Monomer–Dimer solution equilibria of 2,4,6-trialkylnitrosobenzenes and 2,4,6-trialkylnitrosobenzene/nitrosobenzene mixtures. A study using one- and two-dimensional NMR techniques

Abstract

2,4,6-Trimethylnitrosobenzene in CDCI3 exists as a mixture of monomer and Z- and E-azodioxy dimers. The dissociation kinetics of both dimers were measured by one-dimensional time-dependent NMR spectroscopy on non-equilibrium solutions, and by two-dimensional exchange spectroscopy (2D-EXSY) on equilibrium solutions. 2,4,6-Tri-t-butylnitrosobenzene is entirely monomeric in CDCl3 but forms mixed azodioxy dimers in the presence of nitrosobenzene. The dissociation kinetics of the mixed E-dimer were followed by NMR techniques. The activation energy parameters for these dissociation equilibria were compared with previous data on related nitrosobenzene and dimethylnitrosobenzene systems.