Hydrogen bonding overtone region

Final proof of the existence of the hydrogen bonding between NO2 and OH groups in nitroalcohols was given by further experiments of T. Urbanski and co-workers. The following methods were used in their experiments measurement and calculation of dipole moments [67], ultraviolet, infra-red (including overtone region), NMR spectroscopy [68a, b). 

The OH group of phenol participates in two additional modes, in-plane and out-ofplane bending vibrations. The latter is also called the torsional mode toe observed near 300 cm (see Table 8) in the IR spectra of phenol vapour and of dilute solutions of phenol in w-hexane. In the associated molecules, it appears as a rather broad featureless band in the region of 600-740 cm ". It results from the hydrogen-bonded association. The spectra of liquid and solid phenol-OD also exhibit a variety of broad bands near 500 cm . The first overtone of the ton was found at 583 cm in the IR spectrum of phenol vapour. This assignment of the torsional mode allows one to model the torsional motion of the OH group of phenol by assuming that it is described by the... 

The near-infrared region (between 4000 and 12 500 cmcontains the combination bands connected with the hydrogen atom and the harmonic overtone bands, e.g., the first overtones of the O—H vibration at around 7140 cm" and the N—N vibration at 6667 cm" These bands are sensitively affected by the formation of hydrogen bonds, which strongly influence the vibrations, and by coordination of the O or N donor atom. 

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