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Two arene ruthenium(II) complexes [η 6 -(C 6 H 6 )Ru(pprip)Cl]PF 6 (Ru1; pprip = 2-(3-phenyl-1H-pyrazol-4-yl)-imidazolo[4,5-f][1,10]phenanthroline) and [η 6 -(C 6 H 6 )Ru(H 2 iiP)Cl]PF 6 (Ru2; H 2 iiP = 2-(indole-3-yl)-imidazolo[4,5-f][1,10]phenanthroline) have been synthesized and characterized in this work. Binding properties of Ru1 and Ru2 with the triplex RNA poly(U)•poly(A)*poly(U) were investigated by spectrophotometry and spectrofluorometry as well as viscosimetry. Analysis of spectroscopic titrations and viscosity measurements show that the two complexes bind with the triplex through intercalation, while the binding affinity for Ru2 toward the triplex is stronger than that for Ru1. Melting experiments indicate that the stabilizing effects of Ru1 and Ru2 toward the triplex differ from each other. Under the conditions used herein, Ru1 only stabilizes the Hoogsteen base-paired strand (third strand) without affecting stabilization of the Watson-Crick base-paired strand (the template duplex) of the triplex, while Ru2 stabilizes both the template duplex and the third strand. Although the two complexes prefer to stabilizing the third strand rather than the template duplex, the third-strand stabilization effect of Ru2 is stronger than that of Ru1. The obtained results of this work reveal that the planarity of the intercalative ligands plays an important role in the triplex stabilization by arene Ru(II) complexes., (© 2023. The Author(s), under exclusive licence to Society for Biological Inorganic Chemistry (SBIC).)

A series of novel surface Ru-H bipyridine complexes-grafted TiO 2 nanohybrids were for the first time prepared by a combined procedure of surface organometallic chemistry with post-synthetic ligand exchange for photocatalytic conversion of CO 2 to CH 4 with H 2 as electron and proton donors under visible light irradiation. The selectivity toward CH 4 increased to 93.4% by the ligand exchange of 4,4'-dimethyl-2,2'-bipyridine (4,4'-bpy) with the surface cyclopentadienyl (Cp)-RuH complex and the CO 2 methanation activity was enhanced by 4.4-fold. An impressive rate of 241.2 μL·g -1 ·h -1 for CH 4 production was achieved over the optimal photocatalyst. The femtosecond transient IR absorption results demonstrated that the hot electrons were fast injected in 0.9 ps from the photoexcited surface 4,4'-bpy-RuH complex into the conduction band of TiO 2 nanoparticles to form a charge-separated state with an average lifetime of ca. 50.0 ns responsible for the CO 2 methanation. The spectral characterizations indicated clearly that the formation of CO 2 •- radicals by single electron reduction of CO 2 nanoparticles was the most critical step for the methanation. Such radical intermediates were inserted into the explored Ru-H bond to generate Ru-OOCH species and finally CH 2 and H 4 O in the presence of H 2 O in the presence of H 2 .

Designing hydrogen evolution reaction (HER) electrocatalysts for facilitating its sluggish adsorption kinetics is crucial in generating green hydrogen via sustainable water electrolysis. Herein, a high‐performance ultra‐low Ruthenium (Ru) catalyst is developed consisting of atomically‐layered Ru nanoclusters with adjacent single Ru sites, which executs a bridging‐Ru‐H activation strategy to kinetically accelerate the HER elementary steps. Owing to its optimal electronic structure and unique adsorption configuration, the hybrid Ru catalyst simultaneously displayed a drastically reduced overpotential of 16 mV at 10 mA cm−2 as well as a low Tafel slope of 35.2 mV dec−1 in alkaline electrolyte. When further coupled with a commercial IrO2 anode catalyst, the ensembled anion‐exchange membrane water electrolyzer achievs a current density of 1.0 A cm−2 at a voltage of only 1.70 Vcell. In situ spectroscopic analysis verified that Ru single atom and atomically‐layered Ru nanoclusters in the hybrid materials play a critical role in facilitating water dissociation and weakening *H adsorption, respectively. Theoretical calculations further elucidate the underlaying mechanism, suggesting that the dissociated proton at the single atom Ru site orients itself adjacently with Ru nanoclusters in a bridged structure through targeted charge transfer, thus promoting Volmer‐Heyrovsky dynamics and boosting the HER activity. [ABSTRACT FROM AUTHOR]

