Copper 1,19-Diaza-21,24-dicarbacorrole: A Corrole Analogue with an N−N Linkage Stabilizes a Ground-State Singlet Organocopper Species

A copper complex of a heterocorrole analogue with an N–N linkage, 1,19-diaza-21,24-dicarbadibenzocorrole ( Cu-5 ), was successfully synthesized via oxidative metalation–cyclization of a tetrapyrrolic precursor. The N–N linkage in the skeleton of Cu-5 , which serves as a mediator of π-electron delocalization, features an 18π aromatic system. The electronic structure of Cu-5 is best described as a ground-state singlet species stabilized by the distinct NNCC coordination core. This finding shows how the ligand's design can be used to modulate the Cu orbital energy, thereby making such compounds invaluable for copper-based catalytic applications.     

Double‐Gyroid Nanostructure Formation by Aggregation‐Induced Atropisomerization and Co‐Assembly of Ionic Liquid‐Crystalline Amphiphiles

We report a new molecular‐design principle for creating double‐gyroid nanostructured molecular assemblies based on atropisomerization. Ionic amphiphiles containing two imidazolium rings close to each other were designed and synthesized. NMR data revealed that the rotation of the imidazolium rings is restricted, with an activation energy as high as 63 kJ mol^?1 in DMSO‐d₆ solution (DFT prediction for a model compound in the vacuum: 90–100 kJ mol^?1). Due to the restricted rotation, the amphiphiles feature “double” atropisomeric axes in their ionic segments and form three stable atropisomers: meso, R, and S. These isomers co‐organize into ‐type bicontinuous cubic liquid‐crystalline mesophases through nanosegregation of the ionic and non‐ionic parts. Considering the intrinsic characteristic of ‐type bicontinuous cubic structures that they are composed of intertwined right‐ and left‐handed single gyroids, we propose that the simultaneous presence of both R‐ and S‐atropisomers is an important contributor to the formation of double‐gyroid structures.     

Phosphazenyl Phosphines: The Most Electron‐Rich Uncharged Phosphorus Brønsted and Lewis Bases

It was discovered that phosphazenyl phosphines (PAPs) can be stronger P‐superbases than the corresponding Schwesinger type phosphazene N‐superbases. A simple synthetic access to this class of PR₃ derivatives including their homologization is described. XRD structures, proton affinities (PA), and gas‐phase basicities (GB) as well as calculated and experimental pK values in THF are presented. In contrast to their N‐basic counterparts, PAPs are also privileged ligands in transition metal chemistry. In fact, they are currently the strongest uncharged P‐donors known, exceeding classical and more recently discovered ligands such as PtBu₃ and imidazolin‐2‐ylidenaminophosphines (IAPs) with respect to their low Tolman electronic parameters (TEPs) and large cone angles.     

In Situ Generated Gold Nanoparticles on Active Carbon as Reusable Highly Efficient Catalysts for a C −C Stille Coupling

Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional C ?C cross‐coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form C ?C bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross‐coupling reaction of an organic halide and an organometallic reagent.     

A Rare Low‐Spin CoIV Bis(β‐silyldiamide) with High Thermal Stability: Steric Enforcement of a Doublet Configuration

Attempted preparation of a chelated Co^II β‐silylamide resulted in the unprecedented disproportionation to Co⁰ and a spirocyclic cobalt(IV) bis(β‐silyldiamide): [Co[(N^tBu)₂SiMe₂]₂] ( 1 ). Compound 1 exhibited a room‐temperature magnetic moment of 1.8 B.M. and a solid‐state axial EPR spectrum diagnostic of a rare S= configuration for tetrahedral Co^IV. Ab initio semicanonical coupled‐cluster calculations (DLPNO‐CCSD(T)) revealed the doublet state was clearly preferred (?27 kcal mol^?1) over higher spin configurations only for the bulky tert‐butyl‐substituted analogue. Unlike other Co^IV complexes, 1 had remarkable thermal stability, and was demonstrated to form a stable self‐limiting monolayer in preliminary atomic layer deposition (ALD) surface saturation experiments. The ease of synthesis and high stability make 1 an attractive starting point to investigate otherwise inaccessible Co^IV intermediates and for synthesizing new materials.     

