Synthesis, structure and magnetic properties of new polymeric compounds containing manganese(II)–Pzdc (PzdcH2: 2,3-Pyrazinedicarboxylic acid)

Abstract When 2,3-pyrazinedicarboxylic acid (PzdcH 2 ) reacts separately with two manganese(II) salts: MnCl 2 and Mn(OAc) 2 in aqueous solution, two different products are obtained: a mononuclear complex Mn(Pzdc) 2 ⋅2H 2 O and a polymeric complex [MnPzdc(H 2 O) 2 ⋅2H 2 O] n which has been determined by X-ray diffraction at room temperature. The manganese atoms are located in a distorted octahedral coordination environment with two oxygen atoms O(5), O(6) from two water molecules, the other three oxygen atoms O(1), O(3a), O(4a) from carboxylate groups of three adjacent 2,3-pyrazinedicarboxylate anions and one nitrogen atom N(1) from the 2,3-pyrazinedicarboxylic acid. Therefore, the infinite `ladder-like' chains consisting of Mn 2+ and the Pzdc dianion are formed. The ladder-like chains are linked together with hydrogen bonds from coordinated and uncoordinated water molecules. The magnetic susceptibilities of the two manganese complexes have been determined over the temperature range 1.5–300 K. The study of magnetic properties shows that there is a weak antiferromagnetic interaction between two metal ions in the complex [MnPzdc(H 2 O) 2 ⋅2H 2 O] n , but a paramagnetic behavior in MnPzdc(H 2 O) 2 .