Synthesis and Chemistry of Bis(borylphosphino)silanes and -germanes

The reactions of Me2SiCl2, Ph2SiCl2, and Ph2GeCl2 with LiP(H)B(NiPr2)2 in a 1:2 ratio and the reaction of Ph2SiCl2 with LiP(H)B(NiPr2)[N(SiMe3)2] in a 1:2 ratio give good yields of the respective diphosphinosilanes, Me2Si[P(H)B(NiPr2)2]2, Ph2Si[P(H)B(NiPr2)2]2, Ph2Ge[P(H)B(NiPr2)2]2, and Ph2Si[P(H)B(NiPr2)[N(SiMe3)2]]2. These
species, when combined with BuLi in a 1:2 ratio, give lithium diphosphinosilanes and -germanes of the general
type (DME·Li)2{[PB(NR2)2]2ER‘2}. All of the species have been characterized by spectroscopic methods. The
molecular structures of three of the lithio compounds, (DME·Li)2{[PB(NiPr2)2]2SiPh2} (11), (DME·Li)2{[PB(NiPr2)N(SiMe3)2]2SiPh2} (15), and (DME·Li)2{[PB(NiPr2)2]2GePh2} (13), have been determined by X-ray
diffraction techniques. 11 crystallized in the triclinic space group P1̄ with a = 11.071(2) Å, b = 14.937(3) Å, c
= 18.080(4) Å, α = 91.31(3)°, β = 101.23(3)°, γ = 109.95(3)°, and Z = 2, and 13 crystallized in the triclinic
space group P1̄ with a = 11.083(1) Å, b = 14.978(2) Å, c = 18.134(2) Å, α = 91.17(1)°, β = 101.43(1)°, γ =
110.05(1)°, and Z = 2. 15 crystallized in the monoclinic space group P21/n with a = 11.939(2) Å, b = 24.516(3)
Å, c = 21.572(3) Å, β = 101.52(1)°, and Z = 4. The reactions of the lithio compounds were surveyed with
R2ECl2 reagents. The metathesis reactions are sluggish, but the 1:1 reaction of (DME·Li)2{[PB(NiPr2)2]2GePh2}
with tBu2SnCl2 gave the four-membered-ring compound The 1:2 reaction
of Me2(Cl)SiSi(Cl)Me2 with LiP(H)B(NiPr2)2 yielded the (borylphosphino)silane [Me2SiP(H)B(NiPr2)2]2.

Me2SiCl2、Ph2SiCl2以及Ph2GeCl2与LiP(H)B(NiPr2)2按1:2比例反应，以及Ph2SiCl2与LiP(H)B(NiPr2)[N(SiMe3)2]按1:2比例反应，均能获得相应的双磷硅烷产物，包括Me2Si[P(H)B(NiPr2)2]2、Ph2Si[P(H)B(NiPr2)2]2、Ph2Ge[P(H)B(NiPr2)2]2和Ph2Si[P(H)B(NiPr2)[N(SiMe3)2]]2，产率较高。这些化合物与BuLi按1:2比例混合，可生成通式为(DME·Li)2{[PB(NR2)2]2ER‘2}的锂双磷硅烷和-锗烷。所有化合物均已通过光谱方法进行表征。其中，三种锂化合物的分子结构，即(DME·Li)2{[PB(NiPr2)2]2SiPh2}（11号）、(DME·Li)2{[PB(NiPr2)N(SiMe3)2]2SiPh2}（15号）和(DME·Li)2{[PB(NiPr2)2]2GePh2}（13号），通过X射线衍射技术确定。11号晶体以P1̄三斜空间群结晶，晶胞参数为a = 11.071(2) Å，b = 14.937(3) Å，c = 18.080(4) Å，α = 91.31(3)°，β = 101.23(3)°，γ = 109.95(3)°，Z = 2；13号晶体以P1̄三斜空间群结晶，晶胞参数为a = 11.083(1) Å，b = 14.978(2) Å，c = 18.134(2) Å，α = 91.17(1)°，β = 101.43(1)°，γ = 110.05(1)°，Z = 2；15号晶体以P21/n单斜空间群结晶，晶胞参数为a = 11.939(2) Å，b = 24.516(3) Å，c = 21.572(3) Å，β = 101.52(1)°，Z = 4。锂化合物的反应已通过R2ECl2试剂进行调研。迁移反应速率较慢，但(DME·Li)2{[PB(NiPr2)2]2GePh2}与tBu2SnCl2的1:1反应生成了四元环化合物。Me2(Cl)SiSi(Cl)Me2与LiP(H)B(NiPr2)2的1:2反应生成了硼基磷硅烷[Me2SiP(H)B(NiPr2)2]2。