C&EN’s Year in Chemistry 2022

Credit: Oak Ridge Leadership Computing Facility at ORNL

The Frontier supercomputer at Oak Ridge National Laboratory is the first of a new generation of machines that will help chemists take on molecular simulations that are more complex than ever before.

Scientists made big discoveries with supersized tools in 2022. Building on the recent trend of chemically competent artificial intelligence, researchers made great strides, teaching computers to predict protein structures on an unprecedented scale. In July, Alphabet-owned company DeepMind published a database containing the structures of almost all known proteins—​200 million-plus individual proteins from over 100 million species—as predicted by the machine learning algorithm AlphaFold. Then, in November, the tech company Meta demonstrated its progress in protein prediction technology with an AI algorithm called ESMFold. In a preprint study that has not yet been peer-reviewed, Meta researchers reported that their new algorithm is not as accurate as AlphaFold but is quicker. The increased speed meant that the researchers could predict 600 million structures in just 2 weeks (bioRxiv 2022, DOI: 10.1101/2022.07.20.500902).

Biologists at the University of Washington (UW) School of Medicine are helping expand computers’ biochemical capabilities beyond nature’s template by teaching machines to propose bespoke proteins from scratch. UW’s David Baker and his team created a new AI tool that can design proteins by either iteratively improving on simple prompts or by filling in the gaps between selected parts of an existing structure (Science 2022, DOI: 10.1126/science.abn2100). The team also debuted a new program, ProteinMPNN, that can start from designed 3D shapes and assemblies of multiple protein subunits and then determine the amino acid sequences needed to make them efficiently (Science 2022, DOI: 10.1126/science.add2187; 10.1126/science.add1964). These biochemically savvy algorithms could aid scientists in building blueprints for artificial proteins that could be used in new biomaterials and pharmaceuticals.

Credit: Ian C. Haydon/UW Institute for Protein Design

Machine learning algorithyms are helping scientists dream up new proteins with specific functions in mind.

As computational chemists’ ambitions grow, so do the computers used to simulate the molecular world. At Oak Ridge National Laboratory (ORNL), chemists got a first glimpse at one of the most powerful supercomputers ever built. ORNL’s exascale supercomputer, Frontier, is among the first machines to calculate more than 1 quintillion floating operations per second, a unit of computational arithmetic. That computing speed is about three times as fast as the reigning champion, the supercomputer Fugaku in Japan. In the next year, two more national laboratories plan to debut exascale computers in the US. The outsize computer power of these state-of-the-art machines will allow chemists to simulate even bigger molecular systems and on longer timescales. The data collected from those models could help researchers push the boundaries of what’s possible in chemistry by narrowing the gap between the reactions in a flask and the virtual simulations used to model them. “We’re at a point where we can start really asking questions about what is it that’s missing from our theoretical methods or models that would get us closer to what an experiment is telling us is real,” Theresa Windus, a computational chemist at Iowa State University and project lead with the Exascale Computing Project, told C&EN in September. Simulations run on exascale computers could help chemists invent novel fuel sources and design new climate-resilient materials.

Across the country, in Menlo Park, California, the SLAC National Accelerator Laboratory is installing supercool upgrades to the Linac Coherent Light Source (LCLS) that could allow chemists to peer deeper into the ultrafast world of atoms and electrons. The facility is built on a 3 km linear accelerator, parts of which are cooled with liquid helium down to 2 K, to produce a type of superbright, superfast light source called an X-ray free-electron laser (XFEL). Chemists have used the instruments’ powerful pulses to make molecular movies that have enabled them to watch myriad processes, such as chemical bonds forming and photosynthetic enzymes going to work. “In a femtosecond flash, you can see atoms stand still, single atomic bonds breaking,” Leora Dresselhaus-Marais, a materials scientist with joint appointments at Stanford University and SLAC, told C&EN in July. The upgrades to LCLS will also allow scientists to better tune the energies of X-rays when the new capabilities become available early next year.

Credit: SLAC National Accelerator Laboratory

SLAC National Accelerator Laboratory's X-ray laser is built on a 3 km linear accelerator in Menlo Park, California.

