Extended charge delocalization to 4‐phenoxy substituent in benzhydryl solvolysis: possible contribution of non‐canonical resonance structure in the cationic transition state

Abstract

AbstractSolvolytic reactivities of 4‐nitrobenzhydryl bromides (2b–5b) and chlorides (2c–5c) were studied using single‐ and dual‐parameter Grunwald–Winstein‐type correlation analyses with YBnX and Y xBnX scales, respectively. Extended charge delocalization over two aryl rings at cationic transition states were found for 3 and 5, but not for 2 or 4. Calculations of the charge distributions in 3c and in the corresponding cation 3a were performed using a Hartree–Fock approximation (RHF/6‐31G* basis set) and density functional models (pBP/DN** and other basis sets), respectively, on Mulliken population analysis and on electrostatic potential analysis. The possible contribution of non‐canonical resonance structure is discussed. Copyright © 2001 John Wiley & Sons, Ltd.