Nitrogen oxides (NOx) are major environmental pollutants and to neutralize this long-term environmental threat, new catalytic methods are needed. Although there are biological denitrification processes involving four different enzymatic reactions to convert nitrate (NO3−) into dinitrogen (N2), it is unfortunately difficult to apply in industry due to the complexity of the processes. In particular, nitrate is difficult to functionalize because of its chemical stability. Thus, there is no organometallic catalysis to convert nitrate into useful chemicals. Herein, we present a nickel pincer complex that is effective as a bifunctional catalyst to stepwise deoxygenate NO3− by carbonylation and further through C−N coupling. By using this nickel catalysis, nitrate salts can be selectively transformed into various oximes (>20 substrates) with excellent conversion (>90 %). Here, we demonstrate for the first time that the highly inert nitrate ion can be functionalized to produce useful chemicals by a new organonickel catalysis. Our results show that the NOx conversion and utilization (NCU) technology is a successful pathway for environmental restoration coupled with value-added chemical generation.

Electrochemical hydrogen peroxide (H2O2) production via two-electron oxygen reduction reaction (2e− ORR) has received increasing attention as it enables clean, sustainable, and on-site H2O2 production. Mimicking the active site structure of H2O2 production enzymes, such as nickel superoxide dismutase, is the most intuitive way to design efficient 2e− ORR electrocatalysts. However, Ni-based catalysts have thus far shown relatively low 2e− ORR activity. In this work, we present the design of high-performing, atomically dispersed Ni-based catalysts (Ni ADCs) for H2O2 production through understanding the formation chemistry of the Ni-based active sites. The use of a precoordinated precursor and pyrolysis within a confined nanospace were found to be essential for generating active Ni–Nx sites in high density and increasing carbon yields, respectively. A series of model catalysts prepared from coordinating solvents having different vapor pressures gave rise to Ni ADCs with controlled ratios of Ni–Nx sites and Ni nanoparticles, which revealed that the Ni–Nx sites have greater 2e− ORR activity. Another set of Ni ADCs identified the important role of the degree of distortion from the square planar structure in H2O2 electrosynthesis activity. The optimized catalyst exhibited a record H2O2 electrosynthesis mass activity with excellent H2O2 selectivity.

While covalent organic frameworks (COFs) have been extensively investigated in the field of organic electrolyte materials, there is potential for further enhancement of their room-temperature ionic conductivity. This study introduces a novel methodology to induce self-exfoliation in the parent COF during synthesis through a postmodification technique. This process yields covalent organic nanosheets that feature pyridinium sulfobetaine groups, referred to as PS-CON. Due to the strategic arrangement of pyridinium cations and sulfobetaine anions, the charge distribution in PS-CON varies substantially, leading to a significant enhancement in lithium-ion dissociation. The methodically organized one-dimensional pore channels, along with the linear structure of the pyridinium sulfobetaine groups, facilitate the lithium-ion transport. PS-CON demonstrated a remarkable ionic conductivity of 2.19 × 10–4 S cm–1and a low activation energy (0.26 eV) coupled with a broad electrochemical stabilization window (4.05 V). Furthermore, the symmetrical cell (Li|Li@PS-CON|Li) demonstrates stable Li plating/stripping for more than 1200 h, which highlights the vast potential of pyridinium-sulfobetaine based zwitterionic nanosheets as high-performance organic electrolytes.

Plasmon photocatalysis reactions are thought to occur through vibrationally activated reactants, driven by nonthermal energy transfer from plasmon-induced hot carriers. However, a detailed quantum-state-level understanding and quantification of the activation have been lacking. Using anti-Stokes surface-enhanced Raman scattering (SERS) spectroscopy, we mapped the vibrational population distributions of reactants on plasmon-excited nanostructures. Our results reveal a highly nonthermal distribution with an anomalously enhanced population of multiquantum excited states  (v ≥ 2). The shape of the distribution and its dependence on local field intensity and excitation wavelength cannot be explained by photothermal heating or vibronic optical transitions of the metal–molecule complex. Instead, it can be modeled by hot electron-molecule energy transfer mediated by the transient negative ions, establishing direct links among nonthermal reactant activation, plasmon-induced hot electrons, and negative ion resonances. Moreover, the presence of multiquantum excited reactants, which are far more reactive than those in the ground state or first excited state, presents opportunities for vibrationally controlling chemical selectivities.

