Department of Chemistry

《Editor's Note: What does it take to make something work better? The answer may be to pare back what is unnecessary, rethink how existing parts are arranged, find another route around a constraint, or widen the frame of the problem itself. This month's UNIST research offers answers in many forms—from leaner AI systems and redesigned material structures to an unexpected route for electron transfer and a broader view of cancer drug resistance. Some of those answers run counter to what we might expect. 》 Less Can Be Enough “How much does AI really need?” AI has spent years scaling up. But recent UNIST research asks a different question—how much can be taken away while keeping what matters? At ACL 2026, researchers introduced GMoE, an architecture that shares experts across layers rather than repeatedly storing similar ones. It cut model parameters by about 63 percent, from 549 million to 204 million, while average accuracy remained virtually unchanged—39.51 percent, compared with 39.55 percent for the baseline. The next target was data. Presented at ICML 2026, CSOR removes redundant training images while preserving meaningful variation within each identity. Using roughly half the original dataset, models retained more than 95 percent of full-data performance in re-identification (ReID) tasks. A third study moved to hardware. An automated design framework for logic-in-memory (LiM) computing optimized the placement and routing of computing elements, cutting computation cycles by 19.6 percent under area constraints. ■ GMoE—Expert Sharing for Smaller AI Models (ACL 2026) ■ CSOR—Less Training Data for ReID AI (ICML 2026 ) ■ LiM—Smarter Chip Design (IEEE TCAD) Arrangement Matters “In materials, where can matter as much as what.” More iron, less corrosion. Iron (Fe) is one of magnesium's most damaging impurities, yet UNIST researchers produced a Mg alloy containing more than six times as much Fe as ultra-high-purity Mg—and it still corroded more slowly. Instead of removing the impurity, the team added scandium (Sc) to form core–shell particles that isolate Fe-rich regions from the surrounding Mg. The corrosion rate fell from 22.2 to 0.38 millimeters per year, nearly a 60-fold reduction. At the molecular scale, thermal annealing changed the packing of an organic semiconductor, more than tripling its absorption dissymmetry and even reversing its preferred handedness of circularly polarized light (CPL). The resulting near-infrared (NIR) photodetector achieved a dissymmetry factor of 0.1 at 850 nanometers. The scale shifts again in perovskite solar cells (PSCs). The same high-efficiency formulation crystallized differently depending on the buried interface beneath it. Tailoring the chloride chemistry to the inverted architecture produced a device with 26.3 percent efficiency and a fill factor (FF) of up to 86.8 percent. ■ Mg Alloy—Shielding Fe to Slow Corrosion (Science Advances) ■ NIR Photodetector—Turning Molecular Packing (Advanced Science) ■ PSCs—Why Architecture Changes Performance (Joule) Another Way Through “How spin opens a new route for electron transfer.” Conventional energetics suggested that electron transfer should be unfavorable. Yet in manganese (Mn)-doped quantum dots (QDs), spin-exchange interactions enabled transfer more than ten times faster than in undoped QDs. The mechanism could help capture energetic hot electrons before their excess energy dissipates—a longstanding challenge in photocatalysis and solar-energy conversion. ■ Hot Electrons—Spin-Enabled Transfer (Nature Communications) Beyond the Tumor “The cells helping cancer resist treatment.” Some of the cells helping breast cancer resist treatment are not part of the tumor at all. UNIST researchers found that nearby fat cells can become cancer-associated adipocytes, which release complement factor D and activate survival signaling in cancer cells. In mouse models, disrupting this TRAP1-driven communication improved the response to chemotherapy, pointing to surrounding adipocytes as potential therapeutic targets alongside the tumor itself. ■ Breast Cancer—How Nearby Fat Cells Drive Drug Resistance (STTT) Explore the latest issue and follow 『The UNIST Brief』 on LinkedIn to stay updated. Subscribe via LinkedIn

