Forging a Cage into a Chain: Stepwise Transformation of P4 by Silylenes to a Si3P4 Motif

We have discovered a route to access the longest low-valent molecular silaphospha-chain, a seven-membered chain structure that incorporates three silicon and four phosphorus atoms by stepwise activation of white phosphorus (P-4) using two different silylene precursors. The chain species was formed via a highly reactive polyphosphide intermediate. The isolation of a stable analogue of this reaction intermediate was achieved by stepwise reaction with mono and bis(silylenes). Due to the rigidity of the ferrocenediyl framework of the bis (silylene), the isomerization process of the chain structure was hampered. Theoretical studies such as natural bond orbital and atoms in molecules analyses of the seven-membered chain species indicated some degree of delocalization of the double bond system. [GRAPHICS]

Automated summary

By stepwise activation of white phosphorus using two different silylene precursors, we have discovered a route to access a seven-membered chain structure that incorporates three silicon and four phosphorus atoms. The isolation and analysis of stable analogues of the reactive intermediates provide insights into the synthesis, stability and structural features of the chain species.