Direct Covalent Functionalization of H-Terminated 2D Germanane with Thiolated Molecules: Passivation and Tuning of Optoelectronic Properties.

Covalent molecular functionalization allows the physicochemical properties of 2D materials to be precisely tuned and modulated on-demand. Nonetheless, research on the molecular functionalization of 2D monoelemental graphene-like materials─known as Xenes─remains scarce, being mainly restricted to a specific type of solid-state chemical reaction based on the topotactic transformation of bulkier Zintl phases. Herein, a robust and general chemical approach is reported for the direct functionalization of commercially available H-terminated 2D germanene () with thiolated molecules () via Ge-S bond formation.

Versatile Organometallic Synthesis of 0D/2D Metal@Germanane Nanoarchitectonics for Electrochemical Energy Conversion Applications.

Hydrogen-terminated 2D-Germanane (2D-GeH), a germanium-based 2D material akin to graphene, is receiving enormous attention owing to its predicted optoelectronic characteristics. However, experimental research of 2D-GeH is still in an early stage, and therefore its real implementation for task-specific applications will depend on the correct development of suitable chemical functionalization methods. Herein, a general and straightforward organometallic (OM) approach is provided for the robust functionalization of 2D-GeH with different 0D noble metal nanoparticles (M-NPs), resulting in 0D/2D M@GeH nanoarchitectonics.

Boosting the Oxygen Evolution Activity of FeNi Oxides/Hydroxides by Molecular and Atomic Engineering.

FeNi oxides/hydroxides are the best performing catalysts for oxidizing water at basic pH. Consequently, their improvement is the cornerstone to develop more efficient artificial photosynthetic systems. During the last 5 years different reports have demonstrated an enhancement of their activity by engineering their structures via: (1) modulation of the number of oxygen, iron and nickel vacancies; (2) single atoms (SAs) doping with metals such as Au, Ir, Ru and Pt; and (3) modification of their surface using organic ligands.

MicroRNA cerebrospinal fluid profile during the early brain injury period as a biomarker in subarachnoid hemorrhage patients.

Introduction: Delayed cerebral ischemia (DCI) is a dreadful complication present in up to 30% of patients with spontaneous subarachnoid hemorrhage (SAH). Indeed, DCI is one of the main causes of long-term disability in SAH, yet its prediction and prevention are troublesome in poor-grade SAH cases. In this prospective study, we explored the potential role of micro ribonucleic acid (microRNA, abbreviated miRNAs)-small non-coding RNAs involved in clue gene regulation at the post-transcriptional level-as biomarkers of neurological outcomes in SAH patients.

Influence of Cocatalysts (Ni, Co, and Cu) and Synthesis Method on the Photocatalytic Activity of Exfoliated Graphitic Carbon Nitride for Hydrogen Production.

Exfoliated graphitic carbon nitride (ex-g-CN) was synthesized and loaded with non-noble metals (Ni, Cu, and Co). The synthesized catalysts were tested for hydrogen production using a 300-W Xe lamp equipped with a 395 nm cutoff filter. A noncommercial double-walled quartz-glass reactor irradiated from the side was used with a 1 g/L catalyst in 20 mL of a 10 vol% triethanolamine aqueous solution.

Unravelling the Mechanistic Pathway of the Hydrogen Evolution Reaction Driven by a Cobalt Catalyst.

A cobalt complex bearing a κ-N P ligand is presented (1 or Co (L), where L is (1E,1'E)-1,1'-(pyridine-2,6-diyl)bis(N-(3-(diphenylphosphanyl)propyl)ethan-1-imine). Complex 1 is stable under air at oxidation state Co thanks to the π-acceptor character of the phosphine groups. Electrochemical behavior of 1 reveals a two-electron Co /Co oxidation process and an additional one-electron reduction, which leads to an enhancement in the current due to hydrogen evolution reaction (HER) at E =-1.