Abstract Spin-active dopants offer a powerful yet largely unexplored route for controlling interfacial redox chemistry in quantum-confined semiconductors. Here we show that manganese doping in cadmium selenide quantum dots enables an ultrafast spin-exchange-mediated electron-transfer pathway that allows methyl viologen reduction even when conventional band-edge energetics are unfavorable for charge transfer. Femtosecond transient absorption spectroscopy reveals that manganese dopants accelerate electron-transfer dynamics by more than an order of magnitude while opening a hot-exciton reduction channel in which a manganese ion captures a photoexcited exciton prior to phonon-assisted cooling. Subsequent spin-flip relaxation of the excited manganese ion drives charge separation and reduction of a molecular acceptor. This mechanism operates efficiently across resonant and off-resonant (energy-uphill and downhill) regimes, identifying spin-exchange coupling—rather than band alignment—as the dominant factor governing electron-transfer rates and efficiencies. These findings establish magnetic doping as a viable strategy for harvesting hot carriers and enabling energetically demanding photocatalytic transformations. For decades, researchers have understood electron transfer in photocalysis through one guiding principle. Electrons move most readily when the energy levels of a semiconductor and a reacting molecule are well matched. Researchers at UNIST and Los Alamos National Laboratory (LANL) have demonstrated that spin interactions can provide an alternative pathway, allowing electron transfer even when conventional energy-level alignment is unfavorable. Professor Ho Jin of the Department of Chemistry at UNIST, in collaboration with Dr. Victor I. Klimov of LANL, showed that manganese ions inside semiconductor quantum dots (QDs) create an ultrafast spin-exchange pathway that channels hot-electron energy into photoreduction reactions. The findings offer a new way to design photocatalysts that make better use of sunlight for hydrogen production and carbon dioxide conversion. QDs readily transfer photoexcited electrons to nearby molecules, making them attractive materials for photocatalysis. Their most energetic electrons, however, lose excess energy almost immediately, leaving little time for useful chemical reactions to occur. The team addressed this challenge by introducing magnetic manganese ions into cadmium selenide (CdSe) QDs. Before hot electrons could cool, the manganese ions captured their excess energy through ultrafast spin exchange. As the ions returned to their original spin state, that energy drove electrons into nearby molecules, triggering photoreduction reactions that would otherwise be difficult to achieve. Using femtosecond transient absorption spectroscopy, the researchers followed the electron transfer process in real time. Compared with undoped QDs, manganese-doped particles transferred electrons to methyl viologen more than ten times faster, demonstrating that spin exchange provides an efficient pathway for charge transfer. The team then asked whether the mechanism truly depended on hot-electron energy. When larger QDs were illuminated with higher-energy light, photoreduction readily occurred. Under lower-energy illumination, the reaction largely disappeared. Together, these experiments showed that manganese captures the excess energy of hot electrons before it is lost as heat. “We have traditionally thought of energy-level alignment as the deciding factor in electron transfer,” said Professor Jin. “Our results show that spin exchange can provide an alternative pathway, giving us a new way to harness the energy of hot electrons for photocatalysis.” Professor Ho Jin served as the first author of the study. Their findings were published in Nature Communications on June 26, 2026. Journal Reference Ho Jin, Valerio Pinchetti, Connor Orrison, et al., “Ultrafast photoreduction driven by interfacial spin exchange in manganese-doped quantum dots,” Nat. Commun., (2026).

