Hydrothermal synthesis, structure and magnetic properties of a three-dimensional cobalt(ii) – aminophenyltetrazolate coordination polymer

Abstract

The hydrothermal reaction of cobalt(II) acetate tetrahydrate, 4-aminophenyl tetrazole and water at 135 °C for 48 hours provided orange crystals of [Co₃(OH)₂(H₂O)₂(aptet)₄] (1) (aptet = 4-aminophenyltetrazolate). The three-dimensional structure of compound 1 is constructed from chains of corner- and edge-sharing Co(II) octahedra linked into a framework through the dipodal ligand tethers. The cobalt sites of the chain are linked through tetrazolate groups in the N2,N3-bridging mode, as well as through μ₃-hydroxyl groups into trinuclear Co₃ substructures. The magnetic properties are consistent with a ferrimagnetic chain with the non-compensating resultant moment of one Co(II) per trinuclear Co(II) subunit. The temperature dependence of the ac magnetic susceptibility indicates glassy-like magnetic behavior.