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ELEMENTS

VOL. 3

RESEARCH

UNC CHEMISTRY

SAVING ENERGY Solar energy breakthroughs to greener chemical processes Researchers in UNC’s Department of Chemistry are making bold strides toward a more energy-efficient future. Through innovative approaches that range from advanced material design to the use of light and catalysts, UNC chemists are uncovering new ways to reduce energy usage on a macro and micro level, while harnessing resources more effectively. These discoveries advance fundamental science and lay the groundwork for technologies that can impact everything from consumer products to global energy systems. Read on to discover the latest developments from UNC Chemistry, and to check in with a few of our alums.

The Communications Team

Dave DeFusco

Mandy Melton

Amie Solosky

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CHEMISTS CAN DISCOVER NEW MATERIALS MORE QUICKLY WITH AI

RESEARCHERS BOOST FLEXIBLE ORGANIC SOLAR PANEL EFFICIENCY BY TURNING DOWN THE HEAT

NEW UNC PROFESSOR DEVELOPS WEARABLE DEVICES MONITORING THE BODY’S CHEMISTRY

RESEARCHERS UNCOVER UNUSUALLY LONG-LIVED 'POLAR STATES' IN PROMISING SOLAR MATERIALS

UNC RESEARCHERS USE CHEMICAL ‘GLUE’ TO POWER SOLAR FUEL BREAKTHROUGH

CHEMISTS UNLOCK ROUTE TO TINY MOLECULAR SHAPES THAT COULD POWER NEXT-GEN MEDICINES

UNC CHEMISTS DISCOVER HOW TO SPEED UP KEY REACTION FOR CLEAN ENERGY

CHEMISTS USE LIGHT AND COBALT TO MAKE GREENER, CHEAPER INDUSTRIAL CHEMICALS

ALUM LAUREN MCRAE TURNS MOLECULAR INSIGHTS INTO BENEFITS FOR P&G CONSUMERS

ALUM CHARLOTTE MONTGOMERY’S MOLECULAR DESIGN TWEAKS PAVING THE WAY TO CLEANER ENERGY

Table of Contents

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CHEMISTRY

Frank Leibfarth shows one of the new polymers created using AI

CHEMISTS CAN DISCOVER NEW MATERIALS MORE QUICKLY WITH AI Everyday items like car tires, plastic bags and foam cushions come from materials called polymers that can take years to develop and test. Researchers at Carnegie Mellon University and the University of North Carolina at Chapel Hill have developed a new approach to create better rubber-like materials more quickly by combining artificial intelligence with human expertise. Typically when researchers make a material stronger, it becomes less flexible, while flexible materials tend to be weaker. To fix this problem, the team created a machine learning model that works in tandem with human chemists. Machine learning — a subset of AI research — involves teaching an artificial intelligence to perform a specific task. In one experiment, the researchers collaborated with the AI

tool to create a polymer that is both strong and flexible. “There are so many applications for polymers: construction, car parts, footwear, moldings, coatings,” said Olexandr (Oles) Isayev, Carl and Amy Jones Professor in Interdisciplinary Science. “Whenever you make one for a specific application, it needs certain properties, and it can’t usually withstand force and expand at the same time. These new materials have excellent properties. They can do both.” The group input the properties it wanted in a polymer into the design tool. Then, the model suggested a series of experiments that UNC-Chapel Hill chemists conducted using automated science tools. The researchers tested the produced materials

PAGE 4 Samples of the polymer designed using AI.

and provided feedback to the model, so it could make adjustments. “The AI system suggests an experiment, and after the experiment’s been made, we measure the properties, and we iterate,” Isayev said. “You can dynamically adjust and help the machine navigate to find materials with the desired properties.” Frank Leibfarth, professor of chemistry at UNC-Chapel Hill, said working in this new way was a breath of fresh air. “In our human-augmented approach, we were interacting with the model, not just taking directions,” Leibfarth said. “This allowed us to combine the best aspects of human- and machine-guided processes to come to the optimal solution.” Leibfarth also said he was excited for the potential applications for the polymer. “Materials like this could be used in running shoes, medical devices like 3D printed dental implants, and durable parts for cars,” Leibfarth said. “We’re at this really interesting time in chemistry and chemical engineering of finding out what’s the best strategy to go after the next great material,” said Dylan Anstine, a former postdoctoral fellow in Carnegie Mellon’s Department of Chemistry, who is now an assistant professor of chemical engineering and materials science at Michigan State University. “It’s clear that’s going to involve expert experimental chemists and expert computational chemists using the best data science tools we can. We were really teasing apart what that relationship looks like.” The machine learning model also saved the researchers significant time and money by ruling out methods and chemicals that would not work. The researchers have made the program open source, so any lab can have access to this tool. If adopted in other labs, the tool could reduce the cost and time required for other discoveries. This approach could accelerate the development of advanced materials for medical devices, footwear and electronics. By combining AI predictions with human expertise, the researchers hope they can solve complex materials challenges more effectively. Anstine, Isayev and Leibfarth published “Design of Tough 3D Printable Elastomers with Human-inthe-Loop Reinforcement Learning” in Angewandte Chemie along with Carnegie Mellon graduate students Filipp Gusev and Filipp Nikitin Olexandr Isayev Frank Leibfarth Dylan Anstine as well as UNC-Chapel Hill researchers Johann Rapp, Kelly Yun, Meredith Borden, and Vitall Bhat. Their work was funded by the Air Force Research Laboratory and the National Science Foundation. -Kirsten Heuring Carnegie Mellon

