TORSIONS AROUND THE THE SINGLE BOND IN CONJUGATED MOLECULES
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Date
1964
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Publisher
Ohio State University
Abstract
This paper deals with torsions around the single bond in molecules containing the group $=C-C=$. Butadiene $(CH_{2}=CH-CH=CH_{2})$ and glyoxal (OCH-CHO) are prototypes. Benzaldehyde is included as an example of the system [FIGURE]-C=. Torsional frequencies have been observed between 40 and $170 cm^{-1}$ for a dozen such compounds in the vapor state. The evaluation of a potential function from the infrared frequency is difficult, if not impossible. If it is written as the usual series [FIGURE] at least two of the three parameters $V_{1}, V_{2}$, and $V_{3}$ are important for the butadiene and glyoxal derivatives. Since there is only one experimental datum, the dilemma is obvious. Nevertheless some interesting comparisons can be made between compounds. For benzaldehyde, $V_{1}$ and $V_{2}$ are zero by symmetry and $V_{2}$ can be evaluated. The barrier for benzaldehyde is very different in the gas and the liquid states.
Description
Author Institution: Mellon Institute