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Nitroarenes are readily accessible bulk chemicals and can serve as versatile starting materials for a series of synthetic reactions. However, due to the inertness of the CAr-NO2 bond, the direct denitrative substitution reaction with unactivated nitroarenes remains challenging. Chemists rely on sequential reduction and diazotization followed by the Sandmeyer reaction or the nucleophilic aromatic substitution of activated nitroarenes to realize nitro group transformations. Here we develop a general denitrative chlorination reaction under visible-light irradiation, in which the chlorine radical replaces the nitro moiety through the cleavage of the CAr-NO2 bond. This practical method works with a wide range of unactivated nitro(hetero)arenes and nitroalkenes, is not sensitive to air or moisture and can proceed smoothly on a decagram scale. This transformation differs fundamentally from previous nucleophilic aromatic substitution reactions under thermal conditions in both synthesis and mechanism. Density functional theory calculations reveal the possible pathway for the substitution reaction.

A high-nuclearity {Ni18} complex (1) with a unique 'flying saucer' motif has been prepared from the organic chelate, α-methyl-2-pyridine-methanol (mpmH), in conjunction with bridging azido (N3 -) and peroxido (O2 2-) ligands. Magnetic susceptibility measurements revealed the presence of both ferro- and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end-on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6-bridging peroxides most likely promote the antiparallel alignment of the metals' spin vectors, yielding an overall non-zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single-molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d-metal clusters.

Catechol-functionalized proteins in mussel holdfasts are essential for underwater adhesion and cohesion and have inspired countless synthetic polymeric materials and devices. However, as catechols are prone to oxidation, long-term performance and stability of these inventions awaits effective antioxidation strategies. In mussels, catechol-mediated interactions are stabilized by 'built-in' homeostatic redox reservoirs that restore catechols oxidized to quinones. Mussel byssus has a typical 'core-shell' architecture in which the core is a degradable fibrous block copolymer consisting of collagen and fibroin coated by robust protein networks stabilized by bis-catecholato-metal and tris-catecholato-metal ion complexes. The coating is well-adapted to protect the core against abrasion, hydrolysis and microbial attack, but it is not impervious to oxidative damage, which, during function, is promptly repaired by redox poise via coacervated catechol-rich and thiol-rich reducing interlayers and inclusions. However, when the e- and H+ equivalents from these reducing reservoirs are depleted, coating damage accumulates, leading to exposure of the vulnerable core to environmental attack. Heeding and translating these strategies is essential for deploying catechols with longer service lifetimes and designing more sustainable next-generation polymeric adhesives.

A combination of generalization in neural networks and fast data pipelines enables comprehensive sampling coverage and co-adsorption effects in heterogeneous catalyst models.

Abstract: Electrochemical conversion of CO2 to CO is demonstrated with symmetric-structured metal supported solid oxide cells (MS-SOC). Perovskite Pr0.5Sr0.4Mn0.2Fe0.8O3-δ (PSMF) and Pr6O11 catalysts were infiltrated into the MS-SOC cathode and anode, using 3 cycles with firing at 850C and 8 cycles with firing at 800C, respectively. Upon reduction during operation, the perovskite PSMF was transformed to Ruddlesden–Popper structure with a highly efficient electrocatalytic activity. The impact of operating temperature (600-800C) and overpotential (0-1.8 V) on the CO2 conversion was investigated. The highest CO2 conversion of 57.2% was achieved at 750C and 1.8 V. During extended operation for 150 h at 750C and 1.2V, a cell demonstrated relatively stable performance, with initial current density of 535 mA cm-2 and CO2 conversion of 23%. Degradation mechanisms were studied by posttest characterization.

Four new and one previously reported silver 4,4'-vinylenedipyridine (Vpe) coordination polymers were tested as anion exchange materials to assess their potential for pollutant sequestration and compared to analogous silver 4,4'-bipyridine (bipy) coordination polymers. The materials were synthesized using nitrate, tetrafluoroborate, perchlorate, perrhenate, or chromate as the anion to produce cationic coordination polymers with solubilities ranging from 0.0137(7) to 0.21(5) mM. These values are much lower than silver bipy coordination polymers [0.045(3) to 5.5(5) mM] and agree with thermochemical calculations. [Ag(Vpe)+][BF4-], [Ag2(Vpe)2.52+][CrO42-]·5H2O, and [Ag(Vpe)+][ReO4-]·2H2O structures are reported. Perrhenate and chromate ions in an equimolar solution were fully adsorbed by [Ag(Vpe)+][NO3-]·3H2O [620(2) and 137.1(6) mg/g, respectively] as well as by [Ag(Vpe)+][BF4-] [661.8(3) and 190(3) mg/g, respectively] via anion exchange. DFT calculations show that torsional energetics play a significant role in the formation thermodynamics by reducing the energy cost by as much as 4.8 kJ/mol when bipy is replaced with Vpe in silver-based coordination polymers. The results obtained with the flat Vpe ligand highlight the potential role of coordination polymers in practical anion exchange.

Measuring virus in biofluids is complicated by confounding biomolecules coisolated with viral nucleic acids. To address this, we developed an affinity-based microfluidic device for specific capture of intact severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our approach used an engineered angiotensin-converting enzyme 2 to capture intact virus from plasma and other complex biofluids. Our device leverages a staggered herringbone pattern, nanoparticle surface coating, and processing conditions to achieve detection of as few as 3 viral copies per milliliter. We further validated our microfluidic assay on 103 plasma, 36 saliva, and 29 stool samples collected from unique patients with COVID-19, showing SARS-CoV-2 detection in 72% of plasma samples. Longitudinal monitoring in the plasma revealed our device's capacity for ultrasensitive detection of active viral infections over time. Our technology can be adapted to target other viruses using relevant cell entry molecules for affinity capture. This versatility underscores the potential for widespread application in viral load monitoring and disease management.

Light-driven reduction of CO2 into chemicals using a photoelectrochemical (PEC) approach is considered as a promising way to meet the carbon neutral target. The very top surface of the photoelectrode and semiconductor/electrolyte interface plays a pivotal role in defining the performance for PEC CO2 reduction. However, such impact remains poorly understood. Here, we report an electrodeposition-annealing route for tailoring surface composition of ZnTe photocathodes. Our work demonstrates that a Zn-rich surface on the ZnTe photocathode is essential to impact the CO2 reduction activity and selectivity. In particular, the Zn-rich surface not only facilitated the interfacial charge carrier transfer, but also acted as electrocatalyst for boosting carbon product selectivity and suppressing the hydrogen evolution reaction. This work provides a new avenue to optimize the photocathode, as well as improvement of the CO2RR performance.

