Two-Dimensional Chiral Self-Assembly of Barbituric-Acid-Functionalized Naphthelene Derivatives

Scanning tunneling microscopy is used to investigate the self-assembly of two barbiturate-functionalized naphthalene derivatives on a graphite surface on the nanometer scale. The backbone of the molecules has one or two naphthalene units. The two molecules adopt a head-to-head arrangement, stabilized by double hydrogen-bonds between barbituric acid units of the adjacent molecules. The variation of molecular backbone design appears to govern the number of molecular side-by-side neighbors. The shortest compound is thus forming a chiral lamellar-structure, whereas the longest compound is forming a chiral row-structure on the graphite surface.