Two three-dimensional metal-organic frameworks containing one-dimensional hydroxyl/carboxylate mixed bridged metal chains: syntheses, crystal structures, and magnetic properties.

Two novel three-dimensional complexes formulated as [M(3)(bime)2(mu3-OH)2(HO-BDC)2]n (M = Co, 1; Cu, 2) [bime = 1,2-bis(imidazol-1'-yl)ethane, HO-H2BDC = 5-hydroxyisophthalic acid] have been hydrothermally synthesized and characterized. Both 1 and 2 exhibit similar structural frameworks resulting from one-dimensional metal/oxygen chains extended by HO-BDC, but the bridging modes of HO-BDC and coordination environments of metal centers are different. Complexes 1 and 2 crystallize in the orthorhombic system, space group Pbcn, a = 18.458(2) [18.2119(12) for 2] Angstroms, b = 12.0616(14) [11.6847(7)] Angstroms, c = 11.4859(14) [12.0688(6)] Angstroms, and Z = 4 (4). Magnetic studies show that 1 displays a slow magnetic relaxation, a large hysteresis, and distinct finite-size effects and 2 contains an antiferromagnetic chain.