Kinetic Solvent Effects on the Reaction of an Aromatic Ketone π,π~* Triplet with Phenol. Rate-Retarding and Rate-Accelerating Effects of Hydrogen-Bond Acceptor Solvents

摘要

A fourth mechanism, B, for H-atom abstraction from phenol in PhOH···S HB complexes has been identified and quantified. Although the mechanism B rate increased with the solvents' HBA strength (β_2~H), the overall rate decreased as β_2~H increased. Nevertheless, the exciting possibility remains of "inverse" KSEs where the rates of H-atom abstraction from a HBD actually increase as the solvents become stronger HBAs.