The circadian clock entrained by environmental light–dark cycles enables plants to fine-tune diurnal growth and developmental responses. Here, we show that physical interactions among evening clock components, including PSEUDO-RESPONSE REGULATOR 5 (PRR5), TIMING OF CAB EXPRESSION 1 (TOC1), and the Evening Complex (EC) component EARLY FLOWERING 3 (ELF3), define a diurnal repressive chromatin structure specifically at the PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) locus in Arabidopsis. These three clock components act interdependently as well as independently to repress nighttime hypocotyl elongation, as hypocotyl elongation rate dramatically increased specifically at nighttime in the prr5-1 toc1-21 elf3-1 mutant, concomitantly with a substantial increase in PIF4 expression. Transcriptional repression of PIF4 by ELF3, PRR5, and TOC1 is mediated by the SWI2/SNF2-RELATED (SWR1) chromatin remodeling complex, which incorporates histone H2A.Z at the PIF4 locus, facilitating robust epigenetic suppression of PIF4 during the evening. Overall, these findings demonstrate that the PRR–EC–SWR1 complex represses hypocotyl elongation at night through a distinctive chromatin domain covering PIF4 chromatin.

The excited-state tautomer equilibrium of the urea-fused single-benzene fluorophore was synthetically modulated to produce exceptionally large Stokes shifts (>12 400 cm−1). The key N–H⋯N hydrogen bonding motif utilizes an endogenous proton for long-wavelength emission or an exogenous proton for acid–base chemistry, the balance of which is exploited for fluorescence switching in the solid state.

Blood cell counting typically requires complex machinery. Flow cytometers used for this purpose involve precise optical alignment, costly detectors, and pretreatment with fluorescent labels. Coulter countertype devices, which monitor ion current, are simpler. However, conventional Coulter counters provide only information about size, making it impossible to distinguish similarly sized lymphocytes from red blood cells (RBCs). Inspired by the fact that RBCs have an exceptionally high propensity to absorb light and convert it to heat, i.e., photothermal effect, this study proposes integrating photothermal phenomena into a microfluidic Coulter counting chip. Photothermal heat selectively amplifies the ion current from RBCs over other components including lymphocytes. The combination of ion current monitoring and the photothermal effect for RBC counting suggests an evolution toward versatile flow cytometers.

We present orally administrable prodrugs (OSC-GCDIs) of guanidino oseltamivir carboxylate (GOC) based on guanidine cyclic diimide (GCDI) to treat influenza viruses. By concealing the guanidine group, which significantly limits the intestinal absorption, its prodrugs OSC-GCDIs demonstrate dramatic improvement of oral bioavailability. The most promising antiviral substance OSC-GCDI(P) readily forms covalent adducts with serum proteins via a degradable linker after the intestinal absorption. Subsequently, the active species, GOC, is released from the conjugate in a sustained manner, which greatly contributes to improving pharmacokinetic properties. Because of the remarkable improvements in both oral bioavailability and longevity of its active metabolite, OSC-GCDI(P) demonstrates outstanding therapeutic efficacy against both wild-type and oseltamivir-resistant (H275Y) influenza virus strains in a mouse infection model, even with a single oral administration.

Changsoo LeeJoWith the recent introduction of deep learning techniques into the prediction of biomolecular structures, structure prediction performance has significantly improved, and the potential for biomedical applications has increased considerably. The prediction of protein–ligand complex structures, applicable to the atomistic understanding of biomolecular functions and the effective design of drug molecules, has also improved with the introduction of deep learning. In this paper, it is demonstrated that docking performance can be greatly enhanced by training an energy function that encapsulates physical effects using deep learning within the framework of the traditional protein–ligand docking method. The advantage of this method, called GalaxyDock-DL, lies in its minimal overfitting to the training data compared to several existing deep learning-based protein–ligand docking methods. Unlike some recent deep learning methods, it does not use information about known binding pocket center positions. Instead, the results of this docking method show a systematic dependence on the physical properties of the target protein–ligand complexes such as atomic thermal fluctuations and binding affinity. GalaxyDock-DL utilizes the global optimization technique of the conventional protein–ligand docking method, GalaxyDock, and a neural network energy function trained to stabilize the native state compared to non-native states, just as physical free energy does. This physical principle-based approach suggests directions not only for future structure prediction involving structurally flexible biomolecular complexes but also for predicting binding affinity, thereby providing guidance for the effective design of biofunctional ligands.nghun WonSeongok RyuJinsol YangNuri JungHahnbeom Park

Novel fluorescent scaffolds are highly demanding for a wide range of applications in biomedical investigation. To meet this demand, the pyrido[3,2-b]indolizine scaffold was designed as a versatile organic fluorophore. With the aid of computational modeling, fluorophores offering tunable emission colors (blue to red) were constructed. Notably, constructed fluorophores absorb lights in the visible range (>400 nm) despite their small sizes (<300 g/mol). Among the fluorophores was discovered a highly fluorogenic fluorophore with a unique turn-on property, 1, and it was developed into a washing-free bioprobe for visualizing cellular lipid droplets in living cells. Furthermore, motivated by the core’s compact size and structural analogy to indole, unprecedented tryptophan-analogous fluorogenic unnatural amino acids were constructed and incorporated into fluorogenic peptide probes for monitoring peptide–protein interactions.