Aryl–Aryl Interactions in (Aryl‐Perhalogenated) 1,2‐Diaryldisilanes

Three 1,2‐diaryltetramethyldisilanes X(5)C(6)‐(SiMe(2))(2)‐C(6)X(5) with two C(6)H(5), C(6)F(5), or C(6)Cl(5) groups were studied concerning the importance of London dispersion driven interactions between their aryl groups. They were prepared from 1,2‐dichlorotetramethyldisilane by salt elimination. Their structures were determined in the solid state by X‐ray diffraction and for free molecules by gas electron‐diffraction. The solid‐state structures of the fluorinated and chlorinated derivatives are dominated by aryl–aryl interactions. Unexpectedly, Cl(5)C(6)‐(SiMe(2))(2)‐C(6)Cl(5) exists exclusively as an eclipsed syn‐conformer in the gas phase with strongly distorted Si‐C(6)Cl(5) units due to strong intramolecular interactions. In contrast, F(5)C(6)‐(SiMe(2))(2)‐C(6)F(5) reveals weaker interactions. The contributions to the total interaction energy were analyzed by SAPT calculations.