The reactivity of an osmium-peroxo unit supported by a metallacycle is enhanced upon diminishing metallacycle aromaticity. The less aromatically stabilized osmium-peroxo complex is readily protonated and converts selectively to an osmium-hydroxo complex. This work provides a strategy for tuning the reactivity of metal-oxygen species.

Divergent skeletal modification of aromatic systems is essential for generating molecular diversity, but it remains a significant challenge, typically relying on different individual strategies and starting materials. Herein, we report a tunable dual-to-single carbon insertion into an σ-aromatic metalla-cyclopropene. The key to this approach lies in an E/Z isomerization of two intermediates, in which the E-isomer undergoes dual-carbon insertion and the Z-isomer engages in single-carbon insertion of alkyne into the three-membered ring, proceeding via common [3+2] and unconventional [3+1] pathways, respectively. Both pathways originate from identical reagents, with E-to-Z isomerization of the intermediate achieved by easily modulating the timing of alkyne addition. This work highlights the pivotal role of E/Z isomerization in controlling the reaction selectivity and establishes a new paradigm for temporal control divergent skeletal editing.

Metal vinylidene complexes exhibit rich reactivity and play pivotal roles in catalytic alkyne transformations; however, the reactivity of cyclic metal vinylidene complexes has been scarcely explored, largely due to the limited availability of such species caused by high ring strain. In this work, we report the diverse reactivity of a cyclic osmium vinylidene embedded in a CNC pincer framework. The cyclic osmium vinylidene complex reacts with aryl alkynes to unveil the first shuttle reaction of a metal vinylidene unit. In contrast, halogenation is observed upon treatment with N-halosuccinimides, occurring electrophilic substitution at an alternative site rather than electrophilic addition at the osmium vinylidene carbon, as further rationalized by Fukui function analysis for regioselectivity. Moreover, the reaction of the cyclic osmium vinylidene complexes with isocyanides affords the rarely crystallographically characterized metallacyclopropanimine. Collectively, these findings not only expand the distinctive reactivity of metal vinylidenes but also enrich the chemistry of CNC pincer complexes.

Storing perovskite precursor solutions under ambient conditions poses a significant challenge to commercialization, as humidity and oxidation accelerate ageing and introduce defects in devices. A major contributor to solution ageing and impurity perovskite phases is the deprotonation of hybrid organic cations, specifically methylammonium (MA+) and formamidinium (FA+). In this work, a proton-rich additive, 4-(aminomethyl)pyridine 2-iodide, is used to inhibit MA+ deprotonation in precursor solutions by generating free H+, thereby mitigating the degradation of organic cations under oxygen and humidity stress. The treated precursor stored under ambient conditions for several days exhibits no condensation reaction products. Due to the synergistic effect of H+ and I-, the perovskite films exhibit a pure perovskite phase and inhibit the formation of abnormal "aggregate" perovskite crystals. Therefore, the additive reacts with FA+ to form new complexes, termed N-(4-methylpyridine)formamidinium), which efficiently passivate nonradiative defects. Consequently, this strategy enables the treated perovskite solar cells to achieve a power conversion efficiency (PCE) of 25.25%, demonstrating enhanced long-term stability under both light and thermal stress. Notably, the optimized device retains 95.5% of its initial PCE after 1200 h of continuous illumination and retains 91.61% of its initial PCE after 600 h at 85 °C and 85% relative humidity.

In the quest for cost-effective commercialization of non-fullerene acceptor (NFA) organic solar cells (OSCs), the as-cast devices with no additives or additional treatments show significant potential. However, the accelerated aggregation rate of NFAs often results in moderate crystallinity and poor carrier transport, leading to high trap densities that reduce power conversion efficiency (PCE). To address these challenges, we introduced two new NFAs BTP-S-C12 and BTP-S-DMO, which featured outer alkylthio chains and were synthesized using palladium-catalyzed coupling method. BTP-S-DMO, equipped with short multi-branched alkylthio chains (SMBA), demonstrated superior solubility and crystallinity compared to BTP-S-C12, which has longer linear alkylthio chains. Despite having nearly identical light absorption ranges, BTP-S-DMO exhibited ameliorated molecular packing. In situ spectroscopic characterizations showed that this SMBA approach effectively slowed down the aggregation kinetics of NFA molecules, promoting better packing and a favorable face-on orientation. The well-defined hierarchical morphology in the D18:BTP-S-DMO blend film ultimately resulted in excellent charge transport and lower trap density. This improvement led to an impressive PCE of 18.4% for D18:BTP-S-DMO-based as-cast binary OSCs. Further enhancement was achieved by the ternary strategy that blending D18:BTP-S-DMO:L8-BO together, which can reach a remarkable PCE of 19.0%, one of the highest reported for as-cast OSCs. This study not only presents a straightforward approach to controlling NFA molecular aggregation rate by tuning solubility and crystallinity but also offers significant potential for enhancing photovoltaic performance and advancing the commercialization of OSCs.

