Hydrothermal syntheses, architectures and magnetic properties of six novel MnII coordination polymers with mixed ligands

Six novel manganese(II) coordination polymers, namely [Mn(oba)(4,4'-bpy)],.n(4,4'-bpy) (1), [Mn(oba)(phen)(H2O)](n) (2), [Mn-2(oba)(2)(2,2'-bPY)(2)(H2O)(2)](n)(.)nH(2)oba (3), [Mn-2(cca)(2)-(4,4'-bpy)(2)](n)(.)2n(4,4'-bpy) (4), [Mn(cca)(phen)], (5) and [Mn(cca)(2,2'-bpy)(n)(.)0.25nH(2)O (6) [H(2)oba = 4,4'-oxybis(benzoic acid); 4,4'-bpy = 4,4'-bipyridine; phen 1,10-phenanthroline; 2,2'-bpy = 2,2'-bipyridine; H(2)cca p-carboxycinnamic acid] have been synthesised under hydrothermal conditions. Complexes 1 and 4 possess 3D microporous metalorganic frameworks with free 4,4'-bpy ligands in the channels. The Mn-II ions in complex 2 are bridged into 1D infinite double-chain structures, and those in complex 3 are bridged into 1D zigzag chains. Hydrogen bonds cause the formation of 3D supramolecular networks for complexes 2 and 3. Complex 5 is a complicated 3D metal-organic framework, and the Mn-II ions in complex 6 are linked into 2D layers with cavities; interpenetration of these 2D layers results in the formation of a 3D supramolecular network. Magnetic susceptibility measurements indicate that complex 2 displays a weak ferromagnetic interaction between the Mull ions with the following parameters: J = 0.462(3) cm(-1), g = 2.0387(6), zJ' = -0.0062(3) cm(-1) and R = 8.0 x 10(-6). Complex 4 shows antiferromagnetic coupling between the Mn-II ions with J -0.718(4) cm(-1), g = 1.986(4) and R = 2.3 x 10(-4).