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CHEMISTRY

RESEARCHERS BOOST FLEXIBLE ORGANIC SOLAR PANEL EFFICIENCY BY TURNING DOWN THE HEAT A team of researchers led by Jordan Shanahan, a Ph.D. student in the Department of Chemistry, demonstrated a way to make an important step in organic solar cell manufacturing happen at a temperature of 80 degrees Celsius, or 176 degrees Fahrenheit, lower than normal.

In solar technology, sometimes a small tweak can make a big difference. For a special type of solar panel made from thin, flexible, plastic-like materials, researchers at UNC-Chapel Hill have found that tweak: use less heat.

“We figured out a way to lower the temperature where instead of the device performance decreasing, we get a performance boost,” said Jordan Shanahan, lead author of the study and a Ph.D. chemistry student at UNC.

In a new study published in the Journal of the American Chemical Society, a team of researchers in the Carolina Department of Chemistry showed a way to make an important step in organic solar cell manufacturing happen at a temperature of 80 degrees Celsius, or 176 degrees Fahrenheit, lower than normal. That gentler approach not only prevents damage to the material but also makes the solar cells work better, achieving the best performance ever reported for this type of material.

These flexible solar panels, called organic photovoltaics (OPVs), are made from two main ingredients: a light-absorbing material—the donor polymer—a partner material, the acceptor, that helps carry away the electric charges created by sunlight. To make the light-absorbing material stable, scientists often need to remove tiny chemical “side chains” from its structure. This makes the material pack more tightly and lets electricity move more easily.

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Traditionally, this removal process is done by heating the material to very high temperatures—around 220 degrees Celsius, or 428 degrees Fahrenheit. But there’s a catch: high heat-induced stress can ruin the fine, even blend needed for good performance.

Shanahan and co-authors, including Dr. Wei You, senior author of the paper and Cary C. Boshamer Distinguished Professor of Chemistry and Applied Physical Sciences, found a way to remove those side chains at just 140 degrees Celsius, or 284 degrees Fahrenheit, or even lower by adding a small amount of acid directly into the material before heating.

After testing different types and amounts of acid, they discovered that 5% diphenyl phosphate worked best. The acid speeds up the side chain removal without harming the rest of the solar cell. The researchers also found they could predict how fast the process would happen based on three simple factors: how strong the acid is, how much acid is added and the temperature used. This makes it easier for other scientists to fine-tune the process, almost like following a recipe.

“Lowering the temperature kept the two ingredients more ideally mixed, which led to better performance,” said Professor You. “With this new acid-assisted method, our solar cells reached about 4.5% efficiency—the highest ever reported for this type of material side chain free.”

Wei You

In earlier work, the researchers had shown that removing side chains could make electricity move through the material two to five times faster. The new method keeps that benefit but avoids the damage caused by high heat. Importantly, the new low-heat process doesn’t make the solar cells less stable. Both the highheat and low-heat methods produced materials that could handle higher temperatures over time. The difference is that the low-heat version started off working better.

The research team believes this mild approach could be used to improve many kinds of organic electronic devices.

Jordan Shanahan

“It’s a new tool that we hope others can utilize to achieve better performance and stability with these materials based devices.” said Professor You. -Dave DeFusco UNC-Chapel Hill

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CHEMISTRY

NEW UNC PROFESSOR DEVELOPS WEARABLE DEVICES MONITORING THE BODY’S CHEMISTRY

Netz Arroyo, who joined UNC in July after a highly successful tenure at Johns Hopkins University School of Medicine, is an expert in creating electrochemical biosensors—tiny, highly sensitive devices that can continuously monitor molecules in the body.

Imagine a tiny, wearable or implantable device that could track your body’s chemistry in real time, telling you whether your medication is working, if you’re low on a critical nutrient or even how your fitness routine is affecting your health. For Dr. Netz Arroyo, the newest associate professor in Carolina’s Department of Chemistry, this is not science fiction, it’s his everyday work. Arroyo, who joined UNC in July after a highly successful tenure at Johns Hopkins University School of Medicine, is an expert in creating electrochemical biosensors—tiny, highly sensitive devices that can continuously monitor molecules in the body. His research blends chemistry, engineering and biology to develop tools

that could transform how we understand, track and improve health. “We want to make it possible for people to get detailed, real-time information about their bodies,” said Arroyo. “That information can empower better decisions about diet, exercise, treatments—really, everything that affects health.” The Arroyo Lab and his team design sensors that mimic the body’s natural ability to detect specific molecules. These devices can measure important compounds like drugs, proteins and other chemical signals without needing a blood draw or trip to the lab.

