ChemRxiv has grown into the premier preprint server for the chemical sciences, with a global audience and a wide array of scholarly content. On the service's fifth anniversary, we would like to reflect on the past five years and take a look at what is next for ChemRxiv.

A recent report from Leitch, Browne and co-workers demonstrated how a programmable jar heater delivers an efficient methodology for the Suzuki–Miyaura-type cross coupling reaction of aryl sulfamates and aryl boronic acid species. This methodology can be readily upscaled 200-fold using twin-screw extrusion methodologies, demonstrating scalability of mechanochemical catalytic processes.

Give your chemistry classroom a green overhaul with resources from the American Chemical Society Green Chemistry Institute, Beyond Benign, and the Center for Green Chemistry & Green Engineering at Yale. Many green chemistry online resources, journals, and textbooks for classroom and laboratory are available. Urgent adoption of these resources is needed.

Nanoplastics (NPs) pose a threat to the environment and human health but are challenging to detect and characterize in environmental samples. This Minireview covers established imaging and characterization techniques, with a focus on micro-spectroscopic techniques. More exotic advanced techniques to measure NP morphology and chemical fingerprints simultaneously are discussed, and challenges in detection of NPs using high-resolution imaging are outlined.

Thermocells are a type of battery that produces electricity from a temperature difference between the two electrodes. Recent studies have shown various molecular technologies can be effectively used in thermocells to increase the voltage. This Minireview provides a thorough comparison of four basic strategies—redox entropy, molecular recognition, phase separation, and phase transition—for boosting the thermoelectric efficiency.

Transition-metal-catalyzed denitrogenative annulation is a unique concept that has provided a new dimension for the construction of high-valued nitrogen heterocycles. This Review highlights the denitrogenative annulation concept applied to various 1,2,3-triazoles and 1,2,3,4-tetrazoles.

A highly compatible phototrophic community (HCPC) was developed through the integration of a CO₂ sequestration module and a super-coupled module, V. natriegens. Based on the HCPC platform, various chemicals could be directly synthesized from CO₂, enabling the overall release of −22.27 to −606.59 kgCO₂e kg⁻¹ in the end products. This study provides design guidance for photosynthetic communities and new opportunities for carbon-negative production.

Herein, we report a user friendly, scalable and safe procedure to convert aminoheterocycles to their hydroxylated analogues with a pyrylium tetrafluoroborate salt in combination with a hydroxamic acid. The protocol is characterized by a broad functional group tolerance, permitting the selective modification of biorelevant molecules. Mechanistic experiments allowed the identification of key intermediates involved throughout the transformation.

Reinforcing bismuth nanoparticles on laser-induced graphene nanosheets were introduced for an electrically rechargeable aqueous sodium-ion battery for the first time, which could achieve long-term operation stability based on a chemical anchoring effect.

Reaction of a hexagonal planar palladium complex having a [PdMg₃H₃] core with H₂ is reversible and leads to the formation of a new [PdMg₂H₄] tetrahydride species. DFT calculations support a mechanism for H₂ activation involving a ligand-assisted oxidative addition to Pd. These findings were exploited to develop a catalytic protocol for H/D exchange into magnesium hydride and zinc hydride bonds.

A metal-free double oxidation of unactivated alkenes has been developed to deliver unsaturated conjugated carbonyls. This practical procedure allows valorization of the olefinic feedstock with high chemo- and stereoselectivity as demonstrated by the syntheses of difficult-to-access building blocks and industrially relevant pheromones and kairomones.

Copper-catalyzed enantioconvergent radical C(sp³)−C(sp²) cross-coupling of tertiary alkyl bromides with organoboronate esters is developed to access synthetically valuable α-quaternary chiral β-lactams. The success of this work relies on the utilization of chiral N,N,N-ligands to forge the sterically congested C(sp³)−C(sp²) bonds.

Sodium diphenyl ketone is applied as a reducing reagent to compensate irreversible Na uptake at oxygen-containing functional groups and react with defective carbon for quasi-metallic Na to initiate robust SEI. It leads to ICE of 99.2 % and capacity retention of ≈100 % for 700 cycles in the full cells of presodiated hard carbon//Na₃V₂(PO₄)₃.

