A new two-dimensional managnese(II) coordination polymer constructed by...

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[[μ₃-2,2'-(1,2-phenylene)bis(4-carboxy-1H-imidazole-5-carboxylato)-κ⁶O⁴,N³,N^3',O^4':O⁵:O^5']manganese(II)], [Mn(C₁₆H₈N₄O₈)]_n or [Mn(H₄Phbidc)]_n, has been synthesized by the reaction of Mn(OAc)₂·4H₂O (OAc is acetate) with 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylic acid) (H₆Phbidc) under solvothermal conditions. In the polymer, each Mn^II ion is six-coordinated by two N atoms from one H₄Phbidc^2- ligand and by four O atoms from three H₄Phbidc^2- ligands, forming a significantly distorted octahedral MnN₂O₄ coordination geometry. The Mn^II ions are linked by hexadentate H₄Phbidc^2- 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.