Silaheterocyclen: Molekülstruktur eines 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptans / Silaheterocycles: Molecular Structure of a 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane

Abstract

According to an X-ray structure analysis 1,5-bis(di-tert-butylmethylsilyl)-2,2,4,4,6,6,7,7-octamethyl-3-oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane (1) is a rigid bicyclic molecule consisting of a 1,3-disilacyclobutane ring whose 2,4 positions are bridged by a Me2Si—O—SiMe2 fragment. The four-membered ring is non-planar with a dihedral angle of 33.8° along the C—C axis. The intraring valence angles at carbon are significantly smaller than those at silicon leading to a transannular Si ··· Si distance of only 2.558(1) Å (triclinic, space group P 1̄ with a = 9.125(2), b = 12.668(2), c = 15.499(3) Å, α = 101.25(1), β = 87.87(1), γ = 96.88(1)°, V = 1744.4 Å3 R (wR) = 0.044 (0.051) for 316 refined parameters and 5156 observables).