Knowledge Bank

The absorption spectra of perphenylated derivatives of Group IV, V, VI and VII elements show a few strong bands in the $670770cm-1$ (15-13 microns) region generally attributed to C-H out-of-plane deformations. It is shown that these bands may be divided into tow major categories: those showing heavy atom effects and those dependent primarily on electronegativity. Solvent effect studies support the categorization and shed light on the relationship between frequency shift and solvent polarity.