Chlorogermylenes and -stannylenes stabilized by diimidosulfinate ligands: synthesis, structures, and reactivity

The reaction of the lithium salt of N,N′-di-tert-butyldiimidosulfinate ([PhS(NtBu)2]Li) having a phenyl group on the sulphur atom with ECl2·(dioxane) (E = Ge, Sn) afforded the corresponding chlorogermylene [PhS(NtBu)2]GeCl 1 and -stannylene [PhS(NtBu)2]SnCl 2, respectively. In contrast, treatment of the N,N′-bis(trimethylsilyl)diimidosulfinate ion ([PhS(NSiMe3)2]−) with ECl2·(dioxane) resulted in the unexpected formations of six-membered 1,3-bis(chlorogermylene) [PhS(NSiMe3)2(η1-η1-GeCl)2[μ-NSPh(NHSiMe3)] 7 and -stannylene [PhS(NSiMe3)2(η1-η1-SnCl)2[μ-NSPh(NHSiMe3)] 8. The structures of these chlorometallylene derivatives were fully characterized on the basis of their NMR spectroscopic data and X-ray diffraction. In the crystalline states of 1 and 2, the diimidosulfinate ligands chelate to the metal centre to form slightly hinged four-membered EN2S rings. On the other hand, X-ray analyses of 7 and 8 revealed that the central six-membered E2N3S rings adopt a distorted boat-conformation, and one diimidosulfinate ligand coordinates to the metal centre in a bridging monodentate μ–η1–η1-fashion. As the reactivity of 1 and 2, the oxidation of 1 with elemental chalcogen (S8 or Se) afforded the corresponding tetra-coordinated germanium compounds [PhS(NtBu)2]Ge(Ch)Cl 3 (ChS) and 4 (ChSe). In sharp contrast, the reactions of 2 with elemental chalcogen resulted in the formation of four-membered Sn2Ch2 ring compounds, 1,3,2,4-dichalcogenadistannetanes {(PhS(NtBu)2)SnCl(μ-Ch)}25 (ChS) and 6 (ChSe).