Diorganotin dications stabilized by neutral ligands in the solid state: [R2Sn(H2O)2(OPPh3)2](O3SCF3)2(R = Me, Bu)

The synthesis of [R2Sn(H2O)2(OPPh3)2](O3SCF3)2(R = Me (1), Bu (2)) by the consecutive reaction of R2SnO (R = Me, Bu) with triflic acid and Ph3PO is described. Compounds 1 and 2 feature dialkyltin(IV) dications [R2Sn(H2O)2(OPPh3)2]2+ apparently stabilized by the neutral ligands in the solid state. Compounds 1 and 2 readily dehydrate upon heating at 105 and 86 °C, respectively. The preparative dehydration of 1 afforded [Me2Sn(OPPh3)2(O3SCF3)](O3SCF3)(1a), which features both bidentate and non-coordinating triflate anions. In compounds 1 and 2 the ligands Ph3PO and H2O are kinetically labile in solution and undergo reversible ligand exchange reactions. Compounds 1, 1a and 2 were characterized by multinuclear solution and solid-state NMR spectroscopy, IR spectroscopy, electrospray mass spectrometry, conductivity measurements, thermogravimetry and X-ray crystallography.