title: Complexes of lanthanide nitrates with tri tert butylphosphine oxide.
abstract: Reaction of lanthanide nitrates with (t)Bu(3)PO (=L) lead to the isolation of complexes Ln(NO(3))(3)L(2)·H(2)O·nEtOH (Ln = La (1), Nd(2)), Ln(NO(3))(3)L(2) ·nEtOH (Sm(3), Eu(4)), and Ln(NO(3))(3)L(2) (Dy(5), Er(6), Lu(7)). These have been characterized by elemental analysis, infrared and NMR((1)H, (13)C and (31)P) spectroscopy and single-crystal X-ray diffraction. The structures show L to be positioned on opposite sides of the metal with the nitrates forming an equatorial band. When Ln = Dy, Er, and Lu two distinct molecules are present in the unit cell. A major isomer (70%) has a (P)O-Ln-O(P) angle of less than 180° with one of the nitrate ligands twisted out of the plane of the other nitrates while the lower abundance isomer is more symmetric with the (P)O-Ln-O(P) angle of 180° and the nitrate ligands coplanar giving a hexagonal bipyramidal geometry. These isomers cannot be observed by variable temperature solution (31)P NMR measurements but are clearly seen in the solid-state NMR spectrum of the Lu complex. Variable temperature solid-state NMR indicates that the isomers do not interconvert at temperatures up to 100 °C. Attempts to prepare cationic species [Ln(NO(3))(2)L(3)](+)[PF(6)](-) have not been totally successful and led to the isolation of crystals of Lu(NO(3))(3)L(2) and Tb(NO(3))(3)L(2).CH(3)CN (8).
authors.affiliation: Department of Chemistry and Analytical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6BT, UK.
authors.forename: Allen
authors.initials: A
authors.lastname: Bowden
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.forename: Mateusz B
authors.initials: MB
authors.lastname: Pitak
authors.forename: Andrew W G
authors.initials: AW
authors.lastname: Platt