Asymmetric total synthesis of the hasubanan alkaloids periglaucines A–C, N,O-dimethyloxostephine and oxostephabenine is described. The key strategies include: 1) a Rh^I-catalyzed regio- and diastereoselective Hayashi-Miyaura reaction; 2) an intramolecular photoenolization/Diels–Alder (PEDA) reaction; and 3) bio-inspired intramolecular Michael addition and transannular acetalization.

The electrochemical performances of Zn metal anodes are adjusted using functionalized ionic liquid and phosphate-based safe organic solvents, resulting in high Columbic efficiency (CE) of over 99 %, long cycle life up to 5.0 mA cm⁻², and large areal capacity of 10 mAh cm⁻². The interface derived from ionic liquid effectively accelerates the Zn nucleation, ensures smooth deposition, and reduces side reactions.

Conjugated 3D naphthalene diimide (NDI) based conductive porous coordination polymers (PCPs) with tunable conductivity and pore structure are developed as chemiresistors for room-temperature gas sensors. The Zn−pyNDI can serve as a room-temperature operable chemiresistive sensor selective to acetone.

We report a universal approach for reducing the limit of detection of lateral flow immunoassay. This approach utilizes electrophoresis-driven migration of biotin- and streptavidin-modified gold nanoparticles for layer-by-layer assembly of aggregates directly on the test strip. As a result, a 60-times lower limit of detection of hepatitis B antigen is achieved.

Achieving high-performance electroluminescence under large deformation remains a grand challenge. In this contribution, a general concept based on the self-confinement effect has been proposed for the design and synthesis of non-blended intrinsically stretchable electroluminescent elastomers (ISEEs). High-performance non-blended stretchable OLEDs have been constructed based on the resulting ISEEs.

Precisely designed dual-excimer emissive crystals have been synthesized in which two types of π-stacking patterns coexist alternately in the crystalline state. Consequently, two kinds of excimer emission are observed in the different wavelength regions. Moreover, the steric hindrance of the methyl substituent perturbs the intensity ratio of the two excimer emissions and the fluorescence color can be tuned.

A mild one-pot condensation/light-mediated cyclisation reaction leading to a diverse range of densely functionalised tetrahydroquinoline and quinoline products is described, proceeding via divergent electrocyclisation and photoredox pathways, respectively. Thorough exploration of the reaction substrate scope, reaction intermediates and mechanistic pathways uncovers the key driving forces for the observed reactivity and stereochemistry.

We report a new mechanism where aptamer leverages cellular proteasomal degradation system to degrade protein for cancer treatment. A DNA aptamer binds to extracellular domain of mesenchymal-epithelial transition factor (c-Met), and induces c-Met phosphorylation at Y1003 and Y1349. The phosphorylation of Y1003 recruits the E3 ubiquitin ligase casitas B-lineage lymphoma (c-cbl), which causes c-Met ubiquitination and degradation in proteasome.

The isomerization of pairs of electronically tuned oxoiron(IV) geometrical isomers is described, as a model for the “ferryl flip” observed in non-heme enzymes. The position of the oxo ligand in the coordination sphere of the iron center has a strong impact on the hydrogen-atom transfer (HAT) activity of the oxoiron(IV) compounds, while electronic effects do not play a significant role in HAT reactions.

An aggregation-induced emission (AIE) probe, DNTPH, was designed by balancing hydrophobic and hydrophilic moieties. DNTPH displays excellent blood–brain barrier permeability and binds to β-amyloid Aβ₄₂ fibrils selectively. Remarkably, DNTPH exhibits a strong inhibitory effect on Aβ fibrosis, thus attenuating Aβ-induced neurotoxicity in Alzheimer's disease (AD) mice. DNTPH serves as the first AIE in vivo theranostic agent for near-infrared imaging of Aβ₄₂ plaques and AD therapy.