The potential applications are wideranging: Better medication management by showing exactly how much of a drug is in the body at any moment. Personalized health monitoring, with wearable devices that give a detailed chemical snapshot of your well-being. Smarter drug delivery systems that respond automatically to changes in the body. His group’s recent work has even revealed surprising details about how medicines spread through the brain, and developed new tools for tracking HIV treatment and cancer biomarkers in real time. Arroyo’s impact isn’t limited to the lab bench. In 2025, he became interim editorin-chief of ECS Sensors Plus, an international journal that publishes cuttingedge research on sensing technologies. He has been recognized as a “Rising Star in Sensing” by ACS Sensors and has earned awards for both research and teaching, including Johns Hopkins’ Cecil H. Robinson Teaching Award in 2024. His scientific reach spans collaborations on everything from COVID-19 antibody tracking to new materials for improving sensor performance. In the past two years alone, he’s co-authored studies on brain drug mapping, rapid prototyping of biosensors and DNA-based devices that can detect proteins and genetic material with incredible precision. Beyond his research, Arroyo is committed to building a diverse and welcoming scientific community. His lab actively works to ensure that people from all backgrounds have access to research opportunities and that every voice is respected.

PAGE 8 Arroyo earned his undergraduate degree in chemical sciences from Tecnológico de Monterrey in Mexico, his Ph.D. in analytical chemistry from the University of Texas at Austin, and completed a postdoctoral fellowship at the University of California, Santa Barbara. He joined the faculty at Johns Hopkins in 2019 and quickly built a reputation as a creative researcher and inspiring teacher before making the move to Chapel Hill.

Netz Arroyo

As he settles into his new role at UNC, Arroyo is looking forward to expanding his research and collaborations. His goal is clear: to create technologies that bring laboratory-level chemical analysis into everyday life. “For patients, athletes, doctors and anyone interested in understanding their own biology,” he said, “the future as I envision it is one where chemistry quietly works in the background, helping people live healthier, more informed lives.” -Dave DeFusco UNC-Chapel Hill

“Creativity and innovation come from diversity,” he said. “Different perspectives are what allow us to solve hard problems in new ways.” The Netz Lab just before the move to UNC

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CHEMISTRY

RESEARCHERS UNCOVER UNUSUALLY LONG-LIVED 'POLAR STATES' IN PROMISING SOLAR MATERIALS Above, a perovskite solar cell. A new study led by Carolina chemist Lina Quan and published in Nature Communications, revealed a surprising and potentially game-changing property: when perovskites are hit with light, they can form “polar states” that last an unusually long time—up to microseconds, or millionths of a second.

In the race to create cheaper, more efficient solar panels, scientists have been focusing on a class of materials called metal halide perovskites. These materials can convert sunlight into electricity with high efficiency, are inexpensive to produce and can be made into thin, flexible films. But researchers have long been puzzled by certain behaviors inside perovskites that could hold the key to even better performance. A new study led by Carolina chemist Lina Quan and published in Nature Communications, revealed a surprising and potentially game-changing property: when perovskites are hit with light, they can form “polar states” that last an unusually long time—up to microseconds, or millionths of a

second. That might not sound like much, but in the world of electronics and energy conversion, it’s a lifetime. “This is the longest-lived photoinduced polar state ever seen in this class of materials,” said Quan, senior author of the paper and an assistant professor in UNC’s Department of Chemistry. “It opens up exciting new possibilities for how we can design solar cells and other optoelectronic devices.” A polar state happens when positive and negative charges in a material separate and create a built-in electric field. In perovskites, shining light can trigger this charge separation. The longer that state lasts, the more time the material has to

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to collect and move those charges to where they’re needed, whether that’s to produce electricity in a solar cell or to create light in an LED.

Lina Quan

“Until now, scientists thought these lightinduced polar states in perovskites were too short-lived to be useful,” said Quan. “But our team’s experiments showed that under certain conditions, the effect can last thousands of times longer than similar effects in other materials.” The researchers used ultrafast laser pulses to excite the perovskite and then measured how its structure and electrical properties changed over time. This technique allowed them to capture fleeting changes on timescales ranging from femtoseconds— quadrillionths of a second—to microseconds.

“It’s like the light leaves a faint but longlasting fingerprint in the material’s structure,” said Quan. If scientists can control and harness these long-lived polar states, they could build perovskite solar cells that capture and deliver more of the sun’s energy. The effect might also be useful in other technologies, such as: LEDs with higher brightness and efficiency Light sensors that can detect very faint signals Data storage devices that encode information using light Perovskites can be made at low temperatures using inexpensive manufacturing methods, unlike traditional silicon which requires high-temperature, energy-intensive processing. This could make advanced solar and lighting technologies far more affordable. “This finding gives us a whole new design rule for perovskite-based technology,” said Quan. “It’s a reminder that these materials still have a lot of secrets to reveal.” -Dave DeFusco UNC-Chapel Hill

They found that once the polar state formed, it persisted far beyond the initial flash of light. The persistence appeared to be linked to subtle distortions in the perovskite’s crystal structure—distortions that trap the charges in place without completely immobilizing them.

