Cage Compounds of Heterotrimetallic Mixed Phosphanediide/Silanolate Aggregates with an Alkaline Earth Metal-Centered Phosphorus Octahedron

Abstract

The lithiation of potassium triisopropylsilylphosphanide yields the corresponding phosphanediide. The subsequent metathesis reaction with SrI(2) and BaI(2) in the presence of hexamethyldisiloxane gives hexalithium hexapotassium strontium hexakis(triisopropylsilylphosphanediide)bis(trimethylsilanolate) (1) and the corresponding barium derivative (2), respectively. The alkaline earth metal atoms are surrounded octahedrally by the phosphanediide ligands. Six P(3) faces of the octahedron are capped by the K atoms, and the P-P edges of two opposite P(3) faces are bridged by the lithium atoms. The Li cations are also bonded to the Me(3)SiO substituents giving a coordination number of three for the alkali metals.