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)][Mn-2(ox)(3)] (bpy = 2,2'-bipyridine, ox - oxalate), namely [(Delta)-Ru(bpy)(3)][(Delta)-Mn-2(ox)(3)], (Delta-1) and [(Lambda)-Ru(bpy)(3)][(Lambda)-Mn-2(ox)(3)], (Lambda-1), were obtained as single crystals using [(Delta)-Ru(bpy)(3)](2+) and [(Lambda)-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, P4(3)32 (Delta-1) and P4(1)32 (Lambda-1), with a = 15.492(2) and 15.507(2) angstrom, 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 Delta-1 and Lambda-1 crystals, reveals an antiferromagnetic coupling between the oxalate-bridged manganese ions in the paramagnetic region characterised by a negative Weiss constant Theta = -35 K. Below T-N = 13 K, Delta-1 and Lambda-1 exhibit a canted antiferromagnetic order. (c) 2006 Elsevier Ltd. All rights reserved.