Carbon materials are attractive alternatives to metal catalysts in terms of price and reduced environmental impact. However, the influence of structural modifications on the catalytic activity of carbon materials is poorly understood. General trends in the catalytic activity of nitrogen-doped carbons are identified using a holistic approach to carbocatalysis.

As hibiscus flowers bloom in the morning and close at night, hydrazone derivatives exhibit photoresponsive behavior as a function of an excitation wavelength. While hydrazone “flowers” wilt in the wrong environment, they blossom in a MOF “vase”. Thus, integration of hydrazone-photoswitches in proper 3D environments cultivates solution-like photophysical properties in solid-state materials and allows for modulation of energy transfer processes.

Rectangular π-conjugated ladder polymers of one particular handedness provide a square answer to the question of delocalization of their lowest-energy photoexcitation: the coupling to vibrations makes the excitation shaky. Exciton localization is a dynamic process and the excitation “breathes” in concert with the zero-point vibrational motion.

Simple ortho-phthalaldehyde (OPA) reagent enables a facile and broadly applicable bioconjugation strategy via hetero-selective clamping of two different endogenous amino handles such as ϵ-NH₂ of lysine and α-NH₂ of α-amino acids without any pre-functionalization.

An unprecedented, economical one-pot access to enantiopure N−H tetrahydropyridines is achieved by coupling a few readily available substrates with commercially available 1,3-amino alcohols via catalytic borrowing hydrogen. Highly diastereoselective functionalizations of tetrahydropyridines also result in a general access to enantiopure di- and tri-substituted piperidines, which rank among the most frequent N-heterocycles in commercial drugs.

Amorphous conjugated polymers represent another kind of polymer semiconductor with a different charge transporting mechanism. An n-type conjugated polymer with rigid, straight and planar backbone has now been designed and synthesized. It is amorphous in a thin film but exhibits an electron mobility of 0.34 cm² V⁻¹ s⁻¹.

An unusual catalytic coupling reaction of cycloheptatriene and cycloalkenones with amines proceeds through a skeleton-reorganization process for the selective synthesis of fused 1,2-dihydroquinolines. Mechanistic studies indicate that the reactions proceed through a retro-Mannich-type ring-opening and a subsequent intramolecular Povarov process.

We report on a new class of 1D double perovskite-inspired materials (DFPD)₂M^IInBr₆ (DFPD=4,4-difluoropiperidinium, M^I=K⁺ and Rb⁺), which exhibit an intrinsic warm-white light emission. Further enhancement is achieved by 0.3 % Sb³⁺ doping, which boosts PLQY to ≈92 %. Warm white light-emitting diodes based on single component (DFPD)₂KInBr₆:Sb are fabricated.

Two distinct sites for ion accommodation are found in an electrochromic transition-metal-oxide (ETMO) nanowire film by the galvanostatic transmittance evolution: the normal site and the abnormal site. Ions at the abnormal sites contribute little to coloration but retard the shuttling rate. These findings give a clear picture of the ion shuttling process, allowing the electrochromic performance to be enhanced for the design of efficient smart windows.

Platinum complex OPA shows a potent chemoimmunotherapeutic effect on tumors by impeding DNA replication and inhibiting the triggering receptor expressed on myeloid cells-2 (TREM2). OPA promotes the polarization of macrophages from immunosuppressive M2 to tumoricidal M1 phenotype, and stimulates dendritic, cytotoxic T, and natural killer cells to restrain cancer cells. By transforming the tumor microenvironment, OPA overcomes the tumor resistance to platinum drugs.

Pt clusters of 1.5 nm supported on anatase TiO₂ transform exclusively into CsCl-type PtTi intermetallic compound particles that grow epitaxially along the TiO₂ (101) planes after H₂ reduction at 700 °C. The formation of PtTi occurs through migration of reduced metallic Ti atoms into Pt clusters. The thermally stable PtTi intermetallic exhibits enhanced catalytic activity and promoted catalytic durability for CO oxidation.

