O-H bend

Anhydrous quinazoline hydrochloride absorbs one molecule of water readily, and. the product is difficult to dehydrate completely even in a high vacuum at 60°. Infrared spectral data suggest that this water is covalently bound because of (o) the absence of several bands in the spectrum of the hydrate which are present in the spectrum of the anhydrous hydrochloride and (6) the presence of extra bands at 1474 and 1240 cm that have been attributed to C— H and O— H bending vibrations of the — CHOH group. 

O—H Bending Vibrations The O—H inplane bending vibration occurs in the general region of 1420-1330 cm-1. In primary and secondary alcohols,... 

Fermi resonances of the v0H=l state with over- and combination tones of modes in the fingerprint region are considered a key element determining the spectral envelope of the O-H stretching bands of cyclic carboxylic acid dimers. In principle, such Fermi resonances open up channels for population relaxation of the O-H stretching modes through the O-H bending... 

The vibrational bands of the O-H bending and C-O stretching modes are shown in Fig. 6... 

From Table IV, it may be seen that two frequencies are calculated at 887 and 901 cm-1 that could be attributed to an axial C-l-H vibration. In fact, many atoms were displaced for each vibration. The most prominent vibrations for these two calculated frequencies are shown in Fig. 3. It may be seen from Fig. 3b that the vibration at 901 cm-1 contains coupling of CH2 and C-l-H motions, whereas the calculated frequency of 887 cm 1 exhibits, in Fig. 3c, coupling of CH2 and C-5-H groups, with no observed contributions from C-l-H or C-O-H bending. These observations, combined with... 

Alcohols and phenols. Both these classes of compounds are characterised by the strong absorption resulting from the O—H stretching modes the position and shape of the bands are sensitive to the electronic and steric features of the compound and also to the physical state of the sample. Absorption bands arising from C—O stretching and O—H bending vibrations are also of diagnostic value. 

---