In Nature, the four-electron reduction of O2 is catalyzed at preorganized multimetallic active sites. These complex active sites often feature low-coordinate, redox-active metal centers precisely positioned to facilitate rapid O2 activation processes that obviate the generation of toxic, partially reduced oxygen species. Very few biomimetic constructs simultaneously recapitulate the complexity and reactivity of these biological cofactors. Herein, we report solid-state O2 activation at a triiron(II) active site templated by phosphinimide ligands. Insight into the structure of the O2 reduction intermediates was obtained via in crystallo O2 dosing experiments in conjunction with spectroscopic, structural, magnetic, and computational studies. These data support the in situ formation of an Fe2IIIFeIV-dioxo intermediate upon exposure to O2 that participates in oxygen atom and hydrogen atom transfer reactivity with exogenous substrates to furnish a stable FeIIFe2III-oxo species. Combined, these studies provide an extraordinary level of detail into the dynamics of bond-forming and -breaking processes operative at complex multimetallic active sites.

Specialized or secondary metabolites are small molecules of biological origin, often showing potent biological activities with applications in agriculture, engineering and medicine. Usually, the biosynthesis of these natural products is governed by sets of co-regulated and physically clustered genes known as biosynthetic gene clusters (BGCs). To share information about BGCs in a standardized and machine-readable way, the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard and repository was initiated in 2015. Since its conception, MIBiG has been regularly updated to expand data coverage and remain up to date with innovations in natural product research. Here, we describe MIBiG version 4.0, an extensive update to the data repository and the underlying data standard. In a massive community annotation effort, 267 contributors performed 8304 edits, creating 557 new entries and modifying 590 existing entries, resulting in a new total of 3059 curated entries in MIBiG. Particular attention was paid to ensuring high data quality, with automated data validation using a newly developed custom submission portal prototype, paired with a novel peer-reviewing model. MIBiG 4.0 also takes steps towards a rolling release model and a broader involvement of the scientific community. MIBiG 4.0 is accessible online at https://mibig.secondarymetabolites.org/.

The UCSC Genome Browser (https://genome.ucsc.edu) is a widely utilized web-based tool for visualization and analysis of genomic data, encompassing over 4000 assemblies from diverse organisms. Since its release in 2001, it has become an essential resource for genomics and bioinformatics research. Annotation data available on Genome Browser includes both internally created and maintained tracks as well as custom tracks and track hubs provided by the research community. This last year's updates include over 25 new annotation tracks such as the gnomAD 4.1 track on the human GRCh38/hg38 assembly, the addition of three new public hubs, and significant expansions to the Genome Archive[GenArk) system for interacting with the enormous variety of assemblies. We have also made improvements to our interface, including updates to the browser graphic page, such as a new popup dialog feature that now displays item details without requiring navigation away from the main Genome Browser page. GenePred tracks have been upgraded with right-click options for zooming and precise navigation, along with enhanced mouseOver functions. Additional improvements include a new grouping feature for track hubs and hub description info links. A new tutorial focusing on Clinical Genetics has also been added to the UCSC Genome Browser.

The Genomes OnLine Database (GOLD; https://gold.jgi.doe.gov/) at the Department of Energy Joint Genome Institute is a comprehensive online metadata repository designed to catalog and manage information related to (meta)genomic sequence projects. GOLD provides a centralized platform where researchers can access a wide array of metadata from its four organization levels namely Study, Organism/Biosample, Sequencing Project and Analysis Project. GOLD continues to serve as a valuable resource and has seen significant growth and expansion since its inception in 1997. With its expanded role as a collaborative platform, it not only actively imports data from other primary repositories like National Center for Biotechnology Information but also supports contributions from researchers worldwide. This collaborative approach has enriched the database with diverse datasets, creating a more integrated resource to enhance scientific insights. As genomic research becomes increasingly integral to various scientific disciplines, more researchers and institutions are turning to GOLD for their metadata needs. To meet this growing demand, GOLD has expanded by adding diverse metadata fields, intuitive features, advanced search capabilities and enhanced data visualization tools, making it easier for users to find and interpret relevant information. This manuscript provides an update and highlights the new features introduced over the last 2 years.

Secondary metabolites are compounds not essential for an organism's development, but provide significant ecological and physiological benefits. These compounds have applications in medicine, biotechnology and agriculture. Their production is encoded in biosynthetic gene clusters (BGCs), groups of genes collectively directing their biosynthesis. The advent of metagenomics has allowed researchers to study BGCs directly from environmental samples, identifying numerous previously unknown BGCs encoding unprecedented chemistry. Here, we present the BGC Atlas (https://bgc-atlas.cs.uni-tuebingen.de), a web resource that facilitates the exploration and analysis of BGC diversity in metagenomes. The BGC Atlas identifies and clusters BGCs from publicly available datasets, offering a centralized database and a web interface for metadata-aware exploration of BGCs and gene cluster families (GCFs). We analyzed over 35 000 datasets from MGnify, identifying nearly 1.8 million BGCs, which were clustered into GCFs. The analysis showed that ribosomally synthesized and post-translationally modified peptides are the most abundant compound class, with most GCFs exhibiting high environmental specificity. We believe that our tool will enable researchers to easily explore and analyze the BGC diversity in environmental samples, significantly enhancing our understanding of bacterial secondary metabolites, and promote the identification of ecological and evolutionary factors shaping the biosynthetic potential of microbial communities.

Secondary metabolites are small molecules produced by all corners of life, often with specialized bioactive functions with clinical and environmental relevance. Secondary metabolite biosynthetic gene clusters (BGCs) can often be identified within DNA sequences by various sequence similarity tools, but determining the exact functions of genes in the pathway and predicting their chemical products can often only be done by careful, manual comparative analysis. To facilitate this, we report the first release of the secondary metabolism collaboratory (SMC), which aims to provide a comprehensive, tool-agnostic repository of BGC sequence data drawn from all publicly available and user-submitted bacterial and archaeal genome and contig sources. On the website, users are provided a searchable catalog of putative BGCs identified from each source, along with visualizations of gene and domain annotations derived from multiple sequence analysis tools. SMC's data is also available through publicly-accessible application programming interface (API) endpoints to facilitate programmatic access. Users are encouraged to share their findings (and search for others') through comment posts on BGC and source pages. At the time of writing, SMC is the largest repository of BGC information, holding 13.1M BGC regions from 1.3M source sequences and growing, and can be found at https://smc.jgi.doe.gov.

