The Infrared Spectra of Aromatic Compounds Ⅲ. The 1045-1185 cm- Vibration in Monosubstituted Benzenes

摘要

In monosubstituted benzenes of the type (phenyl)QM, where n 13 the valence of the substituent element M, the frequency of the 1045-1185 cm vibration is directly related to the partial ionic character of the Car-M bond. Using the square of the electro¬negativity of the substituent as a measure of the bond polarity, a plot is presented which relates this parameter to the corres¬ponding frequency. From the four straight-line curves obtained for group IVB, VB, VIB and VIIB elements, an expression is derived equating electronegativity with the observed frequency. Electronegativity values calculated from this equation compare favor¬ably with accepted values.