Silver ion enhanced C–H activation in Pt(ii) hydroxo complexes

Abstract

Reacting neutral Pt(II) hydroxo compounds (NN)Pt(R)(OH) (R = OH, Ph, and Me, NN = bulky terphenyl diimine) with silver bis(trifluromethanesulfonyl)imide produces new hydroxo complexes with the silver binding through the Pt–OH bonds as determined by ¹⁹⁵Pt NMR and X-ray analysis (R = OH). These complexes were found to activate the aromatic C–D bonds of C₆D₆ at significantly enhanced rates relative to the silver free hydroxo complexes. Mechanistic studies for R = Ph are consistent with a homogeneous pathway that is bimolecular (ΔH^‡ = 17(2) kcal mol⁻¹ and ΔS^‡ = −25(6) e.u. and ΔG^‡₂₉₅ = 10(2) kcal mol⁻¹), first order in [Pt] and substrate.