Synthesis and Characterization of the Monomeric Sterically Encumbered Diaryls E{C6H3‐2,6‐(C6H3‐2,6‐Pri2)2}2 (E = Ge, Sn, or Pb)

The reaction of two equivalents of LiC6H3‐2,6‐(C6H3‐2,6‐Pri2)2 with GeCl2·dioxane, SnCl2 or PbBr2 in a diethyl ether solution resulted in the isolation of the monomeric σ‐bonded diaryl tetrylene series E{C6H3‐2,6‐(C6H3‐2,6‐Pri2)2}2 (E = Ge (1), Sn (2), or Pb(3)). Compounds 1‐3 are highly sterically congested blue crystalline solids, which possess V‐shaped structures and wide interligand bond angles. The solid state structures of 1‐3 were determined by single‐crystal X‐ray methods while their solution structures were investigated by UV spectroscopy and in the cases of 2 and 3, respectively, by 119Sn and 207Pb NMR spectroscopy. The series 1‐3 constitutes the most sterically crowded examples of σ‐bonded diorgano group 14 derivatives yet isolated and, in contrast to previously reported: ER2 species, the C‐E‐C angles increase with increasing atomic number.