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The catalytic performance of ruthenium (Ru) in the synthesis and decomposition of ammonia (NH3) has attracted extensive attention and research. Considering its selective adsorption and excellent catalytic effect toward NH3, it holds significant potential in the field of ammonia detection. In this study, we present a high-performance NH3 sensor that was based on a catalytic metal gate field-effect transistor (FET) utilizing Ru nanoparticles as the sensitive gate (Ru-FET). The sensor exhibits a high response of 11.3% to 1 ppm of NH3 at room temperature, with quick response and recovery processes of 8 and 85 s, respectively. Meanwhile, the sensor possesses a detection range of 0.4-20 ppm along with good repeatability and selectivity. The exceptional performance of the Ru-FET sensor suggests the potential of judiciously combining sensitive materials and sensor structures to manufacture high-performance NH3 sensors operating at room temperature. [ABSTRACT FROM AUTHOR]

The rational design of an efficient nanocatalyst is pivotal for catalyzing kinetically sluggish oxygen evolution reaction (OER). However, the uncontrolled nucleation and growth of nanostructures present significant challenges in the effectiveness and economic viability of implementing noble metal-based electrocatalysts. Functionalized metal–organic frameworks (MOFs) exhibit properties that can stabilize unstable nanoclusters in extremely small sizes by mitigating issues related to high surface energy and Ostwald's ripening effect. In this study, we present the synthesis of ultrasmall Ruthenium nanoclusters stabilized through a thiol-functionalized Ni-MOF (RuNC/Ni-M-SH). The stabilization of ruthenium under reduced conditions on the MOF surface is facilitated by the lower electronegativity and increased orbital overlapping effect of sulfur, resulting in an average size of 1.5 nm. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy studies confirm a perturbed electronic structure, providing a fundamental understanding of electronic redistribution. With this favorable electronic structure, the catalytic OER activity of RuNC/Ni-M-SH surpasses that of the state-of-the-art RuO2, exhibiting a 3-fold increase in current density (242 mA cm–2) and a 82 mV reduced overpotential. Furthermore, in situ FTIR and Raman analyses were performed to analyze the catalytically active sites and intermediates. With 95% faradaic efficiency, the turnover frequency (TOF) and mass activity of RuNC/Ni-M-SH are several orders of magnitude higher than RuO2. Remarkably, unlike other Ru-based catalysts, RuNC/Ni-M-SH demonstrates exceptional high stability, as evidenced by over 24 h of chronoamperometry study. These attributes of RuNC/Ni-M-SH established it as an economically sustainable OER electrocatalyst. [ABSTRACT FROM AUTHOR]

Polyol techniques have recently emerged as viable soft chemical approaches for the production of ultrafine metal crystals. In this work, we described a simple method of ruthenium nanochains ornamented on an octahedral palladium (RuNCs@Oct-Pd) hybrid nanonet assembly synthesized by using polyvinylpyrrolidone (PVP, stabilizing agent) and 1,2-propanediol (1,2-PD, reducing solvent). The prepared nanonet assembly plays a vital role for reduction of toxic nitro substances such as (4-nitrophenol, 4-NP) and hazardous antimicrobial agents (nitrofurantoin, NFT). The morphology of the nanonet assembly was tested by XRD, SEM, FE-TEM, XPS, and UV–vis spectral techniques. The RuNCs@Oct-Pd nanonet assembly demonstrates enhanced catalytic reduction of 4-NP and NFT using NaBH4 (reductant) at ambient temperature. The RuNCs@Oct-Pd hybrid nanonet assembly exhibited a higher rate constant (kapp = 0.4332 s–1) and turnover frequency (TOF = 5.0 × 10–2 s–1) than commercial catalysts like Ru/C and Pd/C because of substantial catalytic active sites, high surface-to-volume ratio, rapid surface-hydrogen transfer, and superior stability. Furthermore, the hybrid catalyst in this combination showed outstanding durability and reusability, making it suitable for real-world applications. [ABSTRACT FROM AUTHOR]

Designing a unique metastable interface provides a promising way to achieve high catalytic performance yet remains a great challenge due to the thermodynamics' unstable nature. In this work, we constructed the stabilized metastable interface between metastable ruthenium–nickel alloy and metastable hexagonal–close-packed nickel via a one-step solvothermal method. The optimized nanocatalyst (denoted as hcp RuNi) shows bifunctional performance toward electrochemical hydrogen oxidation and evolution reactions (HOR/HER). Density functional theory calculations reveal that two different reaction sites at the unique interface contribute to the enhanced HER and HOR performances. This work highlights the important role on interface engineering of metastable materials for highly efficient catalysis. [ABSTRACT FROM AUTHOR]

The carbon component in Ti3C2Tx is found to assist the reduction and growth of ruthenium (Ru) during solvothermal processing. As a result, Ti3C2Tx is transformed into TiOx with Ru nanoparticle incorporation. Furthermore, the exfoliated nanosheet configuration of the derived substrate is well preserved under a high OH– concentration, associated with the generation of more defective sites. The achieved Ru@M-OH ensemble possesses a low Ru amount of 3.63%, accompanied by enhanced water adsorption and weakened hydrogen combination capability, promoting the hydrogen production under pH-universal conditions. [ABSTRACT FROM AUTHOR]

We report a one-pot hydrothermal route for the atom-economical biosynthesis of C-aerogel-supported noble-metal nanoparticles. A simple sugar derived from hemicellulose, e.g., xylose, and a natural phenol produced by brown algae, e.g., phloroglucinol, were used as renewable and abundant precursors. We demonstrated the versatility of the one-pot hydrothermal route to prepare Pt/C and Ru/C nanocomposites with tunable properties of both the carbonaceous support and supported metal nanoparticles. We obtained Ru nanoparticles with an unusual face-centered-cubic structure. The Pt/C aerogel nanocomposites showed competitive properties as catalysts for a model hydrogenation reaction compared with analogous M/C catalysts. [ABSTRACT FROM AUTHOR]

