A multinuclear magnetic resonance study of TeFx(OTeF5)4−x, [TeFx(OTeF5)3−x]+[AsFy(OTeF5)6−y]− and Cs+[As(OTeF5)6]−

The [OTeF5]− and F− acceptor properties of AsF5 and As(OTeF5)5 have been investigated for the series TeFx(OTeF5)4−x, resulting in the mixed series [TeFx(OTeF5)3−x]+[AsFy(OTeF5)6−y]−. The latter anions and cations have been studied in solution using 19F and 125Te NMR spectroscopy. Pure Te(OTeF5)4 also reacts with As(OTeF5)5 to give [Te(OTeF5)3]+[As(OTeF5)6]− which has also been characterized by Raman spectroscopy. The interaction of Cs+[OTeF5]− or [(CH3)4N]+[OTeF5]− with As(OTeF5)5 in CH3CN yields the [As(OTeF5)6]− anion. The quadrupolar 75As atom (I = 3/2, 100% natural abundance) [As(OTeF5)6]− possesses cubic local symmetry, permitting the observation of the 75As resonance and a two-bond 125Te75As spin-spin coupling in the 75As and 125Te spectra. The [As(OTeF5)6]− anion represents one of only a few examples with suitable symmetry which can be observed by 75As NMR spectroscopy.