A Protonated Quinone Methide Stabilized by a Combination of Partial Aromatization and pi-Interaction: Spectroscopic and Crystallographic Analysis

摘要

We have expanded the repertoire of cation-pi interactions to include a carbocation-pi system resulting from the protonation of a pi-stacked para-quinone methide (p-QM). This unusual carbocation is stabilized by a combination of partial aromatization of the QM moiety and through-space interaction with the pi-system of the adjacent aromatic ring. Single crystal X-ray analysis of the protonated form reveals a structure consisting of a hydrogen-bound complex involving two molecules of the precursor and one proton.