Synthetic and mechanistic organometallic chemistry; applications of organometallic complexes in organic synthesis; reactions of coordinated ligands; carbon-hydrogen bond activation; mechanisms of migration and insertion reactions; homogeneous catalysis by transition metals, especially olefin polymerizations; oligomerizations, dimerizations, and catalytic reactions based on carbon-hydrogen bond activation.

The Carrow Lab is interested in the design of transition metal catalysts that can enable broadly applicable organic transformations and address challenges in sustainability and materials chemistry. Their approach is interdisciplinary, bridging the fields of organometallic, physical organic, synthetic organic, and polymer chemistry. A core emphasis in the group is the mechanism-informed design of ligands and metal complexes that can manifest new elementary catalytic steps, control speciation between active and inactive catalyst states, and enable new classes of substrate to be integrated into synthetic organic chemistry.

Dr. Comito’s research focuses on new catalytic methods for organic and polymer synthesis. In particular, this program uses main group catalysis to target synthetically valuable transformations that are underserved by established transition metal methods. This approach takes advantage of the complementarity between main group and organometallic chemistry. In general, main group complexes show greater coordinative lability and improved alkyl stability than their transition metal counterparts, potential advantages for reactions designed to incorporate polar functional groups or involving alkyl intermediates.

In polymer chemistry, methods of interest include living olefin polymerization and ambiphilic copolymerization, potentially amenable to advanced polyolefins with improved properties. For organic synthesis, I am interested in olefin difunctionalization and C-H activation, relevant for medicinal chemistry and complex molecule synthesis.

The Conrad Group is broadly interested in the interaction between complex fluids (polymers, colloids, nanoparticles, bacteria, protozoa, cells) and the surfaces that confine or support them. These interactions appear ubiquitously in applications in petroleum engineering (drilling media, microbial corrosion), environmental engineering (biofouling, bioremediation), materials engineering (rapid prototyping, direct-write assembly), and biodefense (diagnostics, biodetection).Moreover, this broad class of problems is scientifically fascinating: both the chemical and mechanical properties of surfaces can influence the adhesion, diffusion, motility, and phase behavior of complex fluids.

Flow and Transport of Complex Fluids in Confinement

Processes involving the flow of complex fluids in confined geometries appear prominently in technological, environmental, and physiological settings. Confinement effects strongly influence multiphase transport properties, and are thus relevant for technological applications involving porous media, such as gel electrophoresis and chromatography, and critical resource applications, such as water remediation and oil extraction from nonconventional sources. Despite their ubiquity, the science underlying these processes remains poorly understood. The group uses confocal and light microscopy to directly image the flow of complex fluids in microchannels. By quantifying the flow behavior in a variety of controlled microscale geometries using high-throughput tracking algorithms, they will identify the effects of confinement on the flow properties of complex fluids and inspire new designs for manipulating these materials on the microscale. Currently, they are investigating the effects of confinement on the structure, dynamics, and phase behavior of quiescent and flowing model colloid-polymer mixtures (in part with Jeremy Palmer), and the transport properties of nanoparticles in microfabricated post arrays and polymer solutions (with Ramanan Krishnamoorti).

Broad interests in synthetic organic and organometallic methodology including:

• Group 11 metal chemistry
• Application of organometallic chemistry to organic synthesis and polymer chemistry
• Development of new enantio- and diastereoselective transformations

Students and postdocs in the Daugulis group are exposed to research at the convergence of organic, organometallic and polymer chemistry, often having direct technological applications. The training provides these individuals with the capacity to make contributions in both science and technology.

Polymerization Catalysis

Although polyolefins are the world’s most common synthetic polymers, there are still numerous opportunities for innovations in their synthesis, processing, and materials properties. Polyolefins are such attractive materials because they could be produced from a broad range of inexpensive building blocks, and their physical characteristics are highly tunable. A major research thrust in the Do Group is to develop stimuli-responsive catalysts that are capable of yielding different polyolefin products from a common catalyst platform, which would streamline polymer synthesis by providing a simple way to prepare user-defined materials. Toward this goal, the Do lab has developed several late transition metal catalyst systems that could be switched by interchanging their pendent cations. They are investigating how to leverage the unique chemical properties of secondary metals to favor polymerization pathways that are inaccessible using conventional catalysts. They also wish to discover new polymerization methods to synthesize environmentally friendly polymers derived from sustainable resources. Novel catalyst design strategies, such as the application of outer coordination sphere and/or non-covalent interactions, will also be explored.