A highly active heterogeneous chiral frustrated Lewis pair system has been achieved for the first time via incorporating the rationally designed bifunctional chiral FLP molecules into MOF under the guidance of computational studies; the afforded CFLP@MOF demonstrated superb catalysis performances in heterogeneous asymmetric hydrogenation with excellent recyclability/regenerability.

Infrared diffusion-ordered spectroscopy is a simple and cost-effective way to simultaneously characterize size and chemical structure of molecules, molecular aggregates/complexes, or small particles.

A novel multifunctional polymer, poly(methyl methacrylate-co-acrylamide), was designed and utilized to synergistically passivate the under-coordinated Pb²⁺ and anchor the I^- of the [PbI₆]⁴⁻ octahedron on the surface of a perovskite film. This passivation leads to an enhancement in the open-circuit voltage from 1.12 to 1.22 V and improved stability in solar cell devices, with the device maintaining 95 % of the initial power conversion efficiency (PCE) over 1000 h of maximum power point tracking. Additionally, a large-area solar cell device was fabricated using this approach, achieving a PCE of 20.64 %.

A host–guest dual-response supramolecular polymer was prepared based on a dimeric hypoxia-responsive azocalixrene and GSH-cleavable CPT dimer (D-CPT), which further self-assembles into nanoparticles and exhibits excellent antitumor therapy performance.

The development of a novel trehalose-based fluorogenic probe that features a molecular rotor turn-on fluorophore with exceptionally bright far-red emission is described (RMR-Tre). RMR-Tre enables rapid, no-wash, low-background fluorescence detection and drug-susceptibility evaluation of live mycobacteria, including Mycobacterium tuberculosis.

The Prelog rule in l-threonine aldolase holds that when the C_α anion of PLP-Gly attacks the carbonyl carbon atom of the aldehyde from the re-face, the (2S,3S)-configured product is formed, whereas attack from the si-face forms the (2S,3R)-configured product. Guided by this rule, mutants of LTA with improved diastereoselectivity of 99.2 %_syn and 97.4 %_anti were obtained.

An excellent enantioselective hydroamination of arylalkenes with Lewis basic secondary amines was developed, via an elegant cobalt-hydride mediated oxidative hydrogen atom transfer (MHAT) process, leading to the synthesis of a series of valuable α-chiral tertiary amines in good to excellent yields and enantioselectivities.

An in vivo selection strategy is presented, in which bacteria addicted to non-canonical amino acids (ncAAs) are complemented by enzymes that can yield these building blocks from synthetic precursors. As growth rates under selective conditions correlate with enzyme activities, serial passaging elicited better biocatalysts from populations harboring enzyme libraries. The platform was used to improve the activity of carbamoylases for ncAA-precursors.

An atypical force distribution along block copolymer (BCP) chains is seen when these are mechanically stressed. Mechanophores are more efficiently activated in a segment in a BCP that is far from the chain center than when in a fully loaded multi-mechanophore homopolymer.

An array of well-controlled Au single particles or oligomers was printed on an electrode surface, and used as a high-throughput platform to investigate the plasmon enhanced electrochemiluminescence (ECL) at the single-nanoparticle level. This ECL microscopy can visualize and quantify the electrochemical reactions of multiple individual NPs from wide-field imaging simultaneously.

We report on a rational strategy to clamp the molecular conformation and facilitate parallel packing of achiral D-A molecules. This leads to spontaneous symmetry breaking during crystallization. When this emergent homochirality is coupled with the optical gain of the molecules, the homochiral crystals can be explored as excellent circularly polarized micro-lasers with low lasing threshold (16.4 μJ cm⁻²) and high dissymmetry factor g_lum (0.9).

Using a series of organic charge transfer cocrystals with structural similarity and physicochemical tunability, we demonstrate the precise construction of various types of hierarchical organic microwires. Branch microwires with multichannel waveguide and core/shell microwires with multicolor waveguide performance can be integrated into branch core/shell microwires for realizing optical logic gates with multi-encoding functions.

