Kinetics of substitution on chloro-1,1,7,7-tetraethyldiethylene-triaminegold(III) in methanol-water mixtures

Summary Rate constants are reported for the replacement of chloride by bromide in the complex Au(Et₄dien-H)⁺ in methanol-water mixtures. This reaction follows the usual two-term rate law = (k_obs = k₁ + K₂Br^–1]) for square planar complexes in all the mixtures studied. The logarithms of the rate constants correlate with Grunwald-Winstein solvent Y values and yield slopes of 0.32 (k₁) and 0.15 (k₂). The results suggest that both reaction paths are associative.Dien complexes of gold(III) yield conjugate base species at low pH; Et₄dien-H = Et₂NCH₂CH₂NCH₂CH₂NEt₂.