Synthesis and molecular structure of EtGe(SePh)3: An unusual example of alkylation by LiEt3BH

Article abstract of DOI:10.1021/om00104a014

The reaction of GeCl₄ with 4 equiv of Li{SePh}, generated by the reductive cleavage of Ph₂Se₂ with LiEt₃BH in tetrahydrofuran, gave a mixture of Ge(SePh)₄ and EtGe(SePh)₃. These products were separated by fractional crystallization from a hexane solution and characterized by ¹H and ⁷⁷Se NMR spectroscopy and single-crystal X-ray diffraction. The latter compound is the first well-characterized example of ethylation of a metal halide via LiEt₃BH. Crystals of Ge(SePh)₄ are orthorhombic, Pbca, with a = 17.111 (2) ?, b = 8.513 (1) ?, c = 8.455 (3) ?, and Z = 2. The structure was solved by direct methods and refined by the full-matrix least-squares method to R = 0.023. Crystals of EtGe(SePh)₃ are triclinic, P1, with a = 10.631 (1) ?, b = 11.022 (2) ?, c = 10.166 (1) ?, α = 115.048 (9)°, β = 99.908 (8)°, γ = 90.864 (9)°, and Z = 2. The structure was solved by the heavy-atom method and refined to R = 0.025. The geometry about the Ge in both compounds is approximately tetrahedral. The Ge-Se bond distances are in the range 2.344-2.356 ?, and the Ge-C distance in EtGe(SePh)₃ is 1.952 ?.