Ring deformation

Temperature = 25°C pressure = 1 bar a-CsN bond not included -NsO bond not included c No ring deformation correction d No cyclopropane ring in method e-C=N- bond not included f Some nitrogen groups not in table 8 No peroxide group in table h Average deviation from experimental values... 

In the wavenumber region 600-700 cm where ring deformation bands are expected, two bands appear at 730 cm and 625 cm in bmimCl Crystal (1)... 

The IR spectra of 2,3 -bipyridine,i " - ° - i 2,4 -bipyridine, " 3,3 -bipyridine, °° and 3,4 -bipyridine °°- have all been reported. From IR spectral assignments it is suggested that 2,3 - and 3,3 -bipyridines adopt the cisoid conformation. The IR spectrum of 4,4 -bipyridine both in the solid state and in solution has attracted much attention, and the spectrum has been fully interpreted.4,4 -Bipyridine has been included in a study of the use of IR intensities as a quantitative measure of intramolecular interactions. Interestingly, changes in the intensities of IR bands due to aromatic ring deformations and C—H deformations on going from the solid to the molten state have been used to show that the aromatic rings of 2,2 - and 4,4 -bipyridines are not coplanar in the liquid phase. The IR spectra of salts of 4,4 -bipyridine have been discussed. ... 

The normal mode calculation was used to elucidate the rotational isomerization equilibrium of the [C4CiIm]X liquids. In the wave number region near 800-500 cm, where ring deformation bands are expected, two Raman bands appeared at —730 cm and —625 cm in the [C4C4lm]Cl Crystal (1). In the [C4CiIm]Br these bands were not found. Here instead, another couple of bands appeared at —701 and —603 cm T To assist the interpretation of the spectra, the normal modes of vibrations calculated by Hamaguchi et al. [50] are shown in Figure 12.8. 

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