Different dimensionality in Mn(II), Co(II) and Ni(II) aminoisophthalate metal-organic compounds: synthesis, characterization and gas adsorption properties

Abstract

Five new 5-aminoisophthalic acid (H(2)aip) complexes with Mn(II), Co(II) and Ni(II) ions, {[Mn-2(mu(3)-aip)(2)(bipy)(2)]center dot 2DMF center dot 2H(2)O)(n) (1), [Co(pmi)(H2O)(4)]center dot 2H(2)O (2), {[Ni(mu-aip)(H2O)(2)(en)]center dot 3H(2)O)(n) (3), [Ni(mu(3)-aip)(im)(H2O)(2)](n) (4) and [Ni(aip)(phen)(H2O)(3)]center dot 2H(2)O (5) (H(2)aip = 5-aminoisophthalic acid, bipy = 2,2'-bipyridine, pmi = 5-(pyridin-2-ylmethylamino)isophthalate, en = ethylenediamine, im = imidazole, phen = 1,10-phenanthroline) were synthesized at room temperature. The compounds were characterized by elemental analysis, magnetic and spectroscopic measurements (UV-Vis and FT-IR), single crystal X-ray diffraction techniques and thermal analysis (TG, DTG and DTA). Furthermore, in order to assess the potentials of the complexes in gas storage applications, we performed atomically detailed simulations. The single crystal X-ray diffraction study of 1 reveals a 2D coordination polymer. The 2D layers are extended into a 3D supramolecular network with 1D channel via interlayer pi center dot center dot center dot pi stacking interactions between bipy ligands. The voids of the channels are filled with guest water and DMF molecules. Schiff base complex 2 has been obtained from H(2)aip, pyridine-2-carboxaldehyde and CoCl(2 center dot)6H(2)O in a one-pot reaction. Compound 2 is a discrete mononuclear complex which crystallizes in the space group P2(1)/c. Complex 3 is a 1D coordination polymer and the Ni(II) ion is six-coordinated in a distorted octahedral geometry. In 3, aip exhibits a new coordination mode as a bis(monodentate) bridging ligand. Complexes 2 and 3 show 2D and 1D metal-water clusters between metal ions and water molecules, respectively. Complex 4 reveals a 2D coordination polymer that crystallizes in the space group P2(1)/c. Adjacent 2D layers are further extended into a 3D supramolecular network by hydrogen bonds and pi center dot center dot center dot pi interactions. The crystal analysis of 5 reveals that it is a mononuclear complex and the Ni(II) ion exhibits a distorted octahedral geometry.