The Quan Lab just before the move to UNC

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CHEMISTRY

UNC RESEARCHERS USE CHEMICAL ‘GLUE’ TO POWER SOLAR FUEL BREAKTHROUGH

Andre Orr, a Ph.D. candidate in the Department of Chemistry, is the lead author of a study supported by the Department of Energy-funded Center for Hybrid Approaches in Solar Energy and Liquid Fuels (CHASE) that attempts to tackle a big question: How do we capture and use sunlight to recycle carbon dioxide, a major greenhouse gas, into value-added products and fuels?

In a step toward a cleaner energy future, UNC-Chapel Hill chemistry researchers have discovered a new way to attach powerful carbon dioxide-reducing molecules to silicon surfaces that could help scientists harness sunlight to turn carbon dioxide into useful fuels and chemicals—essentially storing solar energy in liquid form. Supported by the Department of Energyfunded Center for Hybrid Approaches in Solar Energy and Liquid Fuels (CHASE), the research team tackled a big question in the ACS Applied Materials & Interfaces study, “Immobilizing a Lehn-Type Catalyst with Nitrocyclocondensation Chemistries: CO2 Reduction on Silicon Hybrid Photoelectrodes”: How do we capture and use sunlight to recycle carbon dioxide (CO₂), a major greenhouse gas, into valueadded products and fuels?

To turn sunlight and carbon dioxide into fuel, researchers at CHASE are building special surfaces where materials like silicon can

absorb sunlight and create the electricity needed to power chemical reactions. These reactions are helped along by tiny molecules called catalysts, which turn CO₂ into useful fuels. But there’s a challenge. Those catalysts don’t easily stay attached to the silicon. The UNC team found a way to fix that using a special chemical “glue” made through a reaction called nitrocyclocondensation (NCC). This glue not only keeps the catalyst stuck to the silicon during the reaction, but also makes sure electricity can flow smoothly between the two, helping the system work more efficiently. “Attaching molecules to silicon in a way that survives the harsh conditions needed to reduce CO₂ has always been a challenge,” said Andre Orr, first author of the study and a Ph.D. chemistry student working in the laboratories Professors James Cahoon and Matthew Lockett. “Many previous attempts had limited stability or weren’t flexible enough to incorporate different kinds of molecular catalysts.”

Their method borrows from earlier studies that used NCC reactions to bind molecules onto silicon in highly controlled lab environments, like ultrahigh vacuum chambers. Until now, no one had shown that NCC chemistries were suitable for the conditions needed to generate solar fuels, e.g., immersed in a liquid under illumination with sunlight. “We took that chemistry and applied it in solution, meaning we can now we can perform NCC reactions at a much more practical scale,” said Orr.

PAGE 12 carbon monoxide, a key building block for fuels and industrial chemicals. Under artificial sunlight, their catalyst-coated silicon converted CO₂ into carbon monoxide with 23% efficiency, a performance that outshines similar systems prepared with other methods. “This work gives researchers a toolkit for making more durable and efficient solar fuel devices,” said Dr. Matthew Lockett, senior author of the study and an associate professor in the UNC Department of Chemistry. “The real impact is that it opens the door to attaching many kinds of catalysts in a much simpler way.”

Andre Orr

Silicon is the same material used in most solar panels. It’s cheap, abundant and great at absorbing sunlight. The clean surface needed for attaching molecules is highly reactive, easily forming a thin insulating layer, silicon oxide, that cannot efficiently transfer energy from the material to the attached catalyst. To prepare their modified photoelectrodes, which are special materials that use light to generate electricity and drive chemical reactions, freshly cleaned silicon was placed in a special liquid that promoted the NCC reaction, forming strong nitrogen-silicon bonds. They demonstrated the utility of the NCC reaction on two very different molecules: A redox reporter molecule—a kind of electrochemical indicator to track reaction completion on the surface and the ability of the newly formed interface to transfer electrons from silicon to the attached molecules. A CO₂-reduction catalyst based on a metal called rhenium, known for turning CO₂ into

Matthew Lockett

That flexibility is important because different catalysts can make different products—not just carbon monoxide, but potentially methane, ethylene, alcohols or even jet fuel. “The ability to mix and match catalysts and surfaces with this technique could help us custom-build solar reactors to fit a wide range of liquid energy needs,” said Lockett. The UNC team is now exploring how to improve the amount of catalyst that can be packed onto the surface, test more complex catalysts that produce richer chemical products and scale the process for larger solar devices. “We’re just scratching the surface—literally,” said Orr. -Dave DeFusco UNC-Chapel Hill

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CHEMISTRY

CHEMISTS UNLOCK ROUTE TO TINY MOLECULAR SHAPES THAT COULD POWER NEXT-GEN MEDICINES Researchers in the Department of Chemistry have discovered a new way to make two rare molecular shapes, called spiro[2.2]pentanes and vinylcyclopropanes, more easily and with more design flexibility. The former can make a drug bind more tightly and precisely to its target in the body and, in some cases, adding one has made a drug dozens of times more potent.

Some molecular shapes are so small and tense that making them is like trying to bend a steel spring into a perfect square without snapping it. If chemists can pull it off, these unusual shapes can transform the way medicines work. Researchers in the Department of Chemistry at UNC-Chapel Hill have discovered a new way to make two such rare shapes, called spiro[2.2]pentanes and vinylcyclopropanes, more easily and with more design flexibility. The research, led by Ph.D. student Charles Reece Teeples and Associate Professor Sidney Wilkerson-Hill, was recently published in the journal Organic Letters.

