Synthesis and crystal structure of poly[(3-amino-1,2,4-triazole)(μ-1-benzimidazole-5,6-di-carboxyl-ato)cobalt(II)].

The asymmetric unit of the title coordination polymer, [Co(CHNO)(CHN)] or [Co( )( )] , consists of one crystallographically independent Co centre, one ligand and one ligand ( = 1-benzimidazole-5,6-di-carb-oxy-lic acid, = 3-amino-1,2,4-triazole). The Co centre is coordinated by two carboxyl-ato- atoms from two independent ligands and two nitro-gen atoms from and another ligand. Thus, the metal center adopts a four-coordinate mode, forming a tetra-hedral geometry. Inter-estingly, through the combination of two , two ligands and two Co ions, a basic repeating unit is constructed, resulting in the formation of a one-dimensional straight chain structure. These chains are further expanded to the final three-dimensional framework N-H⋯O hydrogen-bonding inter-actions.