchange requires a negatively charged framework. The intensity of the NH4+ deformation mode increases with increasing aluminum content until a Si/Al (gel) ratio of 7.3. 

The position and intensities of the CH deformation bands depend on the number, orientation, and electronic type of the substituents. Interaction between the CH in-plane deformation and the NH in-plane deformation vibration, which absorbs near 1140 cm-1, does not permit a direct comparison with correspondingly substituted furans or... 

NHs" " at 1620-1600cm , and C02 at 670cm (where y is stretching or valence vibration and d is deformation vibration). The complex with composition 2 1 can be formed as a result from the addition of a second acid molecule to an ion pair (in increased amine concentration). Characteristic absorption band of the carboxylate anion shifts to the lower values of the wave numbers (as compared to the complex with 1 1 composition). ... 

The NH2 deformation mode in primary amides is to be expected in the 1600 cm" region, and the absorption which is found here in all such compounds (amide II band) is generally ascribed to this cause. However, secondary amides also exhibit a strong characteristic band at rather lower frequencies, the origin of which has been the subject of much controversy. It has been variously assigned as an NH deformation mode, a C—N stretching mode and as a mixed vibration involving both types of motion. The band is accompanied in... 

Other characteristic absorptions of secondary amides have been described at lower frequencies, but are of less diagnostic value. These include the out-of-plane NH deformation [79] frequency which occurs near 700 cm and is exceptionally broad in the spectra of solids and concentrated solutions. This has been termed the Amide V absorption by Mizushima et al. [80]. Assignments of Amide IV and Amide VI bands at still lower frequencies have also been made. These are essentially skeletal vibrations, and they have been discussed further by Miyazawa [81]. 

Table 2.1 shows the appearance of new peaks in complex formations with characteristic bands of carboxylic acid group vibrations at 1,488.81 cm (possible -C=C- and -C=0 vibration/stretch and -NH deformation) and 1,829.00 cm (carbonyl COOH... 

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