Enantioselective self-assembly, crystallographic structure and magnetic properties of the two enantiomers of the optically active canted antiferromagnet [Ru(bpy)3][Mn2(ox)3]

The two enantiomers of [Ru(bpy)3][Mn2(ox)3] (bpy = 2,2′-bipyridine, ox = oxalate), namely [(Δ)-Ru(bpy)3][(Δ)-Mn2(ox)3], (Δ-1) and [(Λ)-Ru(bpy)3][(Λ)-Mn2(ox)3], (Λ-1), were obtained as single crystals using [(Δ)-Ru(bpy)3]2+ and [(Λ)-Ru(bpy)3]2+, respectively, as a chiral templating cation. Their structures were determined by single-crystal X-ray diffraction. The compounds crystallise in the enantiomeric chiral cubic space groups, P4332 (Δ-1) and P4132 (Λ-1), with a = 15.492(2) and 15.507(2) Å, respectively (Z = 4). Both structures include a three-dimensional 10-gon 3-connected (10,3) anionic network wrapped around the [Ru(bpy)3]2+ cations. In both crystalline enantiomers, the resolved ruthenium template cation imposes both the topology and the absolute configuration of all the metal centres. The thermal variation of the magnetic susceptibility, measured on Δ-1 and Λ-1 crystals, reveals an antiferromagnetic coupling between the oxalate-bridged manganese ions in the paramagnetic region characterised by a negative Weiss constant Θ = −35 K. Below TN = 13 K, Δ-1 and Λ-1 exhibit a canted antiferromagnetic order.

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