Lithiated Clusters from Primary Silylphosphanes and Silylarsanes: Spherical Bodies with and without Li(2)O Filling.

Molecular clusters with archimedean and platonic shape, which in order to build a closed polyhedron, spontaneously eliminate H(2) or voluntarily encapsulate Li(2)O as a "cluster nucleus", result from the dilithiation of primary silylphosphanes and silylarsanes with BuLi. Thus, the first mixed-valent, decameric P(10)Li(16) cluster 1 was obtained from iPr(3)SiPH(2) and tBuLi (molar ratio 1:2) with strict exclusion of LiOH and Li(2)O, whereas partial metalation in the presence of LiOH initially leads to a dodecameric, Li(2)O-containing cluster 2, from which the three-shell cluster 3 with a [Li(6)O](4+) core is obtained.