Azulene-fused acenes demonstrate enhanced stability, unique aromaticity, and distinctive photophysical properties, rendering them significant in organic electronics. In the present study, we report a new type of nonalternant analogue of pentacene incorporating a non-terminal azulene unit. Aromaticity analyses reveal that the five-membered rings in this analogue exhibit antiaromatic. The extensive conjugated aryl substituents on the acene's side shift the HOMO distributions from the naphthyl ring and metallacycle to the aryl groups, thereby narrowing the HOMO–LUMO energy gap and enhancing absorptions in the low-energy regions. Furthermore, these fused acenes readily react with base rather than acid, resulting in reversible base/acid stimuli responsiveness.

The discovery of ferrocene1 heralded the advent of modern organometallic chemistry. Characterized by the π-coordination of a metal by one or two planar annulene anions, ferrocenes and their analogues2-4 exemplify the archetype of out-of-plane annulene metal complexes. By contrast, the integration of metal within the annulene core to form in-plane annulene metal complexes featuring metal-carbon σ bonds has been obstructed not only by the synthetic difficulty and the non-planarity of annulenes with appropriate internal dimensions, but also by the difficulty of embedding the metal. These challenges have prevented the isolation of such in-plane annulene metal complexes. Here we report the preparation of three metal-centred planar [15]annulene frameworks. The most symmetrical fragment has D5h symmetry, with the metal centre shared by five identical five-membered rings. Density functional theory calculations demonstrate that metal d orbitals participate in conjugation with these five-membered rings, rendering all of them aromatic. The overall framework bears a loose structural and spectroscopic analogy to metallo-expanded porphyrins with multiple aza donors5, which thus provides a nexus between annulene chemistry and classic heteroatom-based coordination chemistry. The present systems display high stability and are easily functionalized. We thus suggest that metal-centred planar annulenes could emerge as promising building blocks for materials science.

Two-dimensional (2D) materials are promising for resistive random-access memory (RRAM) applications due to their notable scalability and switching characteristics. RRAM devices using 2D monolayers experience the shorting issue that reduces device yield. However, synthesizing multilayer 2D materials, for instance, via chemical vapor deposition, is often complicated by the thermodynamic limitations inherent in layer-by-layer epitaxial growth. This letter reports a low-temperature (400 degrees C) synthesis of multilayer molybdenum disulfide MoS2 films via thermal decomposition of spin-coated ammonium tetrathiomolybdate. This method produces uniform MoS2 films with controlled thickness (1.5-5 nm) directly on substrates containing pre-patterned bottom electrodes. The fabricated RRAM devices exhibit nonvolatile switching with SET/RESET voltages of 1.2 V and-0.6 V, respectively, a resistance ratio of 10( 2), and endurance over 10 (5) cycles. DC sweep measurements suggest that SET operation follows trap-controlled space-charge-limited conduction. The transfer-free synthesis method satisfies back-end-of-line (BEOL) thermal constraints and enables scalable integration of 2D materials in memory applications.

Carbonylation reactions are a valuable synthetic method to construct carbonyl compounds and carbonylation reactions of aryl halides stand out as a highly significant tool for generating carbonyl substituted arenes.However,the important reactions have never been realized in aromatic metallacycles.Herein,we present the first carbonylation reactions of metallaaromatics,specifically alkoxycar-bonylation and aminocarbonylation reactions of an osmapentalyne.During the carbonylation process,the electronic and steric prop-erties of nucleophiles are regarded as critical factors.The alcohols with bulky substituents(isopropanol)require more reaction time and tert-butyl alcohol is inert in the reaction.Comparatively,amines,being stronger nucleophiles,exhibit divergent behaviors.Bulky amines undergo aminocarbonylation,whereas small amines prefer direct nucleophilic additions.Control experiments revealed that the intermediate derived from coupling of metal carbyne with CO plays a significant role in the carbonylation reaction.According to these observations,a divergent pathway for the reaction is proposed.Furthermore,the photophysical properties of these carbon-yl-functionalized osmapentalene complexes are studied,and the maximum absorption peak of compound with a carboxylic group ex-hibits a significant red-shift due to the smaller HOMO-LUMO gap.These findings contribute to expanding the reactivity of metallaaromatics and offer new opportunities for the synthesis of carbonyl-functionalized metallacycles.