Understanding the interaction of capping molecules with inorganic nanozymes to modulate catalytic activity is of great interest because it could bring them one step closer to natural enzymes. This study demonstrates the ability of l-cysteine (Cys) to modulate the enzymatic activity of nanozymes by varying their thickness on nanoparticle surfaces. The Cys-functionalized Ru nanoparticles in chain-like two-dimensional nanostructures (Cys-Ru NSs) with excellent peroxidase-like activity were synthesized using a one-pot wet chemical method. Surprisingly, Cys tunes the peroxidase-like activity of Cys-Ru NSs at a specific concentration. Furthermore, Cys excels at controlling the surface properties of Ru nanoparticles, which induces nanoparticle self-assembly and improves colloidal dispersion and stability. A colorimetric assay for lysophosphatidylcholine (LPC) detection was developed by combining hydrogen peroxide produced by enzymatic oxidation of LPC with Cys-Ru NS-catalyzed 3,3′,5,5′-tetramethylbenzidine oxidation. The colorimetric assay demonstrated a broad linear detection range of 10–800 μM with a regression constant of 0.99 and a limit of detection of 10 μM. These colorimetric changes can be seen with the naked eye. In addition, the assay showed good specificity and 106.1–118.1% recovery of LPC from spiked human serum samples. The present Cys-Ru NS-based LPC assay is an excellent way to overcome the shortcomings of existing LPC assays, which does not require expensive equipment, skilled technicians, and lengthy analysis times. [ABSTRACT FROM AUTHOR]

Stacking semiconductor chips allows for increased packing density within a given footprint and efficient communication between different functional layers of the chip, leading to higher performance, improved speed, and reduced power consumption. In such vertical stacking, achieving homogeneous electrical and mechanical bonding between heterogeneous chips is crucial, which is termed Cu to Cu direct bonding (CCDB) technology. However, conventional CCDB required a high temperature of over 250 °C to allow Cu diffusion and a vacuum condition for inhibiting Cu oxidation, limiting its practical utilization. Here, we propose that the covering of the Ru layer enables a reliable CCDB as low as 200 °C without concerns regarding oxidation. The bonding strength was as high as 2.24 MPa, and it was endurable at the -45 and 125 °C temperature cycle test for 500 cycles. Through microscopic analysis, we have identified that Cu diffuses through the intercluster boundaries of the Ru layer and moves to the surface, and these atomic Cu ions are recrystallized at the bonding interface, enabling stable bonding at lower temperatures. Specifically, we observed a trade-off between Cu diffusion distance and oxidation inhibition capability depending on the thickness of Ru and found that a 6 nm-thick Ru is optimal, balancing these factors.

The potential of Ru(III)-mediated advanced oxidation processes has attracted attention due to the recyclable catalysis, high efficiency at circumneutral pHs, and robust resistance against background anions (e.g., phosphate). However, the reactive species in Ru(III)-peracetic acid (PAA) and Ru(III)-ferrate(VI) (FeO 4 2- ) systems have not been rigorously examined and were tentatively attributed to organic radicals (CH 3 C(O)O • /CH 3 C(O)OO • ) and Fe(IV)/Ru(V), representing single electron transfer (SET) and double electron transfer (DET) mechanisms, respectively. Herein, the reaction mechanisms of both systems were investigated by chemical probes, stoichiometry, and electrochemical analysis, revealing different reaction pathways. The negligible contribution of hydroxyl (HO • ) and organic (CH 3 C(O)O • /CH 3 C(O)OO • ) radicals in the Ru(III)-PAA system clearly indicated a DET reaction via oxygen atom transfer (OAT) that produces Ru(V) as the only reactive species. Further, the Ru(III)-performic acid (PFA) system exhibited a similar OAT oxidation mechanism and efficiency. In contrast, the 1:2 stoichiometry and negligible Fe(IV) formation suggested the SET reaction between Ru(III) and ferrate(VI), generating Ru(IV), Ru(V), and Fe(V) as reactive species for micropollutant abatement. Despite the slower oxidation rate constant (kinetically modeled), Ru(V) could contribute comparably as Fe(V) to oxidation due to its higher steady-state concentration. These reaction mechanisms are distinctly different from the previous studies and provide new mechanistic insights into Ru chemistry and Ru(III)-based AOPs.

The synthesis of Co–Ru bimetallic nanoparticles was performed by co-reduction of Co-(II) and Ru-(III) salts in octan-1-ol, acting both as a solvent and a mild reducing agent. The metal composition was varied in the entire range, from pure Co to pure Ru. Although Co and Ru are miscible in the bulk, the formation of nanoalloys is not straightforward and requires careful selection of reaction parameters such as the nature of the solvent and that of the metal precursors. The formation of nanoalloys was unambiguously evidenced by HAADF STEM–EDX analyses. The particle size and the size dispersity were found to decrease with increasing Ru amount, yielding very small and monodisperse particles for the richest compositions in Ru. The unsupported particles were tested for the acceptorless alcohol dehydrogenation using (±)-octan-2-ol and octan-1-ol as model substrates. The results clearly show a synergetic effect since the bimetallic particles exhibit better performances than their monometallic counterparts. [ABSTRACT FROM AUTHOR]

Dopamine (DA) is a type of neurotransmitter that plays an important role in the functions of the central nervous system, as well as renal, hormonal, and cardiovascular systems. In particular, abnormal changes in dopamine concentrations could cause serious diseases such as sleeping and eating disorders, Parkinson's disease, and addictive behaviors associated with drug abuse. However, it is difficult to detect the change in concentration level in a reliable manner when it is present in extremely small levels. In this study, we suggested a ruthenium nanoparticle-immobilized multiscale pore-containing carbon nanofiber (Ru-MPCNF)-based field-effect transistor (FET) nonenzymatic sensor to detect DA. Ru-MPCNF was generated as an active material to target analyte using single-nozzle co-electrospinning and an oxygen plasma method to obtain a uniformly immobilized Ru component in the carbon structure. The porous carbon structure not only promotes the generation of small-size Ru particles but also induces a large active surface area for dopamine. The nonenzymatic sensor electrode showed high sensitivity to DA as low as 1 fM, even in the presence of interfering biomolecules. Moreover, the sensor electrode also displayed stable sensing performance with long lifetimes due to the nonbiological working mechanism. [ABSTRACT FROM AUTHOR]

