Chiral biphenyldicarboxylic acid networks stabilized by hydrogen bonding

The self-assembly of 4,4′-biphenyldicarboxylic acid on a Au(111) surface is investigated by means of in situ ultra-high-vacuum scanning tunneling microscopy. Three types of open networks with increasing interpore distance are observed. Experiments and theoretical calculations reveal that the two-dimensional porous networks are stabilized by various types of hydrogen bonds between carboxyl groups and by van der Waals interactions. Cyclic tetrameric and half-cyclic trimeric hydrogen-bonding motifs are shown to induce chirality in the open networks.