An unprecedented Co(II) cuboctahedron as the secondary building unit in a Co-based metal-organic framework.

A cubic metal-organic framework with an unprecedented octanuclear secondary building unit (SBU) was isolated. The obtained SBU is composed of 8 Co(II) ions at each vertex, 6 μ4-OH groups at each face, and 12 cpt(-) ligands framing the metal core. The cuboctahedra arrange in a ubt framework topology, eliciting a highly symmetrical MOF structure. Magnetic measurements as well as DFT calculations on this crystalline MOF reveal intramolecular antiferromagnetic coupling between Co(II) ions in the octanuclear SBU.