The enantioselective synthesis of topologically chiral mechanically interlocked molecules (MIMs) is challenging due to the need for simultaneous control over covalent and mechanical stereogenic elements. Herein, we report a cobalt/salicyloxazoline-catalyzed enantioselective C–H/N–H annulation of a rotaxane scaffold that simultaneously generates stereochemically rich [2]rotaxanes bearing both macrocyclic planar and mechanical planar chirality in up to 85% yield with excellent enantiocontrol (93%–99% enantiomeric excess [ee]). Crucially, the mechanical bond is shown to be essential as a stereochemical lock, arresting the racemization of the planar chiral macrocycle and enabling the stereochemical transfer from the catalyst to the interlocked system. Furthermore, we employed the second-generation crystalline sponge method to determine the absolute configuration of enantiopure rotaxanes and explored a rotaxane-in-cage topology. This work establishes a catalytic platform for the synthesis of complex chiral MIMs, bridging asymmetric C–H activation with the tailored design of supramolecular stereochemistry.
Despite significant interest in enzymatic plastic degradation, the performance of currently available enzymes remains limited under industrial conditions. Addressing this requires approaches that identify the molecular features controlling catalytic efficiency and guide targeted enzyme engineering. Here, we simulate and compare the catalytic activity of PETase and LCCICCG, two enzymes receiving considerable attention for degrading polyethylene terephthalate and related polyesters. PETase has a more accessible active site but moderate activity and thermal stability, while LCCICCG exhibits superior efficiency at higher temperatures but a less accessible active site. Using an efficient enhanced sampling method based on the committor function, combined with electronic and structural analysis, we characterize how both enzymes operate and identify the molecular reasons for their different efficiencies. We translate these insights into a rational double mutation (W159H and I208V) that enhances PETase activity, shifting its mechanism toward that of LCCICCG and potentially enabling efficient catalysis at lower temperatures.
In an interview with Chem, Jennifer Schomaker, the Edward and Nancy Fody Professor of Chemistry at the University of Wisconsin-Madison, talks about her favorite travel recommendations, the key ingredients to success as a researcher and mentor, and what she hopes the future holds for creating a more sustainable society.
Dr. Grace Han is an expert in renewable energy science and the design of light-responsive organic materials. In this interview with Chem, she discusses her path to synthetic materials chemistry, the development of solar-chargeable organic molecular fuels for clean and sustainable heating, the value of scientific history in driving innovation, and her experience with Chem.
At the University of Minnesota, Dr. Jihye Park runs a materials chemistry lab centered on metal-organic frameworks (MOFs) and the untapped potential of organic linker design. In this interview with Chem, she reflects on her journey into MOF chemistry, what she has learned about mentoring students, and the value of embracing unexpected outcomes in research.
In this interview with Chem, Prof. Guangbin Dong describes the non-scientific conversations he enjoys, offers advice to young scientists, and shares key aspects of his approach to mentorship. He also presents his perspective on exciting developments in synthetic chemistry, the impact of AI on scholarly publishing, and his overall experience with Chem.
Sunlight-driven photothermal water evaporation technology is currently reinventing the landscape of clean water and energy production. However, conventional photothermal evaporators primarily convert solar energy into latent heat for vapor generation, leaving the photochemical potential underutilized. This perspective introduces the concept of photothermal evaporation-coupled catalysis (PECC), in which the photothermal interface is augmented with catalytic functionality to achieve simultaneous sunlight-driven water purification and chemical upgrading. We first elucidate the physicochemical principles of energy partitioning for the synergy between solar water evaporation and catalysis and the materials chemistry principles for energy-efficient PECC design. Furthermore, we categorize the application scenarios of PECC based on interfacial reaction pathways, outline the unsystematized engineering principles of solar thermal management for PECC system integration, and finally propose the CLEAN paradigm to leverage the microscale principles of PECC and macroscale technoeconomic feasibility toward scalable, sustainable solar water-chemical factories.
Precise control over the reactive species generated in oxidant activation systems—specifically hydroxyl radicals (⋅OH), sulfate radicals (SO4⋅–), singlet oxygen (1O2), and high-valent metal-oxo (HVMO) species—is of paramount importance for advancing environmental remediation and selective oxidation. Single-atom catalysts (SACs) have emerged as a powerful and tunable platform to govern this process at the atomic scale. This review systematically elucidates the fundamental mechanisms governing reactive species generation at isolated metal sites, focusing on the key processes of oxidant adsorption, electron transfer, and intermediate transformation. We critically analyze how these elementary steps dictate selective production of target radical and non-radical reactive species and comprehensively discuss the state-of-the-art design strategies—including coordination engineering, defect modulation, and bimetallic site construction—that enable the rational manipulation of these pathways. Finally, we provide a forward-looking perspective on challenges and opportunities, guiding the development of next-generation SACs for sustainable oxidation processes.