Spiro[2.2]pentanes look like two tiny triangles sharing a single corner—a rigid, compact structure that scientists can attach to other chemical pieces. Because of their locked shape, they can make a drug bind more tightly and precisely to its target in the body. In some cases, adding one has made a drug dozens of times more potent. The problem is they’re very hard to make. Their “spring-loaded” structure means traditional methods often fail or only produce a limited variety. The Carolina team tackled the challenge by using sulfones, which are common, stable molecules, as safe stand-ins for unstable and highly reactive particles called carbenes.

PAGE 14 They tried two different strategies: 1. Combining sulfone reagents with methylenecyclopropanes, which are small ring-shaped molecules with an extra reactive bond. 2. Combining sulfones with styrenes— common aromatic molecules—using a special “cyclopropyl sulfone” design. The first method worked as planned, creating 16 types of spiro[2.2]pentanes in good amounts, with the ability to swap in different chemical features. The second method surprised them. Instead of spiro[2.2]pentanes, it produced vinylcyclopropanes, another rare and valuable shape that’s also used in making medicines and complex natural products.

key “atom shuffle” step happens before the final ring forms. Even though the original goal was to make more spiro[2.2]pentanes, the unexpected new way to make vinylcyclopropanes is just as exciting, said Teeples. Both shapes are in high demand among drug designers for their precision and rigidity, which can improve how a medicine works in the body. “This research gives medicinal chemists a new tool,” said Wilkerson-Hill, who is principal investigator on the study. “It lets us make complex shapes using sulfone compounds, which are not as explosive and toxic as the traditionally used diazo compounds.”

“We were aiming for one product, but the chemistry decided to take a different path,” said Teeples, lead author of the study. “That’s part of what makes research exciting. You discover something you weren’t looking for.”

Sidney Wilkerson-Hill

Next, the researchers plan to make the reactions even gentler and more selective so they can be used for sensitive or largescale applications. Charles Reece Teeples

To understand the detour, the team ran tracking experiments that replaced certain hydrogen atoms with a heavier version called deuterium. This helped show that a

As Teeples put it, “A new method to make these unusual building blocks can be enabling to drug discovery campaigns, as well as the broader synthetic community.” -Dave DeFusco UNC-Chapel Hill

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CHEMISTRY

UNC CHEMISTS DISCOVER HOW TO SPEED UP KEY REACTION FOR CLEAN ENERGY In a lab at UNC-Chapel Hill, a group of chemists may have uncovered a missing piece in the puzzle of how to make clean energy more efficiently. Led by Professor Gerald Meyer and two researchers in his lab, Matthew Kessinger and Thomas Whittemore, the team discovered how to speed up a key chemical reaction involved in splitting water into oxygen and hydrogen —a process used in clean energy technologies like solar fuels. “This work helps us understand how to better design catalysts for water splitting,” said Kessinger, a postdoctoral researcher. “That’s a big step toward making renewable energy systems that work faster and more reliably.”

Matt Kessinger

Tom Whittemore

Supported as part of the Center for Hybrid Approaches in Solar Energy to Liquid Fuels (CHASE), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, the Inorganic Chemistry study, “Direct Evidence for Buffer-Enhanced ProtonCoupled Electron Transfer Generation of a High-Valent Metal-Oxo Complex,” examined how a special metal—ruthenium—reacts when it’s part of a molecule attached to a thin glass-like surface. This metal can help pull apart water molecules, a process necessary for a hydrogen-based economy. But there’s a catch: To make this reaction happen, the metal not only has to lose electrons—tiny, charged particles—but get rid of protons, which are part of hydrogen atoms. This dual action—called protoncoupled electron transfer, or PCET—is crucial for clean energy chemistry. Unfortunately, it tends to happen very slowly. “Moving a small particle like an electron is easy, but getting rid of a charged atom, like a proton, at the same time is tricky,” said Whittemore, a Ph.D. student in the

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Department of Chemistry. “That’s where things usually get bogged down.” The breakthrough came when the researchers, including colleagues from the University of Ferrara in Italy and North Carolina State University, added something called a buffer to the reaction. Buffers are common in science labs—they help control the acidity of solutions—but in this case, they did something more. When the buffer concentration was high, the slow steps in the reaction seemed to disappear. Instead of dragging its feet, the reaction sped up—by as much as 10,000 times.

Meyer said the team’s finding offers direct evidence that buffers—those simple, everyday chemicals—can make this step much faster. “For a long time, researchers believed that buffers help these reactions, but we didn’t have clear a explanation for why,” said Meyer. “Now we do. And that opens the door to smarter, faster catalyst designs.”

“That was a wow moment,” said Kessinger. “We saw that with enough buffer, the reaction didn’t go in sequential steps. Everything happened at once. It was much faster.” In chemistry terms, the buffer helped the proton and the electron move together in one smooth motion, called a “concerted” reaction. This is better than having them move separately, which takes more time and energy. This discovery may seem small, but it has big implications. In clean energy technologies, scientists need to generate catalysts with sufficient energy to break water molecules apart. By utilizing concerted reactions, the team believes it can make this chemistry more efficient. However, getting there has been a slow process.

