A Three-Dimensional Hetero-Bimetallic Coordination
Polymer with Unusual (4,5)-Connected Topology and Ferrimagnetic Property
Based on Octacyanotungstate and Polydentate Ligand
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Abstract
A three-dimensional (3D) manganese–tungsten
bimetallic coordination
polymer (CP) {{[μ<sub>5</sub>-W(CN)<sub>8</sub>]<sub>2</sub>[Mn(HMTA)<sub>1.5</sub>]<sub>2</sub>[Mn(HMTA)(H<sub>2</sub>O)<sub>2</sub>]}·2H<sub>2</sub>O}<sub><i>n</i></sub> (CP-<b>1</b>) (HMTA = hexamethylenetetramine) is constructed
by the reaction of the molecular building block [W(CN)<sub>8</sub>]<sup>3–</sup> and tetradentate bridging ligand HMTA with
d<sup>5</sup> transition metal ion Mn<sup>2+</sup>. CP-<b>1</b> has been unambiguously confirmed by Fourier-transform infrared spectroscopy,
elemental analysis, thermogravimetric analysis, and single-crystal
and powder X-ray diffraction. Crystallographic analysis reveals that,
crystallizing in the monoclinic crystal system with <i>P</i>2<sub>1</sub>/<i>c</i> space group, CP-<b>1</b> possesses
an infinite 3D framework and exhibits an unusual (4,5)-connected <b>4,5T7</b> topology with point symbol (3<sup>2</sup>·6<sup>2</sup>·7<sup>2</sup>)(3·4<sup>4</sup>·5<sup>2</sup>·6<sup>2</sup>·7)<sub>4</sub>. The extended 3D structure
is constructed by two-dimensional (2D) cyano-bridged corrugated -W–Mn2–W–Mn2-
layers pillared via the [Mn1(HMTA)(H<sub>2</sub>O)<sub>2</sub>] units.
The magnetic investigation indicates ferrimagnetic behavior for CP-<b>1</b> because of the antiferromagnetic coupling between W<sup>V</sup> (<i>S</i> = 1/2) and Mn<sup>II</sup> (<i>S</i> = 5/2) centers mediated by cyano bridges
