Weak Ferromagnetism in Chiral 3-Dimensional Oxalato-Bridged Cobalt(II) Compounds. Crystal Structure of [Co(bpy)3][Co2(ox)3]ClO4

[Co(bpy)3]3+ and ClO4- ions occupy the vacancies of the chiral 3-dimensional oxalate-bridged [Co2(ox)3]2- net in the compound [Co(bpy)3][Co2(ox)3]ClO4 (1). Magnetic studies for 1 and the isostructural [M(bpy)3][Co2(ox)3] [M = Fe (2) and Ni (3)] complexes show the occurrence of weak ferromagnetism in 1 (Tc = 9.0 K) and 2 (Tc = 6.5 K), whereas no magnetic ordering is observed in 3. The influence of the size of the [M(bpy)3]n+ complex on the spin-canted structure is discussed.