Gerald Meyer

Imagine a future where solar panels don’t just generate electricity, they also store energy by turning sunlight into a sustainable fuel like hydrogen gas. That’s one of the dreams behind solar fuels research. But for that to happen, every piece of the chemical puzzle has to work efficiently. This research helps fill in one of those pieces. “Any way to speed-up these reactions helps,” said Whittemore. “If we can understand and control the chemistry better, we can help make clean energy a reality.” -Dave DeFusco UNC-Chapel Hill

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CHEMISTRY

CHEMISTS USE LIGHT AND COBALT TO MAKE GREENER, CHEAPER INDUSTRIAL CHEMICALS Left to right, Michael Rodriguez, Professor Erik Alexanian and Mason Faculak developed a new method for producing two valuable classes of chemicals—esters and carboxylic acids—which show up in everything from food additives to synthetic textiles and biodegradable materials. Using visible light and a cheap, earth-abundant metal catalyst—cobalt—their process is not only more mild and environmentally friendly but efficient enough for large-scale use, possibly paving the way for cleaner manufacturing of vital chemicals.

Simple molecules called alkenes— commonly produced during oil refining— are an abundant and low-cost starting point for making a wide range of industrial and consumer products, from fuels and plastics to fragrances and pharmaceuticals. Two particularly valuable classes of chemicals are esters and carboxylic acids, which show up in everything from food additives to synthetic textiles and biodegradable materials. While these compounds can be made through various well-established methods, converting alkenes into esters and acids is especially appealing because it offers a direct route from cheap feedstocks. However, this type of transformation, known

as alkene carbonylation, typically requires rare metals, high heat and extreme pressure, making it costly and difficult to scale. The challenge has been finding a milder, more sustainable way to carry it out. In a recent Journal of the American Chemical Society study, Mason Faculak and Michael Rodriguez, UNC Ph.D. chemistry students in the lab of Professor Erik Alexanian, developed a new method to produce esters and carboxylic acids using visible light and a cheap, earth-abundant metal catalyst: cobalt. Their process is not only more mild and environmentally friendly but efficient enough for large-scale use, possibly paving the way for cleaner manufacturing of vital chemicals.

PAGE 18 “We’re taking a method that’s been around for decades and modernizing it for a sustainable future,” said Faculak, a lead author of the study. “The exciting part is, we’re doing it with materials and conditions that are much more practical and accessible for industry and academia.”

The chemical reactions at the heart of this study —called alkoxycarbonylation and hydroxycarbonylation—turn simple oil- and gasbased molecules known as alkenes into more useful ones like esters and carboxylic acids, which are widely used in products from plastics to pharmaceuticals. Traditionally, doing this requires rare and expensive metals like palladium or platinum, extremely high heat (over 250°F) and carbon monoxide gas at pressures more than 40 times what we experience at sea level. In other words, it’s costly, energy-intensive and hard to scale up for industrial use. The UNC team, however, figured out how to carry out these reactions using cobalt carbonyl—a cheap and abundant metal catalyst—under low pressure and mild temperatures using visible light as a source of energy. “Using light, instead of heat, to drive this reaction allows it to be more selective with respect to chemical reactivity and also compatible with more complex molecules,” said Rodriguez, the other lead author of the study. Cobalt by itself wasn’t enough to make the reaction work, so the researchers came up with a smart workaround: they added two simple helper molecules to activate the cobalt. One of them, called DMAP, helped swap out certain parts of the reacting molecules, while the other, triethylammonium tosylate, helped manage the balance between acidic and basic conditions— an important part of keeping the reaction on track. “Through judicious choice of co-catalysts, we developed a system that is incredibly efficient,” said Rodriguez. “In some cases, with these

optimized conditions, we observed yields approaching the theoretical maximum.” The reaction, as it turns out, also works without any added solvent in some cases, which dramatically cuts down on chemical waste and gives it an exceptionally low E factor—a common measure of environmental impact in industrial chemistry. The UNC team tested their method on dozens of different alkenes and alcohols, including simple industrial feedstocks, complex molecules like cholesterol and quinine, and natural product derivatives like menthol and proline. These all reacted cleanly under their mild conditions, contrasting with previous methods under which complex molecules might decompose. “We were happy to see how broad the method was,” said Faculak. “We could pair complex alcohols with complex alkenes and still obtain excellent yields and selectivity.” Because the process only requires one molecule of alcohol per molecule of alkene, rather than large excesses, it produces less waste and thus is more practical for complex synthesis, key traits for making medicines or fine chemicals, where material costs are high. Professor Alexanian, senior author of the study, said the team’s work represents a major step toward making greener, more scalable chemical reactions. “This research shows that you don’t need expensive catalysts or extreme conditions to make valuable products on large scales,” said Alexanian. “By using visible light and earthabundant cobalt, we’re developing methods that enable new reactivity and could help reshape the way essential chemicals are manufactured, especially as industries look to cut costs and reduce their environmental footprint.” -Dave DeFusco UNC-Chapel Hill

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CHEMISTRY

UNC CHEMISTRY ALUM TURNS MOLECULAR INSIGHTS INTO BENEFITS FOR P&G CONSUMERS

At P&G, Lauren McRae applies her background in chemistry and data science to optimize materials for paper products, ensuring they perform well, are cost-effective and align with consumer needs.

