Bimetallic Assemblies [Ni(L)<sub>2</sub>]<sub>3</sub>[Fe(CN)<sub>6</sub>]X<sub>2</sub> (L = Ethylenediamine, Trimethylenediamine; X = PF<sub>6</sub><sup>-</sup>, ClO<sub>4</sub><sup>-</sup>) with a Three-Dimensional Network Extended through Fe<sup>II</sup>−CN−Ni<sup>II</sup> Linkages

Three-dimensional cyanide-bridged bimetallic assemblies [Ni(L)<sub>2</sub>]<sub>3</sub>[Fe<sup>II</sup>(CN)<sub>6</sub>]X<sub>2</sub> ((L, X) = (ethylenediamine (en), PF<sub>6</sub><sup>-</sup>) (<b>1</b>), (trimethylenediamine (tn), PF<sub>6</sub><sup>-</sup>) (<b>2</b>), (tn, ClO<sub>4</sub><sup>-</sup>) (<b>3</b>)) were synthesized and structurally characterized. Compounds <b>1</b>−<b>3</b> crystallize in the trigonal system of the space group <i>R</i>3̄ with <i>a</i> = <i>b</i> = 13.743(1) Å, <i>c</i> = 17.802(2) Å, and <i>Z</i> = 3 for <b>1</b>, <i>a</i> = <i>b</i> = 14.588(1) Å, <i>c</i> = 17.050(2) Å, and <i>Z</i> = 3 for <b>2</b>, and <i>a</i> = <i>b</i> = 14.337(2) Å, <i>c</i> = 17.294(4) Å, and <i>Z</i> = 3 for <b>3</b>. All the assemblies have an isotropic three-dimensional network structure extended through Fe−CN−Ni linkages. The network is based on a cube formed by 8 [Fe(CN)<sub>6</sub>]<sup>4-</sup> anions at the corners and 12 [Ni(L)<sub>2</sub>]<sup>2+</sup> cations at the edges. Two hexafluorophosphate or perchlorate anions are located in the cavity of the Fe<sub>8</sub>Ni<sub>12</sub> cube and align along a diagonal axis that coincides with the <i>c</i> axis. Magnetic measurements show a ferromagnetic interaction between the nearest Ni<sup>II</sup> ions through the diamagnetic Fe<sup>II</sup> ion.