Synthesis and crystal structure of a two-dimensional CoII coordination polymer: poly[(µ3-3-carb-oxy-benzoato)[µ2-5-(pyridin-4-yl)-1H,2'H-3,3'-bi[1,2,4-triazole]]cobalt(II)].

In the title compound, [Co(C8H5O4)(C9H6N7)] n , the divalent CoII atom is six-coordinated to three N atoms from two symmetrical 5-(pyridin-4-yl)-1H,2'H-3,3'-bi[1,2,4-triazole] (H2pyttz) ligands and three O atoms from three symmetrical 3-carb-oxy-benzoate (Hbdic) ligands, leading to a distorted {CoN3O3} octa-hedral coordination environment. Two CoII cations are linked by four bridging carboxyl-ate groups to generate a dinuclear [Co2(CO2)4] unit. The dinuclear units are further connected into a chain along [010] via the Hbdic ligands. The other infinite chain, along [100], is formed through the H2pyttz ligands. Finally, the two kinds of chains are cross-linked, by sharing the CoII cations, into a two-dimensional network. In the crystal, adjacent layers are further linked by O-H⋯N hydrogen bonds into a three-dimensional framework.