Abstract
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.