Ruthenium Ion Research Articles

Reductive amination of levulinic acid to N-substituted pyrrolidones over RuCl3 metal ion anchored in ionic liquid immobilized on graphene oxide

Reductive amination of biomass derived Levulinic acid (LA) for the synthesis of N-substituted pyrrolidones is one of the highly attractive routes for biomass valorization. The supported homogeneous metal precursor into the solid surface is an important context in the field of catalysis because these types of catalysts provide the heterogeneous nature and meet the needs of recyclability. Herein, we have reported a synthesis of catalyst with ruthenium ion supported on ionic liquid immobilized into graphene oxide (Ru@GOIL) and its application for reductive amination reaction. Synthesized catalyst is characterized using different analytical techniques such as FT-IR, XRD, XPS, TGA, FEG-SEM, TEM and EXAFS analysis. The prepared Ru@GOIL found to be highly effective for reductive amination of LA and under these optimized conditions various N-substituted pyrrolidones derivatives were synthesized in excellent yield (78–93%). Ru@GOIL catalyst demonstrated great catalytic performance for reductive amination reaction of LA giving good turnover frequency (TOF = 62 h−1) value in comparison with other catalysts. The Ru@GOIL catalyst was recycled for six reaction runs with slight drop-in activity after 4th cycle. Practical applicability of the developed catalyst was successfully demonstrated by direct transformation of biomass waste (rice husk and wheat straw) derived LA to N-substituted pyrrolidones.

SYNTHESIS AND SPECTRAL CHARACTERISTICS OF PERSPECTIVE NANOSIZED CARBON QUANTUM DOTS FOR ADSORPTION AND CATALYTIC PROCESSES

Processes of interaction between carbon quantum dots (CQDs) and solutions of rhodium, ruthenium and palladium chlorides in the surface layer have been investigated by electron and IR spectroscopy. When rhodium chloride is added to a solution of CQDS, a bathochromic shift of the β- and p-absorption bands (ABs) at 48725 and 41711 cm-1 as well as hypsochromic shift of the α-AB at 28935 cm-1 indicate that rhodium adsorption occurs on the surface of CQDs. The bathochromic shift of the absorption bands at 22400 сm1 together with the hypsochromic shift of ABs corresponding to d-d electron transitions in the metal ions indicates the formation of rhodium with CQDs. When ruthenium and palladium chlorides are added to an aqueous solution of CQDs, the intensive of ABs characterizing the complex anions [RuCl6]3-, [RuCl6]2- or [PdCl4]2- are absent in the UV-Vis spectra. This indicates the passage of adsorption processes of metals on the surface of CQDs. The present of ABs (at 27055 and 25125 сm-1) indicate the trivalent state of ruthenium ion; the p-ABs bathochromic shift as well as α-ABs hypsochromic shift indicates the probable complex formation of CQDs with Ru3+ ions. The change in the position of the absorption bands of d-d electron transitions (at 25448 сm1) together with the bathochromic shift of p-ABs and hypsochromic shift of α-ABs indicates a change in coordination environment in the palladium ion with the possible formation of Pd → N bond. The IR-spectra data of CQDs showed the presence of a number of characteristic ABs for functionalized CQDs: ν(N–H) at 3260 сm1, (C=O) at 1830, 1840 and 1850 сm1, –С=O(NH) at 1770 сm1, ν(C=N) at 1680 and δ(N–H) at 1640 сm1, which confirms the coordination of metals on the surface of CQDs.

Does geometry matter? Effect of the ligand position in bimetallic ruthenium polypyridine siblings.

