New metal-organic architectures of cobalt(II), nickel(II) and zinc(II) with tripodal ligand 5-(1H-imidazol-4-ylmethyl)aminoisophthalic acid

Four new coordination polymers {[Ni(HL)(H2O)]center dot H2O}(n) (1), {[Co(HL)(H2O)]center dot H2O}(n) (2), {[Co(HL)]center dot 4H(2)O}(n) (3) and {[Zn(HL)]center dot 2H(2)O center dot 0.5C(2)H(5)OH}(n) (4) [H3L = 5-(1H-imidazol-4-ylmethyl)aminoisophthalic acid] have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses. Complexes 1 and 2 display (3, 3)-connected 2D network with (4, 8(2)) topology. While 3 and 4 exhibit a binodal (3, 6)-connected 2D network with a Schlafli symbol (4(3))(2)(4(6), 6(6), 8(3)). The complexes 1-4 show remarkable thermal stability and 4 exhibits blue fluorescence with maximum emission at 413 nm upon excitation at 362 nm in the solid state at room temperature. In addition, the magnetic measurements of 3 indicate that there are antiferromagnetic interactions between the neighboring Co(II) centers. (C) 2009 Elsevier Ltd. All rights reserved.