Regulatory elements (enhancers) are major drivers of gene expression in mammals and harbor many genetic variants associated with human diseases. Here, we present an updated VISTA Enhancer Browser (https://enhancer.lbl.gov), a database of transgenic enhancer assays conducted in developing mouse embryos in vivo. Since the original publication in 2007, the database grew nearly 20-fold from 250 to over 4500 experiments and currently harbors over 23 500 images. The updated database provides structured information on experiments conducted at different stages of embryonic development, including enhancer activities of human pathogenic and synthetic variants and sequences derived from a variety of species. In addition to manually curated results of thousands of individual experiments, the new database also features hundreds of manually curated comparisons between alleles. The VISTA Enhancer Browser provides a crucial resource for study of human genetic variation, gene regulation and developmental biology.

Microadditive manufacturing has revolutionized the production of complex, nano- to microscale components across various fields. This work investigates two-photon (2P) and three-photon (3P) fluorescence imaging, as well as third-harmonic generation (THG) microscopy, to examine periodic microarchitected lattice structures fabricated using multiphoton lithography (MPL). By immersing the structures in refractive index matching fluids, we demonstrate high-fidelity 3D reconstructions of both fluorescent structures using 2P and 3P microscopy as well as low-fluorescence structures using THG microscopy. These results show that multiphoton fluorescence (MPF) imaging offers reduced signal decay with respect to depth compared to single-photon techniques in the examined structures. We further demonstrate the ability to nondestructively identify intentional internal modifications of the structure that are not immediately visible with scanning electron microscope (SEM) images and compression-induced fractures, highlighting the potential of these techniques for quality control and defect detection in microadditively manufactured components.

Sulfide solid-state electrolytes (SSEs) are promising candidates to realize all solid-state batteries (ASSBs) due to their superior ionic conductivity and excellent ductility. However, their hypersensitivity to moisture requires processing environments that are not compatible with today's lithium-ion battery manufacturing infrastructure. Herein, we present a reversible surface modification strategy that enables the processability of sulfide SSEs (e. g., Li6PS5Cl) under humid ambient air. We demonstrate that a long chain alkyl thiol, 1-undecanethiol, is chemically compatible with the electrolyte with negligible impact on its ion conductivity. Importantly, the thiol modification extends the amount of time that the sulfide SSE can be exposed to air with 33% relative humidity (33% RH) with limited degradation of its structure while retaining a conductivity of above 1 mS cm-1 for up to 2 days, a more than 100-fold improvement in protection time over competing approaches. Experimental and computational results reveal that the thiol group anchors to the SSE surface, while the hydrophobic hydrocarbon tail provides protection by repelling water. The modified Li6PS5Cl SSE maintains its function after exposure to ambient humidity when implemented in a Li0.5In | |LiNi0.8Co0.1Mn0.1O2 ASSB. The proposed protection strategy based on surface molecular interactions represents a major step forward towards cost-competitive and energy-efficient sulfide SSE manufacturing for ASSB applications.

Polydiacetylenes (PDAs) are conjugated polymers that are well known for their colorimetric transition from blue to red with the application of energetic stimulus. Sensing platforms based on polymerized diacetylene surfactant vesicles and other structures have been widely demonstrated for various colorimetric biosensing applications. Although less studied and utilized, the transition also results in a change from a non-fluorescent to a highly fluorescent state, making polydiacetylenes useful for both colorimetric and fluorogenic sensing applications. Here, we focus on the characterization and optimization of polydiacetylene vesicles to tune their sensitivity for fluorogenic sensing applications. Particularly, we look at how the structure of the diacetylene (DA) hydrocarbon tail and headgroup affect the self-assembled vesicle size and stability, polymerization kinetics, and the fluorogenic, blue to red phase transition. Longer DA acyl tails generally resulted in smaller and more stable vesicles. The polymerization kinetics and the blue to red transition were a function of both the DA acyl tail length and structure of the headgroup. Decreasing the acyl tail length generally led to vesicles that were more sensitive to energetic stimuli. Headgroup modifications had different effects depending on the structure of the headgroup. Ethanolamine headgroups resulted in vesicles with potentially increased stimuli responsivity. The lower energy stimulus to induce the chromatic transition was attributed to an increase in headgroup hydrogen bonding and polymer backbone strain. Boronic-acid headgroup functionalization led to vesicles that were generally unstable, only weakly polymerized, and unable to fully transform to the red phase due to strong polar, aromatic headgroup interactions. This work presents the design of PDA vesicles in the context of biosensing platforms and includes a discussion of the past, present, and future of PDA biosensing.

Circular plastics thrive on the ability to chemically recycle polymers into reusable monomers, ideally closing the loop from manufacturing to the end of life. Mechanisms for polymer deconstruction are complex, involving diffusion and transport of reagents to reactive sites in a material continuously undergoing chemical transformations. A deeper understanding of the deconstruction phenomena would better inform the molecular basis of circularity. Here, we show how nuclear magnetic resonance (NMR) spectroscopy, relaxometry, and diffusometry enable monitoring of the heterogeneous deconstruction of a model elastomer with acid-cleavable diketoenamine bonds. In chaotropic aqueous HBr, polydiketoenamine (PDK) deconstruction is fast, enabled by macro- and microscale swelling, which facilitates acid penetration and protonation of reaction sites deep within the polymer. We observe a previously unrecognized hydrogen-bond-stabilized amine intermediate that is persistent throughout deconstruction. In kosmotropic aqueous H2SO4, PDK deconstruction is notably slower. Here, swelling occurred at a more gradual pace, characterized by low polymer chain mobility, thereby trapping the acid in matrix pores and modifying the activity of the reaction medium under confinement in the process. We find that polymer swelling, chain mobility, and deconstruction kinetics are strongly linked, requiring a multifaceted NMR characterization tool box for in-depth analysis.

