A layered grid divalent cobalt coordination polymer constructed from ferromagnetically coupled linear trimeric units

The layered coordination polymer {[Co3(tBuip)2(HtBuip)2(bpmp)]•bpmp}n (1, tBuip = 5-tert-butylisophthalate, bpmp = bis(4-pyridylmethyl)piperazine) has been prepared by hydrothermal methods and characterized by single-crystal X-ray diffraction. Carboxylate groups of both tBuip and HtBuip ligands construct [Co3(tBuip)2(HtBuip)2]n neutral ribbons with embedded linear {Co3(μ-O)4(μ-OCO)2} trimeric units. Tethering bpmp ligands link the ribbon motifs into [Co3(tBuip)2(HtBuip)2(bpmp)]n grid-like layers. In turn these layers are connected into a supramolecular 3-fold interpenetrated network by hydrogen-bonding mechanisms involving unligated bpmp molecules. Weak ferromagnetic coupling is observed within the trimeric kernels, with some spin canting likely below 3 K.