Mixed-bridging manganese(II) and copper(II) complexes with azide and pyridylbenzoate N-oxide: Structures and magnetic properties

Two Mn(II) and Cu(II) coordination polymers with azide and 4-(3-pyridyl)benzoic acid N-oxide (4,3-Hopybz) were synthesized and structurally and magnetically characterized. They are formulated as [M(4,3-opybz)(μ- N₃)]_n (M = Mn, 1 and Cu, 2). Compound 1 consists of 2D coordination layers in which 1D coordination chains with uniform [(μ-EO-N₃)(μ-COO)(μ-O)] (EO = end-on, μ-O from N-oxide group) triple bridges are interlinked by the 4,3-opybz spacers. Compound 2 also presents a 2D coordination layers in which the Cu(II) ions are triply bridged in a fashion similar to 1, while the azide ions reside at different positions around the metal ions. Magnetic studies demonstrated that the magnetic coupling through the mixed triple bridge is antiferromagnetic in the Mn(II) compound (1) but ferromagnetic in the Cu(II) species (2).