Structural diversity of Ni(ii) coordination polymers containing dipyridyl amide and angular dicarboxylate ligands: synthesis, structures and magnetism

Four new Ni(ii) coordination polymers containing dipyridyl amide and angular dicarboxylate ligands, {[Ni(L super(1))(MBA)].2H sub(2)O} sub( infinity ) [L super(1) = N,N'-di(4-pyridyl)-adipoam ide; H sub(2)MBA = diphenylmethane-4,4'-dicarboxylic acid], 1, {[Ni(L super(1))(OBA)].H sub(2)O} sub( infinity ) [H sub(2)OBA = 4,4'-oxybis(benzoic acid)], 2, {[Ni(L super(1))(SDA)].2H sub(2)O} sub( infinity ) (H sub(2)SDA = 4,4'-sulfonyldibenzoic acid), 3, and {[Ni sub(2)(L super(2))(SDA) sub(2)].6H sub(2)O} sub( infinity ) [L super(2) = N,N'-di(4-pyridyl)suberoam ide], 4, have been synthesized by hydrothermal reactions and were structurally characterized by single crystal X-ray diffraction analyses. Complex 1 is a 1D arrow right 2D polycatenane derived from the helical channels, and the 2D layers are further mutually interdigitated, whereas complex 2 forms 2D rhombic grids with the (6,4) topology, which are interwoven with each other to give a two fold 2D arrow right 2D interpenetrating net. Complex 3 shows the 1D looped chain structure, and complex 4 shows 2D layers which catenate to each other to form a 2D arrow right 3D inclined polycatenation framework with the new (4 super(2).6 super(8) .8.10 super(4))(4) sub(2) topology. The C-X-C (X = CH sub(2), 1; O, 2; and SO sub(2), 3 and 4) angles are important in determining the structural diversity. Complex 1 exhibits a different magnetic reaction in the ZFC and FC processes, revealing the existence of a meta-state of ferromagnetic ordering, whereas the activation energies of spin-orbit coupling and antiferromagnetic interaction of complexes 2-4 are directed by the N...N and Ni...Ni distances, respectively.