PREPARATIONS, STRUCTURES, AND REACTIONS OF MOLYBDENUM COMPLEXES OF TRIORGANO SILYLATED PYRIDINE-2-THIOLS

Reactions of molybdenum halide precursors with 3-(trimethylsilyl)pyridine-2-thiol (1) or 3,6-bis(tert-butyldimethylsilyl)-pyridine-2-thiol (2) yield a variety of mononuclear and binuclear Mo(III) and Mo(IV) complexes depending on reaction conditions. Illustrative of these classes of complexes are the species [MoCl4(2-SC5H3NH-3-SiMe3)2] (3), [MoCl3{2-SC5H2NH-3,6-(SiMe2Bu(t))2}3] (4), [MoCl4{2-SC5H2NH-3,6-(SiMe2Bu(t))2}2].(C2H5)2O (6), (Ph4P)[MoBr4(2-SC5H3NH-3-SiMe3)2] (7), and [MoBr3(2-SC5H3NH-3-SiMe3)3] (8). Reactions of 3 with molecular oxygen in excess and in stoichiometric quantities yield [Mo2O3(2-SC5H3N-3-SiMe3)4 (9) and [MoOCl(2-SC5H3N-3-SiMe3)2] (10), respectively. In contrast, 7 reacts with O2 to yield (Ph4P)[MoOBr3(2-SC5H3N-3-SiMe3)] (11). Organohydrazine ligands react with 3 by halide displacement and formal oxidation to yield the Mo(VI) species [MoCl2(2-SC5H3N-3-SiMe3)2(NNMePh)] (12) and [Mo(NNMePh)2(2-SC5H3N-3-SiMe3)2] (13). Complex 12 exhibits a seven-coordinate pentagonal-bipyramidal geometry similar to that of [Mo(NNMePh)(SC6H4PPhC6H4S)2] (17). Reductions of 3 and 6 with hydrazine yield the binuclear Mo(III) complexes [Mo2Cl6(2-SC5H3NH-3-SiMe3)3].2CH3CN (14) and [Mo2Cl6{(2-SC5H2NH-3,6-(SiMe2Bu(t))2}3] (15), respectively. Crystal data: 4, monoclinic P2(1)/n, a = 17.644 (5) angstrom, b = 17.067 (5) angstrom, c = 25.798 (5) angstrom, beta = 99.17 (1)-degrees, V = 7669.8 (11) angstrom 3, Z = 4, 2472 reflections, R = 0.089; 6, orthorhombic Pcan, a = 16.245 (5) angstrom, b = 13.531 (4) angstrom, c = 23.739 (7) angstrom, V = 5218.4 (12) angstrom 3, Z = 4, 1533 reflections, R = 0.073; 7, triclinic P1BAR, a = 10.689 (1) angstrom, b = 14.511 (3) angstrom, c = 16.713 (3) angstrom, alpha = 104.15 (1)-degrees, beta = 103.58 (1)-degrees, gamma = 95.46 (1)-degrees, V = 2411.6 (8) angstrom 3, Z = 2, 3510 reflections, R = 0.053; 8, orthorhombic, Pbca, a = 33.376 (6) angstrom, b = 18.751 (4) angstrom, c = 11.980 (4) angstrom, V = 7494.6 (13) angstrom 3, Z = 8, 2864 reflections, R = 0.032; 9, monoclinic P2(1)/c, a = 11.719 (4) angstrom, b = 14.258 (7) angstrom, c = 14.081 (3) angstrom, beta = 99.91 (2)-degrees, V = 2317.8 (11) angstrom 3, Z = 2, 1571 reflections, R = 0.086; 10, monoclinic P2(1)/c, a = 12.858 (3) angstrom, b = 13.655 (3) angstrom, c = 13.290 (3) angstrom, beta = 96.67 (2)-degrees, V = 2317.7 (12) angstrom 3, Z = 4, 1843 reflections, R = 0.083; 11 monoclinic C2/c, a = 19.806 (4) angstrom, b = 12.271 (3) angstrom, c = 32.749 (5) angstrom, beta = 96.57 (1)-degrees, V = 7907.4 (12) angstrom 3, Z = 8, 2440 reflections, R = 0.083; 12, monoclinic P2(1)/c, a = 10.727 (3) angstrom, b = 16.428 (5) angstrom, c = 22.800 (6) angstrom, beta = 97.67 (2)-degrees, V = 3981.9 (21) angstrom 3, Z = 4, 2299 reflections, R = 0.072; 13, monoclinic C2/c, a = 22.833 (5) angstrom, b = 10.731 (2) angstrom, c = 14.645 (4) angstrom, beta = 102.25 (1)-degrees, V = 3506.9 (21) angstrom 3, Z = 4, 2402 reflections, R = 0.051; 14, triclinic P1BAR, a = 10.605 (3) angstrom, b = 13.277 (4) angstrom, c = 16.969 (5) angstrom, alpha = 79.82 (1)-degrees, beta = 84.19 (2)-degrees, gamma = 71.51 (1)-degrees, V = 2228.0 (11) angstrom 3, Z = 2, 2249 reflections, R = 0.053; 15, orthorhombic Pbca, a = 15.338 (4) angstrom, b = 30.447 (8) angstrom, c = 33.913 (8) angstrom, V = 15838.2 (27) angstrom 3, Z = 8, 5163 reflections, R = 0.059; 17, monoclinic P2(1)/n, a = 13.466 (2) angstrom, b = 15.023 (2) angstrom, c = 21.565 (3) angstrom, beta = 100.05 (1)-degrees, V = 4296.9 (12) angstrom 3, Z = 4, 4337 reflections, R = 0.038.