In this work, we present the preparation of a complex [(tpy)(bpy)Ru(μ-CN)Ru(py)4(OH2)](PF6)3 (tpy = 2,2',6',2''-terpyridine; bpy = 2,2'-bipyridine; py = pyridine) that combines a ruthenium chromophore linked to another ruthenium ion that bears a labile position trans to the bridge. Substitution in this position is very attractive, as it allows us to place a quencher trans to the chromophore maximizing the separation between them. This complex allowed us to prepare a family of cyanide-bridged ruthenium polypyridines of general formula [Ru(tpy)(bpy)(μ-CN)Ru(py)4(L)]2/3+ (L = Cl-, NCS-, 4-dimethylaminopyridine or acetonitrile) and compare them with the related complexes [Ru(tpy)(bpy)(μ-CN)Ru(bpy)2(L)]2/3+ where the L ligand lies cis to the bridge. The mixed-valence form of these complexes shows evidence of strong coupling between the ruthenium ions and enhanced delocalization as the redox potential of the {Ru(py)4L} fragment increases. (TD)DFT calculations reproduce very well the experimental spectra of these complexes and indicate that when L = acetonitrile, the hole in the mixed-valence complex is almost equally distributed between both ruthenium ions. For L = DMAP and NCS- the π orbitals of the ligands are mixed with dπ orbitals of the Ru ions, resulting in partial delocalization of the charge on the ligands. The latter result illustrates that the trans configuration of these complexes is well-suited to extend the interaction beyond the bridged ruthenium ions.

Vascular tone and angiogenesis modulation by catecholamine coordinated to ruthenium.

Catecholamines participate in angiogenesis, an important tumor development process. However, the way catecholamines interact with their receptors has not been completely elucidated, and doubts still remain as to whether these interactions occur between catechol and/or amine sites and particular amino acid residues on the catecholamine receptors. To evaluate how catechol and amine groups contribute to angiogenesis, we immobilized the catechol site through ruthenium ion (Ru) coordination, to obtain species with the general formula [Ru(NH3)4(catecholamine-R)]Cl. We then assessed the angiogenic activity of the complexes in a chorioallantoic membrane model (CAM) and examined vascular reactivity and calcium mobilization in rat aortas and vascular cells. [Ru(NH3)4(catecholamine-R)]Cl acted as partial agonists and/or antagonists of their respective receptors and induced calcium mobilization. [Ru(NH3)4(isoproterenol)]+ [Ru(NH3)4(noradrenaline)]+, and [Ru(NH3)4(adrenaline)]+ behaved as antiangiogenic complexes, whereas [Ru(NH3)4(dopamine)]+ proved to be a proangiogenic complex. In conclusion, catecholamines and [Ru(NH3)4(catecholamine-R)]Cl can modulate angiogenesis, and catechol group availability can modify the way these complexes impact the vascular tone, suggesting that catecholamines and their receptors interact differently after catecholamine coordination to ruthenium.

Spectro-analytical, antimicrobial and antitumor studies of the first and second generation of cephalosporin combined with ruthenium(III) ion as a drug model

Spectro-analytical, antimicrobial and antitumor studies of the first and second generation of cephalosporin combined with ruthenium(III) ion as a drug model

Quantification of electrogenerated chemiluminescence from tris(bipyridine)ruthenium(ii) and hydroxyl ions.

In this work, we quantify the electrogenerated chemiluminescence arising from the reaction of electrogenerated tris(bipyridine)ruthenium(iii) with hydroxyl ions, in terms of emission intensity and reaction rate. Different electrode materials (glassy carbon and boron-doped diamond) and different supporting electrolytes (perchlorate, phosphate, and carbonate) were investigated with pH variation. Relative quantification of the electrogenerated chemiluminescence was achieved using the Ru(bpy)32+/tri-n-propylamine system, taken as a reference, with relative emission as low as 600 and 230 times that observed at the same coreactant concentration and the same pH, respectively. The kinetics was investigated by foot of the wave analysis of cyclic voltammetry to measure the turnover frequency of the reaction.

Novel Approach to Generate a Self-Deliverable Ru(II)-Based Anticancer Agent in the Self-Reacting Confined Gel Space.

