Separation of phenylenediamine isomers by using decamethylcucurbit[5]uril

Using multiple techniques, this work studied the binding behaviors of decamethylcucurbit[5]uril (Me 10 Q[5]) with o -, m - and p -phenylenediamine (PDA) isomers both in the solid state and in aqueous solution. Experimental data indicate that Me 10 Q[5] forms exclusion complexes with the three PDA isomers, but their binding affinities are significantly different. Their different binding interactions provided an effective method to separate the three PDA isomers by using Me 10 Q[5]: when p -phenylenediamine interacts with Me 10 Q[5] in acidic medium (3.0 mol L −1 HCl), they precipitated immediately and quantitatively; m -phenylenediamine can continuously form microcrystals with Me 10 Q[5] after a period of time; however, o -phenylenediamine cannot form solid substances with Me 10 Q[5] under the same conditions. This work investigated the binding interactions between decamethylcucurbit[5]uril (Me 10 Q[5]) and phenylenediamine isomers, and developed a strategy to isolate phenylenediamine isomers.