Hydrothermal preparation, crystal structures and properties of novel Mn(II) metal-organic frameworks with 5-nitro-1,2,3-benzenetricarboxylate and various dipyridyl ligands

Five Mn(II) coordination polymers, [Mn-3.5(O2N-btb)(2)(O2N-Hbtb)(0.5)(2,2'-bipy)(2)(H2O)(4)]center dot 1.5H(2)O (1), [Mn-3(O2N-btb)(2)(4,4'-bipy)(3)(H2O)(2)]center dot 2H(2)O (2), [Mn-3(O2N-btb)(2)(bpe)(H2O)(8)]center dot bpe(3), [Mn-3(O2N-btb) (2)(bpa)(H2O)(5)]center dot 0.5bpa H2O (4) and [Mn-3(O2N-btb)(2)(bpp)(2)(H2O)(4)] (5), were prepared by hydrothermal reactions of Mn(II) acetate with O2N-H(3)btb (O2N-H(3)btb = 5-nitro-1,2,3-benzenetricarboxylic acid) in the presence of different dipyridyl co-ligands (2,2'-bipy = 2,2'-bipyridyl, 4,4'-bipy 4,4'-bipyridyl, bpe = 1,2-bi(4-pyridyl)ethene, bpa = 1,2-bi(4-pyridyl)ethane and bpp = 1,3di( 4-pyridyl)propane). Their crystal structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra and TG analyses. Complex 1 shows a 3D (3,5)-connected coordination framework with (4(2.)5)(4.12(2))(4.5.7)(2)(4(2).5. 6. 7. 9. 12(3). 13) topology. Notably, the mu(7)-bridging mode of O2N-btb in 1 has never been found in coordination complexes with 1,2,3-benzenetricarboxylate and its derivatives. Complex 2 exhibits a 3D (4,5)connected framework with (4(2). 6(7). 8)(6(4). 8(2))(4(2). 6(4)) topology. Complex 3 shows a 2D 3-connected network with 63 topology. Complex 4 is a 2D (3,4,5)-connected framework with (4(3))(3.4.5)(3.4(2).8(3))(3.4.5.6.7(2).8(2).9.10)(4(3).5(2).6(2).7(2).8) topology, whereas the structure of 5 has a 2D (3,4)-connected (4(2). 6)(4(2). 6(3). 8) framework. The 2D layers in 3 are extended to form a 2-fold interpenetrated 3D supramolecular network, and those in 4 and 5 afford the 3D supramolecular structures via H-bonding interactions. A structural comparison of these complexes demonstrates that the characteristics of auxiliary ligands play a key role in governing the coordination motifs and the final supramolecular lattices. Moreover, the magnetic properties of these Mn(II) complexes were investigated and discussed in detail.