Effects of neutral and anionic substituents on the carbonyl stretching bands of ring-substituted acetophenones

Abstract

Satisfactory single-parameter (σ+) and dual-parameter (according to Yukawa–Tsuno and Taft) correlations have been found between frequencies of the title bands (νCO) and substituent constants. It has been found that use of dimethyl sulphoxide instead of carbon tetrachloride as solvent does not lower the relative accuracy of the studied correlations. The integrated intensities of the νCO bands do not correlate with any type of substituent constants. The constants σ+, σ0, σI, [Formula: see text], and [Formula: see text] of the anionic substituents NC—HC−, O−, CH3CON−, and CO2−, recently determined on the basis of cyano infrared frequencies and intensities, have proved satisfactorily reliable with respect to the νCO of acetophenones. The σ+ constants of m-CH2CO2− (−0.22 ± 0.08) and m-C6H5CON− (−0.66 ± 0.13) have been estimated on the basis of νCO data and νCO/σ+ correlations (solvent DMSO).