LAUSR

The remarkable Metal–Organic Framework (MOF), {[(Co(NCS)2)3(κ3-TPT)4]·a(H2O)·b(MeOH)}n (1), which is used in the revolutionary crystalline sponge method, displays characteristic Single-Molecule Magnet (SMM) behaviour under applied static fields. We report the subtle effects of changes in the coordination environment of the CoII ions in 1, leading to drastically different magnetic behaviors of two additional related compounds, {[(Co(NCS)2)3(κ0–3-TPT)4]·c(H2O)}n (2) and {[(Co(NCS)2(H2O)0.65(MeOH)0.35)3(κ3-TPT)2]·2.4(H2O)}n (3). Magnetic measurements reveal unquenched first order orbital angular momentum, leading to significant magnetic anisotropy in all compounds, which was corroborated through CASSCF-type calculations. Notably, the crystalline sponge is the first example of a 3D network built from CoII Single-Ion Magnets (SIMs) as nodes.