Two-dimensional (2-D) cyano-bridged Cu-W bimetallic assemblies that include halogen-substituted pyridine molecules, [Cu~(II)(3-iodopyridine) _4][Cu~(II)(3-iodopyridine)_2]_2[W ~V(CN)_8]_2 (1) (triclinic crystal structure, P1? space group), [Cu~(II)(3-bromopyridine)_4][Cu ~(II)(3-bromopyridine)_2]_2[W~V(CN) _8]_2 (2) (triclinic, P1?), and [Cu~(II)(3- chloropyridine)_2(H_2O)_2][Cu~(II)(3- chloropyridine)_2]_2[W~V(CN)_8] _2?4H_2O (3) (monoclinic, P2_1/c), were synthesized. Thermogravimetric measurements demonstrate that 1 and 2 have high thermal durability up to ca. 150 °C (423 K) due to the lack of water molecules in the crystal and the stacked Cu-W 2-D layers with halogen bonding between halogen-substituted pyridine and the cyano nitrogen of octacyanotungstate. In contrast, 3 exhibits weight loss above ca. 50 °C (323 K) as the water molecules between the 2-D layers are removed upon heating. Magnetic measurements show that 1-3 are ferromagnets due to parallel ordering of the magnetic spins on Cu~(II) (S = 1/2) and W~V (S = 1/2) with Curie temperatures (T_C) of 4.7 K (1), 5.2 K (2), and 7.2 K (3).
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