This year, scientists also saw just how powerful the long-awaited James Webb Space Telescope (JWST) could be for revealing the chemical complexity of our universe. NASA and its partners—the European Space Agency, the Canadian Space Agency, and the Space Telescope Science Institute—have already released dozens of images, from dazzling portraits of stellar nebulae to the elemental fingerprints of ancient galaxies. The $10 billion infrared telescope is decked out with suites of scientific instruments designed to explore the deep history of our universe. Decades in the making, the JWST has already outperformed the expectations of its engineers by snapping an image of a whirling galaxy as it appeared 4.6 billion years ago, complete with spectroscopic signatures of oxygen, neon, and other atoms. Scientists also measured signatures of steamy clouds and haze on an ­exoplanet, providing data that could help astrobiologists search for potentially habitable worlds beyond Earth.

Credit: Shutterstock

Precipitation around the world contains levels of perfluorooctanoic acid higher than the US Environmental Protection Agency recommends for drinking water.

In August, chemists announced that they could do what has long seemed impossible: break down some of the most durable persistent organic pollutants under mild conditions. Per- and polyfluoroalkyl substances (PFAS), often called forever chemicals, are accumulating in the environment and our bodies at an alarming rate. Their durability, rooted in the hard-to-break carbon-fluorine bond, makes PFAS particularly useful as waterproof and nonstick coatings and firefighting foams, but it means the chemicals persist for centuries. Some members of this large class of compounds are known to be toxic.

The team, led by Northwestern University chemist William Dichtel and then–graduate student Brittany Trang, found a weakness in perfluoroalkyl carboxylic acids and the chemical GenX, which is part of another class of PFAS. Heating the compounds in a solvent clips off the chemicals’ carboxylic acid group; the addition of sodium hydroxide does the rest of the work, leaving behind fluoride ions and relatively benign organic molecules. This breaking of the extremely strong C–F bond can be accomplished at a mere 120 °C (Science 2022, DOI: 10.1126/science.abm8868). The scientists hope to test the method against other types of PFAS.

Before this work, the best strategies for remediating PFAS were to either sequester the compounds or break them down at extremely high temperatures using large amounts of energy—which may not even be totally effective, says Jennifer Faust, a chemist at the College of Wooster. “That’s why this low-temperature process is really promising,” she says.

This new breakdown method was especially welcome in the context of other 2022 findings about PFAS. In August, Stockholm University researchers led by Ian Cousins reported that rainwater around the world contains perfluorooctanoic acid (PFOA) levels that exceed the US Environmental Protection Agency’s advisory level for that chemical in drinking water (Environ. Sci. Technol. 2022, DOI: 10.1021/acs.est.2c02765). The study found high levels of other PFAS in rainwater as well.

“PFOA and PFOS [perfluorooctanesulfonic acid] have been out of production for decades, so it goes to show how persistent they are,” Faust says. “I didn’t think there would be this much.” Cousins’s work, she says, “is really the tip of the iceberg.” Faust has found newer types of PFAS—ones that are not routinely monitored by the EPA—in US rainwater at higher concentrations than these legacy compounds (Environ. Sci.: Processes Impacts 2022, DOI: 10.1039/d2em00349j).

The more scientists look, the more PFAS they seem to find. But what does it all mean? “We’re starting to get a decent amount of evidence that PFAS play a role in metabolic diseases,” says Jesse Goodrich, an environmental health scientist at the University of Southern California. He’s part of a team at USC that found that higher levels of PFAS in people’s blood correlate with greater risk for both nonalcoholic fatty liver disease and the most common form of liver cancer.

Most studies have focused on the health effects of legacy PFAS, like PFOA and PFOS. Researchers need more data about blood levels of the chemicals replacing legacy PFAS and their health effects, Goodrich says. He and his colleagues also want to understand the underlying mechanisms. “We need more research on why PFAS have these effects and what we can do about it,” he says. He notes that the EPA has proposed designating PFOA and PFOS as hazardous chemicals under the Superfund law, a move that would bring remediation efforts and research funding. The public comment period for the rule change ended in November. “I hope this will lead to new approaches to figuring out what we can do about this [PFAS] in the future,” he says.

