title: Homometallic DyIIIComplexes of Varying Nuclearity from 2 to 21: Synthesis, Structure, and Magnetism.
abstract: The synthesis, structure, and magnetic properties of four DyIIIcoordination compounds isolated as [Dy2(LH2)2(μ2-η1:η1-Piv)]Cl⋅2 MeOH⋅H2O (1), [Dy4(LH)2(μ3-OH)2(Piv)4(MeOH)2]⋅4 MeOH⋅2 H2O (2), [Dy6(LH2)3(tfa)3(O3PtBu)(Cl)3]Cl4⋅15.5 H2O⋅4 MeOH⋅5 CHCl3(3) and [Dy21(L)7(LH)7(tfa)7]Cl7⋅15 H2O⋅7 MeOH⋅12 CHCl3(4) are reported (Piv=pivalate, tfa=1,1,1-trifluoroacetylacetone, O3PtBu=tert-butylphosphonate). Among these, 3 displays an equilateral triangle topology with a side length of 9.541 Å and a rare pentagonal-bipyramidal Dy3+environment, whereas complex 4 exhibits a single-stranded nanowheel structure with the highest nuclearity known for a homometallic lanthanide cluster structure. A tentative model of the dc magnetic susceptibility and the low-temperature magnetization of compounds 1 and 2 indicates that the former exhibits weak ferromagnetic intramolecular exchange interaction between the Dy3+ions, whereas in the latter both intramolecular ferromagnetic and antiferromagnetic magnetic exchange interactions are present. Compounds 1, 3, and 4 exhibit frequency-dependent ac signals below 15 K at zero bias field, but without exhibiting any maximum above 2 K at frequencies up to 1400 Hz. The observed slow relaxation of the magnetization suggests that these compounds could exhibit single molecule magnet (SMM) behavior with either a thermal energy barrier for the reversal of the magnetization that is not high enough to block the magnetization above 2 K, or there exists quantum tunneling of the magnetization (QTM).
authors.affiliation: Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
authors.forename: Sourav
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Department of Chemistry, Institute of Infrastructure Technology Research and Management, Ahmedabad, 380026, India.
authors.forename: Sourav
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
authors.forename: Joydev
authors.initials: J
authors.lastname: Acharya
authors.affiliation: Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
authors.forename: Vierandra
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074, Aachen, Germany.
authors.forename: Jan
authors.identifier: http://orcid.org/0000-0003-3688-631X
authors.initials: J
authors.lastname: van Leusen
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074, Aachen, Germany.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0001-7831-3953
authors.initials: P
authors.lastname: Kögerler
authors.affiliation: Departamento de Química Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Herrera
authors.affiliation: Departamento de Química Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
authors.forename: Enrique
authors.identifier: http://orcid.org/0000-0002-6745-9241
authors.initials: E
authors.lastname: Colacio
authors.affiliation: Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.|National Institute of Science Education and Research, Institute of Physics Campus, Sachivalaya Marg, Bhubaneswar, 751 005, India.
authors.forename: Vadapalli
authors.initials: V
authors.lastname: Chandrasekhar
keywords: Schiff base; anisotropy; macrocycle; magnetic properties; polynuclear lanthanide compound; slow magnetic relaxation