Scandium halide complexes of phosphine- and arsine-oxides:: synthesis, structures and 45Sc NMR studies

The reactions of ScCl(3)(.)6H(2)O, ScBr(3)(.)6H(2)O and Scl(3)(.)8H(2)O with Ph3PO, Ph3AsO, Ph2MePO, Me3PO and Me3AsO have been examined in EtOH or Me2CO solution. The new complexes [ScCl(Me3PO)(5)]Cl-2, [Sc(Me3PO)(6)]X-3 (X = Br or 1), [ScX,(Ph3PO)4]X (X = Cl, Br or 1), [ScX2(Ph3AsO)(4)]X, [Sc(Me3AsO)(6)]X-3 (X = Cl, Br or 1), [ScCl3(Ph2MePO)(3)] and [ScBr2(PhMePO)(4)]Br were isolated as solids and were characterised by analysis, IR and multinuclear (H-1, P-31{H}: and Sc-45) NMR spectroscopy and conductance measurements. The crystal structures of [ScBr2(Ph3PO)(4)]Br(.)1/2Et(2)O, [ScCl2(Ph3AsO)(4)]Cl and [Sc(Me3AsO)(6)]Br-3 are also reported. The solution speciation (in CH2Cl2 or MeNO2) in the various systems was examined by multinuclear NMR spectroscopy. The Sc-45 NMR chemical shifts and line widths show systematic trends with donor set and symmetry. which are described. No reaction between these ligands and ScF3.1/2H(2)O was observed. (C) 2002 Elsevier Science Ltd. All rights reserved.