• Silanes;
  • Hexacoordination;
  • N ligands;
  • Borates;
  • Scorpionate analogues


Tetrachlorosilane, trichlorosilane and dichlorosilane react with 1-trimethylsilyl-3,5-dimethylpyrazole (Me3Sipz*), triethylamine/3,5-dimethylpyrazole (Hpz*) or solely Hpz* to afford the new silicon-based scorpionate analogues X4–nSi(pz*)n (1n = 4; 2 X = Cl, n = 3; 3 X = H, n = 3; 4 X = H, n = 2) and the ionic complex [H2Si(Hpz*)4]Cl2 (5). Compounds 1 and 2 are involved in a complex system of equilibria of both Si–Cl vs. Si–N dismutation and intramolecular Si–N exchange. The Si–H bonds in 3 and 4 remain intact, thus intermolecular exchange phenomena like that in compounds Cl4–nSi(pz*)n were not observed. 29Si NMR and Raman spectra indicate that 4 forms oligomers with hexacoordinate Si atoms in solution as well as in the solid state. The Si atom of 5 is also hexacoordinate in the solid state. However, the coordination mode in 5 is completely different to that in 14, because all four Hpz* ligands coordinate by using the available nitrogen lone pairs.