Finding the most effective method for cancer treatment is one of the thought-provoking tasks. Drug delivery by collapsing of metallogel to the cancer cell is an appealing way out. Cancer cells have an acidic environment due to excessive accumulation of lactic acid. In this work, the novel G5 gelator with a strategically free carboxylic acid arm has been designed and fabricated and characterized by several spectroscopic and microscopic techniques. These experiments suggest the formation of an ordered supramolecular gel with clover-leaf-like morphology. Mechanical properties from rheological measurements suggest the viscoelastic nature of the gel. Furthermore, we have obtained crystals of G5 from the pure dimethyl sulfoxide solution, whereas gelation gets induced by addition of water. This G5 gelator loses its gelation capability once the carboxylate is esterified by layering with methanol, which furnished the crystals of Me-G5' (G5' = G5-H). Further, the G5 gelator is used for the formation of ruthenium metallogel. Interestingly, we obtained the monomeric species [Ru(G5')(η6-p-cymene)Cl] [Ru(II)G5] only in confined gel space upon addition of a [Ru2(η6-p-cymene)2Cl4] dimer to G5. The Ru(II)G5 metallogel has an inherent anticancer property with an IC50 value of 10.53 μM for the A549 cancer cell line. Treatment of the Ru(II)G5 metallogel by lactic acid for mimicking the acidic environment of the malignant cell results in collapsing of the gel by releasing the ruthenium metal ion. This released ruthenium ion binds with the lactic acid derivative making the gelator G5 free and producing a new compound Ru(II)L, which has also shown the anticancer property. The molecular docking study revealed that the released G5 could interact with a monocarboxylate transporter to disrupt the lactate transport chain, which might induce apoptosis.

One-step synthesis of ball-shaped metal complexes with a main absorption band in the near-IR region

The design of near-IR materials is highly relevant to energy and pharmaceutical sciences due to the high proportion of near-IR irradiation in the solar spectrum and the high penetration of near-IR light in biological samples. Here, we show the one-step synthesis of hexacoordinated ruthenium and iron complexes that exhibit a main absorption band in the near-IR region. For that purpose, novel tridentate ligands were prepared by condensation of two diimines and four cyanoaryl derivatives in the presence of ruthenium and iron template ions. This method was applied to a wide variety of cyanoaryl, diimine, and metal ion combinations. The relationship between the structure and the optical and electrochemical properties in the resulting complexes was examined, and the results demonstrated that these compounds represent novel near-IR materials whose physical properties can be controlled based on rational design guidelines. The intense absorption bands in the 700–900 nm region were assigned to metal-to-ligand charge transfer (MLCT) transitions, which should allow applications in materials with triplet excited states under irradiation with near-IR light.

Electrochemically Facile Hydrogen Evolution Using Ruthenium Encapsulated Two Dimensional Covalent Organic Framework (2D COF)

AbstractTwo dimensional covalent organic frameworks (2D COFs) are unique class of crystalline porous polymers which are formed by the covalent bonding between the organic building blocks. Their layers are stacked to each other by non‐covalent interactions. The stacking sequence between the layers is highly significant towards various applications. In this article, we have prepared ruthenium ions encapsulated 2D COF (Ru@COF) from a synthesized COF. We have performed an electrochemical hydrogen evolution reaction using Ru@COF as electrocatalyst. Moreover, Ru@COF shows better electrochemical hydrogen evolution reaction (HER) activity compared to bare RuCl3 and COF. The HER activities are measured in 1.5 M H2SO4 medium. Ru@COF shows onset potential 159 mV with the Tafel slope of 79 mV dec−1. The linear Tafel plot with the slope 79 mV dec−1 indicates Volmer‐Heyrovsky‐Tafel mechanism for the Ru@COF catalysed HER. COF plays a crucial role in maintaining stability and catalytic efficiency of the material. Interestingly, Ru@COF acts as exemplary electrocatalyst material that is used as solid binder‐free cathodic electrode on glassy carbon electrode surface.

A Diruthenium Complex of an N-Pyridyl-o-aminophenol Derivative: A Route to Mixed Valency.

An N-pyridyl-o-aminophenol derivative that stabilises mixed-valence states of ruthenium ions is disclosed. A diruthenium complex, [(LIQ 0 )Ru2 Cl5 ]⋅MeOH (1⋅MeOH) is successfully isolated, in which LIQ 0 is the o-iminobenzoquinone form of 2-[(3-nitropyridin-2-yl)amino]phenol (LAP H2 ). In 1, LIQ 0 oriented towards one ruthenium centre is a non-innocent NO-donor redox ligand, whereas another oriented towards another ruthenium centre is an innocent pyridine-donor redox ligand. Complex 1 is a diruthenium(II,III) mixed-valence complex, [RuII (LIQ 0 )(μ-Cl)2 RuIII ], with a minor contribution from the diruthenium(III,III) state. [RuIII (LISQ .- )(μ-Cl)2 RuIII ] contains LISQ .- , which is the o-iminobenzosemiquinonate anion radical form of the ligand. Complexes 1- and 1+ are diruthenium(II,II), [RuII (LIQ 0 )(μ-Cl)2 RuII ], and diruthenium(III,III), [RuIII (LIQ 0 )(μ-Cl)2 RuIII ], complexes, respectively, of LIQ 0 . Complex 12- is a diruthenium(II,II) complex of the o-iminobenzosemiquinonate anion radical (LISQ .- ), [RuII (LISQ .- )(μ-Cl)2 RuII ], with a minor contribution from the diruthenium(III,II) form, [RuIII (LAP 2- )(μ-Cl)2 RuII ]. Complex 12+ is a diruthenium(III,IV) mixed-valence complex of LIQ 0 , [RuIII (LIQ 0 )(μ-Cl)2 RuIV ]. Complexes 1 and 12+ exhibit inter-valence charge-transfer transitions at λ=1300 and 1370 nm, respectively.

