A series of divalent metal coordination polymers based on isomeric tetracarboxylic acids: synthesis, structures and magnetic properties

摘要

Five new coordination polymers, namely, [Mn(2,2'-bipy)(H2O)(2)(H2L1)](n) (1), {[Co(btb)(H2O)(2)(H2L1)]center dot 0.5H(2)O} n (2), [Co(bib)(H2O)(2)(H2L1)](n) (3), [Ni-2(bpm)(H2O)(3)(L-2)](n) (4), and {[Co-2(H2O)(3)(OH)(HL2)]center dot H2O}(n) (5), (H4L1 = 1,1':2',1 ''-terphenyl-4,4',4 '',5'-tetracarboxylic acid, H4L2 = 1,1': 2',1 ''-terphenyl-3,3 '',4',5'-tetracarboxylic acid, 2,2'-bipy = 2,2'-bipyridine, btb = 1,4-bis(1,2,4-triazol-1-yl) butane, bib = 1,4-bis(imidazol-1-yl)butane, bpm = bis(4-pyridyl) amine), have been obtained under hydrothermal conditions. Complex 1 exhibits a 3D supramolecular framework based on 1D chains. Both complexes 2 and 3 are 3D supramolecular frameworks constructed from 1D zig-zag chains. Complex 4 features a 3D tetra-nodal (3,4,4,5)-connected architecture containing 1D mu-COO bridged chains with (5(2).6(2).7.9)(5(2).6(4).7(3).8)(2)(5(2).6)(2)(6(3).7(2).9) topology. Complex 5 shows a 3D penta-nodal (3,4,4,6,6)-connected net containing 1D mu-OH/mu-COO bridged chains and mononuclear Co(II) nodes with a (4(2).6(3).8)(4(3))(2)(4(4).6(2))(2)(4(4).6(6).8(5))(2)(4(4).6(7).8(4)) topology. Variable-temperature magnetic susceptibility measurements reveal that complexes 2 and 3 show antiferromagnetic interactions between the adjacent Co(II) ions, whereas 4 is a ferromagnetic system.