Abstract: Electron ptychography is a powerful computational method for atomic-resolution imaging with high contrast for weakly and strongly scattering elements. Modern algorithms coupled with fast and efficient detectors allow imaging specimens with tens of nanometers thicknesses with sub-0.5 Ångstrom lateral resolution. However, the axial resolution in these approaches is currently limited to a few nanometers, limiting their ability to solve novel atomic structures ab initio. Here, we experimentally demonstrate multi-slice ptychographic electron tomography, which allows atomic resolution three-dimensional phase-contrast imaging in a volume surpassing the depth of field limits. We reconstruct tilt-series 4D-STEM measurements of a Co 3 O 4 nanocube, yielding 2 Å axial and 0.7 Å transverse resolution in a reconstructed volume of ( 18.2 nm ) 3 . Our results demonstrate a 13.5-fold improvement in axial resolution compared to multi-slice ptychography while retaining the atomic lateral resolution and the capability to image volumes beyond the depth of field limit. Multi-slice ptychographic electron tomography significantly expands the volume of materials accessible using high-resolution electron microscopy. We discuss further experimental and algorithmic improvements necessary to also resolve single weakly scattering atoms in 3D.

As clinical evaluations of neuromuscular disorders such as hypertonia mostly rely on perception-based scales, the imprecise subjective ratings make it difficult to accurately monitor treatment progress. To promote objective evaluation, this work used a multi-modal sensing glove in a double-blind study to enable sensitive monitoring of medication effects across 19 participants. The biomechanical measurements from the sensing glove effectively distinguished patient cohorts receiving a baclofen treatment or a placebo with 95% confidence. Consistent monitoring over a two-month period was demonstrated, closely tracking variations in individual responses to treatment. The biomechanical changes were correlated to neural activities as recorded by electromyography, verifying the medication effects. The sensing glove is shown to be a reliable tool for point-of-care settings to facilitate precise evaluation of hypertonia, essential for tailoring individual treatment choices and timely management of chronic symptoms.

Despite the outstanding electric properties and cost-effectiveness of poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives, their performance as hole transport layer (HTL) materials in conventional perovskite solar cells (PSCs) has lagged behind that of widely used spirobifluorene-based molecules or poly(triaryl amine). This gap is mainly from their poor solubility and energy alignment mismatch. In this work, the design and synthesis of a pyrrole-modified HTL (PPr) based on 3,4-propylenedioxythiophene (ProDOT) are presented for efficient and stable PSCs. As a result of the superior defects passivation ability, excellent contact with perovskite, enhanced hole extraction, and high hydrophobicity, the unencapsulated PPr-based PSCs showed the peak PCE of 21.49% and outstanding moisture stability (over 4000 h). This work highlights the potential application of ProDOT-based materials as HTL for PSCs and underscores the importance of the rational design of PEDOT and its derivatives.

The sodium (Na) superionic conductor is a key component that could revolutionize the energy density and safety of conventional Na-ion batteries. However, existing Na superionic conductors are primarily based on a single-anion framework, each presenting inherent advantages and disadvantages. Here we introduce a family of amorphous Na-ion conductors (Na2O2-MCly, M = Hf, Zr and Ta) based on the dual-anion framework of oxychloride. Benefiting from a dual-anion chemistry and with the resulting distinctive structures, Na2O2-MCly electrolytes exhibit room-temperature ionic conductivities up to 2.0 mS cm-1, wide electrochemical stability windows and desirable mechanical properties. All-solid-state Na-ion batteries incorporating amorphous Na2O2-HfCl4 electrolyte and a Na0.85Mn0.5Ni0.4Fe0.1O2 cathode exhibit a superior rate capability and long-term cycle stability, with 78% capacity retention after 700 cycles under 0.2 C (1C = 120 mA g-1) at room temperature. The discoveries in this work could trigger a new wave of enthusiasm for exploring new superionic conductors beyond those based on a single-anion framework.

Disordered rocksalt cathodes exhibit high specific capacities and high energy density; however, their low electronic conductivity poses a great challenge. Herein, we explored an aqueous-solution-based synthesis route that involves controlling the surface charges of Li1.2Mn0.6Ti0.2O1.8F0.2 (LMTOF) to be anchored by a few-layer reduced graphene oxide (rGO) for the first time. The uniform rGO wrapping on the surface of the LMTOF particles is achieved by electrostatic attraction between the negatively charged rGO and positively charged LMTOF particles. Although the initial specific capacity of rGO-LMTOF composite increased by 58 % compared to the pristine LMTOF, the composite experienced a severe capacity fade over cycling. The synthesis process in an aqueous medium resulted in Li+/H+ exchange and TM dissolution as evidenced from inductively coupled plasmon analysis and X-ray diffraction analysis. Therefore, this work suggests the search for alternative media or conditions for the synthesis of carbon-disordered rock salt cathode composite.

Cryogenic transmission electron microscopy (cryo-TEM) combined with single particle analysis (SPA) is an emerging imaging approach for soft materials. However, the accuracy of SPA-reconstructed nanostructures, particularly those formed by synthetic polymers, remains uncertain due to potential packing heterogeneity of the nanostructures. In this study, the combination of molecular dynamics (MD) simulations and image simulations is utilized to validate the accuracy of cryo-TEM 3D reconstructions of self-assembled polypeptoid fibril nanostructures. Using CryoSPARC software, image simulations, 2D classifications, ab initio reconstructions, and homogenous refinements are performed. By comparing the results with atomic models, the recovery of molecular details is assessed, heterogeneous structures are identified, and the influence of extraction location on the reconstructions is evaluated. These findings confirm the fidelity of single particle analysis in accurately resolving complex structural characteristics and heterogeneous structures, exhibiting its potential as a valuable tool for detailed structural analysis of synthetic polymers and soft materials.

Two routes to assemble the complete tricyclic core of alopecurone C are described. In the first-generation route, an efficient synthesis of the "eastern" half of the target, including a decagram-scale rhodium-catalyzed C-H insertion reaction, was developed. When this route proved intractable for assembling the final flavanone ring, a successful second-generation route was developed from a flavanone precursor (naringenin) employing a later stage C-H insertion. Although the second route was ultimately unsuccessful for preparation of the final target, it does provide the basis for the efficient assembly of the complete tricyclic core of alopecurone C and related flavonostilbenoid natural products.

