The Synthesis and the Molecular Structure of Hexakis(carbonyl)hexafluoroantimonato(V)tungsten(II) Undecafluorodiantimonate(V), [W(CO)₆(FSbF₅)][Sb₂F₁₁]

The reaction of tungsten hexacarbonyl, W(CO)6, with antimony(V) fluoride, SbF5, in the conjugate Brønsted−Lewis superacid HF−SbF5 at 40 °C produces quantitatively the salt [W(CO)6(FSbF5)][Sb2F11] as the main product. The observed 2e- oxidation without any loss of CO is unprecedented. The cation [W(CO)6(FSbF5)]+ is seven coordinated with a distorted C2v capped trigonal prismatic structure. [W(CO)6(FSbF5)][Sb2F11] crystallizes in the monoclinic space group P21 (No. 4). a = 8.2051(12) Å, b = 16.511(3) Å, c = 8.1432(2) Å, β = 111.5967(6)°, V = 1025.8(2) Å3, Z = 2. Number of reflections measured = 9112, unique 4410. Residuals on F, I > 3σ(I): R (Rw) = 0.023 (0.023). In the [W(CO)6(FSbF5)]+ cation the FSbF5 group is very tightly coordinated to tungsten with the bridging fluorine nearly equidistant from W and Sb. The details of the molecular structure are compared to those of polymeric [{Mo(CO)4}2(cis-μ-F2SbF4)3]x[Sb2F11]x reported by us very recently.六羰基钨(W(CO)₆)与五氟化锑(SbF₅)在共轭布朗斯特-路易斯超强酸HF−SbF₅中于40 ℃下反应，以定量产率得到作为主要产物的盐[W(CO)₆(FSbF₅)][Sb₂F₁₁]。 所观察到的无任何CO流失的双电子氧化过程前所未有。阳离子[W(CO)₆(FSbF₅)]⁺为七配位结构，具有畸变的C₂v盖帽三角棱柱构型。 [W(CO)₆(FSbF₅)][Sb₂F₁₁]属单斜晶系，空间群为P2₁（编号4）。晶胞参数为：a = 8.2051(12) Å，b = 16.511(3) Å，c = 8.1432(2) Å，β = 111.5967(6)°，晶胞体积V = 1025.8(2) ų，Z = 2。共实测衍射点9112个，其中独立衍射点4410个。对于I > 3σ(I)的衍射点，基于F的残差因子R(Rw) = 0.023(0.023)。 在[W(CO)₆(FSbF₅)]⁺阳离子中，FSbF₅基团与钨原子结合十分紧密，桥连氟原子与钨、锑的距离近乎相等。将该分子结构的细节与我们近期报道的聚合物[{Mo(CO)₄}₂(cis-μ-F₂SbF₄)₃]ₓ[Sb₂F₁₁]ₓ的结构进行了对比。