Abstract Near-infrared (NIR) circularly polarized light (CPL) photodetection is of great importance due to its broad application potential in bioimaging, wearable healthcare, optical communication, and advanced optoelectronic systems. In this study, a supramolecular chirality evolution strategy in chiral low-bandgap fused-ring conjugated molecules (LFCs) is presented for high-performance NIR CPL photodetection using Schottky barrier vertical organic field-effect transistors (SB-VOFETs). Halogen substitution combined with thermal annealing drives inversion and amplification of supramolecular chirality in enantiopure LFC thin films. F-substituted LFCs exhibit progressive domain growth and hierarchical ordering with increasing annealing temperature, whereas Cl-substituted LFCs show limited structural evolution above 150°C. These distinct crystallization behaviors directly correlate with chiroptical responses, with F-substituted LFCs achieving a maximum absorption dissymmetry factor (|gabs|) of ∼0.1. When integrated into SB-VOFETs, the optimized chiral films enable highly efficient NIR CPL photodetection, delivering a photocurrent dissymmetry factor (|gph|) of ∼0.1, a specific detectivity of 4.9 × 1011 Jones, an external quantum efficiency exceeding 900%, and a fast response time of ∼600 µs at 850 nm. These metrics represent the highest performance reported for NIR CPL. This study provides design guidelines for advancing high-performance chiral optoelectronic devices through the synergistic integration of atomic substitution, thermal annealing, and device architecture engineering. Near-infrared (NIR) circularly polarized light (CPL) carries information that conventional light cannot, making it valuable for applications ranging from autonomous vehicle sensors and bioimaging to optical security and advanced communications. Detecting this light accurately, however, has remained difficult because the organic semiconductor films used in these devices often lose the molecular order needed to distinguish different polarization states. A research team, led by Professor BongSoo Kim of the Department of Chemistry at UNIST and Professor Joon Hak Oh of Seoul National University has found a way to overcome that limitation. By controlling how chiral organic semiconductor molecules organize within thin films, the researchers significantly improved the films' ability to distinguish between left- and right-handed CPL. When incorporated into a photodetector, the optimized films delivered what the team reports as the highest performance yet achieved for NIR CPL detection. Unlike conventional light detectors, CPL can distinguish between two different polarization states of light. This additional information can reveal not only an object's shape but also properties, such as its surface composition or molecular structure, making the technology valuable for sensing and imaging applications. The researchers achieved the improvement by applying a simple thermal annealing process to thin films made from fluorine-substituted chiral organic semiconductor molecules. Rather than remaining randomly arranged, the molecules reorganized into larger, more ordered crystal domains. This more ordered molecular arrangement strengthened the film's interaction with CPL. As a result, the film's ability to selectively absorb CPL increased more than threefold after annealing at 250°C, with its absorption dissymmetry factor rising from approximately 0.03 to 0.1. Structural analysis confirmed that the annealed films adopted a highly ordered molecular arrangement closely resembling that of single crystals. The researchers also discovered an unexpected effect. As the molecular packing reorganized, the film reversed the polarization it preferentially absorbed, demonstrating that heat treatment could control not only the strength but also the handedness of the material's optical response. By comparison, similar films containing chlorine instead of fluorine showed little structural change above 150°C and exhibited lower polarization selectivity after annealing. To turn these improved optical properties into measurable electrical signals, the team integrated the optimized films into a vertical organic transistor. The device architecture efficiently collected and amplified charges generated by incoming light, allowing the detector to fully capitalize on the improved molecular organization. The resulting photodetector achieved a photocurrent dissymmetry factor of 0.1 at a wavelength of 850 nanometers, demonstrating excellent discrimination between left- and right-handed CPL. It also recorded a specific detectivity of 4.9 × 10¹¹ Jones, an external quantum efficiency of up to 909%, and a response time of less than 600 microseconds—the highest performance reported to date for NIR CPL detectors. “We found that simply controlling how the molecules organize within a thin film can dramatically improve how the materials respond to CPL,” the research team said. “We hope this strategy will help advance next-generation optical sensors and imaging technologies that rely on precise light detection.” Their findings were published online in Advanced Science on June 28, 2026. The research was supported by the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT (MSIT). Journal Reference Jaeyong Ahn, Kwangmin Kim, Sangwook Lee, et al ., “Thermally Driven Supramolecular Chirality Evolution in Low-Bandgap Fused-Ring Conjugated Molecules for High-Performance NIR Circularly Polarized Light Detection,” Adv. Sci., (2026).

