Reversible formation of yttrium planar cyclo-P4 clusters and their selective conversion: access to mixed PV/PIII cyclo-P4 units

Abstract

The development of sustainable phosphorus chemistry from P₄ remains a significant challenge, particularly in achieving its selective activation and reversible functionalization. Herein, we present a rare-earth silylamido complex that enables solvent-controlling reversible P₄ activation via P–C bond formation and cleavage. Utilizing a dianionic β-diketiminato ligand, we achieved the first dynamic assembly of a planar cyclo-P₄ framework coordinated to rare-earth centers. In tetrahydrofuran (THF), 2 can fully release free P₄ and regenerate the precursor 1. Complex 2 also exhibits high reactivity toward unsaturated small molecules, including p-tolyl isothiocyanate and carbon disulfide, affording oxidation products 3 and 4 featuring unprecedented neutral mixed P^III/P^V planar cyclo-P₄ units. DFT calculations indicate the regioselectivity and underlying mechanism of the functionalization process. This work constitutes the first example of reversible P–C bond formation and P₄ activation under mild, non-photochemical conditions, establishing a dynamic and tunable platform for cyclo-P₄ chemistry with broad implications for main-group element reactivity and ligand design.