Crystal Engineering of Melamine–Imide Complexes; Tuning the Stoichiometry by Steric Hindrance of the Imide Carbonyl Groups

A defined melamine–imide ratio in cocrystals can be selected by changing the steric hindrance around the hydrogen-bond acceptor sites of the imides. Crystalline 1:1, 1:2, and 1:3 complexes of melamine may thus be obtained with succinimide, glutarimide, and 1-N-propylthymine (see picture), respectively.