Ru Cl Research Articles

Syntheses and Applications of Symmetrical Dinuclear Half-Sandwich Ruthenium(II)–Dipicolinamide Complexes as Catalysts in the Transfer Hydrogenation of Ketones

The treatment of [Ru(η6-p-cymene)Cl2]2 with N,N’-(1,2-phenylene)dipicolinamide (H2L1) afforded the double salt complex [{Ru(η6-p-cymene)2-µ-Cl}L1][Ru(η6-p-cymene)Cl3], (Ru1) in moderate yields. Separately, the reactions of ligands (H2L1), N,N’-(4,5 dimethyl-1,2-phenylene)dipicolinamide (H2L2), and N,N’-(4-methoxy-1,2-phenylene)dipicolinamide (H2L3) with the [Ru(η6-p-cymene)Cl2]2 in the presence of KPF6 afforded the respective dinuclear half-sandwich Ru(II) complexes [{(Ru(η6-p-cymene)2--µ-Cl}L1][PF6] (Ru2), [{(Ru(η6-p-cymene)2-µ-Cl}L2][PF6] (Ru3), and [{(Ru(η6-p-cymene)2-µ-Cl}L3][PF6] (Ru4). NMR and FT-IR spectroscopies, ESI-MS spectrometry, and elemental analyses were used to establish the molecular structures of the new dinuclear ruthenium(II) complexes. Single crystal X-ray crystallography was used to confirm the piano-stool geometry of the dinuclear complexes Ru1 and Ru4, as containing N^N chelated ligand and bridging chlorido ligands in each Ru(II) atom. The complexes (Ru1-Ru4) showed good catalytic activities at low catalyst concentrations of 0.005 mol% in the transfer hydrogenation of a wide range of ketone substrates.

Effect of Precursors on the Electrochemical Properties of Mixed RuOx/MnOx Electrodes Prepared by Thermal Decomposition.

Growing thin layers of mixed-metal oxides on titanium supports allows for the preparation of versatile electrodes that can be used in many applications. In this work, electrodes coated with thin films of ruthenium (RuOx) and manganese oxide (MnOx) were fabricated via thermal decomposition of a precursor solution deposited on a titanium substrate by spin coating. In particular, we combined different Ru and Mn precursors, either organic or inorganic, and investigated their influence on the morphology and electrochemical properties of the materials. The tested salts were: Ruthenium(III) acetylacetonate (Ru(acac)3), Ruthenium(III) chloride (RuCl3·xH2O), Manganese(II) nitrate (Mn(NO3)2·4H2O), and Manganese(III) acetylacetonate (Mn(acac)3). After fabrication, the films were subjected to different characterization techniques, including scanning electron microscopy (SEM), polarization analysis, open-circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) experiments. The results indicate that compared to the others, the combination of RuCl3 and Mn(acac) produces fewer compact films, which are more susceptible to corrosion, but have outstanding capacitive properties. In particular, this sample exhibits a capacitance of 8.3 mF cm-2 and a coulombic efficiency of higher than 90% in the entire range of investigated current densities.

Photo-tuneable protein nitration by sensitiser tris(bipyridine)-Ruthenium(II) chloride complex

Post-translational modifications (PTMs) of proteins are a diverse source of variability that impacts on their functions, localisation, regulation, and lifetime. However, one of the main pitfalls in their study is that they appear in rather low frequencies and/or are only transiently observed. To overcome this issue and ease the study in vitro of stress-related protein PTMs, several methods have been proposed to model stress conditions and chemically introduce them. These techniques employ the combination of peroxides with transition metal ions or haem-containing proteins, as well as other possibilities such as peroxy radicals or UV radiation. However, their control, reproducibility and undesired secondary reactions that reduce the process yield are often a matter of concern. Here we introduce a photo-tuneable method that selectively targets nitration of aromatic residues. We initially present the adaptation of an oxidation method based on the photosensitiser tris(2,2′-bipyridine)-Ruthenium(II) chloride complex and ammonium persulfate, in which we employ an alternative radical neutralisation/trapping pathway that uses nitrite ions for the nitration of free l-Tyrosine and L-Tryptophan amino acids. After analysing the effect of several factors, we report the application of the photo-tuneable protein nitration (PTPN) method to four different model proteins in which we evaluate the nitration and oxidation of residues in each case. A mass spectrometry label-free quantitation of Tyr and Trp nitration is also described in order to compare the degree of modification and the accessibility of these residues. The method described could be employed to scale up the production of proteins with a selected range of oxidative PTMs for their characterisation, the assessment of their pathophysiological roles, and the development of detection and quantification methods to validate these PTMs as novel biomarkers associated with oxidative stress-related pathologies, such as in cardiovascular or neurodegenerative diseases.

