Riffle Jared R, Jowers Cash L, Luna Sarah, Smith Mark D, Peryshkov Dmitry V
Department of Chemistry and Biochemistry, University of South Carolina 631 Sumter St. Columbia South Carolina 29208 USA
Chem Sci. 2025 Jul 30. doi: 10.1039/d5sc04058b.
A new concept of ligand ambiphilicity that relies on the redox behavior of the indirectly coordinated boron cluster scaffold instead of the direct involvement of a single center in a ligand is introduced. A copper(i) complex of a carboranyl-based triphosphine, [ P--{CB}-P--{CB}- P]CuPF, in acetonitrile solution coordinates an exogenous X anion (X = Cl or N ) at the phosphorus center of the ligand and not at the cationic metal site to form [ P(X)--{CB}-P--{CB}- P]Cu(CHCN). This first example of a nontraditional ligation behavior for a trigonal phosphine is imparted by an internal two-electron event at the boron cluster, which renders a non-constrained electron-donating phosphine group into an electrophilic coordination site. The observed ligand-centered behavior is reversible and can be switched by a change in solvent system, thus representing an unusual case of metal-ligand anion tautomerism enforced by the redox behavior of the boron cluster backbone. This dynamic system offers new possibilities for changing the coordination environment and reactivity of a metal center and opens new perspectives in molecular switching and catalysis.
引入了一种新的配体双亲性概念，该概念依赖于间接配位的硼簇支架的氧化还原行为，而非单个中心直接参与配体。基于碳硼烷的三膦[P--{CB}-P--{CB}-P]CuPF的铜（I）配合物在乙腈溶液中，在配体的磷中心而非阳离子金属位点配位一个外源X阴离子（X = Cl或N），形成[P(X)--{CB}-P--{CB}-P]Cu(CHCN)。这种三角膦的非传统配位行为的首个例子是由硼簇上的内部双电子事件赋予的，该事件使一个无约束的供电子膦基团转变为亲电配位位点。观察到的以配体为中心的行为是可逆的，并且可以通过改变溶剂体系来切换，因此代表了一种由硼簇骨架的氧化还原行为强制实现的金属-配体阴离子互变异构的不寻常情况。这个动态体系为改变金属中心的配位环境和反应性提供了新的可能性，并为分子开关和催化开辟了新的前景。