Finding new materials has traditionally relied on years of experimental trials and errors. At Technische Universität Dresden (TU Dresden), Dr. Joohan Nam aims to accelerate that process by combining artificial intelligence (AI) with experimental chemistry. Awarded the prestigious Humboldt Research Fellowship from the Alexander von Humboldt Foundation, Dr. Nam will join the research group of Professor Stefan Kaskel at TU Dresden in September 2026. There, he will integrate AI into every stage of porous materials discovery—from molecular design and synthesis to experimental validation—creating a more efficient and systematic approach to identifying promising new materials. The Humboldt Research Fellowship is one of Germany's leading international programs for outstanding early-career researchers. It supports independent research at leading German institutions and recognizes academic excellence, originality, and the potential to establish an independent research career. Dr. Nam earned his Ph.D. in chemistry at UNIST under the supervision of Professor Wonyoung Choe and is currently a postdoctoral researcher in Professor Choe's group. His doctoral research focused on metal-organic frameworks (MOFs)—porous crystalline materials whose structures can be precisely engineered to control how they adsorb and separate molecules. His work established new design principles for controlling the dynamic behavior of MOFs, contributing to advances in hydrogen isotope separation. He has published 12 SCI(E)-indexed papers, including three first-author papers in Angewandte Chemie International Edition. His research has also been recognized with the 2025 S-Oil Outstanding Dissertation Award (2025), the 2025 Outstanding Dissertation Award from the Korean Chemical Society, and the 2025 Young Investigator Award from the Korean Synchrotron Users Association. His collaboration with Professor Kaskel began in 2025 through UNIST's Global Postdoctoral Short-Term Research Program, during which he conducted collaborative research at TU Dresden on MOF design, synthesis, and adsorption-property evaluation. Building on that collaboration, Dr. Nam will further integrate AI with experimental chemistry, enabling computational predictions to be rapidly tested and refined through laboratory experiments. With Dr. Nam's selection, Professor Wonyoung Choe's group has now seen two researchers receive Humboldt Research Fellowships this year, following Dr. Jiyeon Kim's selection earlier this year. "Dr. Nam has built a strong foundation in understanding the structural dynamics of MOFs and translating those insights into functional materials," said Professor Choe. "This fellowship recognizes both his research achievements and his vision of expanding materials discovery through AI. We look forward to seeing him develop new methodologies that bridge chemistry experimental and digital technologies in porous materials research." “This fellowship is especially meaningful because it recognizes the research direction I developed at UNIST,” said Dr. Nam. "By integrating AI-driven predictions with experimental validation, I hope to make the discovery of new materials faster, more systematic, and more precise." He also thanked Professor Choe and Professor Kaskel for their mentorship and support, adding that he hopes to strengthen international collaboration and establish an independent research program through his work in Germany.

UNIST has secured five projects under the national 2026 Basic Research Laboratory (BRL) Project , earning KRW 7.5 billion in government funding over the next three years. The projects span life sciences, physics, materials science, and biomedical engineering, bringing together interdisciplinary teams to address fundamental scientific challenges. Administered by the Ministry of Science and ICT (MSIT), the BRL Program supports collaborative basic research that benefits from the combined expertise of multiple investigators. Each selected project will receive KRW 1.5 billion over three years. Three of the five newly funded projects are led by faculty in the Department of Biological Sciences—an exceptional outcome for a single department. Professor Byoung Heon Kang will lead a project investigating how mitochondrial reprogramming within the tumor microenvironment drives cancer progression and therapeutic resistance. Joining the project are Professors Sebyung Kang, Young Chan Chae, and Sung-Min Hwang from the Department of Biological Sciences, whose expertise spans cancer metabolism, cell signaling, and tumor biology. Professor Sung-ho Park will direct the Center for Tissue-Resident Macrophage Homeostasis, examining how tissue-resident macrophages maintain immune balance and how their functions become disrupted during infection and aging. Professors Sangjoon Lee and Jung-Seok Kim from the Department of Biological Sciences will participate as co-investigators. Professor Jayil Lee will lead a project exploring how the three-dimensional organization of chromatin regulates gene expression. The research will investigate how distant regulatory elements interact with target genes to control transcription, integrating expertise in genome architecture, molecular imaging, and chemical biology through collaborations with Professor Hajin Kim from the Department of Biomedical Engineering, Professor Duyoung Min from the Department of Chemistry, and Professor Inwha Baek of Kyung Hee University. Professor Chaenyung Cha will establish the In Situ Programmable Bioprinting Laboratory for Spinal Cord Regeneration, developing bioprinting technologies that precisely position biomaterials and signaling molecules according to the biological environment of injured spinal tissue. The project brings together Professors Jeong Beom Kim and Jinmyoung Joo from the Department of Biomedical Engineering, and Professor Seong Geun Yoon of Ulsan University Hospital, combining expertise in biomaterials, tissue engineering, and clinical medicine. Professor Jung-Woo Yoo will lead a multidisciplinary team investigating spin structures and spin dynamics in quantum materials. Working with Professors Ho-Seop Jin, Yoonseok Oh, and Seokhyung Lee from the Department of Physics, the researchers aim to establish a unified understanding of spatiotemporal spin correlations, providing a scientific foundation for future quantum devices and spintronic technologies. Together, the five projects reflect UNIST's interdisciplinary research model, bringing together scientists from multiple fields to tackle complex questions in fundamental science. “The selection of these five BRL projects reflects the strength of UNIST's basic research and its collaborative research environment,” said KwanMyung Kim, Dean for Research Affairs at UNIST. “We will continue to strengthen long-term fundamental research and interdisciplinary collaboration, expanding the scientific foundations for future advances in biotechnology, quantum science, and advanced materials.”

