A novel Cu(II)-W(V) bimetallic assembly magnet {[Cu(en)2]3[W(CN)8]2·H2O}∞ (en = ethylenediamine) with cube-like W8Cu12 units from a coordinated anion template self-assembly reactionElectronic supplementary information (ESI) available: selected hydrogen bonding parameters in 1 (Table S1) and perspective view showing the three linkages for the title compound (Fig. S1). See http://www.rsc.org/suppdata/nj/b1/b108791f/

A novel molecular-based magnet of three-dimensional (3-D) cyanide-bridged bimetallic assembly, {[Cu(en)2]3[W(CN)8]2·H2O}∞ (1), where en = ethylenediamine, was synthesized and structurally characterized. The assembly has a three-dimensional network structure extended by three kinds of CuII–NC–WV–CN–CuII linkages with very long axial Cu–Ncyanide interactions due to Jahn–Teller effects. The network is based on a W8Cu12 cube-like unit with eight [W(CN)8]3− anions at the corners of the distorted cube and twelve [Cu(en)2]2+ cations at the middle of the edges, in which a coordination anion [W(CN)8]3− acting as template/guest is capsulated in the cavity of the W8Cu12 cube. Magnetic studies reveal that the complex displays 3-D ferromagnetic ordering over the lattice below the Curie temperature at around 2 K.