Hydrothermal Syntheses, Architectures and Magnetic Properties of Six Novel Mn II Coordination Polymers with Mixed Ligands

Six novel manganese( II ) coordination polymers, namely [Mn(oba)(4,4′‐bpy)] n · n (4,4′‐bpy) ( 1 ), [Mn(oba)(phen)(H 2 O)] n ( 2 ), [Mn 2 (oba) 2 (2,2′‐bpy) 2 (H 2 O) 2 ] n · n H 2 oba ( 3 ), [Mn 2 (cca) 2 (4,4′‐bpy) 2 ] n · 2 n (4,4′‐bpy) ( 4 ), [Mn(cca)(phen)] n ( 5 ) and [Mn(cca)(2,2′‐bpy)] n · 0.25 n H 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 metal‐organic 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 Mn II 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 × 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 × 10 –4 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)