A series of metal–organic frameworks constructed with 2,2′-bipyridine-3,3′-dicarboxylate: Syntheses, structures, and physical properties

To determine the influence of metal ion and the auxiliary ligand on the formation of metal–organic frameworks, six new coordination polymers, {[Mn2(bpdc)(bpy)3(H2O)2] · 2ClO4 · H2O}n (1), {[Mn(bpdc)(dpe)] · CH3OH · 2H2O}n (2), {[Cu(bpdc)(H2O)2]}n (3), {[Zn(bpdc)(H2O)2]}n (4), {[Cd(bpdc)(H2O)3] · 2H2O}n (5), and {[Co(bpdc)(H2O)3] · 0.5dpe · H2O}n (6) (H2bpdc = 2,2′-bipyridine-3,3′-dicarboxylic acid, bpy = 2,2′-bipyridine, dpe = 1,2-di(4-pyridyl) ethylene), have been synthesized and characterized. Compound 1 forms 1D helical chain structure containing two unique MnII ions. In 2, the bridging ligand dpe links Mn-bpdc double zigzag chains to generate a layer possesses rectangular cavities. In 3, bpdc2− ligand connects to three metal centers forming a 2D network. Different from the above compounds, 4 displays a 1D double-wavelike chain. Compound 5 features a helical chain. Compound 6 also displays a helical chain with guest molecule dpe existing in the structure. These diverse structures illustrate rational adjustment of metal ions and the second ligand is a good method for the further design of helical compounds with novel structures and properties. In addition, the magnetic properties of 2, 3 and 6, the thermal stabilities and photoluminescence properties of 4 and 5 were also studied.

To determine the influence of metal ions and the auxiliary ligand on the formation of metal–organic frameworks, six compounds were synthesized and characterized. They show various networks or chain structures. Weak hydrogen bonding and π⋯π stacking contacts link them to form high-dimensional supramolecular architectures. The magnetic properties, the thermal stabilities and luminescence properties were also studied.Figure optionsDownload as PowerPoint slide