Rings stretching

Table 9 Approximate Positions of Ring-stretching Modes for Pyridines, Pyrimidines and Benzenes (cm )...

Table 21 Monosubstituted Heterocycles Ring Stretching Bands in the 1600-1300 cm Region...

The characteristic bands in the IR spectra of thiophenes have been recorded. " 2-Substituted thiophenes show ring-stretching frequences at 1537-1509, 1444-1402, and 1365-1339 cm" which have been assigned to characteristic modes of vibration. The hydrogen in-plane deformation bands occur at 1086-1077 and at 1053-1031 cm. The... 

The correlation analysis of infrared data has been much examined by Katritzky, Topsom and colleagues69,70. Thus, the intensities of the v16 ring-stretching bands of mono- and di-substituted benzenes may be correlated with the oR° values of the substituents and these correlations may be used to find new oR° values. 

In our tip-enhanced near-field CARS microscopy, two mode-locked pulsed lasers (pulse duration 5ps, spectral width 4cm ) were used for excitation of CARS polarization [21]. The sample was a DNA network nanostructure of poly(dA-dT)-poly(dA-dT) [24]. The frequency difference of the two excitation lasers (cOi — CO2) was set at 1337 cm, corresponding to the ring stretching mode of diazole. After the on-resonant imaging, CO2 was changed such that the frequency difference corresponded to none of the Raman-active vibration of the sample ( off-resonant ). The CARS images at the on- and off- resonant frequencies are illustrated in Figure 2.8a and b, respectively. 

Aromatic ring stretching CHa, CH3, C-H bending phenolic C-0 stretching... 

Also for cytosine, red shifts are detected in the NH2 stretching and bending modes. Ring stretchings and deformations, involving the CO vibration, suffer little changes with respect to the isolated base (see Fig. 16). In the overall, the computed frequency shifts are in agreement with the... 

Up to four ring stretches exist in the 1,450-1,600 cm region and two stronger peaks cire in the 1,500-1,600 cm" region. 

G 1610 cm C=C stretch Aromatic ring stretch, broad band possibly obscuring amide N-H bend... 

The FTIR spectrum of the commercially available PEDOT/PSSNa and the enzymatically synthesized PEDOT/PSSNa were compared (Pig. 9). The spectra are scaled individually for clearer comparison. The vibrations at 1195, 1139, and 1089 cm are due to the C-O-C bond stretch in the ethylenedioxy group. The peak at 1521 cm is due to the ring stretching of the thiophene ring. The weak vibration at 1062 cm is possibly due to the C-O stretch. Peaks at 979, 937, and 840 cm are assigned to thiophene C-S bond stretching. As seen in Pig. 3, the PEDOT/PSSNa synthesized enzymatically shows similar features to those of the standard, and no major additional peaks are observed. 

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