Synthesis and reactivity of compounds of formula W(S)(OR)4

In ethereal solutions, WSCl₄ and 4 equiv LiOR (R = Bu^t or Prⁱ) react to form compounds of formula W(S)(OR)₄. A single-crystal X-ray diffraction study of W(S)(O-Bu^t)₄ showed it to have a square-based pyramidal geometry with an apical sulfide ligand. Pertinent bond distances (Å) and angles (°) are: WS = 2.1396(13), WO(av.) = 1.886(3), SWO(av.) = 105.09(10), WOC(av.) = 143.47(27). The tert-butoxide compound is stable toward sulfur atom abstraction by phosphines, and neither compound has shown any tendency to undergo comproportionations with W₂(OR)₆ (R = Prⁱ or CH₂Bu^t) species to form compounds of formula W₃(μ₃-S)(OR)₁₀, in direct contrast to analogous molybdenum and tungsten oxo alkoxides.