Hydrothermal synthesis and structural characterization of the two-dimensional networks [M(H2O)(bpy-dicarb)]•H2O (M=Fe, Co, Ni, Zn; bpy-dicarb=2,2′-bipyridyl-4,4′-dicarboxylic acid)

The hydrothermal reactions of the appropriate divalent metal salt 2,2′-bipyridyl-4,4′-dicarboxylic acid and H2O in an approximate mole ratio of 2:1:2700 at 160 °C for 44 to 61 h yield [M(H2O)(bpy-dicarb)]•H2O [M=Fe(1•H2O), Co(2•H2O), Ni(3•H2O), Zn(4•H2O)]. The isomorphous series of compounds exhibit two-dimensional network structures, constructed from six coordinate M(II) sites linked through the bpy-dicarb ligands, each of which serves to bridge three metal sites. The water molecules of crystallization occupy cavities within the layers and are hydrogen bonded to the pendant carboxylate oxygen atom. Crystal data C12H10N2O6Fe(1•H2O), monoclinic, P21/n: a=11.9721(9) Å, b=8.1977(6) Å, c=12.696(1) Å, β=98.492(1)°, V=1232.4(2) Å3; C12H10N2O6Co(2•H2O), monoclinic, P21/c: a=11.9812(8) Å, b=8.1698(6) Å, c=12.6675(8) Å, β=97.579(1)°, V=1229.1(1) Å3; C12H10N2O6Ni(3•H2O), monoclinic, P21/n: a=11.9740(6) Å, b=8.1866(4) Å, c=12.5407(7) Å, β=97.245(1)°, V=1219.5(1) Å3; C12H10N2O6Zn(4•H2O), monoclinic, P21/n: a=12.0057(5) Å, b=8.2370(3) Å, c=12.6054(5) Å, β=98.924(1)°, V=1231.47(8) Å3.