Adjustable bidirectional extracellular electron transfer between Comamonas testosteroni biofilms and electrode via distinct electron mediators

Bidirectional extracellular electron transfer of strain Comamonas testosteroni I2 was for the first time investigated with electrochemical active biofilms developed under different conditions. The electrochemical active biofilm developed under microbial fuel cell conditions was capable of anodic electron transfer via attached redox species with standard potential of 0.04 V (vs. SCE). Meanwhile the above redox species lost its catalytic capability when the biofilm was developed under a constant potential (− 0.4 V vs. SCE). Instead, the microbe adjusted its electron transfer strategy to a soluble shuttle (standard potential − 0.20 V vs. SCE) and enabled a cathodic current. Air exposure experiment verified that the soluble shuttle at negative potential had a positive response to the oxygen; meanwhile the anodic electron transfer via the attached species was rarely influenced.     

Multidimensional system enabling deglycosylation of proteins using a capillary reactor with peptide-N-glycosidase F immobilized on a porous polymer monolith and hydrophilic interaction liquid chromatography–mass spectrometry of glycans

A reactor with immobilized peptide-N-glycosidase F on a monolithic polymer support in a capillary has been developed that allows fast and efficient release of N-linked glycans from immunoglobulin G molecules. Two different monolithic scaffolds based on poly(glycidyl methacrylate-co-ethylene dimethacrylate) and poly(butyl methacrylate-co-ethylene dimethacrylate) were prepared. A multistep photografting process was used to reduce non-specific adsorption of proteins and to obtain support containing reactive azlactone functionalities enabling the preparation of highly active immobilized peptide-N-glycosidase F. Performance of these reactors was determined through glycan release from several glycoproteins including ribonuclease B, chicken albumin, and human immunoglobulin G and their detection by matrix-assisted laser desorption-ionization/time-of-flight mass spectrometry. The optimized reactor was integrated into a multidimensional system comprising on-line glycan release and their separation via hydrophilic interaction liquid chromatography followed by electrospray ionization/time-of-flight mass spectrometry detection. Using the optimized monolithic reactor with immobilized peptide-N-glycosidase F, human immunoglobulin G was deglycosylated at room temperature in 5.5 min to an extent similar to that achieved with soluble enzyme after 24 h at 37 °C.     

Capabilities of mixed-mode liquid chromatography coupled to inductively coupled plasma mass spectrometry for the simultaneous speciation analysis of inorganic and organically-bound selenium

This work investigates for the first time the potential of mixed-mode (anion-exchange with reversed-phase) high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous retention and selective separation of a range of inorganic and organically-bound selenium (Se) species. Baseline separation and detection of selenocystine (SeCys₂), Se-methyl-selenocysteine (SeMC), selenomethionine (SeMet), methylseleninic acid (MSA), selenite, γ-glutamyl-methyl-selenocysteine (γ-glutamyl-SeMC), and selenate in a Se standard mixture by mixed-mode HPLC-ICP-MS was achieved by switching between two citrate mobile phases of different pH and ionic strength within a single chromatographic run of 20 min. Limits of detection obtained for these Se species ranged from 80 ng kg^?1 (for SeMC) to 123 ng kg^?1 (for selenate). Using this approach as developed for selenium speciation, an adequate separation of inorganic and organic As compounds was also achieved. These include arsenite, arsenate, arsenobetaine (AsB) and dimethylarsenic acid (DMA), which may coexist with Se species in biological samples. Application of the newly proposed methodology to the investigation of the elemental species distribution in watercress (used as the model sample) after enzymatic hydrolysis or leaching in water by accelerated solvent extraction (ASE) was addressed. Only SeMet, SeMC and selenate could be tentatively identified in watercress extracts by mixed-mode HPLC-ICP-MS and retention time matching with standards. Recoveries (n = 3) of these Se species from samples spiked with standards averaged 102% (for SeMC), 94.9% (for SeMet) and 98.3% (for selenate). Verification of the presence of SeMet and SeMC in an enzymatic watercress extract was achieved by on-line HPLC-ESI MS/MS in selected reaction monitoring (SRM) mode.     

