Biphen[n]arenes (n = 3, 4) are a new family of macrocyclic molecular containers. They are made up of biphenol or biphenol ether units linked by methylene bridges, and have gained a lot of attention since their discovery in 2015.

Chunju Li, Shanghai University, and colleagues have demonstrated the host‒guest interactions of hydroxylated biphen[4]arene with a series of cationic molecules. This box-type macrocycle exhibited strong binding affinities with pyridinium-based 1,1’-dibutyl-4,4’-bipyridylium bis(hexafluorophosphate), 2,7-dibutyldiazapyrenium bis(hexafluorophosphate), and an organometallic salt, cobaltocenium hexafluorophosphate.

Due to their novel topological structures and good cavity properties, biphen[n]arenes are expected to be popular molecular containers in supramolecular chemistry, similar to calixarenes and pillararenes.

• Molecular Recognition Properties of Biphen[4]arene,
  Suxiang Ma, Huanqing Chen, Jian Li, Prof. Xueshun Jia, Chunju Li,,
  Chem. Asian J. 2015, 11 (23), 3449–3453.
  DOI: 10.1002/asia.201601373