Cyclobenzoins: Uses in Energy and Environmental Studies

Cyclobenzoins are organic macrocycles prepared in a single air- and moisture-tolerant step by the benzoin condensation of aromatic dialdehydes. Despite their simple structures, they are characterized by a range of interesting properties: electrochemical activity, porosity in the solid state, and well-developed derivatization chemistry. We have explored these properties in the context of energy-related uses. Cyclobenzil hydrazones have been shown to capture iodine from vapors, solutions, and interfaces, while cyclobenzils themselves have been employed as components of organic electrode materials for lithium-ion batteries. Meanwhile, acetylated cyclotetrabenzoin has been shown as a supramolecular host for linear pi-electron rich guests, including terminal alkynes and CO2. Together with the colleagues at the University of Limerick in Ireland, we have also shown that cyclotetrabenzoin acts as a superior platform for the separation of C3 hydrocarbons, with the greatest affinity for propyne. Derivatization of cyclobenzoins into other macrocyclic species will also be discussed.