Magnetic double-resonance study of some derivatives of tungsten hexafluoride and tungsten oxotetrafluoride

Abstract

The compounds WF_6–n(OR)_n(R = Me, n= 1–5; R = Ph, n= 1,2), WOF₄L [L = Me₂O or (MeO)₂P(O)Me] and (MeO)₃PMe⁺WOF₅^– have been studied by use of ¹⁹F–{¹⁸³W}, ¹⁹F–{¹⁹F}, ¹H–{¹⁹F}, and ¹H–{³¹P} double-resonance techniques. ¹⁸³W Chemical shifts are reported and the factors affecting these and the ¹⁹F shifts are discussed. By similar techniques WOF₄,OS(OMe)₂ and the µ-fluoro-bis[oxotetrafluorotungstate(VI)] anion, W₂O₂F₉^–, have been identified as products from the reaction of WF₅OMe with (MeO)₂SO. The coupling constants ²J(F_cF_t), ¹J(F_cW), and ¹J(F_tW)(F_c,F_t, cis and trans respectively to oxygen) all have the same sign in WF₅OR and cis-WF₄(OMe)₂ but ¹J(F_cW) is of opposite sign to J(F_cW) and J(F_cF_t) in WOF₅^– and W₂O₂F₉^–.