Proton exchange membrane water electrolysis (PEMWE) has emerged as a promising platform for sustainable hydrogen production. However, its large-scale implementation is constrained by the high cost and inefficient utilization of iridium (Ir)-based oxygen evolution reaction (OER) catalysts. Beyond intrinsic catalytic activity, the performance of a practical membrane electrode assembly is governed by the interplay of multiple transport processes within the anode catalyst layer, including water delivery, oxygen removal, proton conduction, and electron transport. This review presents a transport-oriented framework for the rational design of OER catalyst layers in PEMWE. We first elucidate the fundamental transport mechanisms and their limitations during OER electrocatalysis, followed by recent advances in transport regulation through four key strategies: catalyst architecture, ionomer engineering, hierarchical pore design, and interface engineering. Finally, we summarize emerging design principles and outline future directions for developing ultralow-Ir, transport-efficient OER catalyst layers that enable scalable, durable, and economically viable PEMWE.
The design and synthesis of mechanically interlocked macromolecules with complex chemical topologies and precise composition remain challenging. Herein, we report the rational design and cellular synthesis of protein olympiadanes—[5]catenanes comprising five mechanically interlocked polypeptide macrocycles—via co-expression of multiple genes encoding orthogonal heterodimeric entangling motifs and split inteins. After optimizing the expression conditions and purifying the assemblies via affinity chromatography and size-exclusion chromatography (SEC), the resulting protein olympiadanes were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), liquid chromatography-mass spectrometry (LC-MS), and proteolytic digestion. Differential scanning calorimetry (DSC) revealed their high thermal stability, thus highlighting the potential of mechanical interlocking for protein engineering. This work not only showcases an elegant and robust method for constructing complex mechanically interlocked architectures but also spurs the imagination of leveraging protein topology in making macromolecular machinery, echoing the evolution of synthetic molecular machines.
Gabriela S. Schlau-Cohen, PhD, the Haslam-Dewey Professor of Chemistry at the Massachusetts Institute of Technology, was selected to participate in Chem’s 10th anniversary interview series because of her contributions to the journal in spectroscopy and photosynthetic light harvesting. In this Q&A, she discusses the teachers who inspired her, the importance of carving one’s own path, and the excitement of making unexpected discoveries.
Devleena Samanta is an assistant professor of chemistry at The University of Texas at Austin (UT Austin), an associate member of the UT Austin Cancer Research Institute, and a member of the Texas Materials Institute. She received her Ph.D. from Stanford University and completed postdoctoral training at Northwestern University. Her laboratory develops nanoscale tools to sense and program biomolecular function, with applications in diagnostics, therapeutics, and biocatalysis. She is a 2024 Packard Fellow for Science and Engineering and a 2026 Cottrell Scholar.
Stereogenic C(sp3)–C(sp3) bond formation through catalytic radical-radical cross-coupling (RRCC) reactions relies heavily on stereoconvergent coupling of two alkyl precursors facilitated by chiral ligands or auxiliaries. In Science, Baran and coworkers developed a stereoretentive RRCC that directly couples two distinct transient alkyl radicals, derived from enantioenriched sulfonylhydrazides and achiral alkyl halides, in the presence of an achiral ligand, which enables the coupling of two alkyl radicals together with precise stereochemical control.
In this interview with Chem, Junichiro Yamaguchi reflects on his unconventional journey to becoming an organic chemist, the mentors who inspired him, and the challenges he has faced throughout his career. He also discusses the importance of friendship and mentorship in science, his experiences with Chem, and his perspectives on research, education, community building, and sustaining a passion for science.
Yoonsu Park received his B.S. and Ph.D. degrees in chemistry from the Korea Advanced Institute of Science and Technology (KAIST), completing his doctoral studies under the supervision of Prof. Sukbok Chang. He then pursued postdoctoral research with Prof. Paul J. Chirik at Princeton University, where he investigated visible light-driven catalysis and metalloradical reactivity. In 2022, he returned to KAIST to begin his independent career as an assistant professor in the Department of Chemistry and was promoted to associate professor in 2025. His research group focuses on developing sustainable catalysis such as single-atom skeletal editing reactions.
Axially chiral skeletons provide a molecular foundation for constructing chiral environments in asymmetric catalysis by leveraging their rigid conformational architectures and tunable electronic properties. This perspective systematically elucidates the applications of such skeletons, from metal ligands to organocatalysts, through representative case studies. In metal catalysis, coordination with diverse metal centers enables efficient asymmetric induction. In organocatalysis, mechanisms such as hydrogen bonding and ion pairing allow direct substrate activation and stereochemical control. Notably, their applications in cooperative catalysis and photo-/electrocatalysis have led to breakthroughs in stereodiscrimination of highly reactive intermediates, expanding the frontiers of asymmetric synthesis. Future developments in this field will focus on function-oriented catalyst design, innovations in photo-/electrocatalytic systems, and industrial translation, thereby providing sustained driving force for the precise construction of complex chiral molecules.
