Hammett Analyses of Halocarbene–Halocarbanion Equilibria

Substituted arylchlorocarbenes (X = H, <i>p</i>-Cl, <i>p</i>-CF<sub>3</sub>, <i>p</i>-F, <i>m</i>-Cl) reacted reversibly with Cl<sup>–</sup> in dichloroethane to form the corresponding aryldichloromethide carbanions. Equilibrium constants and rate constants for the forward and reverse reactions were correlated by the Hammett equation. DFT methods were used to compute equilibrium constants and electronic absorption spectra.