Spectrophotometric Investigation of the Charge–Transfer Interaction of 2,3-Dicyano-1,4-naphthoquinone with N-Ethylaniline in Chlorinated Solvents

The charge–transfer interaction between 2,3-dicyano-1,4-naphthoquinone (DCNQ) and N-ethylaniline was studied in the halocarbons chloroform and dichloromethane and a 1:1 (v/v) mixture of these two solvents. A rapid interaction between DCNQ and N-ethylaniline results in the formation of the monosubstituted final product. The reaction is found to proceed through an initial charge–transfer (CT) complex intermediate. The equilibrium constants of the π -complex, in all the three media, were evaluated along with first-order and second-order rate constants for the appearance and disappearance of the π - and σ -complexes. The final product was isolated and characterized by IR, NMR and elemental analysis. Based on the kinetic results a mechanism was proposed for the reaction.