Synthesis and Characterization of Imidocubanes with Exocube GeIV and SnIV Substituents: [M(μ3-NGeMe3)]4 (M = Sn, Ge, Pb); [Sn(μ3-NSnMe3)]4

Abstract

The heteroleptic lithium amide, [(Me₃Sn)(Me₃Ge)NLi·(Et₂O)]₂ (2), reacts with MCl₂ (M = Sn, Ge, Pb) to yield the corresponding cubane complexes [M(μ₃-NGeMe₃)]₄ [M = Sn (3), Ge (4), Pb (5)]. In an analogous reaction with SnCl₂, the lithium stannylamide, [(Me₃Sn)₂NLi·(Et₂O)]₂ (1), produces the mixed-valent Sn congener [Sn(μ₃-NSnMe₃)]₄ (6). All imidocubanes contain both di- and tetravalent group 14 metals that are bridged by N. These structures are comprised of M₄N₄ (M = Sn, Pb, Ge) cores that possess varying distortion from perfect cube geometry. The Pb derivative (5) exhibits enhanced volatility and vapor-phase integrity.