Interfacial metal-support interaction (MSI) significantly affects the dispersion of active metals on the surface of the catalyst support and impacts catalyst performance. Understanding MSI is crucial for developing highly active and stable catalysts with a low metal loading, particularly for noble metal catalysts. In this work, we synthesized LaRu x Cr 1- x O 3 catalysts with low Ru loading ( x = 0.005, 0.01, and 0.02) using the sol-gel self-combustion method. We found that all of the Ru atoms immediately above or below the metal-support interface are closely bonded to the perovskite LaCrO 3 surface lattice through Ru-O bonds, enhancing the MSI via interfacial reaction and charge transfer mechanisms. We identified a variety of Ru species, including small 3D Ru nanoparticles, 2D dispersed Ru surface atoms, and even 0D Ru single atoms. These highly dispersed Ru species exhibit high activity and stability under dry reforming of methane (DRM) conditions. The LaRu 0.01 Cr 0.99 O 3 catalyst with very low Ru loading (0.42 wt %) was stable over a 50 h DRM test and the carbon deposition was negligible. The CH 4 and CO 2 conversions at 750 °C reached 83 and 86%, respectively, approaching the theoretical thermodynamic equilibrium values.

Hydrogen-based energy systems hold promise for sustainable development and carbon neutrality, minimizing environmental impact with electrolysis as the preferred fossil-fuel-free hydrogen generation method. Effective electrocatalysts are required to reduce energy consumption and improve kinetics, given the need for additional voltage (overpotential, η) despite the theoretical water splitting potential of 1.23 V. To date, platinum has been acknowledged as the most effective but expensive hydrogen evolution reaction (HER) catalyst. Hence, we introduce a cost-effective (∼2-fold cheaper) ruthenium-modified tungsten diphosphide (Ru/WP 2 ) catalyst on carbon fiber for HER in ∼0.5 M H 2 SO 4 , with η ≈ 34 mV at -10 mA cm -2 which can be comparable (only ∼2-fold higher) to benchmark Pt/C (η ≈ 17 mV). The HER performance of WP 2 can be enhanced through the modification of ruthenium, as indicated by the electrochemical characterizations. Considering the Tafel value of ∼40 ± 0.2 mV dec -1 , it can be inferred that Ru/WP 2 follows the Volmer-Heyrovsky reaction pathway for hydrogen generation. Furthermore, the Faradaic efficiency estimation indicates that Ru/WP 2 demonstrates a minimal loss of electrons during the electrochemical reaction with an estimated value of ∼98.7 ± 1.4%. Therefore, this study could emphasize the potential of the Ru/WP 2 electrode in advancing sustainable hydrogen production through water splitting.

Cancer-related extracellular vesicles (EVs) are considered important biomarkers for cancer diagnosis because they can convey a large amount of information about tumor cells. In order to detect cancer-related EVs efficiently, an electrochemiluminescence (ECL) sensor for the specific identification and highly sensitive detection of EVs in the plasma of cancer patients was constructed based on dual recognitions by glycosyl-imprinted polymer (GIP) and aptamer. The characteristic glycosyl Neu5Ac-α-(2,6)-Gal-β-(1-4)-GlcNAc trisaccharide on the surface of EVs was used as a template molecule and 3-aminophenylboronic acid as a functional monomer to form a glycosyl-imprinted polymer by electropolymerization. After glycosyl elution, the imprinted film specifically recognized and adsorbed the EVs in the sample, and then the CD63 aptamer-bipyridine ruthenium (Aptamer-Ru(bpy)) was added to combine with the CD63 glycoprotein on the extracellular vesicle's surface, thus providing secondary recognition of the EVs. Finally, the EVs were quantitatively detected according to the ECL signal produced by the labeled bipyridine ruthenium. When more EVs were captured by the imprinted film, more probes were obtained after incubation, and the ECL signal was stronger. Under the optimized conditions, the ECL signal showed a good linear relationship with the concentration of EVs in the range of 9.5 × 10 2 to 9.5 × 10 7 particles/mL, and the limit of detection was 641 particles/mL. The GIP sensor can discriminate between the EV contents of cancer patients and healthy controls with high accuracy. Because of its affordability, high sensitivity, and ease of use, it is anticipated to be employed for cancer early detection and diagnosis.

Ru-related catalysts have shown excellent performance for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR); however, a deep understanding of Ru-active sites on a nanoscale heterogeneous support for hydrogen catalysis is still lacking. Herein, a click chemistry strategy is proposed to design Ru cluster-decorated nanometer Ru x Fe 3- x O 4 heterointerfaces (Ru/Ru x Fe 3- x O 4 ) as highly effective bifunctional hydrogen catalysts. It is found that introducing Ru into nanometric Fe 3 O 4 species breaks the symmetry configuration and optimizes the active site in Ru/Ru x Fe 3- x O 4 for HER and HOR. As expected, the catalyst displays prominent alkaline HER and HOR performance with mass activity much higher than that of commercial Pt/C as well as robust stability during catalysis because of the strong interaction between the Ru cluster and the Ru x Fe 3- x O 4 support, and the optimized adsorption intermediate (H ad and OH ad ). This work sheds light on a promsing approach to improving the electrocatalysis performance of catalysts by the breaking of atomic dimension symmetry.

Methods for computational de novo design of inorganic molecules have paved the way for automated design of homogeneous catalysts. Such studies have so far relied on correlation-based prediction models as fitness functions (figures of merit), but the soundness of these approaches has yet to be tested by experimental verification of de novo-designed catalysts. Here, a previously developed criterion for the optimization of dative ligands L in ruthenium-based olefin metathesis catalysts RuCl 2 (L)(L')(═CHAr), where Ar is an aryl group and L' is a phosphine ligand dissociating to activate the catalyst, was used in de novo design experiments. These experiments predicted catalysts bearing an N-heterocyclic carbene (L = 9 ) substituted by two N-bound mesityls and two tert -butyl groups at the imidazolidin-2-ylidene backbone to be promising. Whereas the phosphine-stabilized precursor assumed by the prediction model could not be made, a pyridine-stabilized ruthenium alkylidene complex ( 17 ) bearing carbene 9 was less active than a known leading pyridine-stabilized Grubbs-type catalyst ( 18 , L = H 2 IMes). A density functional theory-based analysis showed that the unsubstituted metallacyclobutane (MCB) intermediate generated in the presence of ethylene is the likely resting state of both 17 and 18 . Whereas the design criterion via its correlation between the stability of the MCB and the rate-determining barrier indeed seeks to stabilize the MCB, it relies on RuCl 2 (L)(L')(═CH 2 ) adducts as resting states. The change in resting state explains the discrepancy between the prediction and the actual performance of catalyst 17 . To avoid such discrepancies and better address the multifaceted challenges of predicting catalytic performance, future de novo catalyst design studies should explore and test design criteria incorporating information from more than a single relative energy or intermediate.