Insights into the light-driven hydrogen evolution reaction of mesoporous graphitic carbon nitride decorated with Pt or Ru nanoparticles.

Ru or Pt nanoparticles have been prepared following the organometallic approach and deposited onto the surface of mesoporous graphitic carbon nitride (mpg-CN). Three different Ru-based samples have also been compared to investigate the effect of 4-phenylpyridine as a stabilizing agent. The photocatalytic performance towards the hydrogen evolution reaction (HER) has been tested showing that all hybrid systems clearly outperform the photocatalytic activity of bare mpg-CN.

Consecutive Ligand-Based Electron Transfer in New Molecular Copper-Based Water Oxidation Catalysts.

Water oxidation to dioxygen is one of the key reactions that need to be mastered for the design of practical devices based on water splitting with sunlight. In this context, water oxidation catalysts based on first-row transition metal complexes are highly desirable due to their low cost and their synthetic versatility and tunability through rational ligand design. A new family of dianionic bpy-amidate ligands of general formula H LN (LN is [2,2'-bipyridine]-6,6'-dicarboxamide) substituted with phenyl or naphthyl redox non-innocent moieties is described.

Water oxidation electrocatalysis using ruthenium coordination oligomers adsorbed on multiwalled carbon nanotubes.

Photoelectrochemical cells that utilize water as a source of electrons are one of the most attractive solutions for the replacement of fossil fuels by clean and sustainable solar fuels. To achieve this, heterogeneous water oxidation catalysis needs to be mastered and properly understood. The search continues for a catalyst that is stable at the surface of electro(photo)anodes and can efficiently perform this reaction at the desired neutral pH.

Local infiltration analgesia for total knee arthroplasty: Does a mixture of ropivacaine and epinephrine have an impact on hemodynamics? An observational cohort study.

Purpose: High doses of local anesthetic administered intra-articularly and peri-articularly during local infiltration analgesia (LIA) for total knee arthroplasty (TKA) may have potential effects on patient hemodynamics. The aim of this study was to know if hemodynamic changes are associated with LIA in patients undergoing TKA.

Methods: In a prospective observational design, elective patients undergoing orthopedic surgery for TKA and treated with LIA consisting of a mixture of ropivacaine (300 mg) and epinephrine (1 mg) were investigated for changes in selected hemodynamic parameters: heart rate (HR), non-invasively registered mean arterial blood pressure (MAP), and incidence of arrhythmias during the perioperative course, consisting of the following periods: period 1.

Effect of Ligand Chelation and Sacrificial Oxidant on the Integrity of Triazole-Based Carbene Iridium Water Oxidation Catalysts.

We report the effect of replacing the pyridine group in the chelating trz Ir-water oxidation catalysts by a benzoxazole and a thiazole moiety. We have also evaluated if the presence of bidentate ligands is crucial for high activities and to avoid the decomposition into undesired heterogeneous layers. The catalytic performance of these benzoxazole/thiazole-triazolidene Ir-complexes in water oxidation was studied at variable pH using either CAN (pH = 1) or NaIO (pH = 5.

Organocatalytic vs. Ru-based electrochemical hydrogenation of nitrobenzene in competition with the hydrogen evolution reaction.

The electrochemical reduction of organic contaminants allows their removal from water. In this contribution, the electrocatalytic hydrogenation of nitrobenzene is studied using both oxidized carbon fibres and ruthenium nanoparticles supported on unmodified carbon fibres as catalysts. The two systems produce azoxynitrobenzene as the main product, while aniline is only observed in minor quantities.

Ruthenium Nanoparticles for Catalytic Water Splitting.

Both global warming and limited fossil resources make the transition from fossil to solar fuels an urgent matter. In this regard, the splitting of water activated by sunlight is a sustainable and carbon-free new energy conversion scheme able to produce efficient technological devices. The availability of appropriate catalysts is essential for the proper kinetics of the two key processes involved, namely, the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER).

