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

Abstract: 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 =−35K. Below T N =13K, Δ -1 and Λ -1 exhibit a canted antiferromagnetic order. [Copyright &y& Elsevier]