title: Trivalent lanthanide lacunary phosphomolybdate complexes: a structural and spectroscopic study across the series [Ln(PMo11O39)2]11-.
abstract: We report the syntheses and crystal structures of (NH4)11[Ln(III)(PMo11O39)2.xH2O (where Ln = every trivalent lanthanide cation except promethium) in which two lacunary [PMo11O39]7- anions sandwich an 8-coordinate Ln(III) cation to yield the complex anion, [LnIII(PMo11O39)2]11-. The 14 salts crystallise in two different space groups, C2/c or P1, but the LnIII containing anions are isostructural across the whole series, a very rare example of such a complete study. Solid state and solution 31P NMR, Raman and IR spectroscopies have been used to prove the stability of [Ln(PMo11O39)2]11- in aqueous solution. As expected, the LnIII cation contracts across the series and the Ln-O bond distances decrease uniformly. Interestingly, the splitting in the nu(P-O) mode within the [PMo11O39]7- unit increases uniformly across the series, which we attribute to the stronger interaction with the smaller, higher charge density LnIII cation as the series is traversed. For the 31P NMR measurements a direct comparison of Lanthanide Induced (paramagnetic) Shift could be made with the analogous [P(W11O39)2]11- complexes.
authors.affiliation: Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Manchester, UKM13 9PL.
authors.forename: Roy
authors.initials: R
authors.lastname: Copping
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gaunt
authors.forename: Iain
authors.initials: I
authors.lastname: May
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarsfield
authors.forename: David
authors.initials: D
authors.lastname: Collison
authors.forename: Madeleine
authors.initials: M
authors.lastname: Helliwell
authors.forename: Iain S
authors.initials: IS
authors.lastname: Denniss
authors.forename: David C
authors.initials: DC
authors.lastname: Apperley
mesh_terms: D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008982:Molybdenum / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D028581:Lanthanoid Series Elements; D010756:Phosphoric Acids; D008982:Molybdenum; C003125:phosphomolybdic acid