Periodic and nonperiodic chiral self-assembled networks from 1,3,5-benzenetricarboxylic acid on Ag(111).

Surface-catalyzed reactions provide a versatile route to synthesizing new 2D materials. Here, we show that the statistical nature of an activated reaction can lead to a diversity of intermolecular bonding motifs through partially-reacted molecules. With increasing annealing, we observe different periodic, well-defined phases of 1,3,5-benzenetricarboxylic acid on Ag(111), where the surface structure in each case is defined by the degree of deprotonation of the carboxylic groups. Over a wide range of deprotonation levels (∼50% to near 100%), we observe a granular alloy comprising two distinct phases in a continuous network. This ordered phase lacks well-defined translational symmetry, is stabilized through both intermolecular interactions and epitaxy, and demonstrates a design approach to creating non-crystalline phases by capitalizing on the chemical diversity of partially reacted molecules on a surface.