Hydrothermal Synthesis, Structure, and Magnetism of [Co2(OH){1,2,3-(O2C)3C6H3}(H2O)]⋅H2O and [Co2(OH){1,2,3-(O2C)3C6H3}]: MagneticΔ-Chains with Mixed Cobalt Geometries

Corner-sharing Co3(μ3-OH) triangles make up the framework of two novel compounds obtained by hydrothermal synthesis from CoCl2, NaOH, and benzene-1,2,3-tricarboxylic acid. In the structure (see picture) of one of these—[Co2(OH){1,2,3-(O2C)3C6H3}(H2O)]⋅H2O—octahedral (crosshatched) and tetrahedral (dotted) Co sites alternate, and trigonal-bipyramidal sites (striped) are attached at bridging OH groups. The compounds are rare examples of the Δ-chain topology, and both have unusual magnetic behavior.