Credit: Alex Aves/University of Canterbury

Microplastics (shown here under a microscope) in a variety of shapes and colors are transported via the atmosphere.

The year also brought research on another weird precipitation phenomenon: it’s raining plastic. Microplastic pollution has mostly been seen as an aquatic problem. But as researchers find more of this pollution in some of the planet’s most isolated places, including remote parts of national parks and both of Earth’s poles, it has become clear that plastic can also be transported in the atmosphere.

A February C&EN story explored research on atmospheric microplastics. Observations of this phenomenon were first published in the scientific literature in 2019, but it has probably been going on since the 1960s. Like PFAS, plastic persists in the environment for long periods. But plastics change as they age and move through the planet’s land, waterways, and atmosphere. Plastics break into micro- and nanoplastics, leach their additives, and absorb other organic molecules.

As with PFAS, scientists would like to know much more about what the health and environmental implications of this persistent pollution are—and how to solve the problem. Chemists wonder, for example, whether these tiny particles affect the upper atmosphere’s warming potential. But this field, too, needs more data. “Until we have a really good picture of the atmospheric distribution and burden of microplastics, it’s hard to inform risks to health, environment, and climate,” Laura Revell, an environmental physicist at the University of Canterbury, told C&EN in February.

Evolved enzymes built biaryl bonds

Chemists use biaryl molecules, which feature aryl groups tethered to one another by a single bond, as chiral ligands, materials building blocks, and pharmaceuticals. But making the biaryl motif with metal-catalyzed reactions, such as Suzuki and Negishi cross-couplings, typically requires several synthetic steps to make the coupling partners. What’s more, these metal-catalyzed reactions falter when making bulky biaryls. Inspired by enzymes’ ability to catalyze reactions, a team led by the University of Michigan’s Alison R. H. Narayan used directed evolution to create a cytochrome P450 enzyme that builds a biaryl molecule via oxidative coupling of aromatic carbon-hydrogen bonds. The enzyme weds aromatic molecules to create one stereoisomer around a bond with hindered rotation (shown). The researchers think this biocatalytic approach could become a bread-and-butter transformation for making biaryl bonds (Nature 2022, DOI: 10.1038/s41586-021-04365-7).

Recipe for tertiary amines relied on a little salt

Mixing electron-hungry metal catalysts with electron-rich amines typically kills the catalysts, so metal reagents can’t be used to build tertiary amines from secondary amines. M. Christina White and colleagues at the University of Illinois Urbana-Champaign realized they could get around this problem if they added some salty seasoning to their reactant recipe. By transforming secondary amines into ammonium salts, the chemists found they could react these compounds with terminal olefins, an oxidant, and a palladium sulfoxide catalyst to create myriad tertiary amines with a variety of functional groups (example shown). The chemists used the reaction to make the antipsychotic drugs Abilify and Semap and to transform existing drugs that are secondary amines, such as the antidepressant Prozac, into tertiary amines, demonstrating how chemists might make new drugs out of existing ones (Science 2022, DOI: 10.1126/science.abn8382).

Azaarenes underwent carbon contraction

This year chemists added to the repertoire of molecular editing, which are reactions that make changes to the cores of complex molecules. In one example, researchers developed a transformation that uses light and acid to clip a single carbon out of six-membered azaarenes in quinoline N-oxides to form N-acylindoles with five-membered rings (example shown). The reaction, developed by chemists in Mark D. Levin’s group at the University of Chicago, is based on a reaction that involved a mercury lamp, which put out multiple wavelengths of light. Levin and colleagues found that using a light-emitting diode that emits light at 390 nm gave them better control and allowed them to make the reaction general for quinoline N-oxides. The new reaction gives molecule makers a way to remodel the cores of complex compounds and could help medicinal chemists looking to expand their libraries of drug candidates (Science 2022, DOI: 10.1126/science.abo4282).

Megamagnets made from lanthanides

Credit: Nature

Unpaired electrons in the dysprosium ions of this complex make it highly magnetic (Dy = cyan, I = purple, C = gray).

