A new two-dimensional managnese(II) coordination polymer constructed by 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylate).

In recent years, N-heterocyclic carboxylate ligands have attracted much interest in the preparation of new coordination polymers since they contain N-atom donors, as well as O-atom donors, and have a rich variety of coordination modes which can lead to polymers with intriguing structures and interesting properties. A new two-dimensional coordination polymer, namely poly[[μ-2,2'-(1,2-phenylene)bis(4-carboxy-1H-imidazole-5-carboxylato)-κO,N,N,O:O:O]manganese(II)], [Mn(CHNO)] or [Mn(HPhbidc)], has been synthesized by the reaction of Mn(OAc)·4HO (OAc is acetate) with 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylic acid) (HPhbidc) under solvothermal conditions. In the polymer, each Mn ion is six-coordinated by two N atoms from one HPhbidc ligand and by four O atoms from three HPhbidc ligands, forming a significantly distorted octahedral MnNO coordination geometry. The Mn ions are linked by hexadentate HPhbidc ligands, leading to a two-dimensional structure parallel to the ac plane. In the crystal, adjacent layers are further connected by N-H...O hydrogen bonds, forming a three-dimensional structure in the solid state.