Porous organic polymers with improved proton conductivity were prepared by modulating substituents with different electronic effects. The sulfonated materials showed top-tier conductivity, excellent long-term stability, and low activation energy.

Shape-persistent organic cages, porphyrin boxes (PBs), have been used to construct synthetic monosaccharide channels. These cages facilitate the transmembrane transport of glucose and fructose through their windows, while impeding the transport of larger sized sugars because of the limited size of the cage windows, thus facilitating size-selective transport. Live cells treated with the PBs show glucose uptake and enhanced cell viability.

The internalization of two bioorthogonal components mediated by the corresponding receptors, followed by inverse electron-demand Diels–Alder reaction leads to specific activation of the photodynamic action inside the target cells. This dual receptor-mediated bioorthogonal activation approach works as an AND logic device that can greatly enhance the precision of antitumoral photodynamic therapy.

The long-term ambiguity in mechanistic understanding of charge-transfer routes toward electrochemiluminescence generation has been deciphered in this study through the design of highly tunable quantum dot aerogels as novel luminophores. The interparticle charge-transfer route has been explicitly demonstrated and selectively enhanced based on the strong electronic coupling of quantum dot aerogels.

Two chemical-fuel-driven non-equilibrium DNA-based enzymatic reaction networks have been coupled with a RNA transcription system to achieve cross-regulation and feedback between each other. This approach gives different types of signal outputs, including repression, promotion, repression-recovery, and promotion-stop.

Redox organic molecules feature reversible redox-tuned discrete-aggregate conversion in solution. The resultant aggregation-regulated electrochemistry (ARE) offers a new mechanism to optimize the flow battery's performance.

With utilization of conformationally controlled ligand converters, different kinds of non-nucleic acid molecules, including both small molecules and proteins, can be integrated into nucleic acid computation to construct circuitries with increased complexity and scalability and to even perform algorithmic calculations. This hybridized system establishes a universal platform for molecular computation.

Reticulation of chiral 1,1′-biphenol-based imidodiphosphoric acid (IDP) into two Dy metal-organic frameworks (MOFs) allows controlling the organocatalyst conformations and local chiral microenvironments. The MOF containing the 4-connected IDPs has a less compact shape and can be an efficient and recyclable heterogeneous Brønsted acid catalyst for the challenging asymmetric O,O-acetalization of diol and aldehyde with up to 96 % ee.

Mono-alkene-inserted [n]cycloparaphenylenes ([n]CPP) 1 with n=6, 8, and 10, mono-ortho-phenylene-inserted [6]CPP 2, and di-alkene-inserted [n]CPP with n=4, 6, and 8 were synthesized by inserting alkene or ortho-phenylene units into a CPP skeleton. 1 and 2 exhibited a Möbius topology only in the solid state, but mono-alkene-inserted [6]CPP with eight 1-pyrrolyl groups preserved the Möbius topology even in solution.

A rapid and scalable synthesis of aldehydes from carboxylic acids is achieved by employing pinacolborane as a reducing agent and a triflylpyridinium as an activating reagent. Theoretical studies exhibit that the reduction of acylpyridinium requires a lower activation free energy than that of product aldehyde. This method features a wide substrate scope. Flow synthesis and the synthesis of deuterated aldehydes are achieved.

This work discovered that fluorescence protein chromophore analogs can undergo triplet excitation state, enabling photo-crosslinking and photo-sensitizing chemistries. Exploration of these synthetic fluorescent protein chromophores resulted in photo-crosslinkers for biomolecules, photo-catalysts for organic reactions, and photosensitizers for chromophore-assisted light inactivation and photodynamic therapies.

We report an unprecedentedly high power- and energy-density supercapacitor through the chlorine respiration in porous carbon materials. Both electrochemical results and theoretical calculations show that porous carbon with pore size around 3 nm delivers the best chlorine evolution and adsorption performance.

A dimethylaminocarbene-mediated orifice expansion gave the first near-infrared-absorbing chiral open [60]fullerenes. The introduced aminomethylidene moiety is well-conjugated with the fullerene cage, thus considerably elevating the HOMO level as supported by the electrochemical analysis. The optical resolution revealed a large dissymmetry factor of g_abs=±0.12 at 820 nm in o-dichlorobenzene.