Lanthanides paired up to form the most magnetic molecule ever made (Science 2022, DOI: 10.1126/science.abl5470). Hulking aromatic ligands sandwich the ion pair, either terbium or dysprosium, with three iodide anions sitting between them. The lanthanides share a single electron in a bonding orbital. This aligns unpaired electrons on both ions, which gives the compounds their massive magnetism at low temperatures.

Say hi to this strange 2D electride

Credit: Scott Warren/University of North Carolina at Chapel Hill

Scandium carbide is a 2D semiconducting electride.

Two-dimensional electrides, a group of materials known for planes of delocalized electrons and high conductivity, welcomed an unexpected member into their weird little family in 2022. While electrides are usually metallic, this new one is not: it’s a semiconductor. This 2D electride is made from scandium carbide (Sc₂C) and aluminum carbide (Al₂C) (J. Am. Chem. Soc. 2022, DOI: 10.1021/jacs.2c03024). Researchers think this addition suggests that the class of inorganic materials may have more tricks up its sleeve.

Breaking all the rules

This year, chemists invented a rebellious organic light-emitting diode (OLED) that fluoresces blue by chucking a quantum principle out the window (Nature 2022, DOI: 10.1038/s41586-022-05132-y). The group used computational simulations to find heptazine molecules with higher energies in the excited triplet state than in the singlet state, which defies Hund’s rule. The researchers synthesized HzTFEX₂ and used the compound to make an unusually efficient blue-light OLED.

Tied up with a bow

Credit: Zoe Ashbridge/University of Manchester

This schematic shows the topology of the trefoil-of-trefoils triskelion molecular knot. Purple spheres show the positions of metal ions used to template the assembly.

Chemists tied a molecular knot with a record-breaking 12 crossings this year. David A. Leigh’s trefoil of trefoils is a three-way crossing of three-way crossings and contains a dizzying 378 atoms (Science 2022, DOI: 10.1126/science.abm9247). The behemoth molecule is made of one continuous strand that took 3 years to complete. The researchers had to spend time purifying the compound and proving that its complicated structure is what they intended to make.

Supersize me

Credit: Angew. Chem., Int. Ed.

The largest of the new cavitands has an acridane[4]arene base and triptycene-quinoxaline walls and can bind a bulky C₇₀ molecule. Alkyl groups on the base are not shown.

Open wide! In 2022, chemists created the largest cavitand to date (Angew. Chem., Int. Ed. 2022, DOI: 10.1002/anie.202209885). Scientists make these types of hollow molecular containers with an opening on one side to scoop up other molecules for applications such as sensing, environmental clean-up, or catalysis. The acridane[4]arenes have an internal volume of 814 ų, twice the size of the previous huge cavitand.

A cube catches an electron

Perfluorocubane is a quirky little molecule. This year, chemists synthesized the never-before-seen C₈F₈ compound, made up of a cube of carbon atoms with fluorine atoms attached to each of its eight vertices (Science 2022, DOI: 10.1126/science.abq0516). The molecule’s C–F antibonding orbitals can trap an electron inside the cube, creating a short-lived radical anion.

Pepto-Bismol mystery

Credit: Nat. Commun.

Bismuth subsalicylate's structure (Bi = pink; O = red; C = gray)

This year, a team of researchers from Stockholm University cracked a century-old mystery: the structure of bismuth subsalicylate, the active ingredient in Pepto-Bismol (Nat. Commun. 2022, DOI: 10.1038/s41467-022-29566-0). Using electron diffraction, the researchers found that the compound is arranged in rodlike layers. Along the center of each rod, oxygen anions alternate between bridging three and four bismuth cations. The salicylate anions, meanwhile, coordinate to bismuth through either their carboxylic or phenolic groups. Using electron microscopy techniques, the researchers also discovered variations in the layer stacking. They believe this disordered arrangement might explain why bismuth subsalicylate’s structure has managed to evade scientists for so long.

Blood pressure tattoos

Credit: Courtesy of Roozbeh Jafari

Graphene sensors adhered to the forearm can provide continuous blood pressure measurements.

