Unexpected coordination of aminoiminophosphoranate ligands with alkali metals

Abstract

The crystal structures of the derivatives [Ph2P(Me3SiN)zLi(THF)2],l[ Na(THF)6][Na((NSiMe3)2PPh2)2],[PhzP(Me3SiN)zK(THF)d], [PhzP(Me);? Rb(THF)]2, and [Ph2P(Me3SiN)2Cs2],- have been determined by low-temperature X-ray structure analysis. The lithium and the potassium compounds form monomeric structures, whereas the sodium derivative forms a previously unheard of sodium-sodiumate structure, where one sodium is surrounded by two anions and the other by six THF molecules. The rubidium and the cesium derivatives adopt a stair-shaped dimeric structure. In the latter, a very close intramolecular metal-?r system contact is observed. A long-range intermolecular metal- system contact binds the dimers in an overall polymeric area, resulting in molecular rods.