The recently synthesized monolayer fullerene network in a quasi-hexagonal phase (qHP-C60) exhibits superior electron mobility and optoelectronic properties compared to molecular fullerene (C60), making it highly promising for a variety of applications. However, the microscopic carrier dynamics of qHP-C60 remain unclear, particularly in realistic environments, which are of significant importance for applications in optoelectronic devices. Unfortunately, traditional ab initio methods are prohibitive for capturing the real-time carrier dynamics of such large systems due to their high computational cost. In this work, we present the first real-time electron-nuclear dynamics study of qHP-C60 using velocity-gauge density functional tight binding, which enables us to perform several picoseconds of excited-state electron-nuclear dynamics simulations for nanoscale systems with periodic boundary conditions. When applied to C60, qHP-C60, and their solvated counterparts, we demonstrate that water/moisture significantly increases the electron-hole recombination time in C60 but has little impact on qHP-C60. Our excited-state electron-nuclear dynamics calculations show that qHP-C60 is extremely unique and enable exploration of time-resolved dynamics for understanding excited-state processes of large systems in complex, solvated environments.

The development of a colloidal synthesis procedure to produce nanomaterials with high shape and size purity is often a time-consuming, iterative process. This is often due to quantitative uncertainties in the required reaction conditions and the time, resources, and expertise intensive characterization methods required for quantitative determination of nanomaterial size and shape. Absorption spectroscopy is often the easiest method for colloidal nanomaterial characterization. However, due to the lack of a reliable method to extract nanoparticle shapes from absorption spectroscopy, it is generally treated as a more qualitative measure for metal nanoparticles. This work demonstrates a gold nanorod (AuNR) spectral morphology analysis tool, called AuNR-SMA, which is a fast and accurate method to extract quantitative structural information from colloidal AuNR absorption spectra. To demonstrate the practical utility of this model, we apply it to three distinct applications. First, we demonstrate this model's utility as an automated analysis tool in a high-throughput AuNR synthesis procedure by generating quantitative size information from optical spectra. Second, we use the predictions generated by this model to train a machine learning model to predict the resulting AuNR size distributions under specified reaction conditions. Third, we apply this model to spectra extracted from the literature where no size distributions are reported and impute unreported quantitative information on AuNR synthesis. This approach can potentially be extended to any other nanocrystal system where absorption spectra are size dependent, and accurate numerical simulation of absorption spectra is possible. In addition, this pipeline could be integrated into automated synthesis apparatuses to provide interpretable data from simple measurements, help explore the synthesis science of nanoparticles in a rational manner, or facilitate closed-loop workflows.

The construction of multinuclear lanthanide-based molecules with significant magnetic exchange interactions represents a key challenge in the realization of single-molecule magnets with high operating temperatures. Here, we report the synthesis and magnetic characterization of two series of heterobimetallic compounds, (Cp*2Ln)2(μ-Co(pdt)2) (Ln = Y3+, Gd3+, Dy3+; pdt2- = 1,2-diphenylethylenedithiolate) and [K(18-crown-6)][(Cp*2Ln)2(μ-Co(pdt)2)] (Ln = Y3+, Gd3+), featuring two lanthanide centers bridged by a cobalt bis(1,2-dithiolene) complex. Dc magnetic susceptibility data collected for the Gd congeners indicate significant Gd-Co ferromagnetic exchange interactions with fits affording J = +11.5 and +7.33 cm-1, respectively. Magnetization decay and ac magnetic susceptibility measurements carried out on the single-molecule magnet (Cp*2Dy)2(μ-Co(pdt)2) reveal full suppression of quantum tunneling and open-loop hysteresis persisting up to 3.5 K. These results, along with those of high-field EPR spectroscopy, suggest that transition metalloligands can enforce strong exchange interactions with adjacent lanthanide centers while maintaining a geometry that preserves molecular anisotropy. Furthermore, the magnetic properties of [K(18-crown-6)][(Cp*2Gd)2(μ-Co(pdt)2)] show that increasing the spin of the ground state of the bridging complex may be a viable alternative to increasing J in obtaining well-isolated, strongly coupled magnetic ground states.

The capture of carbon dioxide (CO2) is crucial for reducing greenhouse emissions and achieving net-zero emission goals. Metal-organic frameworks (MOFs) present a promising solution for carbon capture due to their structural adaptability, tunability, porosity, and pore modification. In this research, we explored the use of a copper (Cu(II))-based MOF called m CBMOF-1. After activation, m CBMOF-1 generates one-dimensional channels with square cross sections, featuring sets of four Cu(II) open metal sites spaced by 6.042 Å, allowing strong interactions with coordinating molecules. To investigate this capability, m CBMOF-1 was exposed to ammonia (NH3) gas, resulting in hysteretic NH3 isotherms indicative of strong interactions between Cu(II) and NH3. At 150 mbar and 298 K, the NH3-loaded (∼1 mmol/g) material exhibited a 106% increase in CO2 uptake compared to that of the pristine m CBMOF-1. Carbon-13 solid-state nuclear magnetic resonance spectra and density functional theory calculations confirmed that the sequential loading of NH3 followed by CO2 adsorption generated a copper-carbamic acid complex within the pores of m CBMOF-1. Our study highlights the effectiveness of sequential pore functionalization in MOFs as an attractive strategy for enhancing the interactions of MOFs with small molecules such as CO2.

Advances in lithium-metal anodes have inspired interest in discovery of Li-free cathodes, most of which are natively found in their charged state. This is in contrast to today's commercial lithium-ion battery cathodes, which are more stable in their discharged state. In this study, we combine calculated cathode voltage information from both categories of cathode materials, covering 5577 and 2423 total unique structure pairs, respectively. The resulting voltage distributions with respect to the redox pairs and anion types for both classes of compounds emphasize design principles for high-voltage cathodes, which favor later Period 4 transition metals in their higher oxidation states and more electronegative anions like fluorine or polyanion groups. Generally, cathodes that are found in their charged, delithiated state are shown to exhibit voltages lower than those that are most stable in their lithiated state, in agreement with thermodynamic expectations. Deviations from this trend are found to originate from different anion distributions between redox pairs. In addition, a machine learning model for voltage prediction based on chemical formulas is trained and shows state-of-the-art performance when compared to two established composition-based ML models for material properties predictions, Roost and CrabNet.