The controllable and low-cost synthesis of nanometal particles is highly desired in scientific and industrial research. Herein, size-tunable Ru nanoparticles were synthesized by using a novel ion-sieve-confined reduction method. The H 2 TiO 3 ion-sieve was used to adsorb Ru 3+ into the hydroxyl-enriched porous [TiO 3 ] 2- layers. The confined environment of the interlayer space facilitates Ru-Ru collision and bonding during annealing, achieving a precise reduction from Ru 3+ to Ru 0 without additional reductants. Owing to the confinement effect, Ru 0 nanoparticles are uniformly embedded in the pores on the surface of the postannealed TiO 2 matrix (Ru@TiO 2 ). Ru@TiO 2 exhibited a lower overpotential than Pt/C (57 vs 87 mV at 10 mA cm -2 ) for the HER in 0.1 M KOH solution. The confinement-induced reduction of metal ions was also preliminarily proved in ion-exchanged zeolites, which provides facile and abundant approaches for the size-controllable synthesis of nanometal catalysts with high catalytic activity.

The establishment of rapid target identification and analysis methods for antibiotic resistance genes (ARGs) is urgently needed. In this study, we unprecedently designed a target-catalyzed hairpin assembly (CHA) electrochemiluminescent (ECL) biosensor for the ultrasensitive detection of ampicillin resistance genes (ARG AMP ) based on a novel, efficient near-infrared ruthenium carbene complex/TPrA/PEI ternary ECL system with low oxidation potential. The ternary NIR-ECL system illustrated in this work displayed double ECL intensity in comparison with their corresponding traditional binary ECL system. The as-prepared ECL biosensor illustrated in this work demonstrates highly selective and sensitive determination of ARG AMP from 1 fM to 1 nM and a low detection limit of 0.23 fM. Importantly, it also exhibits good accuracy and stabilities to identify ARG AMP in plasmid and bacterial genome DNA, which demonstrates its excellent reliability and great potential in detecting ARG AMP in real environmental samples.

A ruthenium aqua photoredox catalyst has been successfully heterogeneneized on graphene oxide (GO@trans-fac- 3 ) and graphite rods (GR@trans-fac- 3 ) for the first time and have proven to be sustainable and easily reusable systems for the photooxidation of alcohols in water, in mild and green conditions. We report here the synthesis and total characterization of two Ru(II)-polypyridyl complexes, the chlorido trans-fac-[RuCl(bpea-pyrene)(bpy)](PF 6 ) (trans-fac- 2 ) and the aqua trans-fac-[Ru(bpea-pyrene)(bpy)OH 2 ](PF 6 ) 2 (trans-fac- 3 ), both containing the N -tridentate, 1-[bis(pyridine-2-ylmethyl)amino]methylpyrene (bpea-pyrene), and 2,2'-bipyridine (bpy) ligands. In both complexes, only a single isomer, the trans-fac, has been detected in solution and in the solid state. The aqua complex trans-fac- 3 displays bielectronic redox processes in water, assigned to the Ru(IV/II) couple. The trans-fac- 3 complex has been heterogenized on different types of supports, (i) on graphene oxide (GO) through π-stacking interactions between the pyrene group of the bpea-pyrene ligand and the GO and (ii) both on glassy carbon electrodes (GC) and on graphite rods (GR) through oxidative electropolymerization of the pyrene group, which yield stable heterogeneous photoredox catalysts. GO@trans-fac- 3 - and GR/poly trans-fac- 3- modified electrodes were fully characterized by spectroscopic and electrochemical methods. Trans-fac- 3 and GO@trans-fac- 3 photocatalysts (without a photosensitizer) showed good catalytic efficiency in the photooxidation of alcohols in water under mild conditions and using visible light. Both photocatalysts display high selectivity values (>99%) even for primary alcohols in accordance with the presence of two-electron transfer processes (2e - /2H + ). GO@trans-fac- 3 keeps intact its homogeneous catalytic properties but shows an enhancement in yields. GO@trans-fac- 3 can be easily recycled by filtration and reused for up to five runs without any significant loss of catalytic activity. Graphite rods (GR@trans-fac- 3 ) were also evaluated as heterogeneous photoredox catalysts showing high turnover numbers (TON) and selectivity values.

Carbon dots (CDs) as an emerging type of carbon nanomaterials exhibit great potential in bioimaging applications owing to their superior optical properties and excellent biocompatibility. However, it is still challenging to fabricate sole carbon dots with integrated functionalities of diagnostic and therapeutic modalities. Herein, we developed a facile strategy to prepare the ruthenium-containing carbon dots (Ru-CDs) via a hydrothermal method using the 5-amino-1,10-phenanthroline ruthenium-(II) complex (Ru-Aphen) and citric acid as starting materials. The structure and morphology of Ru-CDs were verified by transmission electron spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier transform infrared spectra. The Ru-CDs exhibited good water solubility, intense red emission, and efficient reactive oxygen species (ROS) generation. The MTT assay against HeLa cells demonstrated favorable biocompatibility and distinct photodynamic effect of Ru-CDs. Owing to strong luminescence in water (QY = 20.79%) and efficient ROS generation, Ru-CDs were not only applied as bioimaging agents for tumor cells and zebrafish embryos, but also as photodynamic nanoagents for cancer therapy. Finally, the DNA photocleavage of Ru-CDs was verified through the experiment of gel electrophoresis. The results suggested that the plasmid DNA could only be damaged in the presence of Ru-CDs and light. Thus, the as-prepared Ru-CDs showed good prospects and a wide range of biological applications. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) has attracted significant interest in the analysis of cancer cells, where the ruthenium(II)-based emitter demonstrates urgency and feasibility to improve the ECL efficiency. In this work, the self-enhanced ECL luminophore was prepared by covalent anchoring of Pd nanoclusters on aminated metal organic frameworks (Pd NCs@MOFs), followed by linkage with bis(2,2'-bipyridine)-5-amino-1,10-phenanthroline ruthenium(II) (RuP). The resultant luminophore showed 214-fold self-magnification in the ECL efficiency over RuP alone, combined by promoting the interfacial photoelectron transfer. The enhanced mechanism through ion annihilation was critically proved by controlled experiments and density functional theory (DFT) calculations. Based on the above, a "signal off" ECL biosensor was built by assembly of tyrosine kinase 7 (PTK-7) aptamer (Apt) on the established sensing platform for analysis of human lung cancer cells (A549). The built sensor showed a lower detection limit of 8 cells mL -1 , achieving the single-cell detection. This work reported a self-enhanced strategy for synthesis of advanced ECL emitters, combined by exploring the ECL biosensing devices in the single-cell analysis of cancers.