A deep insight into the structural characteristics of Yilan oil shale kerogen through selective oxidation

The structural characteristics of oil shale are important to its application. In this work, a deep insight into the structural characteristics of Yilan oil shale kerogen (YLK) was studied using alkali-oxygen oxidation at different times and ruthenium ion catalyzed oxidation (RICO). The results indicate that YLK is gradually converted to humic acids (HAs), water-soluble acids (WSAs), carboxylic acids (CAs), CO2 and H2O. 13C NMR analyses of YLK, residues and HAs indicate that C–O bonds, especially Car–O bonds of YLK, are easily cleaved. The condensed aromatic rings and long alkyl chains are difficult to be oxidized during the oxidation process. With increasing oxidation time, the molar fraction of aromatic bridgehead carbon (Xb) of YLK and the residues increases from 0.174 to 0.201, and that of HAs increases from 0.225 to 0.267. The result indicates that the aromatic structures of YLK are composed of 1-ring aromatic clusters (26.5%), 2-ring aromatic clusters (67.1%) and 3 or more-ring aromatic clusters (6.4%). Also, the average methylene chain (Cn) of YLK and the residues increases from 2.0 to 5.1, and that of HAs increases from 1.3 to 2.7, indicating that the alkyl chain length is not average but has a distribution. 2.5% methylene carbons exist as long n-alkyl chains in the alkyl side chains groups (SCGs) on the aromatic rings in YLK. The carbon number of SCGs ranges from 5 to 22, and C15 and C17 are predominant. 3.8% methylene carbons exist as alkyl bridges linkages (BLs) connecting aromatic rings in YLK. The carbon number of BLs connecting aromatic rings ranges from 6 to 19, and C8 is predominant. Because of the existence of above long n-alkyl chains, 93.7% methylene carbons in YLK exist as alkyl chains with an average length of 1.84.

The ORR and OER Performances of Bismuth Ruthenate As the Cathode of Air Battey Using KOH Solution