Purpose: The ruthenium complex cis-[Ru(H-dcbpy-)2(Cl)(NO)] (DCBPY) is a nitric oxide (NO) donor and studies suggested that the ruthenium compounds can inactivate O2-. The aim of this study is to test if DCBPY can revert and/or prevent the endothelial dysfunction. Methods: Normotensive (2K) and hypertensive (2K-1C) wistar rats were used. To vascular reactivity study, thoracic aortas were isolated, rings with intact endothelium were incubated with: DCBPY: 0.1; 1 and 10μM, DCBPY plus hydroxocobalin (NO scavenger) or tempol during 30 minutes, and concentration effect curves to acetylcholine were performed. The potency values (pD2) and maximum effect (ME) were analyzed. The O2- was generated using hypoxantine xantine oxidase and the reduction of cytochrome c, NO consumption by O2- and the effect in avoid NO consumption was measured. Results: In 2K-1C DCBPY at 0.1; 1 or 10μM improved the relaxation endothelium dependent induced by acetylcholine in aortic rings compared to control 2K-1C, and also improved ME. In rings from 2K incubation with DCBPY (0.1; 1.0 and 10 μM) did not change pD2 or ME. Incubation with 0.1 μM of DCBPY plus hydroxocobalamin did not modify the potency and ME in 2K-1C compared to DCBPY (0.1 μM). DCBPY and SOD inhibits the reduction of cytochrome c and inhibited the NO consumption by O2-, showing that O2- has been removed from the solution. Conclusion: Our results suggest that DCBPY at a lower concentration (0.1 µM) is not an NO generator, but can inactivate superoxide and improves the endothelial function. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Graphical abstract The compound Cp(IPr)Ru(H) 2 SiH(Ph)Cl (IPr = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) (1) was subject to low temperature (30 K), high resolution X-ray structural analysis to obtain a high quality electron density map. This map was subject to a Bader analysis to ascertain the possibility of a Ru–H⋯Si interaction. For comparison, DFT calculations employing the well known B3LYP functional in conjunction with a triple zeta basis set was employed. Thus, we not only report the results of a possible Ru–H⋯Si interaction but also benchmark the use of the employed level of theory against experimental results. Highlights • High resolution X-ray determination. • Experimental Bader analysis. • Theoretical Bader analysis. • DFT calculations. Abstract The compound Cp(IPr)Ru(H) 2 SiH(Ph)Cl (IPr = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) (1) was subject to low temperature (30 K), high resolution X-ray structural analysis to obtain a high quality electron density map. This map was subject to a Bader analysis to ascertain the possibility of a Ru–H⋯Si interaction. For comparison, DFT calculations employing the well known B3LYP functional in conjunction with a triple zeta basis set was employed. Thus, we not only report the results of a possible Ru–H⋯Si interaction but also benchmark the use of the employed level of theory against experimental results. [ABSTRACT FROM AUTHOR]

The dihydrogen complex Ru(H 2 ) 2 H 2 (P(C 5 H 9 ) 3 ) 2 has been investigated, via ab initio accelerated molecular dynamics, to elucidate the H ligands dynamics and possible reaction paths for H 2 /H exchange. We have characterized the free energy landscape associated with the H atoms positional exchange around the Ru centre. From the free energy landscape, we have been able to estimate a barrier of 6 kcal mol -1 for the H 2 /H exchange process. We have also observed a trihydrogen intermediate as a passing state along some of the possible reaction pathways.