Tin(IV) fluoride complexes with neutral phosphine coordination and comparisons with hard N- and O-donor ligands.

The reactions of -[SnF(PMe)] with one, two or three equivalents of MeSiOSCF (TMSOTF), respectively, in anhydrous CHCl form six-coordinate [SnF(PMe)(OTf)] ( = 1-3), which have been characterised by microanalysis, IR and multinuclear NMR (H, F{H}, P{H} and Sn) spectroscopy. The crystal structure of [SnF(PMe)(OTf)] reveals the three fluorines are in a -arrangement with mutually PMe ligands. The multinuclear NMR spectra confirm this structure is retained in solution, and show that [SnF(PMe)(OTf)] has -phosphines, while [SnF(PMe)(OTf)] has PMe groups and hence -triflate ligands. The [SnF(PMe)(OTf)] are unstable in solution and the decomposition products include [MePF] and the tin(II) complexes [Sn(PMe)(OTf)] and [SnF(OTf)], both of the latter identified by their crystal structures. The reaction of -[SnF(PPr)] containing the bulkier phosphine, with one and two equivalents of TMSOTf produced unstable mono- and bis-triflates, which the NMR data also suggest contain weakly coordinated triflate, [SnF(PPr)(OTf)] and [SnF(PPr)(OTf)], again with axial phosphines, although some OTf dissociation from the former to give [SnF(PPr)] may occur in solution at room temperature. The new phosphine complexes of SnF, -[SnF(PPr)] and () [SnF(κ-triphos)] (triphos = CHC(CHPPh)) have also been fully characterised, including the crystal structure of [SnF(κ-triphos)]. Attempts to promote P-coordination by further treatment of this complex with TMSOTf were unsuccessful. The [SnF(L)] (L = dmso, py, pyNO, DMF, OPPh) complexes, which exist as mixtures of and isomers, react with one equivalent of TMSOTf, followed by addition of one equivalent of L, to form the ionic [SnF(L)][OTf] complexes, which were characterised by microanalysis, IR and multinuclear NMR spectroscopy. In nitromethane solution they are a mixture of and isomers based upon multinuclear NMR data (H, F{H}, Sn). Reaction of [SnF(OPPh)] with two equivalents of TMSOTf and further OPPh produced [SnF(OPPh)][OTf], which is a mixture of and isomers in solution. The crystal structure of [SnF(OPPh)][OTf] confirms the isomer in the solid state, with the triflate ionic. These complexes are rare examples of fluorotin(IV) cations with neutral monodentate ligands.