Small-Molecule Intracellular Catalysis

Small-molecule intracellular metal catalysts (SIMCats) are molecular inorganic complexes that catalyze bioorthogonal reactions inside living environments and are non-toxic to their biological hosts. The most well-known SIMCats are copper catalysts that promote click reactions commonly used in bioconjugation and related applications. Similar to artificial metalloenzymes, SIMCats provide opportunities for scientists to carry out new to nature reactions, which could be useful for enhancing native biochemical functions or accessing novel therapeutic modes of action (among other applications). In the Do Group’s SIMCat discovery program, they are developing protocols to efficiently screen and optimize catalyst candidates for their biocompatibility and methods to study their chemical and biological behavior inside cells and organisms. They are currently focused on studying SIMCats that mediate transfer hydrogenation catalysis, but other catalytic transformations are also of interest. Their ultimate research goal is to create SIMCat-based technologies that either improve human health or enable green chemical synthesis. They expect that this work will lead to new fundamental knowledge as well as practical solutions to important biological problems.

The Harth Lab is developing polymerization techniques to make specialized polymer materials with applications in industry and the biomedical field. Metal-organic synthesis and radical polymerization techniques are being explored to find new polymerization pathways to bridge the gap between monomer families such as olefins and acrylates. The invented metal-organic Insertion/Light Initiated Radical (MILRad) polymerization allows the group to design distinct block copolymer architectures with selected functionalities in a one-step process guided by light irradiation.

Nano-networks built from intermolecular crosslinking and photoactivation processes are explored as drug delivery systems and additives in plastics. Hydrogels built from organic crosslinked backbones developed as biomaterials are used to explore the fundamental understanding of cellular processes in tissues.

Materials for a Sustainable Future

Nanomaterials for Filtration Membranes

Current surface water resources will soon be insufficient to meet the needs of coming generations. One solution is reuse of water through purification. Wastewater is now contaminated with oil and other organic compounds due to the rapid rise in petrochemical, pharmaceutical, and food processing industries. Membranes present an easy and energy-efficient solution for the removal of both particulate and oily matter from wastewater. The self-assembling characteristics of block copolymers (BCPs) provide a promising pathway in developing ultrafiltration membranes with continuous nanoporous channels. Such uniquely defined morphologies can be further tuned by selectively partitioning an active species into the pore-forming domain of BCP. The Karim Lab is developing processes for easy fabrication and modification of such polymeric membranes for oil/water, particulate, and gas separations. They are also developing 2D MXene-based membranes with high percentages of dye and salt rejection.

Chitin-based Biomaterials

Chitin is the second-most abundant biopolymer in Nature, where it is expressed in composite structures with impressive mechanical properties such as in the shells of crustaceans. The Karim Lab is interested in developing multilayer thin-film composites using chitin and its derivatives (e.g., chitosan and functionalized variants) as major components. A variety of different layer types are under development (e.g., an impact resistance layer), and each layer is intended to impart its properties to the multilayer composite. One avenue through which such properties are being pursued is chitosan-based hydrogels systems with enhanced strength, Young’s modulus, and impact characteristics. Additionally, they are developing biopolymer-based sensors. Humidity sensors play an essential role in monitoring product quality in the manufacturing and pharmaceutical process industries. Lately, thermoplastic polymers and semiconducting inorganic materials-based sensors are raising environmental concerns owing to non-degradable nature despite their performance. They are leveraging chitosan’s propensity to swell in the presence of moisture for the development of thin-film structural color-based humidity sensors with good mechanical stability.

Nanomaterials for Energy

Flexible Triboelectric Nanogenerators

Triboelectric nanogenerators or TENGs are state of art electronics to harness mechanical motions in the environment and convert them to energy, and this can be another step towards the internet of things (IoT) by making them valuable for acting as chargers in self-sufficient electronics devices. TENGs need dielectric material with triboelectric properties and majority of material with this property are made of polymers that can be synthesized or natural polymers. The Karim Lab chose PDMS as a good negative triboelectric polymer and tried to modify the dielectric constant with the help of different nanoparticles.

Flexible Harsh Environment Resistance Supercapacitors

The lab is making flexible gel supercapacitors modified by graphene oxide and Li ions in PVA gel electrolyte. The goal is adding new modifications that the device be capable of working in very low and high temperature. When the temperature decreases below 0 C, the hydrogels containing large amounts of water inevitably enter a frozen state, accompanied by losing mechanical softness and conductivity, which makes the assembled supercapacitors undergo serious capacitance degradation or even failure in a cold environment. Here they suggest a system with lower content of water and higher ion conductivity to overcome the temperature variation problem.

