Dynamic, Reversible Oxidative Addition of Highly Polar Bonds to a Transition Metal

The
combination of Pt0 complexes and indium trihalides
leads to compounds that form equilibria in solution between their
In–X oxidative addition (OA) products (PtII indyl
complexes) and their metal-only Lewis pair (MOLP) isomers (LnPt→InX3). The position of the equilibria
can be altered reversibly by changing the solvent, while the equilibria
can be reversibly and irreversibly driven toward the MOLP products
by addition of further donor ligands. The results mark the first observation
of an equilibrium between MOLP and OA isomers, as well as the most
polar bond ever observed to undergo reversible oxidative addition
to a metal complex. In addition, we present the first structural characterization
of MOLP and oxidative addition isomers of the same compound. The relative
energies of the MOLP and OA isomers were calculated by DFT methods,
and the possibility of solvent-mediated isomerization is discussed.