Early-late heterobimetallic Rh-Ti and Rh-Zr complexes via addition of early metal chlorides to mono- and divalent rhodium

摘要

Early-late heterobimetallic complexes have attracted interest because of the potential for new reactivity engendered by the distinctive cooperation of a typically electron-rich late metal center and a typically electron-poor early metal center.1"3 The cooperation is at its strongest when a direct metal-metal bond is present. The construction of an early-late metal-metal bond (and, in fact, other metal-metal bonds as well) is typically accomplished through one of the following: (1) reaction of a late metallate anion with an early metal halide complex; (2) protonolysis of an early metal-alkyl or -amido bond with a relatively acidic late metal hydride; (3) co-reduction of late and early metal halides, usually already bound together with bridging ligands.1"3 We noted that one type of reaction is conspicuously missing4 from this list: insertion of a low-valent late metal center into an early metal-halogen bond which can be viewed as M-Hal oxidative addition (OA)5 to a late metal.