Utilizing rhodium complexes to catalyze 2-vinylbenzaldehyde derivatives has proven to be a valuable strategy in constructing indanone moieties. In this study, the stoichiometric reactions of Wilkinson's catalyst RhCl(PPh3)3 with 2-vinylbenzaldehyde derivatives were investigated, leading to the formation of rhodaindanone complexes (2). Notably, the transformation of of rhoda-1-indanone (2 a) to rhoda-2-indanone (3) was achieved for the first time. In comparision, the reactivity of IrCl(PPh3)3 and Ir(CO)(CH3CN)(PPh3)2 & sdot; BF4 towards 2-vinylbenzaldehyde derivatives affords irida-2-indanone complexes (4) and fused iridacycles (5), respectively. These newly prepared coumpounds represent the first metellacycles resulting from the reactions between 2-vinylbenzaldehyde derivatives and rhodium/iridium complexes and may provide further insights into the catalytic processes involving 2-vinylbenzaldehyde derivatives for synthesizing indanone compounds. The stoichiometric reactions between the 2-vinylbenzaldehyde derivatives and rhodium/iridium complexes were investigated and several rare examples of metallaindanones were isolated. Moreover, the transformation of rhoda-1-indanone to rhoda-2-indanone was realized for the first time. image

Isomerization reactions of unsaturated molecules offer an efficient strategy in atom-economical synthesis. Although isomerization reactions of unsaturated organic and organometallic compounds, such as alkenes, alkynes, and metal carbynes, have been achieved, those of metal vinylidene units that contain cumulated double bonds have never been reported. Herein, we inaugurally discovered isomerization reactions of metal vinylidene units via protonation and deprotonation reactions of metal carbenes. Experimental and theoretical investigations indicate that the electrical characteristics of substituents on the rings play a crucial role in controlling the formation of metal vinylidene units. The isomerization reactions of metal vinylidene units were driven by thermodynamic forces. Moreover, one of the angles at metal vinylidenes was found as 126.9 degrees, representing the smallest angle in metal vinylidenes and the first cyclic 4d transition metal (Ru) vinylidene complex was successfully isolated. These investigations unveil novel structures and reactivity for metal vinylidenes, offering a fresh perspective on the isomerization reactions of unsaturated molecules containing cumulative unsaturated bonds. Isomerization reactions of unsaturated molecules offer an efficient strategy in atom-economical synthesis.

Comprehensive Summary Metallacyclopentadienes are important metallacycles and regarded as intermediates in many reactions, therefore, new methods to achieve them are anticipated. In this study, a formal [3+2] method, through the reactions of an osmapentalyne with benzyl carbanions, was developed. The reactions underwent a nucleophilic attack of carbanions to the Os≡C bond, followed by C—H activation to form the five‐membered osmacyclopentadiene ring. Most of the reactions were carried out at room temperature, the substituents on the aromatic rings of benzyl carbanions are diverse, and the resulting products contain an Os—H bond, representing a novel type of 10C‐carbolong complexes. This work provides a new convenient route to construct metallacyclopentadienes, which is expected to further promote the development of such a type of substances.

Light-emitting perovskite solar cells are emerging optoelectronic devices that integrate light-emitting and electricity-generating functions in one device. This type of device unlocks new possibilities for applications as outdoor light sources, in multifunctional architecture, smart automobiles, self-powered displays and portable power floodlights.

Metallacyclopentadienes play a vital role in transition-metal mediated and catalyzed cycloaddition reactions of alkynes. Though versatile reactions of metallacyclopentadienes with alkynes have been disclosed, [2+1] cycloadditions of metallacyclopentadienes and alkynes have never been discovered. In present work, we report the formal [2+1] cycloadditions of a metallacyclopentadiene unit with a broad scope of commercial alkynes, providing a facile strategy to construct tetracyclic conjugated compounds. The deuterated experiment indicates a metal vinylidene intermediate has been involved in [2+1] cycloaddition. Moreover, the electrophilic substitution reaction of the tetracyclic conjugated compound with the aid of density functional theory (DFT) calculated Fukui functions is investigated. These tetracyclic conjugated compounds exhibit broad absorption spectra in the whole visible region which could be employed as potential photovoltaic materials.

