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

The compounds WF6–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(FcFt), 1J(FcW), and 1J(FtW)(Fc,Ft, cis and trans respectively to oxygen) all have the same sign in WF5OR and cis-WF4(OMe)2 but 1J(FcW) is of opposite sign to J(FcW) and J(FcFt) in WOF5– and W2O2F9–.