Synthesis and crystal structure of the potassium iminophosphanide [K4(thf)3(Me3SiNPEt2)2(OSiMe2OSiMe2O)]2

potassium iminophosphanide complex [K-4(thf)(3)(Me3SiNPEt2)(2)(OSiMe2OSiMe2O)](2) has been obtained by a melt reaction of Me3SiNPEt3 with potassium hydride at 140degreesC in the presence of silicon grease (-OSiMe2-)(n) and subsequent crystallization from thf solution. The colourless moisture sensitive single crystals are characterized by X-ray diffraction: Space group PI, Z = 1, lattice dimensions at -70degreesC: a = 1135.9(3), b = 1250.0(3), c = 1866.1(4) pm, alpha = 92.65(1)degrees, beta = 100.80(1)degrees, gamma = 93.57(1)degrees, R-1 = 0.0604. The centrosymmetric dimeric cluster aggregate is formed by two of the eight potassium ions which are connected with the central oxygen atom of both the (OSiMe2OSiMe2O)(2-) chains as well as with one of their terminal O atoms each. The remaining potassium ions are connected with the phosphorus atoms of the iminophosphanide groups (Me3SiNPEt2)(-) as well as with its nitrogen atoms. They are terminally solvated by thf molecules.