Electrochemical power sources that use oxygen as a reactant may play an essential role in the future energy needs of the society. Fuel cells, aqueous metal-air batteries, and metal hydride (MH)/air batteries hold promise as the power sources. Especially, for rechargeable batteries, an oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER) are the cathode reactions during charge and discharge. Therefore, the development of highly active catalysts (i.e., low activation overpotential) for the reactions is required and remains challenging. Then, we attempted to develop the electrode catalysts which decrease in the overpotential for ORR and OER in an alkaline aqueous solution. Especially, we focus on the pyrochlore type metal oxide including bismuth and ruthenium ions as Bi2Ru2O7 (BRO) and evaluated the overpotential and Tafel slopes for both ORR and OER by using the rotating ring-disk electrode (RRDE) technique as well as a half-cell test. We also have investigated the effect of aluminum ion addition to BRO, which is called as ABRO, by the addition of aluminium nitrate [Al(NO3)3] during the synthesis of BRO. BRO and ABRO were prepared by a precipitation method. In order to prepare BRO, the method is denoted bellow. At first, Bi(NO3)3 and RuCl3 aqueous solutions were separately prepared and well mixed in a 1 : 1 molar ratio. The mixture solution was heated up to 75 oC and stirred for 1 hour. Then, NaOH aqueous solution was added to the mixed solution to produce a precipitate and stirred for 72 hour. After that, the precipitate was made for calcination under atmospheric air at 500 and 600oC for 3 hours and then it was washed with pure water and dried at 120 oC for 3 hours. On the other hand, Al(NO3)3 was also added to the mixture solution during the synthesis to investigate an effect of aluminum ion on the ORR and OER of BRO. These products were obtained after the calcination at the desired temperatures as 500 and 600oC in air. X-ray diffraction (XRD) and Field emission scanning electron microscope (FE-SEM) observation were performed for characterization. The catalytic behavior was investigated by a RRDE. The disk and ring electrodes were made by titanium (Ti) and Pt, respectively. BRO or ABRO powder was loaded on Ti disk. Hg|HgO reference electrode and a Ni mesh counter electrode were used. The electrochemical cell was made of polytetrafluoroethylene (PFA). The electrolyte was 0.1 mol dm-3 KOH aqueous solution. We also measured constant current charge-discharge measurements to evaluate BRO as the cathode catalyst for the air-battery. In this test, 6.0 mol dm-3 KOH aqueous solution was used as the electrolyte. The peaks in the XRD patterns of BRO were assigned to Bi2Ru2O7, when the calcination temperature was 500oC; on the other hand, the peaks were assigned to Bi1.87Ru2O6.903 when the calcination temperature was 600oC. In addition to these, tiny diffraction peaks of Bi2O3 were also confirmed. These results indicated that both of oxygen and bismuth were decreased between 500oC and 600oC due to the elimination of oxygen from BRO. In the case of ABRO, the peaks were assigned to Bi1.87Ru2O6.903 at 500oC and to Bi1.88Ru2O6.906 at 600oC and simultaneously, Al2O3 was also confirmed in both cases. Table 1 shows the overpotentials and Tafel slopes for ORR and OER of BRO and ABRO. The overpotentials and Tafel slopes for OER of BRO@500oC were around 0.14 V and 70 mV dec.-1, respectively. The overpotential was increased when the calcination temperature was at 600oC, but the Tafel slope was unchanged. The overpotential of ABRO for OER was estimated at 0.11 V, which shows that the aluminium nitrate addition would be effective to decrease in the overpotential. In this presentation, we will report the catalyst performances during the constant current charge-discharge measurements as the air-battery. This work was supported by “Development of Hydrogen|Air battery”, “Advanced Low Carbon Technology Research and Development Program (ALCA)” of Japan Science and Technology Agency (JST). Table 1 The overpotentials and Tafel slopes for ORR and OER of BRO and ABRO. Sample Overpotential / V Tafel slope / mV dec.-1 ORR OER ORR OER BRO@500 0.34 0.14 -69 71 BRO@600 0.33 0.19 -64 74 ABRO@500 0.37 0.11 -51 62 ABRO@600 0.35 011 -41 41

Layer dependent antiferromagnetism in the Sr4Ru3O10 ruthenate at the metamagnetic-like transition

We have investigated the metamagnetic-like transition in the triple layer ruthenate Sr4Ru3O10 by means of neutron diffraction from single crystals. The magnetic structure of the compound appears to be determined in a complex way by the two substructures of inequivalent ruthenium ions. At Tc=105K the system has a sharp transition into a ferromagnetic state along the c-axis which is driven by the ruthenium atoms in the central octahedra of the triple layers whereas the substructure of the outer ruthenium atoms tend to align in the ab plane achieving an antiferromagnetic order at the metamagnetic transition T*~50K. Below T* the strong anisotropy along c prevails, the outer ruthenium tend to align along the c-axis and the in-plane antiferromagnetic order disappears. This finding confirms the delicate balance between antiferro and ferromagnetic couplings in the (Sr,Ca)n+1RunO3n+1 family of compounds, and proves the layer dependence of the magnetic anisotropy in Sr4Ru3O10.

Ruthenium-Based Macromolecules as Potential Catalysts in Homogeneous and Heterogeneous Phases for the Utilization of Carbon Dioxide.