Modular and Selective Arylation of Aryl Germanes (C−GeEt3) over C−Bpin,C−SiR3 and Halogens Enabled by Light‐Activated Gold Catalysis

Selective C –C couplings are powerful strategies for the rapid and programmable construction of bi‐ or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd‐catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd⁰/Pd^II catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe₃, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light‐/gold‐catalyzed couplings of Ar–N₂⁺, which were specialized in Ar–N₂⁺ scope, we present conditions to efficiently couple electron‐rich, electron‐poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron‐poor Ar–N₂⁺ salts are readily activated by gold under blue‐light irradiation, there is a competing dissociative deactivation pathway for excited electron‐rich Ar–N₂⁺, which requires an alternative photo‐redox approach to enable productive couplings.     

Tuning the Hybridization of Local Exciton and Charge‐Transfer States in Highly Efficient Organic Photovoltaic Cells

Decreasing the energy loss is one of the most feasible ways to improve the efficiencies of organic photovoltaic (OPV) cells. Recent studies have suggested that non‐radiative energy loss ( ) is the dominant factor that hinders further improvements in state‐of‐the‐art OPV cells. However, there is no rational molecular design strategy for OPV materials with suppressed . Herein, taking molecular surface electrostatic potential (ESP) as a quantitative parameter, we establish a general relationship between chemical structure and intermolecular interactions. The results reveal that increasing the ESP difference between donor and acceptor will enhance the intermolecular interaction. In the OPV cells, the enhanced intermolecular interaction will increase the charge‐transfer (CT) state ratio in its hybridization with the local exciton state to facilitate charge generation, but simultaneously result in a larger . These results suggest that finely tuning the ESP of OPV materials is a feasible method to further improve the efficiencies of OPV cells.     

A Long Cycle‐Life High‐Voltage Spinel Lithium‐Ion Battery Electrode Achieved by Site‐Selective Doping

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) is a promising cathode candidate for the next‐generation high energy‐density lithium‐ion batteries (LIBs). Unfortunately, the application of LNMO is hindered by its poor cycle stability. Now, site‐selectively doped LNMO electrode is prepared with exceptional durability. In this work, Mg is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in the Fd m structure. This site‐selective doping not only suppresses unfavorable two‐phase reactions and stabilizes the LNMO structure against structural deformation, but also mitigates the dissolution of Mn during cycling. Mg‐doped LNMOs exhibit extraordinarily stable electrochemical performance in both half‐cells and prototype full‐batteries with novel TiNb₂O₇ counter‐electrodes. This work pioneers an atomic‐doping engineering strategy for electrode materials that could be extended to other energy materials to create high‐performance devices.     

Solvate‐Induced Semiconductor to Metal Transition: Flat [Bi1−] Zigzag Chains in Metallic KBi⋅NH3 versus [Bi1−] Helices in Semiconducting KBi

Polymeric [Bi]^? in KBi?NH₃ has planar zigzag chains with two‐connected Bi atoms and metallic properties, whereas KBi, which has helical chains of Bi atoms, is semiconducting. The isomerization of the Bi chain is induced by solvate molecules. In the novel layered solvate structure uncharged [KBi] layers are separated by intercalated NH₃ molecules. These layers are a structural excerpt of the iso(valence)electronic CaSi, whose metallic properties arise from the planarity of the zigzag chain of Si atoms. Computational studies support this view, they show an anisotropic metallic behavior along the Bi chain. Electron delocalization is also found in the new cyclic anion [Bi₆]^4? isolated in K₂[K(18‐crown‐6)]₂[Bi₆]?9 NH₃. Although [Bi₆]^4? should exhibit one localized double bond, electron delocalization is observed in analogy to the lighter homologues [P₆]^4? and [As₆]^4?. Both compounds were characterized by single‐crystal X‐ray structure determination.     

Harnessing Plasticity in an Amine‐Borane as a Piezoelectric and Pyroelectric Flexible Film

We demonstrate that trimethylamine borane can exhibit desirable piezoelectric and pyroelectric properties. The material was shown to be able operate as a flexible film for both thermal sensing, thermal energy conversion and mechanical sensing with high open circuit voltages (>10 V). A piezoelectric coefficient of d₃₃≈10–16 pC N^?1, and pyroelectric coefficient of p≈25.8 μC m^?2 K^?1 were achieved after poling, with high pyroelectric figure of merits for sensing and harvesting, along with a relative permittivity of 6.3.     

