Syntheses, structures and properties of three metal pyridinecarboxylates

Three new metal pyridinecarboxylates, namely [Co2(pydc)2(H2O)5] (1), [Mn(pydc)(H2O)2] (2) and [Cd2(OH)2(2,4-pydc)] (3), were hydrothermally synthesized. X-ray single crystal structural analysis revealed: 1 and 2 have polymeric one-dimensional chain-like structure constructed by dinuclear cobalt units and Mn–O chains, respectively; 3 has a three-dimensional layer pillared structure constructed from inorganic Cd–O layer and pydc pillars. 1 shows antiferromagnetic interaction but 2 shows alternative antiferromagnetic and ferromagnetic interactions.