Synthesis, structure, and reactivity of homoleptic tin(II) and lead(II) chalcogenolates and their conversion to metal chalcogenides. X-ray crystal structures of {Sn[TeSi(SiMe3)3]2}2 and (PMe3)Sn[TeSi(SiMe3)3]2

Article abstract of DOI:10.1021/ja00071a034

The preparation and characterization of homoleptic tin(II) and lead(II) tellurolates, selenolates, and thiolates incorporating bulky ESi(SiMe₃)₃ ligands (E = Te, Se, S) are described. The derivatives M [ESi(SiMe₃J₃]₂ (M = Sn: 1, E = Te; 3, E = Se; 5, E = S. M = Pb: 2, E = Te; 4, E = Se; 6, E = S) are prepared via protonolysis of M[N(SiMe₃)₂]₂ with HESi(SiMe₃)₃ X-ray diffraction shows 1 to be dimeric in the solid state; it crystallizes in the space group P2/c with a = 14.536(2) ?, b = 9.310(1) ?, c = 29.605(6) ?, β = 97.72(1)°, V = 3970.2(19) ?³, Z = 4, R = 3.73%, and R_w = 3.85%. Reaction of 1 with PMe₃ affords the monomeric tin tellurolate (PMe₃)Sn[TeSi(SiMe₃)₃]₂ (10), while addition of 1 equiv of dmpe [dmpe = 1,2-bis(dimethylphosphino)ethane] to 1, 3, and 5 yields the dmpe-bridged stannyl chalcogenolates {Sn[TeSi(SiMe₃)₃]₂}₂(dmpe) (7, E = Te; 8, E = Se; 9, E = S). Complex 10 crystallizes in the space group P1^- with a = 9.625(1) ?, b = 14.236(3) ?, c = 16.973(4) ?, α = 100.59(2)°, β = 103.95(2)°, γ = 91.48(1)°, V = 2212.5(16) ?³, Z = 2, R = 3.56%, and R_w = 4.52%. Pyrolysis of 1, 2, and 4 at relatively low temperatures (ca. 250 °C) under N₂ affords the cubic solids SnTe, PbTe, and PbSe and a single byproduct E[Si(SiMe₃)₃]₂ (E = Te, Se). The composition and crystallinity of these solids were confirmed by elemental analysis and X-ray powder diffraction. Related decomposition reactions also occur at even lower temperatures by thermolysis, UV irradiation, or addition of Lewis bases to hydrocarbon solutions.