Four diaza-osmapentalenes were prepared by two-step reactions, through the treatment of an alkyne-coordinated osmium complex with azo compounds, followed by the addition of AgSbF6/CO. Their aromaticity was confirmed by crystal parameters, NMR spectra and theoretical calculations. These complexes are the first diaza-metallapentalenes representing a new class of metallaaromatics.

The σ bond is an important concept in chemistry, and the metal-carbon (M-C) σ bond in particular is a central feature in organometallic chemistry. Synthesis of stable complexes with five coplanar M-C σ bonds is challenging. Here, we describe the synthesis of two different types of stable complexes with five coplanar M-C σ bonds, and examine the stability of such complexes which use rigid conjugated carbon chains to chelate with the metal center. Density functional theory (DFT) calculations show that the M-C σ bonds in these complexes have primarily a covalent character. Besides the σ nature, there are also a π conjugation component among the metal center and carbons, which causes delocalization. This work expanded the coplanar M-C σ bonds to five.

The development of electrochemical DNA biosensors has been limited by their reliability and reproducibility due to many interfering factors such as electrode properties, DNA surface densities, and complex biological samples. In this work, we developed a nanobalance polyA hairpin probe (polyA-HP), which was effectively assembled onto the gold electrode surface through the affinity between the central polyA fragment and the Au surface. One flanking probe of the polyA-HP captured the target sequence together with a MB-labeled signal probe, and the other flanking probe captured a reference probe simultaneously. The MB signal related to the amount of target was normalized by the reference Fc signal; thus, the signal-to-noise (S/N) was as high as 2000, and the reproducibility was remarkably improved to 2.77%, even facing deliberately changed experiment conditions. By designing a hairpin structure at the terminal of the polyA-HP, the selectivity and specificity were dramatically improved for the analysis of mismatched sequences. The analysis performance of biological samples was dramatically improved after normalization, which is critical for its practicability. Our novel biosensor is a universal single-molecule platform for ratiometric biosensors with excellent performance in real samples, indicating great potential for next-generation high-precision electrochemical sensors.

As a priority pollutant in many regions, phenol in environment may cause severe damage to human health and ecosystem. For the simultaneous detection of phenol in environment, a novel electrochemical sensor has been constructed in this work based on the 2D nickel cobalt pyrophosphate (denoted as NCppi) nanosheets modified glass carbon electrode (GCE). The nickel cobalt pyrophosphate was prepared by a facile hydrothermal method. The prepared 2D nickel cobalt pyrophosphate nanosheet was characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The bimetal nickel cobalt pyrophosphate exhibited favorable catalytic activity in phenol detection. The excellent sensing performance of nickel cobalt pyrophosphate was attributed to its charge transfer mobility and abundant catalytic sites. The nickel cobalt bimetal pyrophosphate was applied to modify glass carbon electrode (denoted as NCppi/GCE) and the obtained sensor processed satisfactory analytic performance in practical detection of phenol. Cyclic voltammetry (CV) was employed to characterize electrochemical behavior of modified GCE and bare GCE in 100 mu M phenol solution. Electrochemical impedance spectroscopy (EIS) and CV were employed to characterize the charge transfer process and redox nature of different electrodes in 4 mM Fe(CN)63-/4- containing 0.1 M KCl. Square wave voltammetry (SWV) was employed to detect phenol in 0.2 M phosphate buffer solution (pH=7.0). The fabricated electrochemical sensor with optimized Ni/Co ratio also exhibited a limit of detection (LOD) of 0.25 mu M, a limit of qualification (LOQ) of 0.45 mu M and a linear range of 0.5-100 mu M with a sensitivity of 0.0269 mu A/mu M using square wave voltammetry (SWV) toward phenol. Besides, the electrochemical sensor showed desirable selectivity. In standard addition test of tap water sample from Longwangzui Water Plant and river water from Xunsi River, the sensor displayed reliable recoveries. The electrochemical sensor still maintained 87.5% current response after 3week storage. The GCE was 50 $ and the cost of catalytic ink could be ignored. The active surface area of NCppi/ GCE was 0.12 cm2.