Interpretation of IR spectra of the N-acethyl-4-dimethylaminopyridinium salts

In a harmonic approximation we calculate the frequencies of normal vibrations and their modes for a salt cation of N-acethyl-4-dimethylaminopyridinium hexachlorstibiate and of its three deuteroderivatives obtained on deuteration over a CH₃-group, over a ring, and over a ring and a CH₃-group. From the results of calculation, an interpretation of the IR spectra of the salts considered is carried out. To whom correspondences should be addressed. L. M. Litvinenko Institute of Physical and Organic Chemistry and the Chemistry of Coal, National Academy of Sciences of Ukraine, 70, R. Luxemburg Str., Donetsk, 340114, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 158–162, March–April, 1999.     

Vibrational spectrum of pyridine hydrochloride

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 2, pp. 222–228, February, 1992.     

Concerning the nature of the doublet at 2200 cm−1 in the vibrational spectra of cyanoguanidine

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 1, pp. 53–57, July, 1991.     

Energy of the C = C Double Bond

Determination of the bond energy as the difference between the experimental energy of the double bond and standard value of the C-C bond energy does not take into account changes in the energy of the C-C bond as it becomes shorter. The change in the single bond energy upon its shortening by 0.2 Å was evaluated from the compressibilities of diamond and polyethylene, and also by quantum-chemical calculations. With this value taken into account, the energies of the and bonds in ethylene become close, which proves the equivalence of the traditional and banana models of the C = C bond.