Magneto−Structural Correlation in a Metamagnetic Cobalt(II)-Based Pillared Trilayer Motif Constructed by Mixed Pyridyl-Type Carboxylate Ligands

The first structurally authenticated example of coordinated polymer featuring homometallic pillared-trilayer structure, [Co₃(ina)₂(pico)₂(H₂O)₂]_n (1), was built from mixed pyridyl-type monocarboxylates, isonicotinate (ina) and 3-hydroxypicolinate (pico), containing Kagomé-type [Co₃(pico)₂(H₂O)₂]_n²ⁿ⁺ trilayers. The magnetic phase diagram of 1 shows a metamagnetic transition below 3.2 K, arising from the competing interactions between the antiferromagnetic intralayer couplings in different amplitudes with obviously noncompensated moments versus weak AF interlayer coupling.