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.