Surface impurities can have a significant influence on hydrogen uptake of materials. Examples such as the hydrogen spillover effect demonstrate that even very small surface impurity quantities can lead to order-of-magnitude changes in the total amount of hydrogen taken up by a material. In this work, we report the first experimental demonstration of promoted deuterium uptake in Ru thin films by Sn. Deuterium plasma exposures were carried out for Ru-capped targets covered by Sn up to a few atoms in thickness. After the exposure, the residual Sn content and the deuterium retention were measured to quantify the Sn etching and the deuterium uptake, respectively. By increasing the amount of Sn from zero to one atomic layer on Ru, we found after the exposure that the Sn content stays unchanged while the deuterium uptake rate severely increases with the Sn content by 2-3 orders of magnitude. These results can be understood by simulations using a reaction-diffusion model with multiple surface species and the lateral surface migration of deuterium. By contrast, as the as-deposited Sn content goes above one atomic layer, Sn removal takes place, and the deuterium uptake rate decreases with the as-deposited Sn content. Possible explanations are proposed by considering the interplay between Sn etching and deuterium uptake. In all, this work provides insights into interactions between multiple surface species in relation to plasma-induced hydrogen uptake. By further development, this could eventually lead to a potential mitigation method to circumvent the promoted hydrogen uptake in Ru-capped films.

Low-temperature catalytic oxidation is of significance to the degradation of halogenated volatile organic compounds (HVOCs) to avoid hazardous byproducts with low energy consumption. Efficient molecular oxygen (O 2 ) activation is pivotal to it but usually limited by the insufficient electron cloud density at the metal center. Herein, Ru-B catalysts with enhanced electron density around Ru were designed to achieve efficient O 2 activation, realizing dibromomethane (DBM) degradation T 90 at 182 °C on RuB 1 /TiO 2 (about 30 °C lower than pristine Ru/TiO 2 ) with a TOF Ru value of 0.055 s -1 (over 8 times that of Ru/TiO 2 ). Compared to the limited electron transfer (0.02 e) on pristine Ru/TiO 2 , the Ru center gained sufficient negative charges (0.31 e) from BO x via strong p-d orbital hybridization. The Ru-B site then acted as the electron donor complexing with the 2π* antibonding orbital of O 2 to realize the O 2 dissociative activation. The reactive oxygen species formed thereby could initiate a fast conversion and oxidation of formate intermediates, thus eventually boosting the low-temperature catalytic activity. Furthermore, we found that the Ru-B sites for O 2 activation have adaptation for pollutant removal and multiple metal availability. Our study shed light on robust O 2 activation catalyst design based on electron density adjustment by boron.

In this work, combined with the high amplification efficiency of hybridization chain reaction (HCR), high specificity of the CRISPR/Cas12a system, and convenience of the homogeneous electrochemiluminescence (ECL) assay based on the regulation of negative charge on the reporting probes, a sensitive ECL biosensor for hepatitis B virus DNA (chosen as a model target) had been developed. The initiator chain trigger DNA that can induce HCR amplification is modified on the surface of ruthenium bipyridine-doped silica nanoparticles (Ru@SiO 2 NPs) first, and large amounts of negative charges modified on the particles were achieved through the HCR amplification reaction. The efficiency of the nanoparticles reaching the negatively charged working electrode can be regulated and realize the change of the ECL signal. In addition, long DNA on the surface of the luminescent body may prevent the coreactant from entering the pore to react with ruthenium bipyridine. These factors combine to produce a low-background system. The presence of the target can activate the CRISPR/Cas12a system and make trigger DNA disappear from the nanoparticle surface, and strong ECL can be detected. The sensor does not require a complex electrode modification; therefore, it has better reproducibility. Additionally, due to dual signal amplification, the sensor has a high sensitivity. In the range of 10 fM to 10 nM, the ECL intensity exhibits a strong linear relationship with the logarithm of the target concentration, and the detection limit is 7.41 fM. This sensor has shown high accuracy in detecting clinical samples, which holds significant potential for application in clinical testing.

The application of transition-metal catalysts in living cells presents a promising approach to facilitate reactions that otherwise would not occur in nature. However, the usage of metal complexes is often restricted by their limited biocompatibility, toxicity, and susceptibility to inactivation and loss of activity by the cell's defensive mechanisms. This is especially relevant for ruthenium-mediated reactions, such as ring-closing metathesis. In order to address these issues, we have incorporated the second-generation Hoveyda-Grubbs catalyst (HGII) into polymeric vesicles (polymersomes), which were composed of biodegradable poly(ethylene glycol)- b -poly(caprolactone- g -trimethylene carbonate) [PEG- b -P(CL- g -TMC)] block copolymers. The catalyst was either covalently or non-covalently introduced into the polymersome membrane. These polymersomes were able to act as artificial organelles that promote endosomal ring-closing metathesis for the intracellular generation of a fluorescent dye. This is the first example of the use of a polymersome-based artificial organelle with an active ruthenium catalyst for carbon-carbon bond formation.

Oxo-bridged dibenzoazocines are furnished within a single synthetic step at room temperature via ruthenium-catalyzed [4 + 3]-cycloannulation of aza- ortho -quinone methides with carbonyl ylides. Exclusive diastereoselectivity, excellent yield, mild reaction conditions, and broad substrate scope are distinguishing features of this protocol. The product could be prepared on a gram scale and could be further functionalized into diverse substituted dihydroisobenzofuran derivatives and a dibenzoazocine scaffold.

