The tetraiodotetrasilane (tBu3Si)SiI2SiI2(SitBu3) can be prepared from precursor (tBu3Si)SiH2SiH2(SitBu3). When (tBu3Si)SiH2SiH2(SitBu3) was treated with an excess of iodine at 120 °C, (tBu3Si)SiI2SiI2(SitBu3) was formed. X-ray quality crystals of (tBu3Si)SiI2SiI2(SitBu3) were grown from benzene at ambient temperature. The tetraiodotetrasilane (tBu3Si)SiI2SiI2(SitBu3) crystallizes in the monoclinic space group C2/c, a = 10.0110(10) Å, b = 13.9130(10) Å, c = 25.422(2) Å, β = 99.072(4)°, V = 3496.6(5) Å3, Z = 4, d calcd = 1.829 g cm3; R 1 = 0.0844, wR 2 = 0.1854 for 3,017 reflections with I > 2σ(I). X-ray-crystallographic data show that the bromo and iodo derivatives (tBu3Si)SiX2SiX2(SitBu3) (X = Br, I) are isomorphous. The solid-state structure of (tBu3Si)SiI2SiI2(SitBu3) as well as those of (tBu3Si)SiX2SiX2(SitBu3) (X = Cl, Br) reveals a staggered conformation which adopts a trans-orientation of the supersilyl substituent. Unequal dihedral angles as found in (tBu3Si)SiX2SiX2(SitBu3) (X = Cl, Br, I) indicate that these compounds are sterically overcrowded.
Graphical Abstract
In the solid-state (tBu3Si)SiI2SiI2(SitBu3) features a staggered conformation which adopts a trans-orientation of the supersilyl group. However the solid-state structure of (tBu3Si)SiI2SiI2(SitBu3) reveals unequal dihedral angles.