Layered cobalt hydroxysulfates with both rigid and flexible organic pillars: Synthesis, structure, porosity, and cooperative magnetism

The synthesis and characterization of two members of a family of porous magnetic materials is described. The structures of Co-4(SO4)(OH)(6)(C2N2H8)(0.5). 3H(2)0 and Co-4(SO4)(OH)(6)(C6N2H12)(0.5).H2O and their thermal stability can be tailored via the choice of organic pillar. The interactions between the pillaring agent and the compositionally complex inorganic layer are discussed. The influences of two pillaring agents i.e., the flexible ethylenediamine and the relatively rigid 1,4-diazabicyclo[2,2,2]octane, on thermal stability, rigidity upon guest loss, and magnetic behavior of the pillared solids are compared. The magnetism of the pillared layered cobalt hydroxides is complex due to the influences of multiple metal sites, inter- and intralayer exchange, spin-orbit coupling, and geometrical frustration. The wide variety of potential pillars, oxyanions, and possible metal substitutions at the octahedral and tetrahedral sites offers the possibility of tailoring the magnetic and porous properties, of these materials.