Hierarchical cobalt-formate framework series with (412⋅63)(49⋅66)n (n = 1–3) topologies exhibiting slow dielectric relaxation and weak ferromagnetism

The employment of linear di-, tri-, and tetra-ammoniums has generated a hierarchy in the binodal (412⋅63)(49⋅66)n topologies with n = 1, 2, and 3, respectively, for the cobalt formate frameworks with increasing length of the cavities to match the ammoniums. This indicates the length-directing effect of the polyammoniums. The dynamic movements of polyammoniums between favored sites or orientations within the cavities lead to slow dielectric relaxations. All materials are spin-canted antiferromagnets in low temperatures and show reduced spontaneous magnetizations from di- and tri-, to tetra-ammoniums, because of the increased number of unique Co ions or the antiferromagnetically coupled sublattices.