New Two-Dimensional Manganese(II)-Azido Polymers with Bidentate Coligands: Structure and Magnetic Properties

Two two-dimensional azido-bridged Mn(II) coordination polymers with bidentate coligands have been synthesized and structurally characterized, and their magnetic properties were studied. The complexes are of formula [Mn(bphz)(N₃)₂]_n (1) and [Mn(mipc)(N ₃)₂]_n (2), where bphz = 2-benzoylpyridine hydrazone and mipc = methyl imidopyrazinecarboxylate. Both complexes consist of (6,3) layers in which double end-on (EO) azido-bridged dimers are interlinked by single end-to-end (EE) azido bridges, representing new examples of the sparse 2D Mn(II)-azido polymers assisted by bidentate coligands. Magnetic studies on the complexes reveal that ferromagnetic and antiferromagnetic interactions are mediated through the EO and EE azido bridges, respectively, with the global effect being antiferromagnetic. Both complexes exhibit spin canting related to the lack of inversion centers between the EE azido-bridged Mn(II) ions. Complex 1 behaves as a weak ferromagnet below 20 K, due to the long-range ordering of the residual spins originating from spin canting, but long-range ordering of the residual spins is not achieved in complex 2.