Synthesis, structure and magnetic properties of two new azido-Co(II) coordination architectures: from ferromagnetic coupling to single-chain-magnets

Two new azido-Co(II) complexes with pyrazine carboxylato ligands, Co(N(3))(L)·H(2)O](n) (L = pyrazine-2-carboxylato) (1) and CoNa(N(3))(2)(L)](n) (2), have been obtained by carefully tuning the Co(II):N(3)(-) ratio. Here we present the structural and magnetic characterization of these new species. Modulation of the coordination environment of Co(II) leads to a variation of the magnetic properties of the obtained compounds. Complex 1 exhibits ferromagnetically coupled Co(2)] units that form the rungs of the ladder with a nearly negligible coupling between these units, while complex 2 is a 2D arrangement of 1D Co(II) single-chain magnets.