As a product of the dynamic equilibrium between solubilized building blocks and self-assembled structures, supramolecular architectures are fragile compositions where minor changes in temperature, solvent dielectric, and building-block concentration can trigger the dismantlement of superstructures and a concomitant loss of the emergent properties associated with them. Undeniably, developing molecular strategies to covalently polymerize superstructures can provide entirely new nanoscale platforms with which to elucidate structure-function properties that remain elusive by current supramolecular methodologies. We will introduce the design principles to tether 1-dimensional supramolecular polymers built from π-conjugated subunits using molecular locker that differ in length and structural rigidity. Confirmed by atomic force microscopy and transmission electron microscopy, organic nanomaterials created in this manner are best characterized by a nanowire morphology than span the nano-to-mesoscale dimensions suggesting that conformation of supramolecular 1D assemblies can be captured. We will show that modifying the structure of molecular locks provides new avenues to regulate excitonic coupling between neighboring units by design. Furthermore, investigation of the electronic properties of length-sorted nanowires exploiting spectroelectrochemical measurement methods reveals a non-negligible stabilization of the energy of the conduction band with respect to that of the parent, non-polymerized self-assembly. It is important to note that the presented strategy delivers a new tool to not only capture conformation of supramolecular assemblies but also to enforce the formation of emergent electronic properties not accessible in pristine, non-covalent assemblies.

Tuning electronic properties of well-defined nanoscale objects by locking in pi-conjugated superstructures

2019 Fall National Meeting

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