Studies on enhancing the keeping quality of peach (Prunus persica Bausch) Cv. Elberta by gamma-irradiation

The effect of gamma-irradiation on keeping quality of peach fruit was studied. The fruit, after harvesting at proper maturity stage, was irradiated in the dose range of 1.0–2.0 kGy, stored under ambient (temp. 25±2 °C, RH 70%) and refrigerated (temp. 3±1 °C, RH 80%) conditions and evaluated periodically for firmness, total soluble solids (TSS), anthocyanins, water-soluble pectic fractions, loss in weight and decay percentage. The anthocyanin evaluation of the fruits revealed that irradiation enhanced the colour development under both the storage conditions. The gamma-irradiation dose range of 1.2–1.4 kGy proved effective in maintaining higher TSS concentration, reducing weight loss and significantly (p⩽0.05) delaying the decaying of the fruit by 6 days under ambient conditions and by 20 days under refrigerated storage conditions.     

Quaternary (liquid + liquid) equilibria of aqueous two-phase poly (ethylene glycol), poly (DMAM–TBAM), and KH2PO4: Experimental and generalized Flory–Huggins theory

Quaternary (liquid + liquid) equilibrium (LLE) data of the aqueous two-phase poly (ethylene glycol), poly (N,N-dimethylacrylamide-t-butylacrylamide) with abbreviation name poly (DMAM–TBAM) as a hydrophobic association water-soluble copolymer and KH₂PO₄ has been determined experimentally at T = 338.15 K. Furthermore, the generalized Flory–Huggins theory with two electrostatic terms (the Debye–Hückel and Pitzer–Debye–Hückel) was used for correlation of the phase behavior of the quaternary system and the interaction parameters between all species were calculated.It was found that addition of poly (DMAM–TBAM) copolymer as well as changing the temperature can shift the binodal curves of aqueous two-phase systems containing polyethylene glycol (PEG) and salt. Also, the phase behavior of the DMAM–TBAM copolymer with some salts containing sodium chloride, ammonium hydrogen phosphate, potassium hydrogen phosphate, and sodium carbonate were studied experimentally at T = 338.15 K and the effect of the salt type on the their binodal curves was determined.     

Internal standardization in graphite furnace atomic absorption spectrometry: Comparative use of As and Ge to minimize matrix effects on Se determination in milk

Arsenic and germanium have been evaluated as internal standards to minimize matrix effects on the direct determination of selenium in milk by graphite furnace atomic absorption spectrometry (GFAAS) using tubes with integrated platform, pre-treated with W together with Pd as chemical modifier. The efficiency of As and Ge as internal standards for 25 μg L^− 1 Se plus 500 μg L^− 1 As or Ge in diluted (1 + 9 v/v) milk plus 1.0% (v/v) HNO₃ was evaluated by means of correlation graphs plotted from the normalized absorbance signals (n = 20) of internal standard (axis y) versus analyte (axis x). The equations that describe the linear regression were: A^As = − 0.004 ± 0.019 + 1.02 ± 0.019 A^Se (r = 0.9967 ± 0.005); A^Ge = − 0.017 ± 0.015 + 1.01 ± 0.015 A^Se (r = 0.9978 ± 0.004). Samples and reference solutions were automatically spiked with 500 μg L^− 1 Ge or As and 1.0% (v/v) HNO₃ by the autosampler. For 20 μL of aqueous standard solutions, analytical curves in the 5.00–40.0 μg L^− 1 Se range were established using the ratio of Se absorbance to internal standard absorbance (A^Se / A^IS) versus analyte concentration, and good linear correlations were obtained. The characteristic mass was 40 pg Se. Limits of detection were 0.55 and 0.40 μg L^− 1 with As and Ge as the internal standard, respectively. Relative standard deviations (RSD) for a sample containing 25 μg L^− 1 Se were 1.2% and 1.0% (n = 12) using As and Ge, respectively. The RSD without internal standardization was about 6%. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values were in the 99–105% range with IS and in the 70–80% range without IS. Using Ge as the internal standard, results of analysis of standard reference materials were in agreement with certified values at a 95% confidence level. The selenium concentration for 10 analyzed milk samples varied from 5.0 to 20 μg L^− 1.     

LIF technique offers the potential for the detection of cadmium-induced alteration in photosynthetic activities of Zea Mays L.

