COO stretching vibrations

Then, we calculated the < > values for the transition moments of the major bands of the 11-monolayer LB film of C12AzoC5-Ba by Eq. (2) from the observed absorbance ratios between the transmission and RA spectra. The results are shown in Table 1. The angles (a and P ) of the transition moments of the antisymmetric and symmetric CH2 stretching vibrations are 72° and 70°, and those of the antisymmetric and symmetric COO stretching vibrations are 85° and 29°, respectively. Furthermore, those of the... 

In the case of isobutanol dehydration, a promotional effect is observed (47). Isobutanol forms a surface carboxylate under reaction conditions (340), and this surface species gives rise to a typical symmetric COO -stretching vibration at 1567 cm 1. The CH-stretching vibration of the methylene group of isobutanol at 2870 cm-1 disappears on formation of the oxidized species. Consequently, the intensity of the 1567-cm 1 band can be taken as a measure of the surface concentration of the carboxylate species, whereas the intensity of the 2870-cm 1 band represents the surface concentration of molecular alcohol. The concentra-... 

As an example of base-catalyzed reactions over zeolites of different basicity (Cs, Na-Y, Cs, Na-X, CsOH/Cs, Na-Y), the aldol condensation of n-butyraldehyde was explored by Weitkamp et al. [910] using in-situ FTIR to monitor the conversion. During the reaction a band emerged at 1580 cm, which could be ascribed to a COO stretching vibration of a carboxylate anion. These anions were suspected to poison the active basic sites and cause the catalyst deactivation. 

Strong bands due to the anti-symmetrical and symmetrical stretching vibrations of the COO- grouping. 

The carboxylate groups in the metal complexes give rise to bands at 1,550 to 1,575 cm" which are assigned to the antisymmetric stretching vibration v (COO). 

Finally, infrared (IR) analysis was obtained from the PS-PDMS product materials to try to detect the nature of the chemical reaction between the amine group in amine-PDMS and the acid group in the S-block- S-stat-MAA) material. Based on IR reference samples (Pouchert, 1981, 1989), if the carboxyl unit and amine unit have reacted to form covalent bonds with the liberation of water to form a CONH-group, the C=0 band should appear at 1,640 cm . If no water was produced and carboxyl units and amine units were ionically bonded as (COO) ((NH3)+, the stretching vibration of the C=0 in the ionic bond should appear at 1,550 cm . IR results of the la PS-PDMS product show an absorption at 1,545 cm , which looks like the band in pure PDMS that appears at 1,594 cm . The 1,594 cm absorption for PDMS is the bending vibration of the N-H of the amine unit, which shifted to 1,545 cm in the PS-PDMS product because of the formation of ionic bonds. Also the IR result of the S-block-(S-stat-MAA) material showed a big absorption at 1,700 cm which represents the C=0 stretch of the carboxyl unit. 

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