Intrinsically stretchable organic photovoltaics by redistributing strain to PEDOT:PSS with enhanced stretchability and interfacial adhesion.

Intrinsically stretchable organic photovoltaics have emerged as a prominent candidate for the next-generation wearable power generators regarding their structural design flexibility, omnidirectional stretchability, and in-plane deformability. However, formulating strategies to fabricate intrinsically stretchable organic photovoltaics that exhibit mechanical robustness under both repetitive strain cycles and high tensile strains remains challenging. Herein, we demonstrate high-performance intrinsically stretchable organic photovoltaics with an initial power conversion efficiency of 14.2%, exceptional stretchability (80% of the initial power conversion efficiency maintained at 52% tensile strain), and cyclic mechanical durability (95% of the initial power conversion efficiency retained after 100 strain cycles at 10%). The stretchability is primarily realised by delocalising and redistributing the strain in the active layer to a highly stretchable PEDOT:PSS electrode developed with a straightforward incorporation of ION E, which simultaneously enhances the stretchability of PEDOT:PSS itself and meanwhile reinforces the interfacial adhesion with the polyurethane substrate. Both enhancements are pivotal factors ensuring the excellent mechanical durability of the PEDOT:PSS electrode, which further effectively delays the crack initiation and propagation in the top active layer, and enables the limited performance degradation under high tensile strains and repetitive strain cycles.

Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis.

Hexavalent iridium (IrVI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (IrVI-ado) for proton exchange membrane (PEM) water electrolysis. The IrVI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 × 105 amperes per gram of iridium) and turnover number (1.5 × 108) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of IrVI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of IrVI-ado showcase its promise as an anode material for PEM electrolysis.

Copper sulfide mineral performs non-enzymatic anaerobic ammonium oxidation through a hydrazine intermediate.

Anaerobic ammonium oxidation (anammox)-the biological process that activates ammonium with nitrite-is responsible for a significant fraction of N2 production in marine environments. Despite decades of biochemical research, however, no synthetic models capable of anammox have been identified. Here we report that a copper sulfide mineral replicates the entire biological anammox pathway catalysed by three metalloenzymes. We identified a copper-nitrosonium {CuNO}10 complex, formed by nitrite reduction, as the oxidant for ammonium oxidation that leads to heterolytic N-N bond formation from nitrite and ammonium. Similar to the biological process, N2 production was mediated by the highly reactive intermediate hydrazine, one of the most potent reductants in nature. We also found another pathway involving N-N bond heterocoupling for the formation of hybrid N2O, a potent greenhouse gas with a unique isotope composition. Our study represents a rare example of non-enzymatic anammox reaction that interconnects six redox states in the abiotic nitrogen cycle.

Triple Isomerism in 3D Covalent Organic Frameworks.

Isomerism in covalent organic frameworks (COFs) has scarcely been known. Here, for the first time we show 3D COFs with three framework isomers or polymorphs constructed from the same building blocks. All isomers were obtained as large (>10 µm) crystals; although their crystal shapes were distinctly different, they showed identical FT-IR and solid-state NMR spectra. Our structural analyses revealed unprecedented triple isomerism in 3D COFs (noninterpenetrated dia, qtz, and 3-fold interpenetrated dia-c3 nets). Furthermore, this Communication reports the first known COF with qtz topology for which the structure determination was based on Rietveld analysis. We achieved triple framework isomerism by reticulating a tetrahedral building block with a flexible junction and a linear building block with PEO side chains and by varying solution compositions. Our energy calculations, along with the discovery of interisomer transition, revealed that the isomer with qtz topology was a kinetic isomer. Thus, this simple yet little-explored concept of reticulating only flexible building blocks is an effective pathway to significantly broaden the diversity of 3D COFs, which have been proposed for a myriad of applications.

Long Time CO2 Storage Under Ambient Conditions in Isolated Voids of a Porous Coordination Network Facilitated by the "Magic Door" Mechanism.

A coordination network containing isolated pores without interconnecting channels is prepared from a tetrahedral ligand and copper(I) iodide. Despite the lack of accessibility, CO2 is selectively adsorbed into these pores at 298 K and then retained for more than one week while exposed to the atmosphere. The CO2 adsorption energy and diffusion mechanism throughout the network are simulated using Matlantis, which helps to rationalize the experimental results. CO2 enters the isolated voids through transient channels, termed "magic doors", which can momentarily appear within the structure. Once inside the voids, CO2 remains locked in limiting its escape. This mechanism is facilitated by the flexibility of organic ligands and the pivot motion of cluster units. In situ powder X-ray diffraction revealed that the crystal structure change is negligible before and after CO2 capture, unlike gate-opening coordination networks. The uncovered CO2 sorption and retention ability paves the way for the design of sorbents based on isolated voids.

Chemical Storage of Ammonia through Dynamic Structural Transformation of a Hybrid Perovskite Compound.

Toward renewable energy for global leveling, compounds that can store ammonia (NH3), a carbon-free energy carrier of hydrogen, will be of great value. Here, we report an organic-inorganic halide perovskite compound that can chemically store NH3 through dynamic structural transformation. Upon NH3 uptake, a chemical structure change occurs from a one-dimensional columnar structure to a two-dimensional layered structure by addition reaction. NH3 uptake is estimated to be 10.2 mmol g-1 at 1 bar and 25 °C. In addition, NH3 extraction can be performed by a condensation reaction at 50 °C under vacuum. X-ray diffraction analysis reveals that reversible NH3 uptake/extraction originates from a cation/anion exchange reaction. This structural transformation shows the potential to integrate efficient uptake and extraction in a hybrid perovskite compound through chemical reaction. These findings will pave the way for further exploration of dynamic, reversible, and functionally useful compounds for chemical storage of NH3.

