Complexes of Group 15 Metals with Sterically Hindered Thiolate Ligands. Crystal and Molecular Structures of [Sb(2-SC₅H₄N)₃], [Sb(2-SC₅H₃N-3-SiMe₃)₃], and [Bi(2-SC₅H₃N-3-SiMe₃)₃]

The complexes [Sb(2-C₅H₄N)₃] (1), [Sb(2-SC₅H₃N-3-SiMe3)3] (2), and [Bi(2-SC₅H₃N-3-SiMe₃)₃] (3) were prepared from the reaction of the appropriate metal salt and the ligand in methanol. The structure of 1 consists of a distorted octahedral arrangement of S and N donors, which adopt a facial ligand arrangement. The stereochemically active lone pair of the Sb(III) center occupies a position capping the N₃ face of the octahedron. In contrast, the donor groups in 2 are so disposed that the lone pair occupies an octahedral vertex trans to a sulfur donor, with one nitrogen donor now defining the face capping position. The structure of the bismuth derivative (3) is analogous to that of 2. Crystal data: C₁₅H₁₂N₃S₃Sb (1); trigonal R3c, a = 12.562 (2) Å, c = 37.960 (4) Å, V- 5187.6 (10) ų, Z = 12, R = 0.026; C₂₄H₃₆N₃Si₃S₃Sb (2), monoclinic P2₁/c, a = 17.876 (3) Å, b = 10.772 (2) Å, c = 18.617 (4) Å, β = 116.08 (1)°, V = 3219.8 (11) ų, Z = 4, R = 0.028; C₂₄H,₆N₃Si₃S₃Bi (3), monoclinic C2/c, a = 24.682 (4) Å, b = 12.927 (2) Å, c = 24.782 (4) Å, β = 123.04 (1)°, V = 6629.1 (12) ų, Z = 8, R = 0.049.