Synthesis and characterisation of tin(IV) fluoride complexes of phosphine and arsine oxide ligands

The pseudooctahedral complexes [SnF4L2] (L = Ph3PO, Ph3AsO, Me3PO, Me3AsO) and [SnF4(L–L)] (L–L = Ph2P(O)CH2P(O)Ph2, o-C6H4(P(O)Me2)2, o-C6H4(P(O)Ph2)2) have been prepared from [SnF4(MeCN)2] and the appropriate ligand in dichloromethane solution. The complexes have been characterised by analysis, IR, 1H, 31P{1H}, 19F{1H} and 119Sn NMR spectroscopy as appropriate; the NMR studies showing that the complexes of the monodentate ligands exist as mixtures of trans and cis isomers in solution. The crystal structures of trans-[SnF4(OPMe3)2], [SnF4{o-C6H4(P(O)Ph2)2}] · CH2Cl2 · H2O and [o-C6H4(P(O)Ph2)2] · CH2Cl2 have been determined. Comparison of the structural and NMR spectroscopic data of the tetrafluorotin complexes with those of related [SnX4L2] (X = Cl, Br or I) shows that SnF4 is the strongest Lewis acid in the series towards hard Lewis bases.

The pseudooctahedral complexes [SnF4L2] (L = Ph3PO, Ph3AsO, Me3PO, Me3AsO) and [SnF4(L–L)] (L–L = Ph2P(O)CH2P(O)Ph2, o-C6H4(P(O)Ph2)2, o-C6H4(P(O)Me2)2) have been prepared and the X-ray crystal structures of trans-[SnF4(OPMe3)2], [SnF4{o-C6H4(P(O)Ph2)2}] · CH2Cl2 · H2O and [o-C6H4(P(O)Ph2)2] · CH2Cl2 have been determined. The structural and NMR spectroscopic data on [SnX4L2] (X = F, Cl, Br or I) show that SnF4 is the strongest Lewis acid in the series towards hard Lewis bases.Figure optionsDownload as PowerPoint slide