π-π interactions in the self-assembly of melamine and barbituric acid derivatives

Self-assembly of a pair of complementary molecular components, 5-(4-dodecyloxyben-zylidene)-(1H,3H)-2,4,6-pyrimidinetrione (PB12) and 4-amino-2,6-didodecylamino-1, 3, 5-triazine(M12) was studied by cyclic voltammogram, surface photovoltage spectroscopy, fluorescencespectroscopy, FTIR and X-ray diffraction. It is found that after mixing equimolar amount of PB12and M12 at room temperature, not only triply complementary hydrogen bonds are formed betweenPB12 and M12 but also further self-assembly of the supermolecules based on network of hydrogenbonds occurs via π-π interactions. During the self-assembly of the supermolecules, π-π interactionsare induced by delocalized interactions between the HOMO of M12 and the LUMO of PB12, result-ing in the formation of a supramolecular nanotube with a layered structure bearing a d value of0.41 nm and PB12 and M12 are arranged alternatively between adjacent supermolecules.