Structural diversity and magnetic properties of three metal–organic frameworks assembled from a T-shaped linker†
Three metal–organic frameworks, [Mn(bpydc)]·DMA (JLU-Liu11), [Co(bpydc)DMSO]·(DMSO)(H2O) (JLU-Liu12) and [Co(bpydc)H2O]·H2O (JLU-Liu13), were solvothermally synthesized by reacting a T-shaped linker, 2,2′-bipyridyl-5,5′-dicarboxylic acid (H2bpydc) ligand with transition metals. These compounds exhibit three different types of structures. In JLU-Liu11, two oxygen atoms and two nitrogen atoms of the H2bpydc ligand coordinate to five manganese centers to form an ant net, and JLU-Liu11 displays two types of helical chains with opposite helical directions, which are composed of vertex-sharing 4-rings propagating along the  direction. In JLU-Liu12, H2bpydc ligands coordinate to cobalt centers to form a new (3,3)-connected net with two different tiles (6·124) and (62·126). In JLU-Liu13, H2bpydc ligands coordinate to cobalt centers to form a two-dimensional layer which then interacts with terminal water molecules via hydrogen bonds to construct a three-dimensional supramolecular structure, JLU-Liu13 shows exceptional stability in water. Additionally, the magnetic properties of all the compounds were studied.