Linking Composition,Structure and Thickness of CoOOH layers to Oxygen Evolution Reaction Activity by Correlative Microscopy

The role of β-CoOOH crystallographic orientations in catalytic activity for the oxygen evolution reaction (OER) remains elusive. We combine correlative electron backscatter diffraction/scanning electrochemical cell microscopy with X-ray photoelectron spectroscopy, transmission electron microscopy, and atom probe tomography to establish the structure–activity relationships of various faceted β-CoOOH formed on a Co microelectrode under OER conditions. We reveal that ≈6 nm β-CoOOH(01 0), grown on [ 0]-oriented Co, exhibits higher OER activity than ≈3 nm β-CoOOH(10 3) or ≈6 nm β-CoOOH(0006) formed on [02 - and [0001]-oriented Co, respectively. This arises from higher amounts of incorporated hydroxyl ions and more easily reducible Co^III−O sites present in β-CoOOH(01 0) than those in the latter two oxyhydroxide facets. Our correlative multimodal approach shows great promise in linking local activity with atomic-scale details of structure, thickness and composition of active species, which opens opportunities to design pre-catalysts with preferred defects that promote the formation of the most active OER species.     

An Artificial Single Molecular Channel Showing High Chloride Transport Selectivity and pH-Responsive Conductance

Inspired by the unique structure and function of the natural chloride channel (ClC) selectivity filter, we present herein the design of a ClC-type single channel molecule. This channel displays high ion transport activity with half-maximal effective concentration, EC₅₀, of 0.10 μM, or 0.075 mol % (channel molecule to lipid ratio), as determined by fluorescent analysis using lucigenin-encapsulated vesicles. Planar bilayer lipid membrane conductance measurements indicated an excellent Cl⁻/K⁺ selectivity with a permeability ratio P /P up to 12.31, which is comparable with the chloride selectivity of natural ClC proteins. Moreover, high anion/anion selectivity (P /P =66.21) and pH-dependent conductance and ion selectivity of the channel molecule were revealed. The ClC-like transport behavior is contributed by the cooperation of hydrogen bonding and anion–π interactions in the central macrocyclic skeleton, and by the existence of pH-responsive terminal phenylalanine residues.     

Unprecedented Relaxivity Gap in pH-Responsive FeIII-Based MRI Probes

Two mononuclear ferric complexes are reported that respond to a pH change with a 27- and 71-fold jump, respectively, in their capacity to accelerate the longitudinal relaxation rate of water-hydrogen nuclei, and this starting from a negligible base value of only 0.06. This unprecedented performance bodes well for tackling the sensitivity issues hampering the development of Molecular MRI. The two chelates also excel in the fully reversible and fatigue-less nature of this phenomenon. The structural reasons for this performance reside in the macrocyclic nature of the hexa-dentate ligand, as well as the presence of a single pendant arm displaying a five-membered lactam or carbamate which show (perturbed) pK_a values of 3.5 in the context of this N6 N5O1 coordination motif.     

Perdeuterated Conjugated Polymers for Ultralow‐Frequency Magnetic Resonance of OLEDs

The formation of excitons in OLEDs is spin dependent and can be controlled by electron‐paramagnetic resonance, affecting device resistance and electroluminescence yield. We explore electrically detected magnetic resonance in the regime of very low magnetic fields (<1 mT). A pronounced feature emerges at zero field in addition to the conventional spin‐ Zeeman resonance for which the Larmor frequency matches that of the incident radiation. By comparing a conventional π‐conjugated polymer as the active material to a perdeuterated analogue, we demonstrate the interplay between the zero‐field feature and local hyperfine fields. The zero‐field peak results from a quasistatic magnetic‐field effect of the RF radiation for periods comparable to the carrier‐pair lifetime. Zeeman resonances are resolved down to 3.2 MHz, approximately twice the Larmor frequency of an electron in Earth's field. However, since reducing hyperfine fields sharpens the Zeeman peak at the cost of an increased zero‐field peak, we suggest that this result may constitute a fundamental low‐field limit of magnetic resonance in carrier‐pair‐based systems. OLEDs offer an alternative solid‐state platform to investigate the radical‐pair mechanism of magnetic‐field effects in photochemical reactions, allowing models of biological magnetoreception to be tested by measuring spin decoherence directly in the time domain by pulsed experiments.     

