Deformation band, amine oxide

Table n. IR Band Assignments of the Deformation Modes of Aqueous Solutions of Amine Oxides at 25 C... 

Primary amines may be readily distinguished from secondary and tertiary analogues by the presence of two absorption bands in the infrared spectrum between 3320 and 3500 cm-1 (symmetric and antisymmetric NH str.). Secondary amines exhibit a single absorption band at about 3350 cm-1 (NH str.). In both cases deformation modes for the NH bond appear at about 1600 cm-1. There is no satisfactory absorption to allow a definitive characterisation in the case of tertiary amines. In the nuclear magnetic resonance spectrum of primary and secondary amines, the nitrogen-bound hydrogens are recognisable by their replaceability on the addition of deuterium oxide. 

The Si, A1, and H spectroscopy were used to characterize (Fe,Al)-FER, synthesized in the presence of ethylene glycol and ethylene diamine [lOCl]. Some Si and Al MAS NMR spectra are depicted in Fig. 46. The Al NMR spectra show that most of aluminum occupies tetrahedral positions, characterized by a hne at 54 ppm. The line at <5 = 14 ppm and the broad contribution at <5 = 35 ppm were assigned to deformed extraframework A1 and Al-oxide species [97S2]. The Si NMR spectra have been analyzed based on the presence of two different crystallographic Si atoms, A and B [97B3]. The parameters determined by the analyses of the spectra are listed in Table 11. The Si NMR lines are broader compared to samples without iron, suggesting that the Fe ions were incorporated in the framework. The NMR spectra of the samples synthesized in the presence of ethylene diamine exhibited a small line of amine at S= 39.3 ppm, but most of these initial molecules were transformed into oligomers and aromatic molecules. The rather broad bands at <5 = 120 and 130 ppm are... 

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