Synthesis and structural characterisation of monomeric Group 14 metal dialkyls MR2 [R = CPh(SiMe3)(C5H4N-2) or CH(SiMe3)(C9H6N-8); M = Ge, Sn or Pb]

Abstract

A series of heavier main Group 14 metal dialkyls MR₂ [R = R¹ = CPh(SiMe₃)(C₅H₄N-2), M = Ge 1 or Sn 2; R = R² = CH(SiMe₃)(C₉H₆N-8), M = Sn 3 or Pb 4] has been synthesized by the reaction of 2 equivalents of the appropriate lithium reagents LiR(tmen) (tmen = Me₂NCH₂CH₂NMe₂) with GeCl₂(diox) (diox = 1,4-dioxane), SnCl₂ or Pb[N(SiMe₃)₂]₂ in diethyl ether solution. Crystal structure analysis has shown that compounds 1–4 are monomeric with the N-functionalized alkyl ligands R¹ or R² bonded to the metal centre in a C,N-chelate fashion and the geometry around the metal is pyramidal, consistent with a stereoactive lone pair at the metal.