Scandium, yttrium and lanthanum nitrate complexes of tertiary arsine oxides:: synthesis and multinuclear spectroscopic studies.: X-ray structures of [M(Me3AsO)6](NO3)3 (M = Sc or Y), [Sc(Ph3AsO)3(NO3)2]NO3, [M"(Ph3AsO)4(NO3)2]NO3 (M" = Y or La) and [La(Ph3AsO)2(EtOH)(NO3)3]

The reaction of Ph3AsO with Sc(NO3)(3). 5H(2)O, Y(NO3)(3). 6H(2)O or La(NO3)(3). 6H(2)O in acetone gave [Sc(Ph3AsO)(2)(NO3)(3)], [Y(Ph3AsO)(4)(NO3)(2)]NO3, [La(Ph3AsO)(4)(NO3)(2)]NO3, and [La(Ph3AsO)(3)(NO3)(3)], whilst from ethanol solution [Sc(Ph3AsO)(3)(NO3)(2)]NO3, [Y(Ph3AsO)(2)(EtOH)(NO3)(3)] and [La(Ph3AsO)(2)(EtOH)(NO3)(3)] were produced. Similar reactions using Me3AsO produced [M(Me3AsO)(6)](NO3)(3) (M = SC, Y or La) and [La(Me3AsO)(2)(H2O)(NO3)(3)]. All complexes were characterised by analysis, IR and H-1, Sc-45 or Y-89 NMR spectroscopy, and conductance measurements. The solution speciation and interconversions of the Sc and Y complexes have been probed by Sc-45 and Y-89 NMR spectroscopy. X-Ray crystal structures are reported for the 6-coordinate [M(Me3AsO)(6)](NO3)(3) (M = Sc or Y), seven-coordinate [Sc(Ph3AsO)(3)(NO3)(2)]NO3, eight-coordinate [M"(Ph3AsO)(4)(NO3)(2)]NO3 (M" = Y or La), and nine-coordinate [La(Ph3AsO)(2)(EtOH)(NO3)(3)]. (C) 2001 Elsevier Science Ltd. All rights reserved.