Abstract Direct photopatterning with photoactivated cross-linkers provides a powerful route to highly integrated, solution-processed electronics. We introduce Diazo-6Bx, a six-branched diazo-based cross-linker that combines high miscibility with organic semiconductors and efficient C–H insertion reactivity. Comparative studies with azide-functionalized cross-linkers (phenyl- and tetrafluorophenyl-based structural analogues, namely, Ph-6Bx and 6Bx, respectively) reveal that the fluorine-free structure of Diazo-6Bx and its superior compatibility with host materials enable highly uniform cross-linking. This results in high-fidelity photopatterning with steep taper angles, excellent pattern retention, and minimal line-width variation. In solution-processed organic thin-film transistors (OTFTs), Diazo-6Bx enables the fabrication of unit devices that outperform those based on 6Bx, as well as large-area, high-resolution transistor arrays and logic circuits with excellent operational stability and scalability. These results demonstrate that a careful cross-linker design will play a crucial role in patterning next-generation electronic materials in extremely high fidelity. Printing electronic circuits from solution offers a promising route to lightweight, flexible electronics, but producing fine circuit patterns without sacrificing device performance remains a persistent manufacturing challenge. Professor BongSoo Kim and his research team in the Department of Chemistry at UNIST, working with collaborators at Yonsei University, have developed a new photo-crosslinker that enables more precise patterning of organic semiconductor circuits while improving the stability of the resulting devices. The material, Diazo-6Bx, was designed to blend more uniformly with hydrocarbon-based organic semiconductors than existing photo-crosslinkers. During ultraviolet patterning, it forms cross-linked networks that preserve circuit geometry, producing cleaner edges and more consistent feature sizes. In photopatterning experiments, Diazo-6Bx reduced line-width variation from 10.3 μm to 2.5 μm—roughly one quarter that of a widely used conventional photo-crosslinker. Circuit edges also became significantly sharper, with taper angles increasing from 67.9° to 87°, approaching nearly vertical sidewalls. The improved material compatibility also reduced charge-trapping defects, resulting in more stable transistor performance during prolonged operation. Organic thin-film transistors fabricated using Diazo-6Bx maintained more stable electrical characteristics under prolonged operation than devices produced with conventional crosslinking materials. The researchers also demonstrated that both p-type and n-type organic semiconductors could be patterned sequentially using the same solvent process. Using the same process, the researchers fabricated an 84-transistor organic thin-film transistor (OTFT) array together with complementary NOT, NAND, and NOR logic gates, demonstrating the scalability of the approach for complex organic electronic circuits. “This photo-crosslinker improves both patterning precision and device stability,” said Professor BongSoo Kim of the Department of Chemistry at UNIST. "Its compatibility with both p-type and n-type organic semiconductors simplifies solution processing and could help simplify manufacturing of large-area flexible displays and wearable electronic devices." The study was conducted in collaboration with Professor Jeong Ho Cho of Yonsei University. The findings were published in ACS Nano on June 23, 2026. The research was supported by the Samsung Future Technology Incubation Program and the National Research Foundation of Korea (NRF) through funding from the Ministry of Science and ICT (MSIT). Journal Reference Hyobin Ham, In Cheol Kwak, Daeyeon Lee, et al. , “Diazo-6Bx, a Six-Branched Diazo Cross-Linker, Enables High-Fidelity Patterning for Solution-Processed Electronics with Stable Operation,” ACS Nano, (2026).

