Tungsten(VI) fluoride is known to form complexes with different hard Lewis bases, e.g., pyridines. In contrast to this, only very few examples of high-oxidation-state metal fluorides with soft Lewis bases, e.g., phosphines or arsines, are known.
Gillian Reid and colleagues, University of Southampton, UK, have prepared the first arsine complexes of WF6, as well as other metal fluoride complexes with chelating soft neutral phosphine and arsine ligands with the highest metal oxidation state to date. The team combined WF6 with AsR3 (R = Me, Et) in CH2Cl2 at 77 K to room temperature to give [WF6(AsR3)]. The chelating o-phenylene ligands o-C6H4(EMe2)2 (E = P, As) were also reacted with WF6 to give [WF4{o-C6H4(EMe2)2}2][WF7].
The products are extremely moisture-sensitive. The team, nevertheless, succeeded in obtaining crystals containing [WF4{o-C6H4(EMe2)2}2]2+ cations. The compounds were also characterized using 31P, 19F, and 1H NMR spectroscopy. According to the researchers, these results suggest that, under suitable reaction conditions, similar complexes with neutral ligands could also exist for other “hard” transition metal hexafluorides.
- Neutral and cationic tungsten(VI) fluoride complexes with tertiary phosphine and arsine coordination,
William Levason, Francesco M. Monzittu, Gillian Reid, Wenjian Zhang,
Chem. Commun. 2018.
https://doi.org/10.1039/c8cc05598j
