Molecular Borophosphate Cages

A synthetic procedure for the synthesis of two molecular borophosphate cages is described. Heating of ethyl phosphate with phenylboronic or 4-formylboronic acid in toluene gives [6+6] condensation products of the general formula EtOPO3BAr. Crystallographic analyses show that the compounds form cages, which can be described as dimers of 12-membered (EtOPO3BAr)(3) macrocycles. The successful incorporation of aldehyde functions on the cage exterior demonstrates that these borophosphates can be decorated with reactive groups.