Heteropolymetallic assemblies constructed from homometallic coordination polymers and paramagnetic metal-containing anions. Synthesis, crystal structure and magnetic properties of [Mn(4,4′-bipyridine-N,N′-dioxide) (H2O)4][Cr(bipy)(C2O4)2]2 · 8H2O

The reaction of the Mn2+ (aq) and [Cr(bipy)(C2O4)2]− (aq) ions with 4,4′-bipyridine-N,N′-dioxide leads to a heteropolymetallic system, [Mn(4,4′-bipyridine-N,N′-dioxide) (H2O)4][Cr(bipy)(C2O4)2]2·8H2O (1). The crystal structure of 1 consists of one-dimensional chains, ∞1[Mn(4,4′-bipyridine-N,N′-dioxide) (H2O)4]n2n+, with Mn(II) ions bridged by 4,4′-bipyridine-N,N′-dioxide ligands. The infinite homometallic chains are interconnected through hydrogen bonds with the water molecules and the [Cr(bipy)(C2O4)2]− anions. The cryomagnetic measurements of compound 1 reveal weak anti-ferromagnetic interactions between the manganese(II) ions within the chain (J=−1.2 cm−1).