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[[mu(3)-2,2'-(1,2-phenylene) bis(4-carboxy-1H-imidazole-5-carboxylato)-kappa O-6(4),N-3,N-3',O-4 ('): O-5 : O-5']-manganese(II)], [Mn(C16H8N4O8)](n) or [Mn(H(4)Phbidc)](n), has been synthesized by the reaction of Mn(OAc)(2).4H(2)O (OAc is acetate) with 2,2'-(1,2-phenylene)-bis(1H-imidazole-4,5-dicarboxylic acid) (H(6)Phbidc) under solvothermal conditions. In the polymer, each Mn II ion is six-coordinated by two N atoms from one H(4)Phbidc(2-) ligand and by four O atoms from three H(4)Phbidc(2-) ligands, forming a significantly distorted octahedral MnN2O4 coordination geometry. The Mn II ions are linked by hexadentate H(4)Phbidc(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.