The Brozek Lab is a group of synthetic chemists making new materials capable of energy capture, catalysis, and novel electronic properties. Molecular inorganic and organic chemistry forms the basis of how we build new materials and how we think about chemical and physical problems. We study redox processes in the "nanoscale gap" between small molecules and macroscopic materials. Systems of this intermediary size are useful for addressing challenges in catalysis, energy capture, and environmental sustainability, and yet they resist description by conventional concepts and tools. Our goal is to understand compounds that blur the distinction between molecules and materials, and design functional materials that harness their distinct set of properties.

We synthesize "soft materials", such as MOFs, colloidal nanocrystals, clusters, and ionic liquids, that behave as both small molecules and extended solids, and study their redox chemistry through physical inorganic methods. Current targets include colloidal clusters, porous polymers, and ionic liquids. Studying molecularly precise systems allows us to ask: What is the relationship between conductivity and reactivity? How does dynamic bonding impact delocalized behavior? and Can we control entropy-driven energy capture through molecular synthesis? In addition to studying these areas, students acquire training in air-free synthesis, spectroscopy, electrochemical techniques, and solid-state characterization.

Self-healing conductive networks

Tens 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 capture

Greater 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 metalloligands

Molecular 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.