The analysis of the solution absorption spectrum of the plutonyl ion in an aqueous environment was given by Eisenstein and Pryce (E&P) in 1968. In 2011 a new spectrum was published of the (PuO2)2+ ion in 1 M HClO4. We have been provided with the original data of this spectrum and have found in the data a previously unreported low-lying transition at 7385 cm-1 which we have assigned as a magnetic dipole transition. We have fit most of the near-infrared and optical transitions with Gaussian fits and tabulated a new energy level list up to 22,000 cm-1 which mostly agrees with the data of E&P. We assumed a crystal field of D∞h (only axial symmetry) and utilized the intensity calculations published for the isoelectronic (NpO2)1+ ion using a complete basis set for the 5f2 problem including the Coulombic, spin-orbit as well as the crystal field Hamiltonian. Our results differ substantially from those of E&P. Subsequently, we used a truncated Hamiltonian to try to establish the effects of assuming the σ antibonding orbitals are at such high energies that we can ignore their contributions to the lower lying φ and δ orbitals.

Organometallic antimony(V) complexes were prepared as model compounds to better understand the interactions of chiral chelating diols with this metalloid. These complexes feature three aryl groups (meta-xylyl or para-tolyl) and a bidentate trans-2,3-butanediolate. The meta-xylyl and para-tolyl complexes of either enantiomerically pure 2R,3R-butanediolate or 2S,3S-butanediolate (compounds 1-4) crystallized in Sohncke space groups, as expected. In each case, though, pseudoinversion centers were present that mimic higher-symmetry space groups through global pseudosymmetry. We hypothesized that the crystallization of 1:1 mixtures of the enantiomeric complexes would produce crystals in the centrosymmetric space group approximated by the pseudosymmetry. The enantiomerically pure meta-xylyl complexes each crystallized in space group P1 (approximating P1̅), and the racemic compound did indeed crystallize in P1̅. The enantiomerically pure para-tolyl complexes each crystallized in space group P21 (approximating P21/c), but the racemic compound crystallized in P1̅. Although the enantiomerically pure and racemic compounds are not isostructural, there are similarities in their 3D structures that are analyzed.

Recent studies have revealed critical roles for the local environments surrounding metallocofactors, such as the newly identified CuD site in particulate methane monooxygenases (pMMOs) and the second sphere aromatic residues in lytic polysaccharide monooxygenases (LPMOs), implicated in the protection against oxidative damage. However, these features are subjects of continued debate. Our work utilizes biotin-streptavidin (Sav) technology to develop artificial metalloproteins (ArMs) that mimic the active sites of natural copper metalloenzymes. By engineering ArMs with aromatic residues within their secondary coordination spheres, we systematically investigate the influence of these residues on Cu reactivity and oxidant activation. We demonstrate that the placement and orientation of tyrosine relative to the Cu cofactor critically affect the oxidation outcomes upon exposure to hydrogen peroxide. A key finding is the interplay between the coordination of an active site asparagine and the incorporation of aromatic residues proximal to the artificial Cu cofactor, which are the only variants where oxidation of an engineered residues is observed. These findings underscore the importance of the secondary coordination sphere in modulating Cu center reactivity, suggest a role for amide coordination in C-H bond activation by pMMOs, and potential inactivation pathways in natural copper enzymes like LPMOs.

Rare earth tris(alkyl) complexes such as M(CH2SiMe3)3(sol) n are widely used as precursors for many compounds and as homogeneous catalysts for alkene polymerization and alkane functionalization. However, the thermal instability of those most conveniently made from the commercially available lithium salt of the neosilyl anion, LiCH2SiMe3, Li(r), restricts their utility. We present a new range of synthetically useful, more kinetically stable rare earth neosilyl solvates, derived from a full kinetic study of the various possible decomposition mechanisms of 7 known and 12 new solvated rare earth neosilyl complexes M(CH2SiMe3)3(sol) n M = Sc(iii), Y(iii), Lu(iii), Sm(iii), and sol = THF; TMEDA; DMPE; diglyme ((CH3)2(OCH2CH2)2O, G2), triglyme ((CH3)2(OCH2CH2)3O, G3). Surprisingly, simply using higher-denticity donors to sterically disfavor neosilyl γ-H elimination is not effective. While Sc(r)3((CH3)2(OCH2CH2)2O) has a half-life, t 1/2, of 258.1 h, six times longer than for Sc(r)3(C4H8O)2 (t 1/2 = 43 h), Lu(r)3((CH3)2(OCH2CH2)2O) and Y(r)3((CH3)2(OCH2CH2)2O) do not show the expected, analogous increased t 1/2. This is because new decomposition pathways appear for poorly fitting donors. Finally, kinetic studies demonstrate the impact of small, and increasing amounts of LiCl on the kinetics of the reactivity of the smaller alkyls Y(r)3(THF)2 and Lu(r)3(THF)2; molecules used in hydrocarbon chemistry and catalysis for fifty years. A new route to pure Y(r)3(THF)2, which avoids the traditional use of Li(r), is presented.

A method is presented for high-precision chemical detection that integrates quantum sensing with droplet microfluidics. Using nanodiamonds (ND) with fluorescent nitrogen-vacancy (NV) centers as quantum sensors, rapidly flowing microdroplets containing analyte molecules are analyzed. A noise-suppressed mode of optically detected magnetic resonance is enabled by pairing controllable flow with microwave control of NV electronic spins, to detect analyte-induced signals of a few hundredths of a percent of the ND fluorescence. Using this method, paramagnetic ions in droplets are detected with low limit-of-detection using small analyte volumes, with exceptional measurement stability over >103 s. In addition, these droplets are used as microconfinement chambers by co-encapsulating ND quantum sensors with various analytes such as single cells, suggesting wide-ranging applications including single-cell metabolomics and real-time intracellular measurements from bioreactors. Important advances are enabled by this work, including portable chemical testing devices, amplification-free chemical assays, and chemical imaging tools for probing reactions within microenvironments.

