Lanthanide tri- and tetrathionates and their complexes with triphenylphosphine oxide

Lanthanide tri- and tetrathionate containing species have been prepared in solution by the reaction of potassium tri- and tetrathionate with lanthanide perchlorates. Unstable solid materials from these reactions have been examined by infrared spectroscopy and electrospray mass spectrometry (ESI MS). There was evidence of the formation of S3O62- and S4O62- coordination to lanthanide ions, but it was not possible to produce material suitable for single crystal x-ray studies. The reaction of ethanol solutions from Ln(ClO4)3 / K2SnO6 (n = 3,4) with triphenylphosphine oxide yielded crystalline materials which have been characterised by infrared spectroscopy, electrospray mass spectrometry, elemental analysis and single crystal X-ray diffraction. The trithionate complexes [Ln(S3O6)(Ph3PO)4]ClO4.3H2O (Ln = Nd, Tb) have been isolated. The tetrathionate / Ph3PO reaction gave rise to significant disproportionation giving a small quantity of [Nd(S4O6)(Ph3PO)4(H2O)]ClO4, a different isomer of [Nd(S3O6)(Ph3PO)4H2O]ClO4, neodymium sulfate and elemental sulfur. The crystal structures of the two isomers of [Nd(S3O6)(Ph3PO)4H2O]ClO4 and that of [Nd(S4O6)(Ph3PO)4H2O]ClO4 are reported. The structure of [Er(H2O)5(Ph3PO)2].5Ph3PO.3[ClO-4], formed during the attempted preparation of erbium trithionate complexes, is also described.