Intricate Hydrogen-Bonded Networks: Binary and Ternary Combinations of Uracil, PTCDI, and Melamine

We report the formation of two- and three-component porous supramolecular networks from combinations of uracil, PTCDI, and melamine. The structures, which are formed on Au(111) in ultra-high vacuum (UHV) and studied by scanning tunneling microscopy (STM), are stabilized by hydrogen bonds. We show that two bimolecular networks comprising uracil and PTCDI can be formed, one of which contains two pore geometries and is composed of 28 molecules per unit cell. In addition, we observe two different ordered structures from mixtures of melamine and uracil. By combining all three of these species, we demonstrate the formation of a single ternary structure that contains 33 molecules per unit cell. Our results demonstrate the capacity of hydrogen bonding to produce highly complex structures, and open up the possibility of forming a wide range of new structures from combinations of nucleic bases and other small organic molecules.