Bimetallic Assemblies [Ni(L)2]3[Fe(CN)6]X2 (L = Ethylenediamine, Trimethylenediamine; X = PF6-, ClO4-) with a Three-Dimensional Network Extended through FeII−CN−NiII Linkages

Three-dimensional cyanide-bridged bimetallic assemblies [Ni(L)2]3[FeII(CN)6]X2 ((L, X) = (ethylenediamine (en), PF6-) (1), (trimethylenediamine (tn), PF6-) (2), (tn, ClO4-) (3)) were synthesized and structurally characterized. Compounds 13 crystallize in the trigonal system of the space group R3̄ with a = b = 13.743(1) Å, c = 17.802(2) Å, and Z = 3 for 1, a = b = 14.588(1) Å, c = 17.050(2) Å, and Z = 3 for 2, and a = b = 14.337(2) Å, c = 17.294(4) Å, and Z = 3 for 3. 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)6]4- anions at the corners and 12 [Ni(L)2]2+ cations at the edges. Two hexafluorophosphate or perchlorate anions are located in the cavity of the Fe8Ni12 cube and align along a diagonal axis that coincides with the c axis. Magnetic measurements show a ferromagnetic interaction between the nearest NiII ions through the diamagnetic FeII ion.