Metal complexes have many proven applications in the caging and photochemical release of biologically active compounds. Photocaging groups derived from Ru(II) traditionally have been composed of ancillary ligands that are planar and bi- or tridentate, such as 2,2'-bipyridine (bpy), 2,2':6',2"-terpyridine (tpy), and 1,10-phenanthroline (phen). Complexes bearing ancillary ligands with denticities higher than three represent a new class of Ru(II)-based photocaging groups that are grossly underdeveloped. Because high-denticity ancillary ligands provide the ability to increase the structural rigidity and control the stereochemistry, our groups initiated a research program to explore the applications of such ligands in Ru(II)-based photocaging. Ru(TPA), bearing the tetradentate ancillary ligand tris(2-pyridylmethyl)amine (TPA), has been successfully utilized to effectively cage nitriles and aromatic heterocycles. Nitriles and aromatic heterocycles caged by the Ru(TPA) group show excellent stability in aqueous solutions in the dark, and the complexes can selectively release the caged molecules upon irradiation with light. Ru(TPA) is applicable as a photochemical agent to offer precise spatiotemporal control over biological activity without undesired toxicity. In addition, Ru(II) polypyridyl complexes with desired photochemical properties can be synthesized and identified by solid-phase synthesis, and the resulting complexes show properties to similar to those of complexes obtained by solution-phase synthesis. Density functional theory (DFT) calculations reveal that orbital mixing between the π* orbitals of the ancillary ligand and the Ru-N dσ* orbital is essential for ligand photodissociation in these complexes. Furthermore, the introduction of steric bulk enhances the photoliability of the caged molecules, validating that steric effects can largely influence the quantum efficiency of photoinduced ligand exchange in Ru(II) polypyridyl complexes. Recently, two new photocaging groups, Ru(cyTPA) and Ru(1-isocyTPQA), have been designed and synthesized for caging of nitriles and aromatic heterocycles, and these complexes exhibit unique photochemical properties distinct from those derived from Ru(TPA). Notably, the unusually greater quantum efficiency for the ligand exchange in [Ru(1-isocyTPQA)(MeCN)2](PF6)2, Φ400 = 0.033(3), uncovers a trans-type effect in the triplet metal-to-ligand charge transfer (3MLCT) state that enhances photoinduced ligand exchange in a new manner. DFT calculations and ultrafast transient spectroscopy reveal that the lowest-energy triplet state in [Ru(1-isocyTPQA)(MeCN)2](PF6)2 is a highly mixed 3MLCT/3ππ* excited state rather than a triplet metal-centered ligand-field (3LF) excited state; the latter is generally accepted for ligand photodissociation. In addition, Mulliken spin density calculations indicate that a majority of the spin density in [Ru(1-isocyTPQA)(MeCN)2](PF6)2 is localized on the isoquinoline arm, which is opposite to the cis MeCN, rather than on the ruthenium center. This significantly weakens the Ru-N6 (cis MeCN) bond, which then promotes the ligand photodissociation. This newly discovered effect gives a clearer perception of the interplay between the 3MLCT and 3LF excited states of Ru(II) polypyridyl complexes, which may be useful in the design and applications of ruthenium complexes in the areas of photoactivated drug delivery and photosensitizers. [ABSTRACT FROM AUTHOR]

Exploiting NF-κB transcription factor peptide conjugation, a Ru(II)-bis-tap complex (tap = 1,4,5,8 tetraazaphenanthrene) was targeted specifically to the nuclei of live HeLa and CHO cells for the first time. DNA binding of the complex within the nucleus of live cells was evident from gradual extinction of the metal complex luminescence after it had crossed the nuclear envelope, attributed to guanine quenching of the ruthenium emission via photoinduced electron transfer. Resonance Raman imaging confirmed that the complex remained in the nucleus after emission is extinguished. In the dark and under imaging conditions the cells remain viable, but efficient cellular destruction was induced with precise spatiotemporal control by applying higher irradiation intensities to selected cells. Solution studies indicate that the peptide conjugated complex associates strongly with calf thymus DNA ex-cellulo and gel electrophoresis confirmed that the peptide conjugate is capable of singlet oxygen independent photodamage to plasmid DNA. This indicates that the observed efficient cellular destruction likely operates via direct DNA oxidation by photoinduced electron transfer between guanine and the precision targeted Ru(II)-tap probe. The discrete targeting of polyazaaromatic complexes to the cell nucleus and confirmation that they are photocytotoxic after nuclear delivery is an important step toward their application in cellular phototherapy. [ABSTRACT FROM AUTHOR]

Reactions of the triruthenium clusters {Cp*Ru(μ-H)}3(μ3-H)2 (1) and (Cp*Ru)3(μ3-H)(μ-H)2(μ-CO) (12) (Cp* = η5-C5Me5) with benzonitrile were investigated in relation to the selective hydrogenation of benzonitrile to benzylamine. Benzonitrile undergoes consecutive transformations into μ3-η2:η2(⊥)-nitrile, μ3-η²:η²(⊥)-imidoyl, μ3-η²(∥)-imidoyl, μ3-η²-alkylideneamido, μ3-imido, and μ-amido ligands on the Ru3 plane accompanied by the uptake of dihydrogen. The reactions are analogues of nitrile hydrogenation on a metal surface. The complexes are structural models of chemisorbed species and catalyze the hydrogenation of benzonitrile. Complex 1 catalyzes benzonitrile hydrogenation without additives but exhibits only moderate selectivity toward benzylamine. Although the μ3-benzylimido complex {Cp*Ru(μ-H)}3(μ3-NCH2Ph) (4) was obtained by reaction of 1 with benzonitrile, it was readily transformed into to the μ3-imidoyl complexes (Cp*Ru)3(μ-H)2{μ3-η²:η²(⊥)-PhCNH} (3) and (Cp*Ru)3(H)4{μ3-η²(∥∥)-PhCNH} (4), which are key intermediates in secondary imine formation. Two benzonitrile molecules were incorporated on the Ru3 plane under the reaction conditions, which decreases the selectivity of primary amine formation. In contrast, μ-carbonyl complex 12 suppresses the incorporation of additional benzonitrile ligands and the formation of μ3-imidoyl species due to the presence of CO. These features of 12 bring about significant improvement in the selectivity of benzonitrile hydrogenation and produce benzylamine in 92% yield. [ABSTRACT FROM AUTHOR]

