Metallamacrocycles (MMCs) are a special class of polynuclear complexes with ringlike shapes. Most MMCs are assembled through bridging mononuclear metallic centers; construction of polymetallic-cluster-based MMCs is still a great challenge.

C.-M. Liu and co-workers, Beijing National Laboratory for Molecular Sciences, China, report a nanoscale [Co₂₄] metallamacrocycle constructed from eight Co₃(MeOH)–p–tert-butylsulfonylcalix[4]arene (TBSOC) subunits and 16 1,2,4-triazolate (trz^–) bridging ligands, [Co₂₄(TBSOC)₈(trz)₁₆(CH₃OH)₈]•28H₂O•14CH₃OH (1, pictured below, nestlike core shown above).

MMC (1) contains trinuclear cobalt–calixarene subunits that are further linked together by trinucleating trz^– bridges to form an unusual square antiprism polyhedron topology. It is the largest cluster complex found to date to be supported by the TBSOC^4– ligand, and magnetism studies confirm that it shows antiferromagnetic properties.

^{Images: © Wiley-VCH}

• Nestlike C₄-Symmetric [Co₂₄] Metallamacrocycle Sustained by p-tert-Butylsulfonylcalix[4]arene and 1,2,4-Triazole
  C.-M. Liu, D.-Q. Zhang, X. Hao, D.-B. Zhu,
  Chem. Eur. J. 2011.
  DOI: 10.1002/chem.201101607