For over 100 years, monitoring your blood pressure has meant having your arm squeezed with an inflatable cuff. One downside of this method, however, is that each measurement represents only a small snapshot of a person’s cardiovascular health. But in 2022, scientists created a temporary graphene “tattoo” that can continuously monitor blood pressure for several hours at a time (Nat. Nanotechnol. 2022, DOI: 10.1038/​s41565-022-01145-w). The carbon-based sensor array operates by sending small electrical currents into the wearer’s forearm and monitoring how the voltage changes as the current moves through the body’s tissues. This value correlates with changes in blood volume, which a computer algorithm can translate into systolic and diastolic blood pressure measurements. According to one of the study’s authors, Roozbeh Jafari of Texas A&M University, the device would offer doctors an unobtrusive way to monitor a patient’s heart health over extended periods. It could also help medical professionals filter out extraneous factors that impact blood pressure—like a stressful visit to the doctor.

Human-generated radicals

Credit: Mikal Schlosser/TU Denmark

Four voluneers sat in a climate-controlled chamber so researchers could study how humans affect indoor air quality.

Scientists know that cleaning products, paint, and air fresheners all affect indoor air quality. Researchers discovered this year that humans can, too. By placing four volunteers inside a climate-controlled chamber, a team discovered that natural oils on people’s skin can react with ozone in the air to produce hydroxyl (OH) radicals (Science 2022, DOI: 10.1126/science.abn0340). Once formed, these highly reactive radicals can oxidize airborne compounds and produce potentially harmful molecules. The skin oil that participates in these reactions is squalene, which reacts with ozone to form 6-methyl-5-hepten-2-one (6-MHO). Ozone then reacts with 6-MHO to form OH. The researchers plan to build upon this work by investigating how levels of these human-​generated hydroxyl radicals might vary under different environmental conditions. In the meantime, they hope these findings will make scientists rethink how they assess indoor chemistry, since humans are not often seen as sources of emissions.

Frog-safe science

Credit: Livia Eberlin

A mass spectrometry pen can sample the skin of poison frogs without harming the animals.

To study the chemicals that poison frogs excrete to defend themselves, researchers need to take skin samples from the animals. But existing sampling techniques often harm these delicate amphibians or even require euthanasia. In 2022, scientists developed a more humane method to sample the frogs using a device called the MasSpec Pen, which uses a pen-like sampler to pick up alkaloids present on the back of the animals (ACS Meas. Sci. Au 2022, DOI: 10.1021/​acsmeasuresciau.2c00035). The device was created by Livia Eberlin, an analytical chemist at the University of Texas at Austin. It was originally meant to help surgeons differentiate between healthy and cancerous tissues in the human body, but Eberlin realized the instrument could be used to study frogs after she met Lauren O’Connell, a biologist at Stanford University who studies how frogs metabolize and sequester alkaloids.

Electrodes fit for an octopus

Credit: Science/Zhenan Bao

A stretchy, conductive electrode can measure the electrical activity of an octopus's muscles.

Designing bioelectronics can be a lesson in compromise. Flexible polymers often become rigid as their electrical properties improve. But a team of researchers led by Stanford University’s Zhenan Bao came up with an electrode that is both stretchy and conductive, combining the best of both worlds. The pièce de résistance of the electrode is its interlocking sections—each section is optimized to be either conductive or malleable so as not to counteract the properties of the other. To demonstrate its abilities, Bao used the electrode to stimulate neurons in the brain stem of mice and measure the electrical activity of an octopus’s muscles. She showcased the results of both tests at the American Chemical Society’s Fall 2022 meeting.

Bulletproof wood

Credit: ACS Nano

This wooden armor can repel bullets with minimal damage.

This year, a team of researchers led by Huazhong University of Science and Technology’s Huiqiao Li created a wood armor strong enough to deflect a bullet shot from a 9 mm revolver (ACS Nano 2022, DOI: 10.1021/acsnano.1c10725). The wood’s strength comes from its alternating sheets of lignocellulose and a cross-linked siloxane polymer. The lignocellulose resists fracturing thanks to its secondary hydrogen bonds, which can re-form when broken. Meanwhile, the pliable polymer becomes sturdier when hit. To create the material, Li drew inspiration from pirarucu, a South American fish with skin tough enough to withstand a piranha’s razor-sharp teeth. Because the wooden armor is lighter than other impact-resistant materials, such as steel, the researchers believe the wood could have military and aviation applications.

