Crystal structures and magnetic properties of two isomorphic nickel(II) and cobalt(II) coordination polymers-based nitrogen-heterocyclic tricarbolylate ligands

5-(3,4-Dicarboxylphenyl) picolinic acid (H3dppa) was applied as a new building block for the synthesis of two isomorphic coordination polymers, namely [Ni1.5dppa(H2O)3]n·nH2O (1), [Co1.5dppa(H2O)3]n·nH2O (2). Two compounds were generated by a hydrothermal self-assembly method using the corresponding metal(II) acetates and H3cppa ligand. Structure analysis reveals that compounds 1 and 2 are isomorphic both featuring a two-dimensional wave structure and are finally extended into the three-dimensional supramolecular architecture though hydrogen bonding interactions. Magnetic susceptibility measurements indicate that domain a weak ferromagnetic exchange coupling between the adjacent Ni(II) centers in 1, and a weak antiferromagnetic coupling between Co(II) ions in for 2.