Oligophosphanid‐Anionen: Synthesen und Molekülstrukturen von [K 2 (PMDETA) 2 (P 4 Ph 4 )], [K 2 (PMDETA)(P 4 t Bu 4 )] 2 und [K(PMDETA)(THF){ cyclo ‐(P 5 t Bu 4 )}] (PMDETA = NMe(CH 2 CH 2 NMe 2 ) 2 )

Oligophosphanide Anions: Syntheses and Molecular Structures of [K 2 (PMDETA) 2 (P 4 Ph 4 )], [K 2 (PMDETA)(P 4 t Bu 4 )] 2 and [K(PMDETA)(THF){ cyclo ‐(P 5 t Bu 4 )}] (PMDETA = NMe(CH 2 CH 2 NMe 2 ) 2 ) The alkali metal tetraphosphanediides [K 2 (PMDETA) 2 (P 4 Ph 4 )] ( 1 ) and [K 2 (PMDETA)(P 4 t Bu 4 )] 2 ( 2 ) [PMDETA = NMe(CH 2 CH 2 NMe 2 ) 2 ] were synthesized via reaction of PhPCl 2 or t BuPCl 2 with 2.5 equiv. potassium and characterized by X‐ray crystallography and 31 P NMR spectroscopy. As in other ion contact complexes of the type M 2 (P 4 R 4 ) (M = alkali metal) the solid‐state structures are retained in solution. While 1 could be prepared in comparatively good yield (54 %), 2 was only isolated in very modest yield and with low purity as [K(PMDETA)(THF){ cyclo ‐(P 5 t Bu 4 )}] ( 3 ) was formed as a side product in this case. 3 was also characterized by X‐ray crystallography and 31 P NMR spectroscopy.