• 77 mA h/g

  The charge capacity of a 3D-printed lithium-ion battery electrode, which is over three times as high as that of a conventionally made electrode. The 3D-printing technique aligns graphite nanoflakes in the material to optimize the flow of lithium ions in and out of the electrode (research reported at the ACS Spring 2022 meeting).

  

  Credit: Soyeon Park

  A 3D-printed battery anode

• 38-fold

  Increase in activity of a new engineered enzyme that degrades polyethylene terephthalate (PET) compared with previous PETases. The enzyme broke down 51 different PET samples over time frames ranging from hours to weeks (Nature 2022, DOI: 10.1038/s41586-022-04599-z).

• 
  Credit: Hal Alper
  A PETase breaks down a plastic cookie container.

• 24.4%

  Efficiency of a perovskite solar cell reported in 2022, setting a record for flexible thin-film photovoltaics. The tandem cell’s efficiency at turning sunlight into electricity beats the previous record holder by 3 percentage points and can withstand 10,000 bends with no loss in performance (Nat. Energy 2022, DOI: 10.1038/s41560-022-01045-2).

• 100 times

  The rate that an electrodialysis device traps carbon dioxide compared with current carbon-capture systems. Researchers calculated that a large-scale system that could trap 1,000 metric tons of CO₂ per hour would cost $145 per metric ton, below the Department of Energy’s cost target of $200 per metric ton for carbon-removal technologies (Energy Environ. Sci. 2022, DOI: 10.1039/d1ee03018c).


Credit: Meenesh Singh
An electrodialysis device for carbon capture
• 
  Credit: Science
  A membrane separates hydrocarbon molecules from light crude oil.

• 80-95%

  Percentage of gasoline-sized hydrocarbon molecules allowed through a polymer membrane. The membrane can withstand high temperatures and harsh conditions and could offer a less energy-intensive way to separate gasoline from light crude oil (Science 2022, DOI: 10.1126/science.abm7686).

• 3.8 billion

  Number of years ago that Earth’s plate tectonic activity most likely began, according to an isotopic analysis of zircon crystals that formed at that time. The crystals, collected from a sandstone bed in South Africa, show signatures resembling ones formed in subduction zones, whereas older crystals do not (AGU Adv. 2022, DOI: 10.1029/2021AV000520).


Credit: Nadja Drabon
Ancient zircon crystals
• 

• 40 years

  Time that elapsed between the synthesis of the perfluorinated Cp* ligand and the creation of its first coordination complex. All previous attempts to coordinate the ligand, [C₅(CF₃)₅]⁻, had failed because its CF₃ groups are so strongly electron withdrawing (Angew. Chem. Int. Ed. 2022, DOI: 10.1002/anie.202211147).

• 1,080

  Number of sugar moieties in the longest and largest polysaccharide synthesized to date. The record-breaking molecule was made by an automated solution-phase synthesizer (Nat. Synth. 2022, DOI: 10.1038/s44160-022-00171-9).

  
  Credit: Xin-Shan Ye
  Automated polysaccharide synthesizer

• 97.9%

  Percentage of sunlight reflected by an ultrawhite paint containing hexagonal boron nitride nanoplatelets. A 150 µm thick coat of the paint can cool a surface by 5–6 °C in direct sun and could help reduce the power needed to keep airplanes and cars cool (Cell Rep. Phys. Sci. 2022, DOI: 10.1016/j.xcrp.2022.101058).

• 
  Credit: Cell Rep. Phys. Sci.
  Hexagonal boron nitride nanoplatelets

• 90%

  Percentage decrease in SARS-CoV-2 infectivity within 20 min of the virus encountering indoor air. Researchers determined that the COVID-19 virus’s lifespan is greatly affected by changes in relative humidity (Proc. Natl. Acad. Sci. U.S.A. 2022, DOI: 10.1073/pnas.2200109119).