Integration of photoresponsive chromophores that initiate multistep catalysis is essential in dye-sensitized photoelectrosynthesis cells and related devices. We describe here an approach that incorporates a chromophore assembly surface-bound to metal oxide electrodes for light absorption with an overlayer of catalysts for driving the half-reactions of water splitting. The assembly is a combination of a core-twisted perylene diimide and a ruthenium polypyridyl complex By altering the connection sequence of the two subunits in the assembly, in their surface-binding to either TiO[sub 2] or NiO, the assembly can be tuned to convert visible light into strongly oxidizing equivalents for activation of an electrodeposited water oxidation catalyst (NiCo[sub 2]O[sub x]) at the photoanode, or reducing equivalents for activation of an electrodeposited water reduction catalyst (NiMo[sub 0.05]S[sub x]) at the photocathode. A key element in the design of the photoelectrodes comes from the synergistic roles of the vertical (interlayer) charge transfer and lateral (intralayer) charge hopping in determining overall cell efficiencies for photoelectrocatalysis. [ABSTRACT FROM AUTHOR]

The electronic structures of the prototypical bimetallic buta-1,3-diyn-1,4-diyl-bridged radical cation complexes [{M(dppe)Cp'}2(μ-C=CC=C)]+ (M= Fe, Cp' = Cp* (1a), Cp (1b); M = Ru, Cp' = Cp* (2a), Cp (2b)) have been (re)investigated using a combination of UV-vis-NIR and IR spectroelectrochemistry, and quantum chemical calculations based on both dispersion-corrected global (BLYP35-D3) and local (Lh-SsirPW92-D3) hybrid functionals. Following analysis of new and existing data, including the IR-active ν(C=C) bands, the iron compounds [1]+ are reclassified as valence-trapped (Robin and Day Class II) mixed-valence complexes, in contrast to the ruthenium complexes [2]+, which are delocalized (Robin and Day Class III) systems. All members of the series exist as a thermally populated distribution of conformers in solution, and the overlapping spectroscopic profiles make the accurate extraction of the parameters necessary for the analysis of [1]+ and [2]+ within the framework of the Marcus-Hush model extremely challenging. Analysis of the spin-density distributions from a range of conformational minima provides an alternative representation of the degree of charge localization, and a comparison between members of the series is presented. [ABSTRACT FROM AUTHOR]

We propose in this work a stepwise approach to construct photoelectrodes. This takes advantage of the self-assembly interactions between thiol with a gold surface and terpyridine ligands with first-row transition metals. Here, a [Ru(bpy)3]2+ photosensitive center bearing a free terpyridine group has been used to construct two linear dyads on gold (Au/[ZnII-RuII]4+ and Au/[CoIII-RuII]5+). The stepwise construction was characterized by electrochemistry, quartz crystal microbalance, and atomic force microscopy imaging. The results show that the dyads behave as rigid layers and are inhomogeneously distributed on the surface. The surface coverages are estimated to be in the order of 10-11 mol cm-2. The kinetics of the heterogeneous electron transfer is determined on modified gold ball microelectrodes using Laviron's formula. The oxidation rates of the terminal Ru(II) subunits are estimated to be 700 and 2300 s-1 for Au/[ZnII-RuII]4+ and Au/[CoIII-RuII]5+, respectively. In the latter case, the rate is limited by the kinetics of electron transfer between an intermediate Co(II) center and the gold surface. For Au/[ZnII-RuII]4+, the Zn-bis-terpyridine center is not involved in the electron-transfer process and the oxidation of the Ru(II) subunit occurs through a superexchange process. In the presence of a tertiary amine in solution, the electrodes at a bias of 0.12 V behave as photoanodes when subjected to visible light irradiation. The magnitude of the photocurrent is around 10 µA cm-2 for Au/[CoIII-RuII]5+ and 5 µA cm-2 for Au/[ZnII-RuII]4+, proving the importance of an electron relay on the photon-to-current conversion. The results suggest an efficient conversion for Au/[CoIII-RuII]5+, since each bound dyad, once excited, injects an electron around 10 times per second. [ABSTRACT FROM AUTHOR]

TiO2 mesoporous crystal has been prepared by one-step corroding process via an oriented attachment (OA) mechanism with SrTiO3 as precursor. High resolution transmission electron microscopy (HRTEM) and nitrogen adsorption-desorption isotherms confirm its mesoporous crystal structure. Well-dispersed ruthenium (Ru) in the mesoporous nanocrystal TiO2 can be attained by the same process using Ru-doped precursor SrTi1-xRuxO3. Ru is doped into lattice of TiO2, which is identified by HRTEM and super energy dispersive spectrometer (super-EDS) elemental mapping. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectroscopy (EPR) suggest the pentavalent Ru but not tetravalent, while partial Ti in TiO2 accept an electron from Ru and become Ti3+, which is observed for the first time. This Ru-doped TiO2 performs high activity for electrocatalytic hydrogen evolution reaction (HER) in alkaline solution. Firstprinciples calculations simulate the HER process and prove TiO2:Ru with Ru5+ and Ti3+ holds high HER activity with appropriate hydrogen-adsorption Gibbs free energies (ΔGH). [ABSTRACT FROM AUTHOR]

Second-generation ruthenium olefin metathesis catalysts bearing aminophosphine ligands were investigated with systematic variation of the ligand structure. The rates of phosphine dissociation (k1; initiation rate) and relative phosphine reassociation (k-1) were determined for two series of catalysts bearing cyclohexyl(morpholino)phosphine and cyclohexyl(piperidino)phosphine ligands. In both cases, incorporating P-N bonds into the architecture of the dissociating phosphine accelerates catalyst initiation relative to the parent [Ru]-PCy3 complex; however, this effect is muted for the tris(amino)phosphine-ligated complexes, which exhibit higher ligand binding constants in comparison to those with phosphines containing one or two cyclohexyl substituents. These results, along with X-ray crystallographic data and DFT calculations, were used to understand the influence of ligand structure on catalyst activity. Especially noteworthy is the application of phosphines containing incongruent substituents (PR1R'2); detailed analyses of factors affecting ligand dissociation, including steric effects, inductive effects, and ligand conformation, are presented. Computational studies of the reaction coordinate for ligand dissociation reveal that ligand conformational changes contribute to the rapid dissociation for the fastest-initiating catalyst of these series, which bears a cyclohexyl-bis(morpholino)phosphine ligand. Furthermore, the effect of amine incorporation was examined in the context of ring-opening metathesis polymerization, and reaction rates were found to correlate well with catalyst initiation rates. The combined experimental and computational studies presented in this report reveal important considerations for designing efficient ruthenium olefin metathesis catalysts. [ABSTRACT FROM AUTHOR]

