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

The layered coordination polymer {[Co-3(tBuip)(2)(HtBuip)(2)(bpmp)]center dot 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 [Co-3(tBuip)(2) (HtBuip)(2)](n) neutral ribbons with embedded linear {Co-3(mu-O)(4)(mu-OCO)(2)} trimeric units. Tethering bpmp ligands link the ribbon motifs into [Co-3(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. (C) 2011 Elsevier B.V. All rights reserved.