Synthesis and Reactivity Studies of Amido‐Substituted Germanium(I)/Tin(I) Dimers and Clusters

Three amide ligands of varying steric bulk and electronic properties were utilized to prepare a series of amido‐germanium(II)/tin(II) halide compounds, (LEX)n, (L= ‐N{B(DipNCH)2}(SiMe3), TBoL; ‐N{B(DipNCH)2}(SiPh3), PhBoL; ‐N(Dip)(tBu), DBuL; Dip=C6H3iPr2‐2,6; E=Ge or Sn; X=Cl or Br; n=1 or 2). Reductions of these with a magnesium(I) dimer, {(MesNacnac)Mg}2 (MesNacnac=[(MesNCMe)2CH]−, Mes=mesityl), afforded singly bonded amido‐digermynes (TBoLGe−GeTBoL and PhBoLGe−GePhBoL), and an amido‐distannyne (PhBoLSn−SnPhBoL), in addition to several low‐valent, amido stabilized tetrel–tetrel bonded cluster compounds, (DBuLGe)4, (DBuLSn)6 and Sn5(TBoL)4. The nature of the products resulting from these reactions was largely dependent on the steric bulk of the amide ligand employed. Cluster (DBuLGe)4 possessed an unusual folded butterfly structure, the bonding and electronic of which were examined using DFT calculations. Reactions of the amido‐germanium(I) compounds with H2 were explored, and gave rise to the amido‐digermene, TBoL(H)Ge=Ge(H)TBoL and the cyclotetragermane, {DBuL(H)Ge}4. Reactions of (DBuLGe)4 with a series of unsaturated small molecule substrates yielded DBuLGeOGeDBuL, DBuLGe(μ‐C2H4)2GeDBuL and DBuLGe(μ‐1,4‐C6H8)(μ‐1,2‐C6H8)GeDBuL. The latter results imply that (DBuLGe)4 can act as a masked source of the digermyne DBuLGeGeDBuL in these reactions. All further reactivity studies indicated that the germanium(I) compounds exhibit a “transition‐metal‐like” behavior, which is closely related to that previously described for bulky digermynes and related compounds. One size does not fit all! Reduction of a variety of amido‐germanium(II)/tin(II) halide complexes with a magnesium(I) dimer afforded a series of amido‐germanium(I)/tin(I) dimers and amido‐germanium(I)/tin(I) cluster compounds (see picture). The nuclearity of the product is typically inversely proportional to the steric bulk of the amide ligand employed. The amido‐germanium(I) species exhibit “transition metal‐like” reactivity towards a variety of small‐molecule substrates.