Ruthenium(III) catalyzed oxidation of paracetamol by chloramine‐T in aqueous alkaline medium – A kinetic and mechanistic pathway

AbstractThe kinetic study of ruthenium(III) chloride catalyzed oxidation of paracetamol by N‐chloro‐p‐toluene sulfonamide (chloramine‐T) in the alkaline medium has been performed. The reaction exhibits second order nature and the effect of the catalyst indicates the occurrence of uncatalyzed reaction simultaneously. Rate is decelerated by hydroxide ions. A plausible reaction mechanism has been suggested and the rate law is derived to account for such experiential observations. The activation parameters have been calculated. No evidence of the participation of free radicals is observed.

Kinetics and mechanism of Ru (III) catalysed oxidation of diethylene glycol by chloramines-T in acidic medium

The rate of oxidation of diethylene glycol in acidic medium, in presence of Ruthenium (III) chloride catalyst has been studied. With each of the reactant, the order of reaction has been determined and it is found that there is first order kinetics with respect to chloramines - T, ethylene glycol, Ru(III) and also first order with respect to medium, i.e., H+ Negligible effect of variation of ionic strength and there is no effect of addition of KCI and Para toluene sulphonamide (P.T.S.).

Phosphorus-Rich Ruthenium Phosphide Embedded on a 3D Porous Dual-Doped Graphitic Carbon for Hydrogen Evolution Reaction.

Metal phosphides have recently emerged as promising electrocatalysts for hydrogen evolution reaction (HER). Herein, we report the synthesis of ruthenium diphosphide embedded on a dual-doped graphitic carbon by pyrolyzing chitosan beads impregnated with ruthenium chloride and phosphorus pentoxide. The as-synthesized RuP2@N-P-C displays a good electrocatalytic activity in acidic, neutral and alkaline media. We show that the HER activity of the electrocatalyst can be tuned by varying the concentration of Li+ cations. Co-diffusion effects on H+ exerted by Li+ on HER in the porous carbon matrix have been observed.

DNA/protein binding and anticancer activity of ruthenium (II) arene complexes based on quinoline dipyrrin

Arene ruthenium complexes [(η6–arene)Ru(L)Cl] (η6–arene = benzene, R1; p-cymene, R2) containing the chelating ligand (2–chloro–3–(di(1H–pyrrol–2–yl)methyl)quinoline) (L) have been synthesized and carefully characterized by various studies (1H and 13C NMR, IR, ESI–MS, UV–vis). The structure of R1 has been verified by X-ray single crystal analyses. Binding of the complexes with calf thymus DNA (CT–DNA) has been investigated by absorption titration, ethidium bromide (EB) displacement and viscosity measurements. Experimental binding constants (5.1 × 104 M−1, R1; 5.7 × 104 M−1, R2) suggested appreciable bonding of the complexes with CT–DNA. Fluorescence, synchronous and 3D fluorescence spectroscopic studies showed that complexes strongly bind with bovine serum albumin. Intercalative interaction of the complexes with DNA has been further supported by DFT studies. Our studies have shown potential anticancer activity of both the complexes R1 and R2 against T cell lymphoma. Among these complexes R2 showed better anticancer activity relative to R1 (IC50, R1, 30 μM and R2, 20 μM).

