Synthese der Silatetraphospholane (tBuP)4SiMe2, (tBuP)4SiCl2 und (tBuP)4Si(Cl)SiCl3 Molekül- und Kristallstruktur von (tBuP)4SiCl2

Synthesis of the Silatetraphospholanes (tBuP)₄SiMe₂, (tBuP)₄SiCl₂, and (tBuP)₄Si(Cl)SiCl₃ Molecular and Crystal Structure of (tBuP)₄SiCl₂ The reaction of the diphosphide K₂[(tBuP)₄] 7 with the halogenosilanes Me₂SiCl₂, SiCl₄ or Si₂Cl₆ in a molar ratio of 1:1 leads via a [4 + 1]-cyclocondensation reaction to the silatetraphospholanes (tBuP)₄SiMe₂ 1,1-dimethyl-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 1 , (tBuP)₄SiCl₂, 1,1-dichloro-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 2 , and (tBuP)₄Si(Cl)SiCl₃, 1-chloro-1-trichlorsilyl-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 3 , respectively, with the 5-membered P₄Si ring system. The reaction leading to 1 is accompanied with the formation of the by-product Me₂(Cl)-Si–(tBuP)₄–Si(Cl)Me₂ 1a (5:1), which has a chain structure. On warming to 100°C 1a decomposes to 1 and Me₂SiCl₂. The compounds 2 and 3 do not react further with an excess of 7 due to strong steric shielding of the ring Si atoms by the t-butyl groups. 1, 2 and 3 could be obtained in a pure form and characterized NMR spectroscopically; 2 was also characterized by a single crystal structure analysis. 1a was identified by NMR spectroscopy only.