A P4 Chain and Cage from Silylene-Activated White Phosphorus

摘要

Transition-metal-mediated degradation of white phosphorus has been extensively studied, and it has attracted considerable interest owing to its demand in industrial applications for a more facile production of organophosphorus derivatives. Recently in a seminal review, Power pointed out that main-group elements in lower oxidation states exhibit an amazing resemblance to transition metals in many ways, for example their ability to activate small molecules, such as dihydro-gen. In fact, Bertrand et al. mentioned that cyclic alkyl amino carbene (CAAC) can activate NH3, which is a much more difficult task for transition metals. The carbene footsteps were immediately followed by its heavier congeners: silylene, germylene, and stannylene, which all display the activation of NH3 under ambient condition. Another remarkable breakthrough in this field is the fragmentation of P4 by a N-heterocyclic carbene (NHC) and related carbene ligands. Among these, the most intriguing example was the activation of P4 by a bulky rigid CAAC and the isolation of the resulting acyclic P4 chain.