Synthesis and anticancer evaluation of trinuclear N^N quinolyl-benzimidazole-based PGM complexes

• Trinuclear N^N quinolyl-benzimidazole-based PGM complexes were prepared. • Comprehensively characterised using various spectroscopic and analytical techniques. • Antiproliferative properties against two human breast cancer cell lines, MCF-7 and MDA-MB-32, were evaluated. • A ruthenium(II) p -cymene complex was found to be the most active complex. The synthesis, characterization and cytotoxicity of a novel tris-benzimidazole-quinoline hybrid ligand and its corresponding cationic trimetallic complexes are described. The synthesis of the ligand was achieved via an acid-catalyzed cyclization-condensation reaction of a tris-benzenediamine precursor with 2-quinolinecarboxaldehyde. The complexation reactions of the bidentate tris-ligand with the appropriate precursor dimers [Ru(η 6 -p-Pr i C 6 H 4 Me)Cl 2 ] 2 , [IrCp*( μ -Cl)Cl] 2 , [RuCl 2 (η 6 -C 6 H 5 OCH 2 CH 2 OH)] 2 and [Os(η 6 -p-Pr i C 6 H 4 Me)Cl 2 ] 2 afforded four new cationic trimetallic complexes. The complexes are moisture and air-stable and were characterized using various spectroscopic techniques ( 1 H, 13 C NMR spectroscopy and FT-IR spectroscopy). UV/Visible spectroscopic studies of the trinuclear metal complexes showed that the complexes are stable in DMSO for 48 h at room temperature and physiological temperature, and are thus compatible for in vitro experiments. The synthesized ligand and complexes were examined for antiproliferative properties against two human breast cancer cell lines: MCF-7 and MDA-MB-231. Preliminary evaluations of the test compounds were conducted at a single dose concentration of the test compounds. The osmium(II) and ruthenium(II) p -cymene complexes showed the greatest anticancer activity of all the synthesized compounds and were selected for multidose screening. The ruthenium(II) p -cymene complex was found to be the most active complex, with IC 50 values of 25.23 μ M and 32.68 μ M in the MCF-7 and MDA-MB-231 cell lines, respectively.

Green Synthesis of Trimetallic Nanocomposite (Ru/Ag/Pd)-Np and Its In Vitro Antimicrobial and Anticancer Activities

In this study, we used the aqueous extract of garlic tunicate leaf to reduce a mixture of equal amounts of ruthenium chloride, silver nitrate, and palladium acetate for the biosynthesis of ruthenium/silver/palladium trimetallic nanocomposite (Ru/Ag/Pd)-Np. Some physicochemical tools were used for nanocomposite characterization, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), UV-Vis spectroscopy (UV-Vis), scanning electron microscope (SEM), and transmittance electron microscope (TEM). XRD revealed that the crystal size of the nanocomposite is 15.67 nm. The TEM images showed that the particle size ranged 50–90 nm. The antimicrobial efficacy of the nanocomposite was examined against Aspergillus flavus, Aspergillus niger, Candida albicans, Candida glabrata, Escherichia coli, and Bacillus cereus. The results showed a potent antimicrobial activity toward all tested microorganisms. (Ru/Ag/Pd)-Np showed antiproliferative activity against Caco-2, HepG2, and K562 cell lines. The antiproliferative potential of (Ru/Ag/Pd)-Np was significantly improved following UV irradiation.

Inkjet-Printed Dual-Mode Electrochromic and Electroluminescent Displays Incorporating Ecofriendly Materials.

Displays and indicators are an integral component of everyday electronics. However, the short lifecycle of most applications is currently contributing to the unsustainable growth of electronic waste. In this work, we utilize ecofriendly materials in combination with sustainable processing techniques to fabricate inkjet-printed, ecofriendly dual-mode displays (DMDs). These displays can be used in a reflective mode or an emissive mode by changing between DC and AC operation due to the combination of an electrochromic (EC) and electrochemiluminescent (ECL) layer in a single device. The EC polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) serves as the reflective layer, while an ECL gel made of dimethylsulfoxide (DMSO), poly(lactic-co-glycolic acid) (PLGA), 1-butyl-3-methylimidazoliumbis(oxalato)borate (BMIMBOB), and tris(bipyridine)ruthenium(II) chloride (Ru2+(bpy)3Cl2) enables the emissive mode. The final dual-mode devices exhibited their maximum optical power output of 52 mcd/m2 at 4 V and 40 Hz and achieved an EC contrast of 45% and a coloration efficiency of 244 cm2/C at a wavelength of 690 nm. The fabricated devices showed clear readability in dark and light conditions when operated in reflective or emissive modes. This work demonstrates the applicability of ecofriendly and potentially biodegradable materials to reduce the amount of hazardous components in versatile display technologies.