Lithium-ion Batteries and Supercapacitors

Due to the fast development of EVs, portable, flexible, and wearable electronic devices, it is vital to develop high-performance energy storage devices. Among these various energy storage systems, batteries and supercapacitors are the two critical technological systems holding a broad range of applications.

Energy storage devices with gel polymer electrolytes are lightweight, safe and flexible. Hence, they can show a great potential in needed power sources for flexible, portable electronics and high cycle life batteries for EVs.

Here, the lab fabricates high-performance, reliable, and safe energy storage deceives with gel-polymer electrolytes.

The goals of Ramanan Krishnamoorti’s research are to develop materials with tailored properties through a detailed understanding and manipulation of molecular level structure, synthesis and most uniquely processing methodologies. While the importance of structure-property correlations for materials has been recognized, the importance of processing conditions on the evolution of structure and hence properties in the case of soft materials have not been fully understood.

Resulting from the long-chain nature, high viscosities, low diffusion coefficients and rapid vitrification or crystallization, the structure and properties of polymeric materials are significantly affected by their processing. The Krishnamoorti Lab is pursuing a detailed research program, in collaboration with researchers in industry and national laboratories, to address the role of processing on the structure and properties of multi-phase polymers including polymer blends, block copolymers and microemulsions. Specific research focuses on understanding traditional polyolefin and polydiene materials and developing amphiphilic block, graft and star polymers for a number of technological applications.

The potential for the use of highly anisotropic nanoparticles such as layered silicates and carbon nanotubes dispersed in polymeric matrices promises the ability to develop combinations of physical, mechanical and thermal properties while not increasing weight and thus a new paradigm in materials technology. The lab has focused its efforts in developing fundamental understanding of the dispersion of the nanoparticles, characterization methodologies that span from the nano to macro length scales, develop correlations to properties and understand how processing can lead to unique microstructures and properties. Specific research focuses on light weighting automobile parts, developing super-strong fibers, strengthened elastomers, materials for fuel cells, longer life lithium ion batteries and improved materials for tissue replacement.

Drug and gene delivery methods are increasingly using bio-inspired membranes as carriers and targeting vehicles. The Krishnamoorti Lab is currently involved in characterizing and modeling the ability of polymeric materials to provide spatio-temporal stability for such bio-membranes using a range of novel experimental and molecular modeling techniques. Further, they are collaborating with a number of researchers from the medical community in Houston towards the synthesis, characterization and development of delivery vehicles using phospholipids and their polymeric analogs.

Five specific projects that are currently pursued in the Krishnamoorti research group are:

• Effect of pressure on the phase behavior of polyolefin blends
• Polymer crystallinity in bulk and thin films
• Phase transitions in block copolymers and block copolymer based balanced microemulsions
• Structure and viscoelasticity of macro- and nano-composites
• Structure and transport in biopolymers

Organic & Materials Research Chemistry

Research in the Lee group can be divided into six general areas: (1) selectively fluorinated organic thin films, (2) complex organic interfaces with controlled local composition, structure, and function, (3) biologically active interfaces, (4) nanoparticle growth and manipulation, (5) biopolymers and conducting polymers, and (6) polymerization catalyst development.

The common thread that ties all of the research areas together is the use of synthesis be it organic, inorganic, organometallic, or solid-state to prepare new materials for technological applications. Progress in each of the areas requires the successful development and integration of a wide range of research skills, starting with the synthesis of new materials, followed by the collection and analysis of data, and ending with the oral and written communication of the results.

As a natural consequence of this integrated approach, students departing from the Lee group are equipped with an unusually broad range of research capabilities. For example, analytical instrumentation commonly employed by the group includes IR, NMR, and UV-vis spectroscopies, GC, GC/MS, HPLC, gel permeation chromatography (GPC), dynamic light scattering (DLS), contact angle goniometry, ellipsometry, polarization modulation reflection absorption spectroscopy (PM-IRRAS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Members of the Lee group also gain experience using other specialized analytical instrumentation in collaborative projects with other research groups. Current studies of fluorinated films utilize self-assembled monolayers (SAMs) to generate nanoscale fluorocarbon thin-film coatings (essentially nanoscale analogs of Teflon) for use in miniaturized electronic device applications and as coatings for biomaterials. Research on complex interfaces targets the development of new types of SAM adsorbates for the purpose of generating structurally defined surfaces that expose a mixture of functional groups designed to elicit specific molecular recognition (e.g., sensor devices) and/or catalysis (e.g., artificial enzymes). Studies of biologically active interfaces utilize SAMs to enhance the growth of protein crystals and to template cell adhesion and proliferation for applications in tissue engineering.