Ruthenium-containing tetraphenylporphyrin (Ru-TPP) molecule was prepared, and the structural elucidation was confirmed using 1H nuclear magnetic resonance (NMR), CHN, and mass spectral analyses. The incorporation of ruthenium ion into the cavities of the macromolecule was confirmed from the disappearance of the 1H NMR signal, characteristic of the N–H bond (−2.72 ppm in TPP). The CHN and mass spectral analyses of the ligand and metallomacromolecules are consistent with the theoretically calculated values. The homogeneous Ru-TPP macromolecule is grafted on the surface of aminosilane-, diaminosilane-, and iodosilane-functionalized SBA-15 molecular sieves. The successful grafting of Ru-TPP on functionalized mesoporous molecular sieve materials was evident from low-angle powder X-ray diffraction, 13C magic angle spinning NMR, and scanning electron microscopy–energy-dispersive X-ray analyses. The resultant homogeneous and heterogenized Ru-TPP catalysts were used for the utilization of carbon dioxide (CO2) under moderate reaction conditions. The homogeneous Ru-TPP catalyst showed first-order kinetics with respect to epoxide with the exclusive formation of cyclic carbonate (about 98%) and an activation energy of 16.07 kg/mol, which is much lower than some of the reported catalysts. Ru-TPP grafted on aminosilane- and iodosilane-functionalized materials showed better catalytic activity (above 90% conversion and 83–96% cyclic carbonate selectivity) and reusability for the chosen reaction.

Nanoclusters prepared from ruthenium(II) and quercetin for fluorometric detection of cobalt(II), and a method for screening their anticancer drug activity.

Ruthenium-quercetin conjugated nanoclusters (Ru-QC NCs) were synthesized via a one-pot reflux reaction. As inhalation of heavy metal ions like cobalt can lead to lung cancer, a fluorescent probe was designed for the determination of Co(II) both in aqueous solutions and living cells. The probe consists of hybrid nanoclusters with an average size of 2nm that were prepared from ruthenium(II) ions and the flavonoid quercetin. These are termed as Ru-QC NCs. They display strong orange-colored emission with a peak at 558nm under 465-nm excitation. The Ru-QC NCs are cell viable and enable imaging of cells and intracellular fluorometric detection of Co(II). The anticancer properties of Ru-QC NCs were screened by using non-small cell lung cancer (A549) and human dermal fibroblast (HDFa) cell lines. The Ru-QC NCs exert considerable cytotoxicity in A549 cells (at levels of 20-50μg·mL-1), whereas no significant cytotoxicity was observed in case of HDFa cells. The anticancer properties of Ru-QC NCs were screened via MTT assay, live-dead staining, and ROS assay, respectively. Morphological changes of cancer cells were observed using atomic force microscopy. The fluorescent probe can detect Co(II) with a detection limit of 9.28nM and with a linear response in the 0.03-100μM concentration range. Graphical abstract Schematic representation of ruthenium-quercetin nanoclusters with potential anticancer properties. They are promising fluorescent probes for intracellular sensing of cobalt (Co2+) and bio-imaging. They exhibited efficient fluorometric detection of Co2+ with the limit of detection (LOD) of 9.28nM.

Positional Isomers of Isocyanoazulenes as Axial Ligands Coordinated to Ruthenium(II) Tetraphenylporphyrin: Fine-Tuning Redox and Optical Profiles.

Two isomeric ruthenium(II)/5,10,15,20-tetraphenylporphyrin complexes featuring axially coordinated redox-active, low-optical gap 2- or 6-isocyanoazulene ligands have been isolated and characterized by NMR, UV-vis, and magnetic circular dichroism (MCD) spectroscopic methods, high-resolution mass spectrometry, and single-crystal X-ray crystallography. The UV-vis and MCD spectra support the presence of the low-energy, azulene-centered transitions in the Q band region of the porphyrin chromophore. The first coordination sphere in new L2RuTPP complexes reflects compressed tetragonal geometry. The redox properties of the new compounds were assessed by electrochemical and spectroelectrochemical means and correlated with the electronic structures predicted by density functional theory and CASSCF calculations. Both experimental and theoretical data are consistent with the first two reduction processes involving the axial azulenic ligands, whereas the oxidation profile (in the direction of increasing potential) is exerted by the ruthenium ion, the porphyrin core, and the axial azulenic moieties.