INVESTIGATION OF SHORT-TERM CHEMICAL CHANGE IN STABLE RUTHENIUM ADDED TO RAINWATER THROUGH X-RAY ABSORPTION FINE STRUCTURE ANALYSIS.

Radioactive ruthenium may be accidentally released from spent nuclear fuel reprocessing plants to the surrounding environment. To obtain basic information regarding the effect of radioactive ruthenium on the environment, we investigated changes in the source form of stable ruthenium added to rainwater through X-ray absorption fine structure analysis. Ruthenium tetroxide (RuO4), ruthenium dioxide (RuO2), ruthenium nitrosyl nitrate (Ru(NO)(NO3)3) and ruthenium chloride (RuCl3) were employed as test sources. The Ru K-edge X-ray absorption near edge structure spectra acquired immediately after addition to ultrapure water differed among various sources. With RuO4 addition, a black deposit was observed 1 d after addition, and the spectrum was similar to that of RuO2. For RuO2, Ru(NO)(NO3)3 and RuCl3, no variances were observed between the spectra acquired immediately after addition and 1 d after addition. These results indicate that the chemical forms of RuO2, Ru(NO)(NO3)3 and RuCl3 did not change within a 1-d span in rainwater.

Computational Evaluation of Potential Molecular Catalysts for Nitrous Oxide Decomposition.

Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with limited use as a mild anesthetic and underdeveloped reactivity. Nitrous oxide splitting (decomposition) is critical to its mitigation as a GHG. Although heterogeneous catalysts for N2O decomposition have been developed, highly efficient, long-lived solid catalysts are still needed, and the details of the catalytic pathways are not well understood. Reported herein is a computational evaluation of three potential molecular (homogeneous) catalysts for N2O splitting, which could aid in the development of more active and robust catalysts and provide deeper mechanistic insights: one Cu(I)-based, [(CF3O)4Al]Cu (A-1), and two Ru(III)-based, Cl(POR)Ru (B-1) and (NTA)Ru (C-1) (POR = porphyrin, NTA = nitrilotriacetate). The structures and energetic viability of potential intermediates and key transition states are evaluated according to a two-stage reaction pathway: (A) deoxygenation (DO), during which a metal-N2O complex undergoes N-O bond cleavage to produce N2 and a metal-oxo species and (B) (di)oxygen evolution (OER), in which the metal-oxo species dimerizes to a dimetal-peroxo complex, followed by conversion to a metal-dioxygen species from which dioxygen dissociates. For the (F-L)Cu(I) activator (A-1), deoxygenation of N2O is facilitated by an O-bound (F-L)Cu-O-N2 or better by a bimetallic N,O-bonded, (F-L)Cu-NNO-Cu(F-L) complex; the resulting copper-oxyl (F-L)Cu-O is converted exergonically to (F-L)Cu-(η2,η2-O2)-Cu(F-L), which leads to dioxygen species (F-L)Cu(η2-O2), that favorably dissociates O2. Key features of the DO/OER process for (POR)ClRu (B-1) include endergonic N2O coordination, facile N2 evolution from LR'u-N2O-RuL to Cl(POR)RuO, moderate barrier coupling of Cl(POR)RuO to peroxo Cl(POR)Ru(O2)Ru(POR)Cl, and eventual O2 dissociation from Cl(POR)Ru(η1-O2), which is nearly thermoneutral. N2O decomposition promoted by (NTA)Ru(III) (C-1) can proceed with exergonic N2O coordination, facile N2 dissociation from (NTA)Ru-ON2 or (NTA)Ru-N2O-Ru(NTA) to form (NTA)Ru-O; dimerization of the (NTA)Ru-oxo species is facile to produce (NTA)Ru-O-O-Ru(NTA), and subsequent OE from the peroxo species is moderately endergonic. Considering the overall energetics, (F-L)Cu and Cl(POR)Ru derivatives are deemed the best candidates for promoting facile N2O decomposition.

