An infrared study on benzeneseleninic acids and salts: assignments and substituent effects

Abstract

The i.r. spectra of several meta- and para-substituted benzeneseleninic acids and salts as solids and in solution have been recorded. The structures of the CSeO₂^– and CSeOOH groups have been assessed from the solid-phase spectra. These assignments have also been tested by use of empirical relationships between force constants on one hand and vibration frequencies or bond orders on the other, and by comparison of the spectra of the benzeneseleninic derivatives with those of diphenyl selenoxide and of diphenyl diselenide. The solution spectra have been used to correlate frequency shifts and Hammett's σ-values. The substituent effect on benzeneseleninic derivatives is intermediate between the corresponding effects on benzoic and on benzenesulphinic acids.