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.

零价铂配合物与三卤化铟结合可生成在溶液中存在平衡的化合物，该平衡存在于其In-X氧化加成（Oxidative Addition，OA）产物（二价铂铟基配合物）与仅金属路易斯对（Metal-only Lewis Pair，MOLP）异构体（LnPt→InX3）之间。平衡位置可通过改变溶剂进行可逆调控；向体系中加入额外给体配体时，可将平衡可逆或不可逆地推向MOLP产物一侧。本研究首次观测到MOLP与OA异构体间的平衡体系，同时也是迄今观测到的可发生可逆氧化加成至金属配合物的极性最强化学键。此外，我们首次完成了同一化合物的MOLP与氧化加成异构体的结构表征。通过密度泛函理论（Density Functional Theory，DFT）方法计算了两类异构体的相对能量，并对溶剂介导的异构化可能性进行了讨论。