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) , (L= -N{B(DipNCH) }(SiMe ), L; -N{B(DipNCH) }(SiPh ), L; -N(Dip)(tBu), L; Dip=C H iPr -2,6; E=Ge or Sn; X=Cl or Br; n=1 or 2). Reductions of these with a magnesium(I) dimer, {( Nacnac)Mg} ( Nacnac=[(MesNCMe) CH] , Mes=mesityl), afforded singly bonded amido-digermynes ( LGe-Ge L and LGe-Ge L), and an amido-distannyne ( LSn-Sn L), in addition to several low-valent, amido stabilized tetrel-tetrel bonded cluster compounds, ( LGe) , ( LSn) and Sn ( L) . The nature of the products resulting from these reactions was largely dependent on the steric bulk of the amide ligand employed. Cluster ( LGe) 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 H were explored, and gave rise to the amido-digermene, L(H)Ge=Ge(H) L and the cyclotetragermane, { L(H)Ge} . Reactions of ( LGe) with a series of unsaturated small molecule substrates yielded LGeOGe L, LGe(μ-C H ) Ge L and LGe(μ-1,4-C H )(μ-1,2-C H )Ge L. The latter results imply that ( LGe) can act as a masked source of the digermyne LGeGe L 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.