Small molecule self-assembly at surfaces offers an efficient route to highly-ordered organic films that can be programmed with function for a variety of chemical and electronic applications. However, the success of these materials depends on our ability to program intermolecular interactions that will lead to excellent ordering at the surface and subsequent stacking into a thin film. Here, we demonstrate new results toward this goal of intelligent, bottom-up molecular design of a prototypical molecular platform of tricarbazolo triazolophane macrocycles (tricarb). Building on this macrocycle framework, we program peripheral alkyl units and other functional groups to steer 2D packing and 3D stacking. The supramolecular assembly is characterized by scanning tunneling microscopy at the solution-graphite interface. Using this approach, the 2D assembly can be steered by molecular design and synthesis between two different architectures that differ in packing density. Each architecture is assembled through hydrogen bonding and close-contact van der Waals interactions. We have also applied these design strategies to achieve ordered 3D growth into multilayers, which also depends strongly on the programming of functional moieties in the molecule that can be tuned to block or limit growth away from the surface. Initial electrochemical studies suggest that highly ordered tricarb multilayers may serve as a platform for electron transport in thin film applications.

Hierarchical self-assembly of functionalized tricarbazolo triazolophane macrocycles at the liquid-solid interface

253rd National Meeting (2017)

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