Reforming of Al-Kasek Naphtha by Ruthenium Chloride Grafted Zeolite

The research included preparing the used catalyst (zeolite) for reforming of naphtha. The process was carried out by adding certain proportions of naphtha and the catalyst to the autoclave reactor with a capacity of (300 cm3) under initial conditions (150, 200, 250, 300 ̊C, catalyst ratio was 0.5% and reaction time was one hour). Naphtha samples were measured firstly by (1HNMR and FTIR), it was found that the best temperature for reforming for naphtha was (300°C) .The optimal conditions for this process were adjusted by increasing the catalyst ratio and reaction time, and it was found that the best conditions are ( The catalyst ratio is 2.5% and the reaction time is 3 hours. The used catalyst showed the ability to cyclisation of paraffins and dehydrogenation of paraffins and naphthenes, which led to an increase the ratio of aromatic compounds from (7.09%) to (29.13%) . In addition to the previous measurements, the gas chromatography of one of the naphtha samples was measured and was identical to those measurements.

Binding and stabilization effect of arene ruthenium(Ⅱ) polypyridyl complexes toward the triple-helical RNA poly(U)•poly(A)⁎poly(U)

To determine the binding properties of η6‑arene Ru(Ⅱ) complexes with the RNA triplex poly(U)•poly(A)⁎poly(U), two arene Ru(Ⅱ) complexes, [(ŋ6-C6H6)Ru(m-npip)Cl]+ (Ru1) and [(ŋ6-C6H6)Ru(m-fpip)Cl]+ (Ru2), have been synthesized and characterized in this study. The binding of Ru1 and Ru2 with the triplex RNA poly(U)•poly(A)⁎poly(U) have been investigated by viscosity measurement and various spectroscopic methods. Results demonstrate that the RNA-binding behaviors of Ru1 and Ru2 are intercalation mode. From the analyses of electronic absorption spectra and fluorescence spectra, we observed that the binding affinity for Ru2 is remarkably stronger than that for Ru1. Furthermore, thermal denaturation studies reflect that Ru1 and Ru2 selectively stabilize the RNA triplex, among them, Ru1 can stabilize the Hoogsteen base-paired strand poly(U) (the third strand), while it is little effect on the Watson-Crick base-paired duplex poly(U)•poly(A) (the template duplex). Contrary to Ru1, Ru2 can stabilize both the template duplex and the third-strand, and Ru2 is more effective for stabilization of the third-strand. To our knowledge, this work is the first example of arene metal complexes interacting with triple-helical nucleic acids. The obtained results suggest that subtle differences of substituent on the intercalation ligand may be the important factor affecting on the binding properties of the both arene Ru(Ⅱ) complexes with the RNA triplex, when Ru1 and Ru2 contain the same ancillary ligands.

Hydrothermal gasification of phenol with Ru added carbon-metal oxide composite-supported Ni catalysts prepared by sol-gel method

Ru promotion effect on carbon-metal oxide composite-supported Ni catalysts were tested for hydrothermal gasification of phenol in aqueous phase as a model process of wastewater treatment. The catalysts were prepared by the combination of aluminum, titanium and zirconium alkoxide, and polyethylene glycol as an organic template, with the addition of active metals, nickel nitrate hexahydrate and ruthenium chloride. In the hydrothermal gasification at 350 °C, pressure 20 MPa and phenol concentration in water 20 g/L, the effect of the addition of Ru to Ni/C/oxide was observed and the conversion of phenol increased. When the effect of metal oxide was compared at 5 wt% of Ru and 16 wt% of Ni contents, the conversion of phenol increased in the order ZrO2 < Al2O3 < TiO2. The activity of Al2O3 -supported catalysts increased with increasing Ru content while that of TiO2 -supported catalysts did not change with the Ru content.

MWCNT/Ruthenium hydroxide aerogel supercapacitor production and investigation of electrochemical performances

In this study, the material obtained from the sonication of the double-walled carbon nanotube and ruthenium chloride was produced as an aerogel. Then, symmetrical supercapacitor devices were made using them, and their electrochemical properties were investigated. XRD and FTIR were used in the structural analysis of the aerogel, STEM in surface images, and elemental analyses in EDX. Electrochemical analysis was performed by galvanostat/potentiostat. From the cyclic voltammetry analysis, the highest specific capacitance for MWCNT/Ruthenium hydroxide aerogels was achieved as 423 F/g at 5 mV/s. On the other hand, the corresponding values calculated from the charge–discharge curves were found to be 420.3 F/g and 319.9 F/g at the current densities of 0.5 A/g and 10.0 A/g, respectively. The capacitance retention of as-synthesized aerogel was 96.38% at the end of the 5000 consecutive consecutive cyclic voltammetry cycles.

