Two-dimensional supramolecular honeycomb networks with cavities of an internal diameter of 2.95 nm were formed by the self-assembly of 4,4',4' '-benzene-1,3,5-triyl-tribenzoic acid (BTA) on a Ag(111) surface at room temperature. Annealing to higher temperatures resulted in two sequential phase transformations into closer-packed supramolecular arrangements. The phase transformations are associated with stepwise deprotonation of the carboxylic acid groups. The voids of the honeycomb network of BTA have a suitable size for the construction of hierarchical structures with guest molecules. Single molecules of the macrocyclic compound mt-33 were successfully confined inside 2D nanocavities of the honeycomb networks and released when the phase was transformed to the close-packed structure.

We report a comparative study on the 2D self-assembly of two related ditopic benzoic acid species, which have similar shape and endgroups but different backbone symmetry. High-resolution scanning tunneling microscopy data reveal how the symmetry information of molecular building blocks is readily expressed in the resulting chiral or nonchiral supramolecular networks. The underlying square Cu(100) surface steers network orientation and accounts for carboxylate formation, resulting in an unusual intermolecular hydrogen bond motif. Our results demonstrate that symmetry and chiral resolution in 2D supramolecular assembly can be controlled via the design of functional molecules and choice of substrate.

In addition: The scope of the title reaction is demonstrated by the synthesis of chiral lactones and lactams. The latter class of compounds is very important for the preparation of the pharmaceutical compounds such as (−)‐paroxetine and (+)‐femoxetine.