Self-healing conductive networksTens of thousands of unique porous coordination polymers are known, but only a handful are electrically conductive. Few, if any, conduct electrons in three dimensions, limiting their practical utility and preventing investigations into the relationship between charge mobility and structural ordering. We synthesize a new class of materials that combines crystalline three-dimensional porosity with ionic and electrical conductivity. Unlike traditional conductors, however, these polymers contain highly dynamic bonds. One chief goal is to use labile bonding and conductivity to enable a new mechanism of rapid and automated self-healing, and to study the fundamental impact of dynamic bonding on delocalized material behavior.
Thermal energy captureGreater than 50% of U.S. energy is lost as waste heat. Thermoelectric devices capture this thermal energy by generating electrical voltages in response to temperature gradients—a phenomenon known as the Seebeck Effect. The magnitude of the voltage depends microscopically on the redox chemistry associated with electrical conduction. Thermal energy often disappates close to ambient temperatures, however. Harnessing the small temperature gradients between the waste heat source and ambient conditions requires thermoelectric devices with anomalously large Seebeck effects. We study how to capture "low-grade waste heat" with low-density conductive polymers and reactive ionic liquids by tacking advantage of their molecular precision and favorable thermoelectric properties. Controlling entropy, electrical conductivity, and thermal resistivity through molecular design will enable superior devices for thermal energy capture, and investigation into the emergence of bulk thermoelectric properties from well-defined molecules.
Electron-reservoir metalloligandsMolecular organometallic chemistry focuses on controlling the symmetry and covalency in the vicinity of a metal center. Few molecules exhibit long-range electrical conduction and fewer store a significant number of electrons. Accessing distant electron reservoirs is crucial to the catalytic activity of industrial and biological systems, however. We design soluble metal clusters with heavily size-dependent electronic structures that span a range from localized molecular orbitals with large HOMO-LUMO gaps to highly dispersive band diagrams exhibiting metallic conductivity. Reimagining these clusters as inorganic ligands for well-defined metal dopants allows us to study the fundamental relationship between electrical conductivity and metal-centered reactivity for designing homogeneous catalysts capable of multi-electron transformations.