title: Magnetic Anisotropies in Rhombic Lanthanide(III) Complexes Do Not Conform to Bleaney's Theory.
abstract: We report a complete set of magnetic susceptibilities of lanthanide complexes with a macrocyclic ligand based on a 3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane platform containing four hydroxyethyl pendant arms (L(1)). The [LnL(1)](3+) complexes are isostructural along the lanthanide series from Ce(3+) to Yb(3+), with the only structural change observed along the series being the monotonous shortening of the Ln-donor distances due to lanthanide contraction. The (1)H NMR spectra point to a D2 symmetry of the [LnL(1)](3+) complexes in aqueous solution, which provides a unique opportunity for analysis of the rhombic magnetic anisotropies with an unequivocal location of the magnetic axes. The contact contributions for the observed paramagnetic shifts have been estimated with density functional theory calculations on the [GdL(1)](3+) complex. Subsequently, the pseudocontact shifts could be factored out, thereby giving access to the axial and rhombic contributions of the magnetic susceptibility tensor. Our results show that the calculated magnetic anisotropies do not follow the trends predicted by Bleaney's theory, particularly in the case of Ho(3+) and Er(3+) complexes.
authors.affiliation: Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo , As Lagoas, Pontevedra, Marcosende 36310, Spain.
authors.forename: Goretti
authors.initials: G
authors.lastname: Castro
authors.affiliation: Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Universidade da Coruña , Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain.
authors.forename: Martín
authors.initials: M
authors.lastname: Regueiro-Figueroa
authors.affiliation: Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Universidade da Coruña , Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Esteban-Gómez
authors.affiliation: Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo , As Lagoas, Pontevedra, Marcosende 36310, Spain.
authors.forename: Paulo
authors.initials: P
authors.lastname: Pérez-Lourido
authors.affiliation: Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Universidade da Coruña , Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Platas-Iglesias
authors.affiliation: Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo , As Lagoas, Pontevedra, Marcosende 36310, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Valencia