  
  Credit: Courtesy of Henry P. Oswin
  Two aerosol droplets at different humidities

Credit: Will Ludwig/C&EN/Shutterstock

Maher El-Kady, chief technology officer, Nanotech Energy, and electrochemist, University of California, Los Angeles

Credit: Courtesy of Maher El-Kady

“In order to eliminate our dependence on fossil fuels and reduce our carbon emissions, the only real alternative is to electrify everything from homes to cars. In the last few years, we have experienced major breakthroughs in the development and manufacture of more powerful batteries that are expected to dramatically change the way we travel to work and visit friends and family. To ensure complete transition to electric power, further improvements in energy density, recharge time, safety, recycling, and cost per kilowatt hour are still required. One can expect battery research to grow further in 2023 with an increasing number of chemists and materials scientists working together to help put more electric cars on the road.”

Klaus Lackner, director, Center for Negative Carbon Emissions, Arizona State University

Credit: Arizona State University

“As of COP27, [the international environmental conference held in November in Egypt], the 1.5 °C climate target became elusive, emphasizing the need for carbon removal. Therefore, 2023 will see advances in direct-air-capture technologies. They provide a scalable approach to negative emissions, but are too expensive for carbon waste management. However, direct air capture can start small and grow in number rather than size. Just like solar panels, direct-air-capture devices could be mass-produced. Mass production has demonstrated cost reductions by orders of magnitude. 2023 may offer a glimpse at which of the proffered technologies can take advantage of the cost reductions inherent in mass manufacture.”

Ralph Marquardt, chief innovation officer, Evonik Industries

Credit: Evonik Industries

“Stopping climate change is a major task. It can only succeed if we use significantly fewer resources. A genuine circular economy is essential for this. The chemical industry’s contributions to this include innovative materials, new processes, and additives that help pave the way for recycling of products that have already been used. They make mechanical recycling more efficient and enable meaningful chemical recycling even beyond basic pyrolysis. Turning waste into valuable materials requires expertise from the chemical industry. In a real cycle, waste is recycled and becomes valuable raw materials for new products. However, we have to be fast; our innovations are needed now to enable the circular economy in the future.”

Sarah E. O’Connor, director, Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology

Credit: Sebastian Reuter

“ ‘-Omics’ techniques are used to discover the genes and enzymes that bacteria, fungi, plants, and other organisms use to synthesize complex natural products. These genes and enzymes can then be used, often in combination with chemical processes, to develop environmentally friendly biocatalytic production platforms for countless molecules. We can now do ‘-omics’ on a single cell. I predict that we will see how single-cell transcriptomics and genomics are revolutionizing the speed in which we find these genes and enzymes. Moreover, single-cell metabolomics is now possible, allowing us to measure the concentration of chemicals in individual cells, giving us a far more accurate picture of how the cell functions as a chemical factory.”

Richmond Sarpong, organic chemist, University of California, Berkeley

Credit: Niki Stefanelli

“A better understanding of the complexity of organic molecules, for example how to discern between structural complexity and ease of synthesis, will continue to emerge from advances in machine learning, which will also lead to acceleration in reaction optimization and prediction. These advances will feed novel ways to think about diversifying chemical space. One way to do this is through making changes to the periphery of molecules and another is to affect changes to the core of molecules by editing the skeletons of molecules. Because the cores of organic molecules consist of strong bonds like carbon-carbon, carbon-nitrogen, and carbon-oxygen bonds, I believe we will see a growth in the number of methods to functionalize these types of bonds, especially in unstrained systems. Advances in photoredox catalysis will also likely contribute to new directions in skeletal editing.”

Alison Wendlandt, organic chemist, Massachusetts Institute of Technology

Credit: Justin Knight

“In 2023, organic chemists will continue to push selectivity extremes. I anticipate further growth of editing methods offering atom-level precision as well as new tools for tailoring macromolecules. I continue to be inspired by the integration of once-adjacent technologies into the organic chemistry toolkit: biocatalytic, electrochemical, photochemical, and sophisticated data science tools are increasingly standard fare. I expect methods leveraging these tools will further blossom, bringing us chemistry we never imagined possible.”

Note: All responses were sent via email.