Crown ether salt-doped ladder-type conducting polymers for air-stable n-type thermoelectric materials.

Thermoelectric energy harvesters based on p- and n-type organic semiconductors are in high demand, while the air stability of n-type devices has long been a challenge. Here, we demonstrate that supramolecular salt-functionalized n-doped ladder-type conducting polymers exhibit excellent stability in the presence of dry air.

Direct Interfacial Excitation from TiO2 to Cu(II) Nanoclusters Enables Cathodic Photoresponse for Hydrogen Evolution under Visible-Light Irradiation.

The titanium dioxide (TiO2 ) photocatalyst is only active under UV irradiation due to its wide-gap nature. A novel excitation pathway denoted as interfacial charge transfer (IFCT) has been reported to activate copper(II) oxide nanoclusters-loaded TiO2 powder (Cu(II)/TiO2 ) under visible-light irradiation for only organic decomposition (downhill reaction) so far. Here, the photoelectrochemical study shows that the Cu(II)/TiO2 electrode exhibits a cathodic photoresponse under visible-light and UV irradiation. It originates from H2 evolution on the Cu(II)/TiO2 electrode, while O2 evolution takes place on the anodic side. Based on the concept of IFCT, a direct excitation of electrons from the valence band of TiO2 to Cu(II) clusters initiates the reaction. This is the first demonstration of a direct interfacial excitation-induced cathodic photoresponse for water splitting without any addition of a sacrificial agent. This study is expected to contribute to the development of abundant visible-light-active photocathode materials for fuel production (uphill reaction).

Chiral Counteranion-Directed Catalytic Asymmetric Methylene Migration Reaction of Ene-Aldimines.

A catalytic asymmetric methylene migration reaction of ene-aldimines directed by chiral counteranions is developed, with the optimal catalyst identified as phenanthryl-substituted (R)-BINOL phosphate. Control experiments and density functional theory computations reveal the importance of the 2-hydroxy group of the ene-aldimine and attractive (e.g., OH···O, CH···O, CH···π, and π···π) interactions for high enantioselectivity (up to 74% ee). The results contribute to the design of asymmetric catalysis for the rearrangement of highly reactive iminium intermediates.

Triphenyleno[1,2-c:7,8-c']bis([1,2,5]thiadiazole) as a V-Shaped Electron-Deficient Unit to Construct Wide-Bandgap Amorphous Polymers for Efficient Organic Solar Cells.

The backbone shape of semiconducting polymers strongly affects their electronic properties and morphologies in films, yet the conventional design principle for building blocks focuses on using linear main chains to maintain high crystallinity. Here, we developed a V-shaped unit, triphenyleno[1,2-c:7,8-c']bis([1,2,5]thiadiazole) (TPTz), featuring two 1,2,5-thiadiazole rings fused to a triphenylene core with strong electron-withdrawing properties and an extended conjugation plane. We used TPTz to prepare a highly soluble copolymer, PTPTz-indacenodithiophene (IDT), which exhibited a wide bandgap of 1.94 eV and energy levels suitable for the donor polymer in organic solar cells (OSCs) in combination with non-fullerene acceptors. Despite the amorphous nature of the polymer film, single-junction OSCs with PTPTz-IDT:Y6 as the active layer achieved a power conversion efficiency of 10.4% (JSC = 19.8 mA cm-2; VOC = 0.80 V; fill factor = 0.66), which is the highest value reported for a single-junction OSC with IDT-based donor polymers. This work demonstrates that TPTz is a promising electron-acceptor unit for developing functional polymers with zigzag structures.

Correction: Synthetic-biology-based discovery of a fungal macrolide from Macrophomina phaseolina.

Correction for 'Synthetic-biology-based discovery of a fungal macrolide from Macrophomina phaseolina' by Yohei Morishita et al., Org. Biomol. Chem., 2020, DOI: 10.1039/d0ob00519c.

Synthetic-biology-based discovery of a fungal macrolide from Macrophomina phaseolina.

A synthetic biology approach based on genome mining and heterologous biosynthesis is a powerful tool for discovering novel natural products from a tremendous gene resource. We carried out fungal genome mining guided by a polyketide synthase gene using a public database and found a putative macrolide biosynthetic gene cluster with a highly reducing polyketide synthase gene and a thioesterase gene in Macrophomina phaseolina. Reconstitution of the cluster in Aspergillus oryzae, a model heterologous host for fungal natural product biosynthesis, produced a new 12-membered macrolide, phaseolide A. The absolute stereochemistry was elucidated by vibrational circular dichroism spectroscopy and the crystalline sponge method.

Brønsted Acid-Initiated Formal [1,3]-Rearrangement Dictated by ß-Substituted Ene-Aldimines.

The rearrangement of ene-aldimines is a useful reaction for affording homoallylic amines. Despite their utilities in synthetic chemistry, the rearrangement for accessing homoallylic amines substituted at the 2-position remains elusive. In this study, the Brønsted acid-initiated formal [1,3]-rearrangement of ene-aldimines was developed to synthesize 2,4,4-substituted homoallylic amines that were otherwise inaccessible previously. Our study reveals an intermolecular pathway in which the rearrangement proceeds via a protonation-mediated 2-azaallenium cation.