Nafion, a perfluorosulfonic acid ionomer, has been well-studied for decades due to its key role as an ion-conductive membrane in electrochemical energy conversion and storage applications. When hydrated, this membrane phase separates into a complex hierarchical nanostructure with hydrophilic domains that facilitate ion transport. Hard X-ray scattering has been a powerful technique in understanding Nafion due to its capabilities in capturing the ionomer’s nanophase separated structure, which gives rise to contrast between polymer and water domains. More recently, resonant X-ray scattering, which tunes to elemental absorption edges to provide specificity on constituent elements, has been explored to highlight key interactions related to the sulfonic acid groups within its structure. Here, we study the Nafion nanostructure by combining hard X-ray scattering and tender resonant X-ray scattering (TReXS) at the sulfur K-edge to reveal a mesoscopic feature corresponding to a correlation length of approximately 40 nm that has been challenging to resolve with hard X-ray studies. Additionally, we study the effect of the dispersion solvent composition that plays a key role in the formation of this mesoscale feature. Notably, TReXS can attain high contrast to decipher this mesoscale morphology even for dry polymer membranes under a vacuum, which typically have reduced contrast for hard X-rays. We find that the correlation length of this mesoscale feature decreases with increasing water fraction in the dispersion, which is the opposite trend exhibited by the smaller intercrystalline feature in the same membranes. This study showcases the utility of TReXS to uncover multiscale morphological details in functional polymers that are not always revealed by other methods like hard X-ray scattering. We illustrate this with Nafion, which is a relevant ion-conducting polymer for electrochemical technologies. (Figure presented.)

Photon avalanche (PA)-where the absorption of a single photon initiates a 'chain reaction' of additional absorption and energy transfer events within a material-is a highly nonlinear optical process that results in upconverted light emission with an exceptionally steep dependence on the illumination intensity. Over 40 years following the first demonstration of photon avalanche emission in lanthanide-doped bulk crystals, PA emission has been achieved in nanometer-scale colloidal particles. The scaling of PA to nanomaterials has resulted in significant and rapid advances, such as luminescence imaging beyond the diffraction limit of light, optical thermometry and force sensing with (sub)micron spatial resolution, and all-optical data storage and processing. In this review, we discuss the fundamental principles underpinning PA and survey the studies leading to the development of nanoscale PA. Finally, we offer a perspective on how this knowledge can be used for the development of next-generation PA nanomaterials optimized for a broad range of applications, including mid-IR imaging, luminescence thermometry, (bio)sensing, optical data processing and nanophotonics.

The directed self-assembly of colloidal nanoparticles (NPs) using external fields guides the formation of sophisticated hierarchical materials but becomes less effective with decreasing particle size. As an alternative, electron-beam-driven assembly offers a potential avenue for targeted nanoscale manipulation, yet remains poorly controlled due to the variety and complexity of beam interaction mechanisms. Here, we investigate the beam-particle interaction of silica NPs pinned to the fluid-vacuum interface of ionic liquid droplets. In these experiments, scanning electron microscopy of the droplet surface resolves NP trajectories over space and time while simultaneously driving their reorganization. With this platform, we demonstrate the ability to direct particle transport and create transient, reversible colloidal patterns on the droplet surface. By tuning the beam voltage, we achieve precise control over both the strength and sign of the beam-particle interaction, with low voltages repelling particles and high voltages attracting them. This response stems from the formation of well-defined solvent flow fields generated from trace radiolysis of the ionic liquid, as determined through statistical analysis of single-particle trajectories under varying solvent composition. Altogether, electron-beam-guided assembly introduces a versatile strategy for nanoscale colloidal manipulation, offering new possibilities for the design of dynamic, reconfigurable systems with applications in adaptive photonics and catalysis.

Metal-Organic Frameworks (MOFs) constructed using cross-linked oligomeric or polymeric ligands (oligoMOFs and polyMOFs respectively) have so far relied on a handful of canonical structural blueprints, in which the cross-links have not played a significant role in determining structure. In this study, we show that cross-links between terephthalate ligands in dabco-based Zn-MOFs (DMOFs) can exert control over the overall phase landscape of resulting oligo- and polyMOFs. We find that cross-links can direct the overall topology of the resulting MOF (pcu vs. kag) based on their length or rigidity, and can influence the phase transformation behavior of the pcu network. We also show the first example of tethered ligand dimers adopting a different MOF structure to the analogous trimer and polymer. Understanding the influence of cross-links on the formation of these MOFs will help guide the design of future MOF-polymer hybrid materials.

Conjugated ladder polymers (CLPs) are difficult yet captivating synthetic targets due to their fully unsaturated fused backbones. Inherent challenges associated with their synthesis often lead to low yields, structural defects, and insoluble products. Here a new method to form CLPs is demonstrated, utilizing a high-yielding dimerization of annulated zirconacyclopentadienes to form cyclooctatetraene (COT) monomer units. The resulting COT-containing polymers form rapidly in a single ladderization step from the bis-zirconacyclopentadiene precursors and display M n up to 29.7 kg mol-1. The polymers represent rare examples of CLPs with negatively curved rings, resulting in the observation of unusual properties. The rigid tub-shaped COT units embedded in the backbone imbue the polymers with microporosity, exhibiting BET surface areas up to 555 m2 g-1. Additionally, the remarkable solubility of these CLPs in organic solvents enables the fabrication of thin films showcasing high dielectric performance with a discharged energy density as high as 6.54 J cm-3 at 650 MV m-1.

The microsomal epoxide hydrolase (mEH) is important in the detoxification of carcinogens in the liver and other tissues but is also a blood biomarker of hepatitis and liver cancer. Improved analytical methods are needed for the study of its role in the metabolism of xenobiotics and endogenous roles as a blood biomarker of diseases. The development of a double nanobody sandwich ELISA offers significant improvements over traditional polyclonal or monoclonal antibody-based assays, enhancing both the homogeneity and the stability of assay production. This study focuses on selecting and optimizing nanobody pairs for detecting human mEH. Four high-affinity nanobodies were identified and tested for thermal stability. Combinations of these nanobodies were evaluated, revealing that the MQ4-MQ30 pair achieved the best performance with a limit of detection (LOD) of 1 ng/mL. Additionally, polyHRP was also employed for signal amplification, enhancing detection capabilities despite challenges related to the small size and single epitope recognition of the nanobodies. Comparative studies using microplates and NHS@MF membranes were also performed. The superior performance of the NHS@MF membranes highlighted their potential as a promising alternative for point-of-care testing. The assay exhibited high specificity for human mEH and minimal cross-reactivity with related enzymes and effectively addressed matrix effects in plasma and tissue samples. These findings underscore the potential of double nanobody sandwich ELISAs for reliable and sensitive biomarker detection.

