Synthesis and spectral characterization of diorganodiaminosilanes [(ArNH)₂SiPhMe] (Ar = 2,6-ⁱPr₂C₆H₃; 2,4,6-Me₃C₆H₂) and lithium silylamide [(2,6-Et₂C₆H₃NLi)(2,6-Et₂C₆H₃NH)SiPh₂]

Abstract

Aminosilanes bearing bulky substituents on nitrogen centers, [(ArNH)₂SiPhMe](Ar = (Ar = 2,6-ⁱPr₂C₆H₃(1), 2,4,6-Me₃C₆H₂)(2)) and half-sandwich lithium silylamide [(2,6-Et₂C₆H₃NLi(2,6-Et₂C₆H₃NH)SiPh₂] (3) have been prepared and characterized by elemental analysis, IR, EI mass and NMR (¹H and ²⁹Si) spectroscopic studies. The solid state structures of 2 and 3 have been determined by single crystal X-ray diffraction studies. The molecule 2 has a C₁ symmetry due to the steric crowding, and the two N-H protons are approximately trans to each other. The amido nitrogen atoms in 2 show significant deviation from trigonal-planar geometry, and as a result, the observed Si-N bonds are marginally longer than those observed in aminosilanes with planar nitrogen atoms. The molecule 3 exists as discrete dimer with an inversion center. The Li ion in 3 forms intramolecular p-complex with the neighboring aryl (2,6-Et₂C₆H₃) group, to form a half-sandwich lithium silylamide.