Synthesis and molecular structure of arene ruthenium(II) complexes containing benzhydrazone derivative ligands with antibacterial and antioxidant properties

A suitable method for the synthesis of ruthenium(II) arene benzhydrazone complexes (1–6) of the general formula [(η6-arene)Ru(L)Cl] (arene = p-cymene or benzene; L= bidentate substituted benzhydrazone derivatives) has been described. The composition of all the complexes have been established by IR, UV-Vis and NMR spectroscopies and ESI-MS. Ruthenium precursors [(η6-arene)RuCl2]2 (arene = p-cymene or benzene) on reacting with benzhydrazone derivative ligands (L1, L2 and L3) resulted in the formation of mononuclear neutral complexes (1-6). All the neutral complexes were further reacted with NaN3 to yield azido complexes (7-12). Then, the binding modes of the benzhydrazone derivatives to the metal center for complexes (1, 5, 6, 7 and 9) have been confirmed by single-crystal X-ray diffraction studies. Further, their in-vitro antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli, Klebsiella pneumoniae) strains have been evaluated for the complexes (1-6) and their ligands. An anti-bacterial study revealed that complex 1 and complex 6 have magnificent activity against S. aureus, E. coli and K. pneumoniae. For antioxidant properties, all the complexes showed a higher percentage of DPPH radical scavenging activity than the ligands.

Synthesis, X-ray diffraction and anti-proliferative biological activity of hispolon derivatives and their (η6-p-cymene)(Hispolonato)Ruthenium[II] chloride complexes

Hispolon is a natural product extracted from Phellinus igniarius and Phellinus linteus fungi that has previously shown antitumor activity. In this study we present the synthesis, chemical characterization and in vitro anti-proliferative activity of three [(η6-p-cymene)Ru(L)Cl] neutral complexes, where L = hispolon derivatives. The single crystal X-ray structures of the three Ru complexes all have the expected piano stool geometry with the p-cymene ligand at the apex of the piano stool and occupying three of the sites in a distorted-octahedral arrangement. Completing the octahedral coordination sphere are two β-diketone oxygen atoms of the deprotonated hispolon derivatives which are coordinated in a bidentate fashionand a chlorine atom. The cytotoxicity of the three hispolon derivatives along with their corresponding complexes was studied for A549 lung, HCT116 colon and U87 glioblastoma cell lines. In the glioblastoma cell line, increase of biological activity (lower IC50) is seen for all three hispolons after arene-ruthenium complexation: 5.1 times higher for 2,3,4-trimethoxy-hispolon (Hisp8), and 1.5 times for both 3-methoxy,4-hydroxy-hispolon (Hisp1) and 3,4-dimethoxy-hispolon (Hisp4). This effect was less pronounced in the colon HCT116 cell line with complexation having 1.2–1.4 times higher biological activity. For the lung cell line A549, there was no such effect and complex formation slightly decreased the biological activity. Regardless, in the glioblastoma cell line, the presence of Hisp8, the most liposoluble agent, either as the pure compound or as ligand in the η6-p-cymene-Ru complex, proved effective as an antitumor agent. More specifically, the [(η6-p-cymene)Ru(Hisp8)Cl] complex showed a decrease in IC50 value for all 3 cell lines, when compared to Hisp8. We also performed molecular mechanics, DFT and docking calculations to determine the inhibitory ability of hispolon analogs towards aldehyde dehydrogenase, which targets glioblastoma stem cells. All three [(η6-p-cymene)Ru(Hisp)Cl] coordination complexes of hispolon derivatives are more effective than the related neutral hispolons in the U87 MG human glioblastoma cell line. Our computational studies clearly indicate an important role for aldehyde dehydrogenase Arg139 amino acid. In addition, computational results indicate hispolonato anions are much better inhibitors of aldehyde dehydrogenase and improve the anti-glioblastoma biological activity, consistent with IC50 data.