Comparison of microbial strains for tolerance to and catabolism of lignin stream constituents toward evaluating microbial hosts for lignin bioconversion.

We propose a trajectory-based quasi-classical method for approximating dynamics in condensed phase systems. Building upon the previously developed optimized mean trajectory approximation that has been used to compute linear and nonlinear spectra, we borrow some ideas from filtering trajectory methods to obtain a novel semiclassical method for the dynamical propagation of density matrices. This new approximation is tested rigorously against standard multistate electronic models, spin-boson models, and models of the Fenna-Matthews-Olson complex. For dissipative systems, the current method is significantly better or as good as many other semiclassical methods available, especially at low temperatures and for off-diagonal density matrix elements, whereas for scattering models, the current method bears similar limitations as mean-field propagation schemes. All results are tested against the numerically exact hierarchical equations of motion method. The new method shows excellent agreement across various parameter regimes with numerically exact results, highlighting the robustness and accuracy of our approach.

Given its relevance across numerous fields, reductive amination is one of the oldest and most widely used methods for amine synthesis. As a cornerstone of synthetic chemistry, it has largely remained unchanged since its discovery over a century ago. Herein, we report the mechanistically driven development of a complementary reaction, which reductively aminates the C-C σ-bond of carbonyls, not the carbonyl C-O π-bond, generating value-added linear and cyclic 3° amines in a modular fashion. Critical to our success were mechanistic insights that enabled us to modulate the resting state of a borane catalyst, minimize deleterious disproportionation of a hydroxylamine nitrogen source, and control the migratory selectivity of a key nitrenoid reactive intermediate. Experiments support the reaction occurring through a reductive amination/reductive Stieglitz cascade, via a ketonitrone, which can be interrupted under catalyst control to generate valuable N,N-disubstituted hydroxylamines. The method reported herein enables net transformations that would otherwise require lengthy synthetic sequences using pre-existing technologies. This is highlighted by its application to a two-step protocol for the valorization of hydrocarbon feedstocks, the late-stage C-C amination of complex molecules, diversity-oriented synthesis of isomeric amines from a single precursor, and transposition of nitrogen to different positions within a heterocycle.

Single-crystal X-ray diffraction and electron paramagnetic resonance (EPR) spectroscopic experiments, complemented by quantum chemical DFT calculations, were carried out on the copper-doped metal-organic hybrid and Tutton salt analogue zinc creatininium sulfate to determine its crystal structure, to characterize the electronic structure of the doped Cu(II) binding site, and to propose a pathway for an excited-state, proton-coupled electron transfer (PCET) process in UV-exposed crystals. The crystal structure is isomorphous to that of cadmium creatininium sulfate, which has the transition ion, not in direct coordination with the creatinine, but forming a hexahydrate complex, which is bridged to a creatininium through an intervening sulfate ion. The EPR g (2.446, 2.112, 2.082) and copper hyperfine (ACu: -327, -59.6, 10.8 MHz) tensor parameters are consistent with doped copper replacing host zinc in the metal-hexahydrate complex. These parameters are similar to those observed for copper hexahydrate in doped Tutton salt systems at low temperature, where the unpaired electron occupies mainly the copper 3dx2-y2 orbital. At room temperature in the Tutton systems, vibration couplings stemming from a dynamic Jahn-Teller effect cause tensor averaging which results in a reduction in their maximum g-tensor and hyperfine tensor values. However, like for the doped isomorphous Cd creatinine crystal, the Cu(II) EPR exhibits little, or no room temperature averaging compared to its low temperature pattern. Samples exposed to 254 nm UV light generate a carbon-centered free radical species, characterized by an isotropic g-tensor (g = 2.0029) and an alpha-proton hyperfine coupling (-24 -14 +4 G). These parameters identify it as a creatinine radical cation formed by the oxidative release of one of its C2 methylene hydrogens. DFT calculations confirm the unpaired electronic structures of both the Cu(II) site and free radical. The growth in radical concentration with an increase in the UV exposure time coincides with a decrease in the copper EPR signal, indicating a coupled light-induced oxidation reduction process. A comparison of the crystal structure with the EPR parameters and DFT results provides evidence for a UV-induced PCET.

It is well-known that addition of a cationic functional group to a molecule lowers the necessary applied potential for an electron transfer (ET) event. This report studies the effect of a proton (a cation) on the mechanism of electrochemically driven hydride transfer (HT) catalysis. Protonated, air-stable [HFe4N(triethyl phosphine (PEt3))4(CO)8] (H4) was synthesized by reaction of PEt3 with [Fe4N(CO)12]- (A -) in tetrahydrofuran, with addition of benzoic acid to the reaction mixture. The reduction potential of H4 is -1.70 V vs SCE which is 350 mV anodic of the reduction potential for 4 -. Reactivity studies are consistent with HT to CO2 or to H+ (carbonic acid), as the chemical event following ET, when the electrocatalysis is performed under 1 atm of CO2 or N2, respectively. Taken together, the chemical and electrochemical studies of mechanism suggest an ECEC mechanism for the reduction of CO2 to formate or H+ to H2, promoted by H4. This stands in contrast to an ET, two chemical steps, followed by an ET (ECCE) mechanism that is promoted by the less electron rich catalyst A -, since A - must be reduced to A 2- before HA - can be accessed.

Emergent magnetic phenomena at interfaces represent a frontier in materials science, pivotal for advancing technologies in spintronics and magnetic storage. In this Letter, we utilize a suite of advanced X-ray spectroscopic and scattering techniques to investigate emergent interfacial ferromagnetism in oxide superlattices composed of antiferromagnetic CaMnO3 and paramagnetic CaRuO3. Our findings demonstrate that ferromagnetism exhibits an asymmetric profile and may extend beyond the interfacial layer into multiple unit cells of CaMnO3. Complementary density functional calculations reveal that the interfacial ferromagnetism is driven by the double exchange mechanism, facilitated by charge transfer from Ru to Mn ions. Additionally, defect chemistry, particularly the presence of oxygen vacancies, can play a crucial role in modifying the magnetic moments at the interface, possibly leading to the observed asymmetry between the top and bottom CaMnO3 interfacial magnetic layers. Our findings underscore the potential of manipulating interfacial ferromagnetism through point defect engineering.