Metal Organic Framework Cubosomes

We demonstrate a general strategy for the synthesis of ordered bicontinuous-structured metal organic frameworks (MOFs) by using polymer cubosomes (PCs) with a double primitive structure (Im m symmetry) as the template. The filling of MOF precursors in the open channel of PCs, followed by their coordination and removal of the template, generates MOF cubosomes with a single primitive topology (Pm m) and average mesopore diameters of 60–65 nm. Mechanism study reveals that the formation of ZIF-8 cubosomes undergoes a new MOF growth process, which involves the formation of individual MOF seeds in the template, their growth and eventual fusion into the cubosomes. Their growth kinetics follows the Avrami equation with an Avrami exponent of n=3 and a growth rate of k=1.33×10⁻⁴, indicating their fast 3D heterogeneous growth mode. Serving as a bioreactor, the ZIF-8 cubosomes show high loading of trypsin enzyme, leading to a high catalytic activity in the proteolysis of bovine serum albumin.     

Ligand‐Enabled Enantioselective C –H Activation of Tetrahydroquinolines and Saturated Aza‐Heterocycles by RhI

The first rhodium(I)‐catalyzed enantioselective intermolecular C –H activation of various saturated aza‐heterocycles including tetrahydroquinolines, piperidines, piperazines, azetidines, pyrrolidines, and azepanes is presented. The combination of a rhodium(I) precatalyst and a chiral monodentate phosphonite ligand is shown to be a powerful catalytic system to access a variety of important enantio‐enriched heterocycles from simple starting materials. Notably, the C –H activation of tetrahydroquinolines is especially challenging due to the adjacent C −H bond. This redox‐neutral methodology provides a new synthetic route to α‐N‐arylated heterocycles with high chemoselectivity and enantioselectivity up to 97 % ee.     

A Symmetry-Broken Charge-Separated State in the Marcus Inverted Region

We report a long-lived charge-separated state in a chromophoric pair ( DC-PDI₂ ) that uniquely integrates the advantages of fundamental processes of photosynthetic reaction centers: i) Symmetry-breaking charge-separation (SB-CS) and ii) Marcus-inverted-region dependence. The near-orthogonal bichromophoric DC-PDI₂ manifests an ultrafast evolution of the SB-CS state with a time constant of =0.35±0.02 ps and a slow charge recombination (CR) kinetics with =4.09±0.01 ns in ACN. The rate constant of CR of DC-PDI₂ is 11 686 times slower than SB-CS in ACN, as the CR of the PDI radical ion-pair occurs in the deep inverted region of the Marcus parabola ( >λ). In contrast, an analogous benzyloxy (BnO)-substituted DC-BPDI₂ showcases a ≈10-fold accelerated CR kinetics with lowering to ≈1536 in ACN, by virtue of a decreased CR driving force. The present investigation demonstrates a control of molecular engineering to tune the energetics and kinetics of the SB-CS material, which is essential for next-generation optoelectronic devices.     

Graphdiyne Interface Engineering: Highly Active and Selective Ammonia Synthesis

A freestanding 3D graphdiyne–cobalt nitride (GDY/Co₂N) with a highly active and selective interface is fabricated for the electrochemical nitrogen reduction reaction (ECNRR). Density function theory calculations reveal that the interface‐bonded GDY contributes an unique p‐electronic character to optimally modify the Co‐N compound surface bonding, which generates as‐observed superior electronic activity for NRR catalysis at the interface region. Experimentally, at atmospheric pressure and room temperature, the electrocatalyst creates a new record of ammonia yield rate (Y ) and Faradaic efficiency (FE) of 219.72 μg h^?1 mg_cat.^?1 and 58.60 %, respectively, in acidic conditions, higher than reported electrocatalysts. Such a catalyst is promising to generate new concepts, new knowledge, and new phenomena in electrocatalytic research, driving rapid development in the field of electrocatalysis.