Steric and Electronic Effects in Basic Dyes. II—Electronic Absorption Spectra of Derivatives of Malachite Green Containing Electron‐withdrawing Substituents in the Phenyl Ring

Absorption spectra of several derivatives of Malachite Green containing electron‐withdrawing groups in the phenyl ring have been examined. Substituents in the 3‐ or 4‐position modify the position of the first‐frequency band to an extent approximately linearly related to the appropriate Hammett substituent constant. Although substituents in the 2‐position show an ortho effect, the intensities of the first bands are generally lower than those of derivatives containing electron‐donating groups.