Synthesis, characterization and structures of diphenyldiaminosilanes bearing bulky substituents on nitrogen

Abstract

Aminosilanes bearing bulky substituents on nitrogen centers, [(ArNH)₂SiPh₂] (Ar=2,6-ⁱPr₂C₆H₃ (1), 2,4,6-Me₃C₆H₂ (2), 2,6-Et₂C₆H₃ (3)), have been prepared in good yields by the addition of dichlorodiphenylsilane to the corresponding substituted monolithiated aniline. The new compounds have been characterized by elemental analysis and IR, EI mass and NMR (¹H and ²⁹Si) spectroscopic studies. The solid-state structures of 1 and 3 have been determined by single crystal X-ray diffraction studies. The molecules have a C_s symmetry and the two N-H protons are approximately trans to each other. The amido nitrogen atoms show significant deviation from trigonal-planar geometry, as a result of which the observed Si-N bonds are marginally longer than those observed in aminosilanes with planar nitrogen atoms. Aminosilanes bearing bulky substituents on nitrogen centers, [(ArNH)₂SiPh₂] (Ar=2,6-ⁱPr₂C₆H₃ (1), 2,4,6-Me₃C₆H₂ (2), 2,6-Et₂C₆H₃ (3)), are accessible in good yields by the addition of dichlorodiphenylsilane to the corresponding monolithiated substituted aniline. The molecules have a Cs symmetry due to the large steric crowding and the two N-H protons are approximately trans to each other.