A bis(silylene)-stabilized diphosphorus compound and its reactivity as a monophosphorus anion transfer reagent

In contrast to the well-established transition-metal-mediated activation of white phosphorus (P4), the metal-free direct functionalization of P4 has remained rare. The conversion of P4 into a reactive zero-valent diphosphorus compound (P2) has proven challenging to carry out without relying on metal reactivity. Herein, we describe the facile degradation of P4 mediated by two divalent silicon atoms in a bis(silylene) scaffold, resulting in a silylene-stabilized zero-valent P2 complex. The presence of two lone pairs of electrons on each P atom in the silylene-stabilized P2 complex enables a rich reactivity towards small molecules; reaction of the P2 species with CO2, water or a borane leads to the formation of P–C, P–H or P–B bonds, respectively. Notably, the P2 complex also serves as a single phosphorus anion (P−) transfer reagent towards metal carbonyls and a chlorogermylene compound, leading to the synthetically valuable phosphaketenide (PCO−) ligand and a phosphinidene germylene complex, respectively. White phosphorus (P4) is very reactive but is relatively difficult to activate without relying on transition metals. Now, it has been shown that the degradation of P4 can be mediated by two divalent silicon atoms in a bis(silylene) scaffold to give a diphosphorus complex that can be further functionalized and also act as a P− transfer agent.