Abstract Nickel-catalyzed hydrofunctionalization reactions, including the hydroboration of alkynes, have been generally proposed to proceed via classical two-electron pathways or, alternatively, through a NiIH-based insertion mechanism. Despite efforts to discern these pathways, explicit spectroscopic observation of NiIH species and relevant mechanistic information on LNiI(alkenyl) species remain lacking. Herein, we provide experimental evidence of formal NiI intermediates, suggestive of a NiIH-based insertion mechanism for alkyne hydroboration. The formation of a NiI catalyst precursor, LnNiI(dpm) (dpm = dipivaloylmethanate anion) and an LnNi(alkenyl) intermediate was confirmed by EPR spectroscopy and HRMS analysis. Their involvement in the catalytic reaction was demonstrated by stoichiometric and catalytic reactivity studies. The origin of the counterintuitive Markovnikov selectivity in the formation of the α-alkenylboronate product was probed by systematic ligand electronic effect studies. Computational analyzes rationalize the selectivity by a kinetic preference for formation of the α regioisomer of the LnNi(alkenyl) intermediate through noncovalent interactions. Researchers at UNIST have introduced a new chemical methodology that employs cost-effective nickel catalysts to achieve site-selective boron addition to alkynes. This breakthrough significantly broadens the repertoire of molecular modifications, with promising implications for pharmaceutical development and advanced material synthesis. Led by Professors Sung You Hong and Jan-Uwe Rohde from the Department of Chemistry, the team focused on terminal alkynes—molecules characterized by a triple bond at one end. Their innovative approach selectively activates and cleaves the triple bond, enabling boron atoms to be introduced internally, rather than at the terminal position. The resulting products can subsequently be transformed into a diverse array of functional compounds. The process involves the controlled cleavage of the alkyne's triple bond facilitated by nickel, which transiently binds to the substrate, directing boron attachment to the internal carbons. Once boron is installed, nickel is released, leaving a boron-containing moiety primed for further synthetic elaboration. This highly regioselective strategy broadens the scope for constructing complex molecular architectures with precision. Application of this methodology to the modification of various substrates—including derivatives of the anticancer agent bexarotene and analogs of pargyline—demonstrates its versatility and potential to streamline the synthesis of pharmaceutical compounds. By enabling targeted modifications, this technique could accelerate the development of new drug candidates and lead to more efficient drug synthesis pathways. Central to the mechanistic understanding of the reaction were the detection and characterization of fleeting nickel intermediates, achieved through electron paramagnetic resonance (EPR) spectroscopy and high-resolution mass spectrometry. Complementary computational studies elucidated the stabilizing noncovalent interactions underlying the reactions's regioselectivity, providing valuable insights into its driving forces. First authors Jeong Woo Lee, Gun Ha Kim, and Seo Yeong Jeong played key roles in the research. Professor Rohde remarked, "The products of a catalytic reaction rarely reveal the route it took. By catching these short-lived nickel intermediates, we could map the reaction pathway to the site where boron is added. This approach gives chemists a more rational basis for designing new catalysts." Professor Hong emphasized the broader significance, noting “The value of nickel here is not only that it is abundant and inexpensive. It lets us control a difficult reaction at a specific site, turning simple alkynes into building blocks that can be used to make medicines and organic materials.” The study was published in ACS Catalysis on April 17, 2026, and supported by the Basic Science Research Program and the ERC Project (Engineering Research Center for Microplastic through Bio/Chemical engineering Convergence Process) funded by the National Research Foundation of Korea (NRF). Journal Reference Jeong Woo Lee, Gun Ha Kim, Seo Yeong Jeong, et al ., "Spectroscopic Evidence of a Reduced Alkenylnickel Intermediate in Catalytic Markovnikov-Selective Alkyne Hydroboration," ACS Catal., 2026, 16, 7551-7561.

