INTERMOLECULAR ARRANGEMENTS OF P-SUBSTITUTED ANILINIUMS IN THE INTERLAYER OF CUPRIC CHLORIDE

Crystal structures and magnetic properties of the layered pervoskite c ompounds, (p-X-C6H4NH3+)(2)CuCl42- with X=CN (1), Cl (2), and NO2 (3), were studied. The compound 1 crystallizes in the triclinic <P(1)over bar> space group. The structure consists of a CuCl layer and an organi c bilayer in which the molecular axis of the cyanoanilinium is nearly perpendicular to the inorganic layer. At the middle of the organic bil ayer, there is a layer of the CN group, in which the CN groups are arr anged to cancel their electric dipoles. The compound 2 has a similar s tructure to that of 1. The crystal of 3 belongs to the orthorhombic Pb ca space group, in which the structure also consists of an inorganic l ayer and an organic bilayer. The bilayer is formed by short contacts b etween the NO2 groups, which appear to incline the molecular axis of t he nitroanilinium with respect to the normal to the CuCl layer. AC and DC magnetic susceptibility measurements were carried out on the three salts. Their behavior can be understood with two parameters, ferromag netic transition temperature T-c and in-plane ferromagnetic coupling c onstant J. The obtained parameters are T-c=9.5 K and J/k(B)=24 K for 1 , T-c=9.1 K and J/k(B)=23 K for 2, and T-c=7.0 K and J/k(B)=17 K for 3 . The values of T-c and J of 3 are smaller than those of the other two . The distortion of the molecular arrangement in the organic layer of 3, is found to result in weakening the magnetic interaction in the CuC l layer.