title: Lanthanide nitrate complexes of tri-isobutylphosphine oxide: solid state and CD2Cl2 solution structures.
abstract: The complexes Ln(NO(3))(3)L(3) between Ln(NO(3))(3) and (i)Bu(3)PO (=L) have been prepared for Ln = La-Lu (excluding Pm). The isolated complexes have been characterized by infrared spectroscopy, mass spectrometry, and elemental analysis. The single crystal X-ray structures have been determined for representative complexes across the series Ln = Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, and Yb and show the coordination geometry around the metal to be the same with 9-coordinate lanthanide ions and bidentate nitrates. Subtle changes in the coordination of the nitrate ligand occur from Sm onward. Changes in the infrared spectra correlate well with changes in the X-ray structures. Solution properties have been examined by variable temperature multinuclear ((1)H, (13)C, (15)N, and (31)P) NMR spectroscopy in CD(2)Cl(2). The spectra of complexes of the early lanthanides are consistent with the presence of a single species in solution while those of the heavier lanthanides show that more than one complex is present in solution and that two inequivalent phosphorus environments are observable at low temperature. The fluxional behavior is lanthanide dependent with smaller ions giving static structures at higher temperature. Complexes with tricyclohexylphosphine oxide show that the dynamic NMR behavior is also related to the size of the ligand. Analysis of the lanthanide induced shifts indicates minor changes in solution structure occur from Sm onward which correlate well with the solid state structures.
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: Peter N
authors.initials: PN
authors.lastname: Horton
authors.forename: Andrew W G
authors.initials: AW
authors.lastname: Platt
mesh_terms: D003903:Deuterium / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008968:Molecular Conformation; D009566:Nitrates / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D012996:Solutions; D013237:Stereoisomerism
chemical_list: D028581:Lanthanoid Series Elements; D009566:Nitrates; D009942:Organometallic Compounds; D010087:Oxides; D010720:Phosphines; D012996:Solutions; C558944:tri-isobutylphosphine oxide; D003903:Deuterium