Since much of the work in the Lee group is collaborative in nature, students often work side-by-side with chemical engineers, physicists, electrical engineers, biochemists, and biomedical engineers. In this type of environment, students gain knowledge and skills beyond those typically encountered in traditional synthetic chemistry laboratories.

Self-Sorting of Dynamic Combinatorial Libraries

Nature is a master of chemoselectivity: in a typical biological cell, hundreds of reactions occur simultaneously, but without any interference, in a complex “soup” of biological precursors. The Miljanic group is seeking to replicate this behavior in complex libraries of synthetic compounds known as dynamic combinatorial libraries (DCLs). They have shown that libraries of as many as 100 members can be reduced in complexity to just a handful of discrete compounds, produced in high purities.

Porous Materials and Porous Molecular Crystals

Porous materials have a plethora of application in industry, mostly related to energy technologies. The group is particularly interested in the synthesis of metal-organic and fully organic porous frameworks through the use of sophisticated organic precursors that assemble into porous structures either on their own, or upon coordination to metals. These frameworks have found applications in binding of fluorocarbons, Freons (CFCs) and fluorinated anesthetics.

Cyclobenzoins

In 2015, the group discovered that benzoin condensation of small aromatic dialdehydes leads to the generation of cyclic trimeric and tetrameric adducts, which they dubbed cyclobenzoins. These new macrocycles are characterized by exceedingly simply synthesis, rigid cavities, and rich chemistry that harks back to the early 19th century days of benzoin condensation.

Rigid Aromatic Fluorophores

The group has developed cross-conjugated X-shaped fluorophores based on benzobisoxazole and benzimidazole nuclei. In these molecules, appropriate substitution of the x- and y-axes results in the spatial isolation of FMOs, leading to predictable and useful sensing response. These systems have been utilized as sensors for carboxylic and boronic acids, phenols, amines, and various anions. More recently, their interest have expanded to the aggregation-induced emission in precursors to porous molecular crystals.

The Miljanić lab relies on supramolecular and synthetic chemistry as its key tools. Synthesis is used in the broad sense of the word, encompassing organic, coordinative inorganic, and organometallic preparations. Spectroscopy, crystallography, and materials characterization are the most relevant analytical tools. Students and postdoctoral researchers in the Miljanić group receive detailed guidance in scientific writing and visualization. This diversified training is intended to prepare them for challenges in both academic and a variety of industrial work environments.

Polymeric Materials: Tailored Structure, Properties, and Function

The objective of the Robertson research group is to develop polymeric materials with enhanced physical properties and function. The group specializes in polymer synthetic techniques, structural characterization (small-angle neutron, x-ray and light scattering), thermodynamics and self-assembly, and development of structure-property relationships.

Research Projects Focus on the Following Areas:

• Sustainable and biodegradable polymers derived from renewable resources.
• Advanced materials for wind energy
• Structure and dynamics of block copolymer micelles
• pH-responsive, antifouling polymer brushes
• Multicomponent and multiphase polymer blend

The Teets group is an experimental physical inorganic group that focuses on molecular inorganic and organometallic compounds. Most of the efforts in the group involve the discovery of synthetic strategies to control and optimize the photophysical and photochemical properties of organometallic compounds, pursuing compounds with enhanced or unique features. In particular, the group is targeting compounds with efficient phosphorescence in the extremes of the visible spectrum, i.e., deep blue and red, and also compounds which can luminesce in the near-infrared with high quantum yields. In related work, the group is preparing complexes, which are powerful photoreductants for application in photoredox catalysis. A separate project in the lab investigates the coordination chemistry of redox-active ligands with heavy transition metals, with a particular emphasis on the electrochemical and optical properties of these constructs.

Research in the Wu Lab focuses on applying computational quantum chemistry to understand structure-property relationships that underlie hydrogen (H-) bond mediated catalyses, self-assembly, and molecular recognition processes. Emphasis is on the development of innovative molecular design principles. The Wu Lab’s mission is to provide chemical insights that will help bridge fundamental physical organic concepts to applications in supramolecular material and organocatalysis design.