A Three-Dimensional Hetero-Bimetallic Coordination Polymer with Unusual (4,5)-Connected Topology and Ferrimagnetic Property Based on Octacyanotungstate and Polydentate Ligand

A three-dimensional (3D) manganese–tungsten bimetallic coordination polymer (CP) {{[μ5-W­(CN)8]2­[Mn­(HMTA)1.5]2­[Mn­(HMTA)­(H2O)2]}­·2H2O}n (CP-1) (HMTA = hexamethylenetetramine) is constructed by the reaction of the molecular building block [W­(CN)8]3– and tetradentate bridging ligand HMTA with d5 transition metal ion Mn2+. CP-1 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 P21/c space group, CP-1 possesses an infinite 3D framework and exhibits an unusual (4,5)-connected 4,5T7 topology with point symbol (32·62·72)­(3·44·52·62·7)4. The extended 3D structure is constructed by two-dimensional (2D) cyano-bridged corrugated -W–Mn2–W–Mn2- layers pillared via the [Mn1­(HMTA)­(H2O)2] units. The magnetic investigation indicates ferrimagnetic behavior for CP-1 because of the antiferromagnetic coupling between WV (S = 1/2) and MnII (S = 5/2) centers mediated by cyano bridges.