10.1021/ic5008582.s001 Pau Díaz-Gallifa Pau Díaz-Gallifa Oscar Fabelo Oscar Fabelo Jorge Pasán Jorge Pasán Laura Cañadillas-Delgado Laura Cañadillas-Delgado Francesc Lloret Francesc Lloret Miguel Julve Miguel Julve Catalina Ruiz-Pérez Catalina Ruiz-Pérez Two-Dimensional 3d–4f Heterometallic Coordination Polymers: Syntheses, Crystal Structures, and Magnetic Properties of Six New Co(II)–Ln(III) Compounds American Chemical Society 2014 matrix dagonalization techniques isostructural compounds Ln 2Co hydrogen bonds crystallization water molecules 2014-06-16 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Two_Dimensional_3d_4f_Heterometallic_Coordination_Polymers_Syntheses_Crystal_Structures_and_Magnetic_Properties_of_Six_New_Co_II_Ln_III_Compounds/2282560 Six new heterometallic cobalt­(II)-lanthanide­(III) complexes of formulas [Ln­(bta)­(H<sub>2</sub>O)<sub>2</sub>]<sub>2</sub>[Co­(H<sub>2</sub>O)<sub>6</sub>]·10H<sub>2</sub>O [Ln = Nd­(III) (<b>1</b>) and Eu­(III) (<b>2</b>)] and [Ln<sub>2</sub>Co­(bta)<sub>2</sub>(H<sub>2</sub>O)<sub>8</sub>]<sub><i>n</i></sub>·6<i>n</i>H<sub>2</sub>O [Ln = Eu­(III) (<b>3</b>), Sm­(III) (<b>4</b>), Gd­(III) (<b>5</b>), and Tb­(III) (<b>6</b>)] (H<sub>4</sub>bta = 1,2,4,5-benzenetretracaboxylic acid) have been synthesized and characterized via single-crystal X-ray diffraction. <b>1</b> and <b>2</b> are isostructural compounds with a structure composed of anionic layers of [Ln­(bta)­(H<sub>2</sub>O)<sub>2</sub>]<sub><i>n</i></sub><sup><i>n</i>–</sup> sandwiching mononuclear [Co­(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup> cations plus crystallization water molecules, which are interlinked by electrostatic forces and hydrogen bonds, leading to a supramolecular three-dimensional network. <b>3</b>–<b>6</b> are also isostructural compounds, and their structure consists of neutral layers of formula [Ln<sub>2</sub>Co­(bta)<sub>2</sub>(H<sub>2</sub>O)<sub>8</sub>]<sub><i>n</i></sub> and crystallization water molecules, which are connected through hydrogen bonds to afford a supramolecular three-dimensional network. Heterometallic chains formed by the regular alternation of two nine-coordinate lanthanide­(III) polyhedra [Ln­(III)­O<sub>9</sub>] and one compressed cobalt­(II) octahedron [Co­(II)­O<sub>6</sub>] along the crystallographic <i>c</i>-axis are cross-linked by bta ligands within each layer of <b>3</b>–<b>6</b>. Magnetic susceptibility measurements on polycrystalline samples for <b>3</b>–<b>6</b> have been carried out in the temperature range of 2.0–300 K. The magnetic behavior of these types of Ln­(III)–Co­(II) complexes, which have been modeled by using matrix dagonalization techniques, reveals the lack of magnetic coupling for <b>3</b> and <b>4</b>, and the occurrence of weak antiferromagnetic interactions within the Gd­(III)−Gd­(III) (<b>5</b>) and Tb­(III)−Tb­(III) (<b>6</b>) dinuclear units through the exchange pathway provided by the double oxo­(carboxylate) and double syn–syn carboxylate bridges.