Seven Coordinated Molecular Ruthenium-Water Oxidation Catalysts: A Coordination Chemistry Journey.

Molecular water oxidation catalysis is a field that has experienced an impressive development over the past decade mainly fueled by the promise of generation of a sustainable carbon neutral fuel society, based on water splitting. Most of these advancements have been possible thanks to the detailed understanding of the reactions and intermediates involved in the catalytic cycles. Today's best molecular water oxidation catalysts reach turnover frequencies that are orders of magnitude higher than that of the natural oxygen evolving center in photosystem II.

Vascular access surgery can be safely performed in an ambulatory setting.

Introduction:: Ambulatory surgery is associated with lower costs, but there is lack of evidence of the safety for ambulatory vascular access surgery. The objective of this study is to substantiate the safety and effectiveness of performing vascular access surgery in an ambulatory setting.

Methods:: A review of our prospectively maintained database including all vascular access open surgeries (creations and repairs) performed by our Vascular Access Unit between 2013 and 2017 was compiled.

Behavior of Ru-bda Water-Oxidation Catalysts in Low Oxidation States.

The Ru complex [Ru (bda-κ-N O )(N-NH ) ] (1; bda =2,2'-bipyridine-6,6'-dicarboxylate, N-NH =4-(pyridin-4-yl)aniline) was used as a synthetic intermediate to prepare new Ru and Ru bda complexes that contain NO , MeCN, or H O ligands. In acidic solution complex 1 reacts with an excess of NO (generated in situ from sodium nitrite) to form a new Ru complex in which the aryl amine ligand N-NH is transformed into a diazonium salt [N-N =4-(pyridin-4-yl)benzenediazonium)] together with the formation of a new Ru(NO) moiety in the equatorial zone, to generate [Ru (bda-κ-N O)(NO)(N-N ) ] (2 ). Here the bda ligand binds in a κ-N O tridentate manner with a dangling carboxylate group.

Rational design of a neutral pH functional and stable organic photocathode.

In this work we lay out design guidelines for catalytically more efficient organic photocathodes achieving stable hydrogen production in neutral pH. We propose an organic photocathode architecture employing a NiO hole selective layer, a PCDTBT:PCBM bulk heterojunction, a compact TiO2 electron selective contact and a RuO2 nanoparticle catalyst. The role of each layer is discussed in terms of durability and function.

Synthesis, Structure, and Redox Properties of a trans-Diaqua Ru Complex That Reaches Seven-Coordination at High Oxidation States.

In this work we have prepared and characterized two Ru complexes that contain the pentadenatate tda ligand (tda = [2,2':6',2″-terpyridine]-6,6″-dicarboxylate) that occupies the equatorial positions and two monodentate ligands aqua and/or dmso that occupy the axial positons: [trans-Ru(tda-κ-NO)(OH)], 3(OH), and [Ru(tda-κ-NO)(dmso)(OH)], 4. The latter is a useful synthetic intermediate for the preparation of Ru-tda complexes with different axial ligands. The two complexes have been characterized in the solid state by single-crystal XRD and by elemental analysis.

Ruthenium Water Oxidation Catalysts based on Pentapyridyl Ligands.

Ruthenium complexes containing the pentapyridyl ligand 6,6''-(methoxy(pyridin-2-yl)methylene)di-2,2'-bipyridine (L-OMe) of general formula trans-[Ru (X)(L-OMe-κ-N )] (X=Cl, n=1, trans-1 ; X=H O, n=2, trans-2 ) have been isolated and characterized in solution (by NMR and UV/Vis spectroscopy) and in the solid state by XRD. Both complexes undergo a series of substitution reactions at oxidation state Ru and Ru when dissolved in aqueous triflic acid-trifluoroethanol solutions as monitored by UV/Vis spectroscopy, and the corresponding rate constants were determined. In particular, aqueous solutions of the Ru -Cl complex trans-[Ru (Cl)(L-OMe-κ-N )] (trans-1 ) generates a family of Ru aquo complexes, namely trans-[Ru (H O)(L-OMe-κ-N )] (trans-2 ), [Ru (H O) (L-OMe-κ-N )] (trans-3 ), and [Ru (Cl)(H O)(L-OMe-κ-N )] (trans-4 ).

