Paper SS2-ThA11
Architectural Complexity, Intermolecular Interactions, and Charge Transfer in Supramolecular Networks at Surfaces

Thursday, November 12, 2009, 5:20 pm, Room N

Self-assembly of two-dimensional supramolecular networks stabilized by hydrogen bonding or metal—organic coordination offers an efficient route to the rational design of functional surface architectures and provides a model system for (bio-)molecular assembly. These systems may contribute to advances in sensors, catalysis, molecular electronics, photovoltaics, and other thin film device applications. Such systems have been demonstrated to form highly-ordered, extended networks by selective and directional coordination bonding. Experiments were made using metal atoms and organic ligands containing carboxylic acid, cyano or pyridyl functional end groups, which were vapor deposited to atomically clean and flat surfaces. Structural characterization by scanning tunneling microscopy allows molecular level insight into the structure and assembly of the systems. X-ray photoelectron spectroscopy provides evidence for chemical interactions within the networks. High-resolution electron energy loss spectroscopy lends insight into intermolecular interactions. These experiments are correlated with density functional theory calculations for a better understanding of the bonding interactions that stabilize the highly ordered surface nanostructures. Binary mixtures of ligands allow for a large variety of metal-organic frameworks based on hierarchical assembly, co-crystallization, or cooperative multi-ligand coordination interactions. Current studies are focusing on understanding chemical function of these systems and how this can be tuned through supramolecular design strategies.