When Lauren McRae arrived at UNC-Chapel Hill in 2018 to begin her Ph.D. in chemistry, she imagined a future where her research on sustainable materials might help shape the next generation of batteries. What she didn’t anticipate was how the problemsolving mindset that she honed in Scott Warren’s lab—learning to think independently, work creatively with data and collaborate across disciplines—would carry her into one of the world’s leading consumer goods companies. Today, as a senior scientist in Procter & Gamble’s Baby, Feminine and Family Care Analytical division, McRae is using that same mindset to transform everyday products. She applies her background in chemistry and data science to optimize materials for paper products, ensuring they perform well, are cost-effective and align with consumer needs.

“A lot of my focus now is on technical efficiency,” said McRae. “How do we make methods more automated, feed those methods data and then use that data to generate insights that improve the consumer experience?” McRae’s doctoral research in Carolina’s Department of Chemistry centered on crystalline phases of new materials that could serve as sustainable alternatives to lithium-ion batteries. The work demanded both computational and experimental approaches, as well as a deep commitment to turning raw data into meaningful insights. “The type of thinking I had to do in my Ph.D. —learning how to research independently, solve problems in unique ways and analyze data efficiently—has really translated well to the challenges we face at P&G,” she said.

PAGE 20 She credits her time in Chapel Hill not just with teaching her technical skills like coding in Python to process data, but with shaping her ability to see the big picture. Her advisor, Associate Professor Scott Warren, played an important role in that growth. “He was really helpful in helping me understand the research, but also in helping me figure out what I wanted to do next,” said McRae. “He supported all the different things I explored inside and outside of research, and that has shaped how I now mentor others.” McRae’s work is grounded in measurement science, or understanding how the fundamental properties of raw materials and polymers translate into product performance. Her experience with datadriven research at UNC has been central to her ability to drive innovation at P&G. In one project, she worked alongside P&G’s mass spectrometry team, which generates massive datasets that can be timeconsuming to analyze. By applying computational techniques like cluster analysis and machine learning, her group uncovered molecular signatures that correlated with consumer feedback about product performance.

In her role with paper products, McRae’s expertise lies in polymer characterization—understanding how chemical and physical properties affect how a product performs in real life. The challenge, she said, is to connect every stage of the process: how the raw material is made, how it performs in production and how it ultimately feels to the consumer. “The most unique and interesting challenge is predicting the consumer experience from the raw material,” she said. “If we can understand the fundamental chemical properties up front, we can innovate more efficiently and in ways that help us identify meaningful solutions much faster.” Whether McRae is analyzing polymers for biodegradability or helping design baby and family care products, she sees science as a means to improve daily life. “There are tons of technical pieces that go into making a product, but ultimately, the singular goal for everyone here is to make the consumer experience better,” she said. “That’s what drives us.” -Dave DeFusco UNC-Chapel Hill

“In a previous project while working on hair care products, one consumer reported their hair felt softer, but it wasn’t clear which molecules were responsible,” she said. “Using computational analysis of the mass spec data, we were able to identify the molecules contributing to performance and build that insight back into product development.” That combination of computational insight and experimental validation has become a hallmark of McRae’s approach. Whether working on biodegradable polymers, feminine pads or family care paper products, she emphasizes the importance of linking raw data to consumer experience.

Lauren McRae in a P&G lab. As a Ph.D. student in the chemistry department, she said Associate Professor Scott Warren was a big influence on her career.

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CHEMISTRY

CHARLOTTE MONTGOMERY’S MOLECULAR DESIGN TWEAKS PAVING THE WAY TO CLEANER ENERGY

Charlotte Montgomery presents her thesis

When Charlotte Montgomery arrived at the University of North Carolina at Chapel Hill to pursue her Ph.D. in chemistry, she didn’t plan on helping solve one of the most complicated problems in clean energy. But she loved puzzles and in the world of chemistry, few puzzles are trickier, or more important, than how to efficiently convert electricity into fuel. Her research, “Impact of Pendant Amine Basicity on Electrochemically-Promoted Cobalt Hydride Formation: Kinetic and Mechanistic Analysis,” recently published in Inorganic Chemistry as part of a special issue on “Proton-Coupled Electron Transfer in Coordination Chemistry,” tackles a highly

specific, but critical, question: how does tweaking tiny chemical features on a molecule affect its ability to form a crucial intermediate called a metal hydride? And how can that information be used to make better catalysts— the molecules that speed up chemical reactions—for clean fuel production? At first glance, this might seem like an obscure detail of academic chemistry, but the impact could be massive. Efficient catalysts that help turn carbon dioxide into fuel using renewable electricity are one of the holy grails of climate technology. They could help us store solar or wind power as usable liquid fuel—essentially bottling sunshine for when we need it.

