title: Enhancement of Tb(III) -Cu(II) Single-Molecule Magnet Performance through Structural Modification.
abstract: We report a series of 3d-4f complexes {Ln2 Cu3 (H3 L)2 Xn } (X=OAc(-) , Ln=Gd, Tb or X=NO3 (-) , Ln=Gd, Tb, Dy, Ho, Er) using the 2,2'-(propane-1,3-diyldiimino)bis[2-(hydroxylmethyl)propane-1,3-diol] (H6 L) pro-ligand. All complexes, except that in which Ln=Gd, show slow magnetic relaxation in zero applied dc field. A remarkable improvement of the energy barrier to reorientation of the magnetisation in the {Tb2 Cu3 (H3 L)2 Xn } complexes is seen by changing the auxiliary ligands (X=OAc(-) for NO3 (-) ). This leads to the largest reported relaxation barrier in zero applied dc field for a Tb/Cu-based single-molecule magnet. Ab initio CASSCF calculations performed on mononuclear Tb(III) models are employed to understand the increase in energy barrier and the calculations suggest that the difference stems from a change in the Tb(III) coordination environment (C4v versus Cs ).
authors.affiliation: WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: María José
authors.initials: MJ
authors.lastname: Heras Ojea
authors.affiliation: WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Milway
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400 076, India.
authors.forename: Gunasekaran
authors.initials: G
authors.lastname: Velmurugan
authors.affiliation: Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
authors.forename: Lynne H
authors.initials: LH
authors.lastname: Thomas
authors.affiliation: Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.affiliation: WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Wilson
authors.affiliation: CNRS, Inst NEEL & Univ. Grenoble Alpes, 38000, Grenoble, France.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wernsdorfer
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400 076, India. rajaraman@chem.iitb.ac.in.
authors.forename: Gopalan
authors.initials: G
authors.lastname: Rajaraman
authors.affiliation: WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK. Mark.Murrie@glasgow.ac.uk.
authors.forename: Mark
authors.identifier: http://orcid.org/0000-0001-7297-2878
authors.initials: M
authors.lastname: Murrie
keywords: copper; heterometallic complexes; lanthanides; magnetic properties; single-molecule magnets