Poly[trans-diaquamanganese(II)-mu-(3-pyridinecarboxylato-N : O)-mu-(3-pyridinecarboxylato-O : N)]

The title complex. [Mn-II(nic)(2)(H2O)(2)](n) [nic is 3-pyridine-carboxylat e (also called nicotinate), C6H4NO2-]. has a two-dimensional layer structur e with the unique Mn atom on an inversion centre. In each layer. all nicoti nate ligands are coordinated to Mn atoms in a bridging/bidentate mode, thus linking the [Mn-II(nic)(2)(H2O)(2)] monomeric units together to form a dat ive-bond-based layered polymer. The intra-layer hydrogen bonds involving al l water molecules and the carboxylate groups may play an auxiliary part in stabilizing the layer. The layers are arranged in an ordered manner along t he n axis through van der Waals forces so as to complete the solid-state st ructure of the crystal.