Indole thiosemicarbazone ligands were prepared from indole-3-carboxaldehyde and N-(un)substituted thiosemicarbazide. The Ru(η6-p-cymene) complexes [Ru(η6-p-cymene)(HL1)Cl]Cl (1) and [Ru(η6-p-cymene)(L2)]2Cl2 (2*) were exclusively synthesized from thiosemicarbazone (TSC) ligands HL1 and HL2, and [RuCl2(p-cymene)]2. The compounds were characterized by analytical and various spectroscopic (electronic, FT-IR, 1D/2D NMR, and mass) tools. The exact structures of the compounds (HL1, HL2, 1, and 2*) were confirmed by single-crystal X-ray diffraction technique. In complexes 1 and 2*, the ligand coordinated in a bidentate neutral (1)/monobasic (2*) fashion to form a five-membered ring. The complexes showed a piano-stool geometry around the Ru ion. While 2* existed as a dimer, 1 existed as a monomer, and this was well explained through free energy, bond parameter, and charge values computed at the B3LYP/SDD level. The intercalative binding mode of the complexes with calf thymus DNA (CT DNA) was revealed by spectroscopic and viscometric studies. The DNA (pUC19 and pBR322 DNA) cleavage ability of these complexes evaluated by an agarose gel electrophoresis method confirmed significant DNA cleavage activity. Further, the interaction of the complexes with bovine serum albumin (BSA) was investigated using spectroscopic methods, which disclosed that the complexes could bind strongly with BSA. A hemolysis study with human erythrocytes revealed blood biocompatibility of the complexes. The in vitro anticancer activity of the compounds (HL1, HL2, 1, and 2*) was screened against two cancer cell lines (A549 and HepG-2) and one normal cell line (L929). Interestingly, the binuclear complex 2* showed superior activity with IC50 = 11.5 μM, which was lower than that of cisplatin against the A549 cancer cell line. The activity of the same complex (IC50 = 35.3 μM) was inferior to that of cisplatin in the HepG-2 cancer cell line. Further, the apoptosis mode of cell death in the cancer cell line was confirmed by using confocal microscopy and DNA fragmentation analysis. [ABSTRACT FROM AUTHOR]

A new approach to the synthesis of 2-phosphinoylindoles through photoredox catalysis without external oxidants has been developed. Promoted by a ruthenium photoredox catalyst, a broad scope of 2-phosphinoylindoles can be synthesized through phosphinoylation/cyclization of diphenylphosphine oxide at room temperature under irradiation without external oxidants. The estrone skeleton isocyan is also an amenable substrate for this cyclization, yielding a molecule that has potential medicinal applications. [ABSTRACT FROM AUTHOR]

A ruthenium-catalyzed C-H allylation of indoles with allyl alcohols via β-hydroxide elimination is reported. Without external oxidants and expensive additives, this reaction features mild reaction conditions, compatibility with various functional groups, and good to excellent regioselectivity and stereoselectivity. [ABSTRACT FROM AUTHOR]

Disilaferra- and disilaruthenacyclic complexes containing mesityl isocyanide as a ligand, 3' and 4', were synthesized and characterized by spectroscopy and crystallography. Both 3' and 4' showed excellent catalytic activity for the hydrogenation of alkenes. Compared with iron and ruthenium carbonyl analogues, 1' and 2', the isocyanide complexes 3' and 4' were more robust under the hydrogenation conditions, and were still active even at higher temperatures (~80 °C) under high hydrogen pressure (~20 atm). The iron complex 3' exhibited the highest catalytic activity toward hydrogenation of mono-, di-, tri-, and tetrasubstituted alkenes among currently reported iron catalysts. Ruthenium complex 4' catalyzed hydrogenation under very mild conditions, such as room temperature and 1 atm of H2. The remarkably high catalytic activity of 4' for hydrogenation of unfunctionalized tetrasubstituted alkenes was especially notable, because it was comparable to the activity of iridium complexes reported by Crabtree and Pfaltz, which are catalysts with the highest activity in the literature. DFT calculations suggested two plausible catalytic cycles, both of which involved activation of H2 assisted by the metal-silicon bond through σ-bond metathesis of late transition metals (oxidative hydrogen migration). The linear structure of M--C≡N--C (ipso carbon of the mesityl group) played an essential role in the efficient hydrogenation of sterically hindered tetrasubstituted alkenes. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a series of arene ruthenium complexes bearing either (3,5-cycloheptadienyl)diphenylphosphine or (cycloheptyl)diphenylphosphine are reported. Upon irradiation or heating, all these complexes lose their arene ligand but then exhibit a different behavior depending on the nature of the phosphine ligand. (Cycloheptadienyl)phosphine complexes 1 and 3 give a cationic dinuclear Ru complex 5 for which the two Ru atoms are bridged by three chlorido ligands and flanked by two tridendate (cycloheptadienyl)phosphines. (Cycloheptyl)diphenylphosphine complexes 2 and 4 undergo arene exchange when toluene is used as solvent or degrade in dichloromethane. ATRA catalytic trials conducted in parallel with these complexes using CCl4 and styrene as standard substrates, highlighted the deep impact of the dienyl moiety on the results. Under smooth conditions (UV irradiation or moderate heating), only (cycloheptyl)phosphine derivatives give Karasch adduct in satisfactory yields. Their performance was considerably improved by combining irradiation and heating. At higher temperature, cationic dinuclear complex 5 was revealed as active and robust, giving turnover numbers as high as 9700 when tetradecene and CCl4 were used as substrates. [ABSTRACT FROM AUTHOR]