Oxalate-Bridged Bimetallic Complexes {NH(prol)3}[MCr(ox)3] (M = MnII, FeII, CoII; NH(prol)3+ = Tri(3-hydroxypropyl)ammonium) Exhibiting Coexistent Ferromagnetism and Proton Conduction

The oxalate-bridged bimetallic complexes {NH(prol)3}[MIICrIII(ox)3] (MII = MnII, FeII, CoII) with hydrophilic tri(3-hydroxypropyl)ammonium (NH(prol)3+) were prepared by a new synthetic procedure, and the effects of the NH(prol)3+ ion upon the structure, magnetism, and electrical conduction were studied. An X-ray crystallographic study of the MnCr dihydrate, {NH(prol)3}[MnCr(ox)3]·2H2O, was performed. Crystal data: hexagonal, P63, a = b = 9.3808(14) A, c = 15.8006(14) A, Z = 2. The structure comprises oxalate-bridged bimetallic layers interleaved by NH(prol)3+ ions. The ions assume a tripodal configuration and are hydrogen bonded to the bimetallic layers together with water molecules, giving rise to a short interlayer separation (7.90 A) and unsymmetrical faces to the bimetallic layer. Cryomagnetic studies demonstrate ferromagnetic ordering with transition temperature of 5.5 K for the MnCr complex, 9.0 K for the FeCr complex, and 10.0 K for the CoCr complex. The interlayer magnetic interaction is negligibl...