Maximizing Coordinative and Electronic Unsaturation: Three-Coordinate Dicationic Platinum Complexes

摘要

Isolable low-coordinate transition-metal complexes could embody the synthetic chemist's somewhat discordant ideals of catalysts that are both conveniently handled and highly active. A number of techniques, chief among them the abstraction of halogeno ligands, can be used to prepare low-coordinate, cationic complexes (or related weakly-coordinated solvent-bound or agostic derivatives), thereby also increasing the electrophilicity of the metal center. Such cationic complexes of Pt have been used to great effect in the activation of C—H bonds, particularly of alkanes. However, an important distinction must be made between truly "low-coordinate" complexes with completely free coordination sites, and their solvent-bound or agostic derivatives.