Magnetic properties of two double-layer structures built from hydroxynaphthoic acids and manganese

Double-layer structures consisting of alternating polar and non-polar layers have been prepared using Mn2+ ions and o-hydroxynaphthoic acids. The polar layers contain the Mn2+ ions, carboxylate groups, hydroxy groups and water molecules. The non-polar layers are built up from the naphthalene moieties. In catena-poly[[diaquamanganese( II)] bis(mu-3-hydroxy-2- naphthoato-kappa(2) O: O')] ( also called manganese 3-hydroxy-2- naphthoate dihydrate), [Mn(C11H7O3)(2)(H2O)(2)](n), ( I), the Mn2+ ions are connected by carboxylate groups to form two-dimensional networks. This compound shows distinct antiferromagnetic interactions and long-range ordering at low temperature. In contrast, tetraaquabis(1-hydroxy-2-naphthoato-kappa O) manganese( II), [ Mn(C11H7O3)(2)(H2O)(4)], ( II), which lacks a close linkage between the Mn2+ ions, reveals purely paramagnetic behaviour. In ( II), the Mn2+ ion lies on an inversion centre.