[t-Bu2P]3P7 und (t-Bu2Sb)3P7 sowie Untersuchungen zur Bildung von Heptaphosphanen(3) mit PMe2-, PF2- und P(CF3)2-Gruppen

t-Bu₂P]₃P₇ and (t-Bu₂Sb)₃P₇, as well as Investigations on the Formation of Heptaphosphanes (3) Containing PMe₂, PF₂, and P(CF₃)₂ Groups Tris(di-tert-butylphospha)heptaphosphanortricyclane (t-Bu₂P)₃P₇ 1 obtained by reacting Li₃P₇ · 3 DME with t-Bu₂PF forms yellow crystals. (t-Bu₂Sb)₃P₇ 2 produced similarly from t-Bu₂SbCl and Li₃P₇ · 3 DME didn't form crystals; it decomposes in a solution of toluene above ?10°C. Both compounds were identified by their ³¹P{¹H} NMR spectra, and 1 also by elemental analysis and single crystal structure determination (space group) P2₁/a, a = 1 712.0(9) pm, b = 1 105.1(7) pm, c = 1 854.0(10) pm, β = 94.96(4)°, Z = 4 formula units in the elementary cell). Attempts to synthesize (Me₂P)₃P₇ 3 , (F₂P)₃P₇ 4 and (F₃C)₂P]₃P₇ 5 failed as dialkylchlorophosphanes as Me₂PCl e. g. with Li₃P₇ · 3 DME react under Li/Cl exchange, dialkylfluorophosphanes (except t-Bu₂PF) disproportionate, and neither PF₃ nor (F₃C)₂PBr with Li₃P₇ · 3 DME give the desired products 4 or 5 , resp.