Dissimilar catalytic behavior of molecular or colloidal palladium systems with a new NHC ligand.

In this work, we describe the synthesis of a new N-heterocyclic carbene (NHC) ligand, derived from a hybrid pyrazole-imidazolium scaffold, namely 1-[2-(3,5-dimethylpyrazol-1-yl)ethyl]-3-((S)-1-phenylethyl)-3H-imidazol-2-ylidene (L). This ligand has been used as a stabilizer for the organometallic synthesis of palladium(0) nanoparticles (Pd NPs). L presents a better stabilizing effect than its pre-carbenic HLCl counterpart, allowing the formation of isolated Pd NPs while HLCl yields aggregated ones.

Photoelectrochemical Behavior of a Molecular Ru-Based Water-Oxidation Catalyst Bound to TiO-Protected Si Photoanodes.

A hybrid photoanode based on a molecular water oxidation precatalyst was prepared from TiO-protected n- or p-Si coated with multiwalled carbon nanotubes (CNT) and the ruthenium-based water oxidation precatalyst [Ru(tda)(py-pyr)(O)], 1(O) (tda is [2,2':6',2″-terpyridine]-6,6″-dicarboxylato and py-pir is 4-(pyren-1-yl)-N-(pyridin-4-ylmethyl)butanamide). The Ru complex was immobilized by π-π stacking onto CNTs that had been deposited by drop casting onto Si electrodes coated with 60 nm of amorphous TiO and 20 nm of a layer of sputtered C. At pH = 7 with 3 Sun illumination, the n-Si/TiO/C/CNT/[1+1(O)] electrodes exhibited current densities of 1 mA cm at 1.

How to make an efficient and robust molecular catalyst for water oxidation.

Energy has been a central subject for human development from Homo erectus to date. The massive use of fossil fuels during the last 50 years has generated a large CO concentration in the atmosphere that has led to the so-called global warming. It is very urgent to come up with C-neutral energy schemes to be able to preserve Planet Earth for future generations to come and still preserve our modern societies' life style.

Mononuclear ruthenium compounds bearing N-donor and N-heterocyclic carbene ligands: structure and oxidative catalysis.

A new CNNC carbene-phthalazine tetradentate ligand has been synthesised, which in the reaction with [Ru(T)Cl] (T = trpy, tpm, bpea; trpy = 2,2';6',2''-terpyridine; tpm = tris(pyrazol-1-yl)methane; bpea = N,N-bis(pyridin-2-ylmethyl)ethanamine) in MeOH or iPrOH undergoes a C-N bond scission due to the nucleophilic attack of a solvent molecule, with the subsequent formation of the mononuclear complexes cis-[Ru(PhthaPz-OR)(trpy)X], [Ru(PhthaPz-OMe)(tpm)X] and trans,fac-[Ru(PhthaPz-OMe)(bpea)X] (X = Cl, n = 1; X = HO, n = 2; PhthaPz-OR = 1-(4-alkoxyphthalazin-1-yl)-3-methyl-1H-imidazol-3-ium), named 1a/2a (R = Me), 1b/2b (R = iPr), 3/4 and 5/6, respectively. Interestingly, regulation of the stability regions of different Ru oxidation states is obtained by different ligand combinations, going from 6, where Ru(iii) is clearly stable and mono-electronic transfers are favoured, to 2a/2b, where Ru(iii) is almost unstable with regard to its disproportionation. The catalytic performance of the Ru-OH complexes in chemical water oxidation at pH 1.