The hydrogen oxidation reaction (HOR) performance of Ru-Ru₂P/C heterostructure is explored in the whole pH range. Unexpectedly, a non-monotonous relationship between the HOR activities and the pH of electrolytes is observed. Moreover, its HOR performance in alkaline media is much higher than that in acidic media, highlighting the role of discrepant intermediates for pH-universal HOR.

An unconventional umpolung protocol was demonstrated for novel 1,5-conjugate additions via palladium hydride catalyst. Three catalytic reaction modes including 1,5-addition cascade with inter- and intramolecular [3+2] cyclization and migratory 1,5-addition were established via palladium or palladium/organo-cocatalysis.

A stereodivergent Csp³−Csp³ coupling of 1,3-dienes with oxindoles was achieved by synergizing a palladium and a chiral phase-transfer catalyst in a biphasic system. Both the syn and anti products, which have vicinal quaternary and tertiary stereocenters, could be selectively achieved in good yields with high enantio- and diastereoselectivities. This is the first stereodivergent synthesis via metal/phase-transfer catalysis.

Coupling mechanochemistry and single-electron transfer processes in a ball mill facilitates an efficient reversible addition-fragmentation chain transfer polymerization reaction. A versatile mechanoredox process is developed to synthesize macromolecules with good molar mass control. This method serves as an alternative to access complex polymers that may be difficult to access using traditional solution-state processes.

Inspired by the unique structure of cell membranes, a mixed-matrix membrane (MMM) with penetrating subnanochannels was developed based on a soft-substrate assisted solution casting method for selective conduction of monovalent metal ions. Thanks to the diversity of nanoporous materials and polymer matrix, we expect that the penetrating MMMs could be developed into a versatile nanofluidic platform and offer new possibilities for practical applications.

Die strukturelle Evaluation des Bam-Komplexes mit Darobactin 9 mittels Kryo-EM, in Verbindung mit der Bewertung der Bioaktivität führte zur Biosynthese neuer Derivate mit erhöhter Aktivität gegen Gram-negative Krankheitserreger, einschließlich klinisch relevanter Isolate. Das derzeit vielversprechendste Derivat Darobactin 22 resultierte aus dem struktur- und aktivitätsgeleiteten Ansatz und zeigte eine bis zu 128-fach erhöhte Aktivität im Vergleich zum nativen Darobactin A.

Die Shuttle-Katalyse entwickelt sich zu einer wirksamen Strategie, um eine noch nie dagewesene synthetische Flexibilität in der organischen Synthese zu erreichen. In diesem Artikel zeigen wir ein seltenes Beispiel für eine Shuttle-Heterodifunktionalisierung zur Übertragung von zwei verschiedenen funktionellen Gruppen zwischen β-Halogensulfiden und Alkinen mit ausgezeichneter Chemo-, Regio- und Stereoselektivität über einen gepaarten Elektrolyseprozess. Dadurch eröffnen sich neue Möglichkeiten für selektive Shuttle-Difunktionalisierungsreaktionen.

A polytriphenylamine (PTPAn) composite cathode is employed for high-voltage (∼3 V) rechargeable Mg and Ca batteries based on the tetrakis(hexafluoroisopropyloxy) borate [B(hfip)₄] anion storage chemistry. Mechanistic studies elucidate the unique redox reactivity of the amine moieties in the active cathode material. These divalent metal batteries exhibit both high energy and high power-density and long cycle-life.

Nachhaltige Batterietechnologie: Die Kombination von Deep Eutectic Solvents (DESs) mit TEMPO-basierten Elektroden eröffnet einen neuen Weg zur umweltfreundlichen Energiespeicherung in vollorganischen Batterien. Insbesondere das eutektische Gemisch des DES aus Natriumbis(trifluormethansulfonyl)imid und N-Methylacetamid ermöglicht stabiles und effizientes Zykeln der Polymerelektroden.