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) {{[μ 5 -W(CN) 8 ] 2 [Mn(HMTA) 1.5 ] 2 [Mn(HMTA)(H 2 O) 2 ]}·2H 2 O} 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 d 5 transition metal ion Mn 2+ . 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 P 2 1 / c space group, CP- 1 possesses an infinite 3D framework and exhibits an unusual (4,5)-connected 4,5T7 topology with point symbol (3 2 ·6 2 ·7 2 )(3·4 4 ·5 2 ·6 2 ·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)(H 2 O) 2 ] units. The magnetic investigation indicates ferrimagnetic behavior for CP- 1 because of the antiferromagnetic coupling between W V ( S = 1/2) and Mn II ( S = 5/2) centers mediated by cyano bridges.