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)center dot H2O](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.