Promising sensitizers for dye sensitized solar cells: A comparison of Ru(II) with other earth's scarce and abundant metal polypyridine complexes

AbstractThere has recently been a growing interest in dye sensitized solar cells (DSSCs) based on ruthenium metal, but due to the scarcity and high price of ruthenium, design of better and cheaper light adsorbent dyes based on more abundant metal ions is one of the key issues for future development of the DSSCs. Using density functional theory (DFT) and time‐dependent DFT we have studied the properties of new and abundant metal ion‐based polypyridyl dyes for p‐type DSSCs and compared with ruthenium and other scarce metal ions. Molecular geometries, electronic structures, and optical absorption spectra have been calculated using an implicit solvent corresponding to acetonitrile. The calculated fair light harvesting efficiency, high hole injection efficiency and Gibbs free energy for the hole injection and longer excited state lifetime (important for reflecting the efficiency of solar cells) for the new abundant metal ions (V3+ and Cr2+) based dyes could provide promising sensitizers for efficient next generation DSSC's for p‐SC.

Ion‐imprinted poly(methyl methacrylate‐vinyl pyrrolidone)/poly(vinylidene fluoride) blending membranes for selective removal of ruthenium(III) from acidic water solutions

While conventional approaches have been studied for removal of ruthenium(III) ions (Ru(III)), this work focuses on the applicability of ion‐imprinted poly(methyl methacrylate‐vinyl pyrrolidone)/poly(vinylidene fluoride) blending membranes (Ru(III)–ion‐imprinted membrane[IIM]) for selective removal of Ru(III) from acidic water solutions. In order to measure the effectiveness of these imprinted membranes, after fabrication, binding experiments were done with aqueous Ru(III) solutions. The results showed that Ru(III)‐IIMs were fabricated successfully at various blending ratios, and their chemical components, microstructures, hydrophilicity, and water fluxes were measured. In pH range 0.5 to 5.0, binding capacity (Qe) of Ru(III) onto Ru(III)‐IIM increases remarkably with pH and then reaches to a maximum value (53.52 mg/g) at pH 1.5. After that, Qe gradually decreases. Compared with a nonimprinted membrane, Ru(III)‐IIM demonstrates higher selectivity for Ru(III) at pH 1.5 in the presence of Ni(II) and Cu(II) ions, and its selectivity coefficients for Ru(III)/Ni(II) and Ru(III)/Cu(II) are 3.70 and 3.32, respectively. Also, Ru(III)‐IIM shows a good chemical stability and reusability. C─N and C═O bonds within poly(vinyl pyrrolidone) segments of poly(methyl methacrylate‐vinyl pyrrolidone) (P(MMA‐VP)) participate the uptake of Ru(III). Ru(III)‐IIM exhibited excellent hydrophilicity and Ru(III) selective adsorption ability and reusability and has potential to be used for Ru(III) removal from acidic water solutions.

Nonporous Nitrogen and Ruthenium Co-Doped Titania Films for Photocatalysis

Nitrogen and ruthenium co-doped titania films synthesized by sol–gel technique exhibit high photocatalytic activity under both UV and visible light. Incorporation of nitrogen and ruthenium ions in titania lattice is proven by XPS. Both doping agents affected the structural properties of the films.

Phosphorogenic and spontaneous formation of tris(bipyridine)ruthenium in peptide scaffolds.

Redox-active ruthenium complexes have been widely used in various fields; however, the harsh conditions required for their synthesis are not always conducive to their subsequent use in biological applications. In this study, we demonstrate the spontaneous formation of a derivative of tris(bipyridine)ruthenium at 37°C through the coordination of three bipyridyl ligands incorporated into a peptide to a ruthenium ion. Specifically, we synthesized six bipyridyl-functionalized peptides with randomly chosen sequences. The six peptides bound to ruthenium ions and exhibited similar spectroscopic and electrochemical features to tris(bipyridine)ruthenium, indicating the formation of ruthenium complexes as we anticipated. The photo-excited triplet state of the ruthenium complex formed in the peptides exhibited an approximately 1.6-fold longer lifetime than that of tris(bipyridine)ruthenium. We also found that the photo-excited state of the ruthenium complexes was able to transfer an electron to methyl viologen, indicating that the ruthenium complexes formed in the peptides had the same ability to transfer charge as tris(bipyridine)ruthenium. We believe that this strategy of producing ruthenium complexes in peptides under mild conditions will pave the way for developing new metallopeptides and metalloproteins containing functional metal-complexes.