Solvent-controlled formation of four Ni(II) coordination polymers based on a flexible bis(imidazole) ligand: syntheses, structural diversification, properties

To further investigate the influence of solvent in the self-assembly process, four new solvent-controlled isomeric Ni(II) coordination polymers based bib and 5-Br-H(2)ip ligands, namely, [Ni(bib)(5-Br-H(2)ip)(CH3CH2OH)](n) (1), [Ni(bib)(5-Br-H(2)ip)](n) (2), {[Ni-2(bib)(5-Br-H(2)ip)(2)(H2O)]center dot 0.5H(2)O}(n) (3), {[Ni(bib)(5-Br-H(2)ip)]center dot DMA}(n) (4) (bib = 1,4-bis(2-methylimidazol-1-yl)butane, 5-Br-H(2)ip = 5-bromoisophthalic acid) were prepared under the same reaction conditions except with diverse solvent systems. Their EA, IR, PXRD, single crystal XRD analysis and TG analysis have been characterized. As controlled different solvent systems, complex 1 exhibits an unusual [2 + 2] dia construction with the point symbol 6(6). Complex 2 shows a 3D non-interpenetrated dia structure with the point symbol 6(6). Complex 3 features a dinuclear 3D pillar-layer pcu network with the point symbol of 4(12).6(3). Complex 4 displays a 2D stacked layer sql net with the point symbol 4(4).6(2). The results demonstrate that solvent has a significant effect on the final structure of coordination polymers. Furthermore, the magnetic properties of complexes 1-4 have also been studied.