title: Synthesis, ab initio X-ray powder diffraction crystal structure, and magnetic properties of Mn3(OH)2(C6H2O4S)2 metal-organic framework.
abstract: A new hydroxythiophenedicarboxylate metal-organic framework based on Mn(II) cations has been obtained by an aqueous two-step procedure including hydrothermal treatment. The structure of Mn(3)(OH)(2)(C(6)H(2)O(4)S)(2) has been determined ab initio from synchrotron X-ray powder diffraction data and consists of infinite inorganic ribbons which are interlinked by 2,5-thiophenedicarboxylate (tdc) molecules (monoclinic, space group P2(1)/c, a = 3.4473(1) Å, b = 19.1287(1) Å, c = 11.0069(1) Å, β = 97.48(1)°, V = 719.65(1) Å(3), and Z = 2). Each ribbon is built of three vertex-sharing chains of edge-sharing MnO(6) octahedrons. These ribbons are bridged together by the carboxylate functions of the tdc molecule to form a pseudo-2D inorganic subnetwork, while this molecule develops in the third dimension to pillar these pseudo-2D layers. An unprecedented hexadentate symmetric bridging mode is adopted by tdc which bridges two chains of a ribbon on one side and two ribbons of a pseudo-2D inorganic subnetwork on the other side. Magnetic measurements suggest that the titled compound is antiferromagnetic below T(N) = 17.7 K. Heat capacity measurements confirm the existence of a magnetic phase transition toward a 3D long-range ordered state. These C(P)(T) data have also been used for the calculation of the thermal variations of both the adiabatic temperature change ΔT(ad) and magnetic entropy change ΔS(m) of the material, namely its magnetocaloric effect.
authors.affiliation: Université de Lorraine, Institut Jean Lamour-UMR 7198, BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex, France. rom.sibille@gmail.com
authors.forename: Romain
authors.initials: R
authors.lastname: Sibille
authors.forename: Thomas
authors.initials: T
authors.lastname: Mazet
authors.forename: Erik
authors.initials: E
authors.lastname: Elkaïm
authors.forename: Bernard
authors.initials: B
authors.lastname: Malaman
authors.forename: Michel
authors.initials: M
authors.lastname: François