title: Muffin-like lanthanide complexes with an N5O2-donor macrocyclic ligand showing field-induced single-molecule magnet behaviour.
abstract: Three mononuclear lanthanide complexes of a 2-pyridylmethyl pendant-armed 15-membered ligand {(3,12-bis(2-pyridylmethyl)-3,12,18-triaza-6,9-dioxabicyclo-[12.3.1]octadeca-1,14,16-triene); L} with general formula [Ln(L)(H2O)(NO3)](NO3)2(Ln = Tb (1), Dy (2), and Er (3)) are reported. Based on X-ray diffraction analysis of 1 and 2, the central lanthanide atoms are nine-coordinated with the N5O4donor set originating from the ligand L and one coordinated water molecule and one monodentate-bonded nitrato ligand. The coordination geometry of the [LnN5O4] cores can be described as a muffin-like shape. Magnetic measurements revealed that all three compounds show field-induced single-molecule magnet behaviour, with estimated energy barriers U ≈ 44-82 K. The experimental study was complemented by CASSCF calculations showing a trend of an increasing first excited energy gap (Tb → Dy → Er) within the muffin-like geometry with the lowest magnetization tunnelling probability for the DyIIIcomplex 2.
authors.affiliation: Department of Inorganic Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic. zdenek.travnicek@upol.cz.
authors.forename: Peter
authors.initials: P
authors.lastname: Antal
authors.affiliation: Department of Inorganic Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic. zdenek.travnicek@upol.cz.
authors.forename: Bohuslav
authors.initials: B
authors.lastname: Drahoš
authors.affiliation: Department of Inorganic Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic. zdenek.travnicek@upol.cz.
authors.forename: Radovan
authors.identifier: http://orcid.org/0000-0001-8262-4666
authors.initials: R
authors.lastname: Herchel
authors.affiliation: Department of Inorganic Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic. zdenek.travnicek@upol.cz.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Trávníček