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

Abstract

The reaction of tungsten hexacarbonyl, W(CO)6, with antimony(V) fluoride, SbF5, in the conjugate Brønsted-Lewis superacid HF-SbF5 at 40 degrees 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) A, b = 16.511(3) A, c = 8.1432(2) A, beta = 111.5967(6) degrees, V = 1025.8(2) A3, Z = 2. Number of reflections measured = 9112, unique 4410. Residuals on F, I > 3 sigma (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 to polymeric [[Mo(CO)4]2(cis-mu-F2SbF4)3]x[Sb2F11]x reported by us very recently.

Lewis Superacids: Classifications, Candidates, and Applications

“…The high Lewis acidity and the oxidative strength coupled with the WCA properties of the formed anionsw ere used to access uniquec ationic Group 14, [143a, 172] Group 15, [173] Group 16, [174] Group 17, [175] Group 18, [176] or dblock metal compounds. [177] Various applications in organic synthesis have been developed as can be found in excellent reviews. [6][7] Another strongn eutrala ntimony LSA is Sb(OTe F 5 ) 5 (FIA [29] 625 kJ mol À1 ), but this decomposes to SbF 5 and polymeric (TeOF 4 ) n and has never been isolated in pure form.…”

Predominantly σ‐Bonded Metal Carbonyl Cations (σ‐Carbonyls): New Synthetic, Structural, and Bonding Concepts in Metal Carbonyl Chemistry

“…In a similar manner, [M(CO) 6 ] (M=Mo, W) undergoes 2 e − oxidation in HFSbF 5 by SbF 5 . In case of tungsten, [W(CO) 6 (FSbF 5 )][Sb 2 F 11 ] is isolated,35 while for Mo condensation produces polymeric [{Mo(CO) 4 } 2 (F 2 SbF 4 ) 3 ][Sb 2 F 11 ] 36…”

Efficient alkene hydrosilation with bis(8-quinolyl)phosphine (NPN) nickel catalysts. The dominant role of silyl-over hydrido-nickel catalytic intermediates

“…The Sb-F distance associated with this interaction is 1.904(4)Å, about 0.03Å longer than the average terminal Sb-F bond. 46,47…”