Abstract Iterative syntheses—repeating sequences of the same reactions to construct complex molecules—can facilitate the synthesis of specific classes of small molecules with structural redundancies, including acenes. Despite the prevalence of zigzag edges in the structures of acenes, few examples that effectively manipulate the edge configurations of acenes exist. In this study, the rationally designed iterative synthesis of three pentacene derivatives with continuous boron–oxygen bonds at the zigzag edges is reported. The simple and efficient two-step iteration employed ipso iodination with a trimethylsilyl group as the directing group and Suzuki cross-coupling/condensation reactions. Because of the fundamental role of pentacene derivatives in a broad spectrum of electronic applications, these findings are valuable across a diverse range of chemical and physical disciplines. Researchers at UNIST have introduced a new, efficient way to alter the backbone of organic semiconductors, giving researchers finer control over the molecules used in flexible displays, sensors, solar cells, and other electronic devices. Led by Professors Young S. Park and Seung Kyu Min from the Department of Chemistry, the team created an iterative synthesis method that places boron–oxygen bonds along the edge of pentacene, a well-known organic semiconductor made of five fused benzene rings. Organic semiconductors are valued because they are light, flexible, and chemically tunable. Small changes in a molecule's length, shape, or atomic makeup can shift how it absorbs light, emits light, or transports charge. But chemists have usually tuned these materials by attaching groups to the outside of the molecule. Changing the carbon framework itself has remained much harder. The new method works inside that framework. It inserts oxygen and boron atoms into the pentacene backbone, reshaping the molecule rather than simply decorating its edges. Dr. Sunghwa Jung, the study's first author, said the process relies on a repeated two-step cycle. “Each cycle begins with iodination at a specific site, followed by ring closure using a boron reagent,” he said. “By repeating the sequence, we can build pentacene structures with consecutive boron–oxygen bonds along the molecular edge.” By carefully controlling these cycles, the team synthesized three different pentacene derivatives, each with distinct boron–oxygen arrangements. The molecules absorbed and emitted light at different wavelengths, showing that their optical properties could be tuned through structure. All three also showed fluorescence quantum yields above 0.70, a sign of efficient light emission. The results point to possible uses in light-emitting organic semiconductors, fluorescent sensors, and optoelectronic materials that require bright, efficient emission. “This work gives us a stepwise way to build new acene molecules with consecutive boron–oxygen bonds,” Professor Park said. “Because the process can control both molecular length and arrangement, it expands the structures available for organic semiconductor design.” The study was published online in Angewandte Chemie International Edition on April 16, 2026. It was supported by funding from the National Research Foundation of Korea (NRF) and the Ministry of Trade, Industry and Energy (MOTIE). Journal Reference Seonghwa Jeong, Si-In Kim, Jonghwan Lee, et al., “Iterative Synthesis of Pentacene Derivatives with Continuous Boron–Oxygen Bonds,” Angew. Chem. Int. Ed. , (2026).

Abstract The formation of multiple and remote C–C bonds remains highly challenging owing to difficulties in reactivity and selectivity control. Herein, we report a nickel-catalyzed twofold conjunctive cross-electrophile coupling that employs an alkene and a 1,3-enyne as conjunctive platforms and alkyl and aryl halides as coupling partners. Through a philicity-alternating radical relay followed by selective radical capture, the reaction enables the formation of three or more C–C bonds. Combined experimental and theoretical investigations provide a rationale for the sequential radical additions to the π systems and the selective capture of a radical intermediate by the nickel catalyst. Furthermore, a five-component coupling showcases the sequential and controlled addition of alkyl and aryl moieties across three conjunctive units, demonstrating the synthetic versatility of the twofold conjunctive coupling. A joint research team from UNIST and DGIST has developed a new chemical synthesis method that links four different compounds together in a single reaction step, offering a faster and more controllable route to building complex molecules vital for pharmaceuticals and advanced materials. The study, led by Professors Sung You Hong and Jan-Uwe Rohde from the Department of Chemistry, in collaboration with Professors Sangwon Seo and Byunghyuck Jung from DGIST, introduces the first nickel-catalyzed twofold conjunctive cross-electrophile coupling system capable of connecting four distinct chemical building blocks through one controlled reaction sequence. Modern chemical synthesis typically excels at connecting two or three molecular components at a time. Extending those reactions to four or more components has remained difficult because reactive intermediates tend to generate unwanted byproducts or trigger uncontrolled polymerization. The research team addressed this challenge through a carefully engineered radical relay mechanism. In the reaction, highly