Transition Metal Complexes of 2,6‐Dibenzhydryl Derived Bisphosphine: Synthesis, Structural Studies and Palladium Complex Promoted Suzuki‐Miyaura Reactions

AbstractTransition metal chemistry of [Ar*N(CH2PPh2)2] (1) derived from the sterically demanding backbone 2,6‐dibenzhydryl‐4‐methylphenyl core is described. The reactions of 1 with 30 % aq. H2O2 and S8 afforded bischalcogenides [Ar*N(CH2P(O)Ph2)2] (2) and [Ar*N(CH2P(S)Ph2)2] (3), respectively. Treatment of 1 with [M(COD)Cl2] (M=Pd, Pt) in 1 : 1 molar ratios produced chelate complexes cis‐[MCl2{Ar*N(CH2PPh2)2}‐κ2‐P,P] (4, M=Pd; 5, M=Pt), whereas similar reaction between 1 and [Pd(η3‐C3H5)Cl]2 afforded dinuclear complex [{Pd(η3‐C3H5)Cl}2{Ar*N(CH2PPh2)2}‐κ1‐P,P] (6). The reaction of 1 with [Ru(η5‐C5H5)Cl(PPh3)2] in 1 : 1 ratio yielded [{Ru(η5‐C5H5)Cl}{Ar*N(CH2PPh2)2}‐κ2‐P,P] (7). Treatment of 1 with [M(C5H11N)2(CO)4] (M=Mo, W) in 1 : 1 molar ratios afforded cis‐[M(CO)4{Ar*N(CH2PPh2)2}‐κ2‐P,P] (8, M=Mo; 9, M=W). The reaction of 1 with copper(I) halides in 1 : 1 molar ratios produced [Cu(μ2‐X)]2 dinuclear complexes [{Cu(μ2‐X)}2{Ar*N(CH2PPh2)2}2‐κ2‐P,P}] [10, X=Cl; 11, X=Br; and 12, X=I]. Most of these compounds show various C−H⋅⋅⋅π interactions. Bischalcogenides 2 and 3 showed intramolecular hydrogen bonding type interactions, C−H⋅⋅⋅O (2.554 Å) and C−H⋅⋅⋅S (2.825 Å) between the methylene hydrogens of –NCH2PPh2 groups with O or S atoms, which was also evinced by QTAIM and NCI analysis. Bisphosphine 1 was found to be very effective in palladium catalyzed Suzuki‐Miyaura couplings of aryl chlorides with aryl boronic acids.

Mixed Valency vs Radical Bridge Formulation in Symmetrically and Asymmetrically Ligated Diruthenium Complexes

Abstract: The asymmetrical dinuclear [{(trpy*)Ru} 2 (µ-adc-Salph)Cl](PF 6 ) 1 (PF 6 ), trpy* = 4,4’,4”-tri- tert -butyl-2,6,2’,6”-terpyridine, adc-Salph = 1-benzoyl-2-salicyloylhydrazido(3-), and the related symmetrical dinuclear [{Cl(trpy*)Ru} 2 (µ,η 2 :η 2 -adc-Ph)](PF 6 ) 2 (PF 6 ), adc-Ph = 1,2-bis(benzoyl)hydrazido(2-), were synthesized and structurally characterized. Both paramagnetic compounds were compared with the previously reported symmetrical [{(trpy*)Ru} 2 (µ,η 3 :η 3 -adc-Sal)](PF 6 ) 3 (PF 6 ) containing the bis-tridentate bridge 1,2-bis(salicyloyl)hydrazido(4-). Molecular structures and magnetic resonance features ( 1 H NMR, EPR) indicate spin density distribution over the metal(s) and the bridging ligand. Reversible one-electron reduction and oxidation were possible in all instances yielding comproportionation constants K c of about 10 9 for the paramagnetic intermediates 1 + - 3 + . Structural results, spin density distribution and UV-Vis-NIR spectroelectrochemistry were analyzed for 1 + with the help of TD-DFT calculations for a model compound ( tert -Bu→Me). Intense absorptions around λ max = 1450-1650 nm for the cations were assigned to mixed metal/ligand transitions with significant inter-valence charge transfer (IVCT) character. For both the symmetrical and asymmetrical arrangements the cationic intermediates can be described as considerably mixed metal/ligand systems.