“Catalysts have a lot of room for improvement,” said Montgomery, “but you don’t know how to fix something until you know why it’s broken. I like studying the nitty-gritty details—figuring out where the bottlenecks are and what we can do to open them up.”

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At the heart of Montgomery’s work is a metal called cobalt. Specifically, cobalt complexes—molecules where a cobalt atom sits at the center, surrounded by ring-like structures called ligands. These complexes can form what’s known as a cobalt hydride, where a hydrogen atom is attached to the metal. That step, forming a metal hydride, is key in converting carbon dioxide into energy-rich products like formate or carbon monoxide—building Charlotte Montgomery blocks for synthetic fuels. But exactly how the hydrogen gets to the cobalt—through what sequence of chemical steps—isn’t always straightforward. To investigate, Montgomery focused on what’s called a “pendant amine”—a nitrogen-containing arm hanging off the side of the molecule that can help transfer protons, a key part of hydrogen atoms, to the metal. Importantly, not all pendant amines are created equal. Some are more basic— willing to grab protons—and some are less. By changing the nature of this pendant amine—making it more or less basic—Montgomery could essentially rewire the mechanism of hydride formation. “This project was really inspired by wanting to understand how those changes in basicity change the pathway of the reaction,” she said. “Do they make it faster? Do they make it more efficient? And how can we use that to make better catalysts?” Montgomery tested three variations of the pendant amine: benzyl (most basic), phenyl (least basic) and methoxyphenyl (somewhere in between). It was more than just a mix-and-match exercise. Each change altered the thermodynamics—how much energy was needed or released— and the kinetics—how fast things happened. “We saw a real marriage between thermodynamics and kinetics,” said Montgomery. “By changing the basicity, we changed the speed and efficiency of the reaction. That’s huge if you’re trying to make fuels fast and cleanly.” Of the three, the benzyl version surprised her the most. It turned out to be the most reactive, allowing access to a variety of reaction pathways. That lucky choice—starting with benzyl—set the tone for her whole dissertation. “I sometimes think about how my dissertation would’ve been different if I’d started with the phenyl version instead,” she said. “That one wasn’t basic enough to even access some of the pathways. The whole project might not have happened.” Montgomery didn’t just rely on trial and error. She used a range of sophisticated tools to figure out exactly where the chemical action was happening. By designing a series of experiments that used acids of varying strength, she was able to track changes in the reaction’s behavior, like a detective watching for subtle clues. She then backed up her experimental findings with computer simulations and theoretical models, Montgomery in the glovebox in the Dempsey Lab.

PAGE 23 which confirmed that the proton—the hydrogen—was initially attaching not to the cobalt metal itself, but to the nitrogen on the pendant amine. “That tells us something really important,” she said. “It shows how critical the ligand—the part of the molecule surrounding the metal—is in controlling the reaction. That’s a huge insight for designing better catalysts.” One of the most exciting outcomes of her study is the realization that by tweaking the pendant amine, chemists can control which product is formed from carbon dioxide. If the pendant amine is very basic and reactive, it helps form a cobalt hydride, which in turn makes formate—a type of liquid fuel. But if the amine is less basic, formate production can become less favorable. In different systems without a pendant amine site, hydride formation may be shut off entirely and a different reaction happens, producing carbon monoxide, which can be converted into methanol or ethanol. That ability to steer the reaction one way or another is known as selectivity. It’s a big deal in chemistry, because it means you can produce the fuel you want with fewer unwanted byproducts. For Montgomery’s mentor, Dr. Jillian Dempsey, Bowman and Gordon Gray Distinguished Term Professor, the study represents more than just a successful dissertation. “Charlotte’s work provides guiding principles for how subtle changes in molecular design can completely reshape a catalyst’s reactivity,” said Dempsey. “Fundamental science like this provide critical foundations for future sustainable energy technologies.” Dempsey said Charlotte’s discoveries offer exactly the kind of deep insight scientists need to design better, faster and more efficient catalysts for tomorrow’s energy technologies. “When developing next-generation catalysts, the types of catalyst structure-reactivity details Charlotte revealed can provide an essential blueprint for what sort of design changes to make to enhance performance,” said Dempsey. “This sort of critical design puts us on an accelerated path toward catalysts that operate with the required metrics for next-generation technologies.” After finishing her Ph.D., Montgomery accepted a position at Exponent, a scientific and engineering consulting firm, where she will apply her chemistry background to real-world legal and business challenges. “It’s kind of a full-circle moment,” she said. “I did an internship at Estée Lauder as an undergrad and another at a startup, AIRCO, working on sustainable aviation fuel during graduate school. Now at Exponent, I’ll be working on cases involving fuels, lubricants and cosmetics.” She first connected with the firm during Industry InSight, a professional development event she helped organize at UNC. “I’ve always loved problem-solving and communicating science clearly,” she said. “Exponent lets me do both, while still staying connected to chemistry.” -Dave DeFusco UNC-Chapel Hill

Montgomery participating in a 3 Minute Thesis Competition at a local retirement community.

DEPARTMENT OF CHEMISTRY UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL 125 South Rd. CB #3290 Chapel Hill, NC 27599 chemistry@unc.edu 919-843-7100