reactive radical intermediates alternately shift between electrophilic and nucleophilic states, guiding molecules to connect in a precise order and at defined positions. The process functions much like a relay race, with each reaction intermediate triggering the next step in sequence. Nickel catalysts play a central role by generating the initial radical species and selectively capturing intermediates at the final stage, preventing side reactions and maintaining control throughout the synthesis. The method enables sequential coupling among alkyl halides, alkenes, 1,3-enynes, and aryl halides to form multiple carbon-carbon bonds in a single operation. Under modified reaction conditions, the system can even be extended to five-component coupling reactions. The study was co-authored by Ji Hwan Jeon and Da Hye Kim of UNIST as first authors. Beyond the technical advance itself, the researchers say the work opens a new middle ground between traditional small-molecule synthesis used in pharmaceuticals and polymer synthesis used in plastics and materials manufacturing. “This study presents a new strategy for connecting multiple molecular components sequentially within a single reaction system,” the research team explained. “It offers a conceptual bridge between precision organic synthesis and macromolecular chemistry.” Professor Hong said the approach could become a foundational technology for designing complex organic molecules and next-generation functional materials. “The method provides a versatile platform for constructing sophisticated molecular architectures with greater efficiency and control,” he said. The findings of this research were published in Advanced Science on April 9, 2026. The study has been supported by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF) through the ERC program (Engineering Research Center for Microplastic through Bio/Chemical engineering Convergence Process). Journal Reference Ji Hwan Jeon, Da Hye Kim, Gun Ha Kim, et al ., “Nickel-Catalyzed Twofold Conjunctive Coupling via Philicity-Alternating Radical Relay,” (2026).

Jiyeon Kim, who earned her Combined MS-Ph.D. degree in chemistry at UNIST under the supervision of Professor Wonyoung Choe, has been awarded the prestigious Humboldt Research Fellowship from the Alexander von Humboldt Foundation. Dr. Kim is currently a postdoctoral researcher in the group of Professor Bettina Lotsch at the Max Planck Institute for Solid State Research (MPI-FKF). Beginning next year, she will continue her independent work at the institute through the fellowship, one of Germany's most internationally respected programs supporting outstanding early-career researchers. The Humboldt Research Fellowship supports exceptional scholars from around the world in conducting independent research at leading German institutions. Fellowship recipients join the global “Humboldtian” academic network, which includes more than 30,000 researchers and numerous Nobel laureates, including Omar Yaghi and Susumu Kitagawa. Dr. Kim entered UNIST in 2013, majoring in chemistry and energy engineering, and completed her doctoral studies in 2024. During her graduate studies, she was selected for Korea's Global Ph.D. Fellowship program and received the Yebong Best Dissertation Award , one of UNIST's highest honors for doctoral research. This fellowship follows another major international recognition earlier this year, when Dr. Kim was selected for the Elisabeth Bauser Fellowship at MPI-FKF. Named after the institute's first female tenured scientist, the fellowship recognizes promising early-career women researchers demonstrating exceptional academic achievement and leadership potential. Her work focuses on advanced materials design and catalyst systems for sustainable energy and carbon-neutral technologies. She has drawn attention for bridging fundamental materials chemistry with catalytic applications, particularly through innovative design strategies involving metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). Dr. Kim also contributed to the development of the “Up-Down Approach,” a materials design strategy featured in Nature's Nobel Prize in Chemistry collection. Her research further explores quasiperiodic moiré phenomena and crystallographic materials systems, connecting inorganic chemistry, structural science, and catalytic reaction control. At MPI-FKF, she is extending these approaches toward controlling chemical reactions within porous COF architectures. By engineering nanoscale reaction environments, the research aims to advance next-generation catalyst platforms for carbon dioxide reduction and sustainable energy production. “It is a tremendous honor to pursue independent research in an environment that strongly values scientific autonomy,” Dr. Kim said. “The materials design experience I gained at UNIST has become an important foundation for my current work at the Max Planck Institute.” She also expressed gratitude to Professor Wonyoung Choe and her collaborators in Korea and Germany for their continued mentorship and support, adding that she hopes to further strengthen academic exchange and collaborative research between the two countries through the fellowship. Dr. Kim previously received the Rising Star Award from the International Union of Crystallography at the Asian Crystallographic Association Conference 2024 in recognition of her contributions to innovative materials design strategies in crystallography and framework chemistry.