title: Electronic Structure and Magnetic Anisotropy in Lanthanoid Single-Ion Magnets with C3Symmetry: The Ln(trenovan) Series.
abstract: We report the syntheses and the magnetic characterization of a new series of lanthanide complexes, in which the Ce, Nd, Gd, Dy, Er, and Yb derivatives show single-molecule magnet behavior. These complexes, named Ln(trenovan), where H3trenovan is tris(((3-methoxysalicylidene)amino)ethyl)amine, exhibit trigonal symmetry and the Ln(III) ion is heptacoordinated. Their molecular structure is then very similar to that of the previously reported Ln(trensal) series, where H3trensal is 2,2',2″-tris(salicylideneimino)triethylamine. This prompted us to use the spectroscopic and magnetic properties of the Ln(trensal) family (Ln = Nd, Tb, Dy, Ho, Er, and Tm) to obtain a set of crystal-field parameters to be used as starting point to determine the electronic structures and magnetic anisotropy of the analogous Ln(trenovan) complexes using the CONDON computational package. The obtained results were then used to discuss the electron paramagnetic resonance (EPR) and ac susceptibility results. As a whole, the obtained results indicate for this type of complexes single-molecule magnet behavior is not related to the presence of an anisotropy barrier, due to a charge distribution of the ligand around the lanthanoid, which results in highly mixed ground states in terms of MJcomposition of the states. The crucial parameter in determining the slow relaxation of the magnetization is then rather the number of unpaired electrons (only Kramers ions showing in-field slow relaxation) than the shape of the charge distribution for different Ln(III).
authors.affiliation: Department of Chemistry "U.Schiff" and UdR INSTM, Università degli Studi di Firenze , Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Eva
authors.initials: E
authors.lastname: Lucaccini
authors.affiliation: Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Universidad del País Vasco CFM CSIC-UPV/EHU-MPC & DIPC , Avenida Tolosa 72, 20018 San Sebastián, Spain.
authors.forename: José J
authors.initials: JJ
authors.lastname: Baldoví
authors.affiliation: Department of Chemistry "G. Ciamician", Università degli Studi di Bologna , Via Selmi 2, 40196 Bologna, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Chelazzi
authors.affiliation: LNCMI-CNRS , 25 Rue des Martyrs, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Barra
authors.affiliation: Department of Chemistry "G. Ciamician", Università degli Studi di Bologna , Via Selmi 2, 40196 Bologna, Italy.
authors.forename: Fabrizia
authors.identifier: http://orcid.org/0000-0003-3895-0979
authors.initials: F
authors.lastname: Grepioni
authors.affiliation: Laboratoire de Chimie de Coordination du CNRS , 205, Route de Narbonne, BP 44099, 31077 Toulouse Cedex 4, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Costes
authors.affiliation: Department of Chemistry "U.Schiff" and UdR INSTM, Università degli Studi di Firenze , Via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Lorenzo
authors.identifier: http://orcid.org/0000-0003-4785-1331
authors.initials: L
authors.lastname: Sorace