The laser-induced fluorescence spectra of leaves of Zea mays L. plants treated with different concentrations (0.01, 0.10 and 1.00 mM) of cadmium were recorded in region 650–800 nm using 488 nm line of Argon Ion laser as excitation source and PMT as detector. Besides this, blue-green fluorescence and Chl fluorescence were also measured using third harmonic (355 nm) of Nd:YAG laser as excitation source and 320 M monochromator with intensified charge coupled device as a detector in the region 400–800 nm. These spectra have been used to analyse the effect of several doses of cadmium on the photosynthetic activities of Z. mays L. plants. The fluorescence intensity ratios (FIR) of control as well as treated Z. mays L. were calculated by evaluating curve-fitted parameters using Gaussian spectral function. In addition, growth parameters like photosynthetic pigments content were also estimated. The chlorophyll fluorescence intensity ratio F685/F735 excited by both 488 and 355 nm lines are strongly correlated with photosynthetic pigments content (total chlorophyll and carotenoids) and their ratios. Consequently, there also existed a correlation between the blue-green fluorescence intensity ratio F470/F540 and photosynthetic pigments content.     

Thermodynamics of binary and ternary interactions in the tin(II)/phytate system in aqueous solutions,in the presence of Cl− or F−

An extensive study of the tin(II)/phytate (Phy) system was carried out in NaNO_3(aq), at different ionic strengths (0.10 ⩽ I/mol · L⁻¹ ⩽ 1.00) and temperatures (278.15 ⩽ T/K ⩽ 328.15), by potentiometric and voltammetric techniques. The stability and formation enthalpy changes of six SnH_qPhy species were determined. To better characterise this system, some potentiometric titrations were also carried out in mixed ionic media (NaNO_3(aq) + NaCl_(aq) and NaNO_3(aq) + NaF_(aq)) at total ionic strength I = 1.00 mol · L⁻¹. The formation of some ternary mixed SnH_qPhyCl and SnH_qPhyF species (charges omitted for simplicity) was found. The formation enthalpies of the complex species were calculated, at I = 0.40 mol · L⁻¹ in NaNO_3(aq), by the dependence of stability constants on temperature obtained by potentiometric titrations, in the range 278.15 ⩽ T/K ⩽ 328.15. The complex formation process is endothermic, and the main contribution to tin(II) complexation by phytate is entropic in nature. For example, for the SnPhy species we have, at T = 298.15 K and I = 0.40 mol · L⁻¹ in NaNO_3(aq): ΔH = 57.7 ± 2.8 kJ mol · L⁻¹, ΔG = −99.9 ± 1.7 kJ mol · L⁻¹, and TΔS = 158 ± 3 kJ mol · L⁻¹. The ionic strength dependence of the formation constants of the simple tin(II)/phytate species, was modelled by the Debye–Hückel and the SIT approaches. The sequestering ability of phytate towards tin(II) was evaluated by calculating the pL_0.5 values (i.e., the total ligand concentration necessary to bind 50% of cation present in trace) at different ionic strengths, ionic media, and pH. The sequestering ability increases with increasing the pH, whilst it decreases with increasing the ionic strength (the same behaviour shown by the stability constants). Moreover, taking into account the different sequestering ability of phytate towards tin(II) in the different ionic media, the trend: pL_0.5 = 5.70 (in NaNO_3(aq) + NaF_(aq)) > pL_0.5 = 5.16 (in NaNO_3(aq) + NaCl_(aq)) > pL_0.5 = 4.86 (in NaNO_3(aq)) was observed at pH 8.1 and I = 1.00 mol · L⁻¹. This is due to the presence of a second ligand (Cl⁻ or F⁻) that stabilizes the complex species with the formation of ternary complex species. Some empirical relationships were also found.     

Effect of gamma irradiation on the expressed proteins in the foodborne pathogen Staphylococcus aureus

A capillary electrophoresis method with UV detection was developed to analyze protein composition of the foodborne pathogen Staphylococcus aureus. Bacterial samples containing 10⁹ CFU/ml, obtained after two cycles of incubations of 24 h, were gamma irradiated at different doses of 1.2, 3.5 and 2.9 kGy to respectively create damage cells, to kill cells and to provoke viable but non cultivable cells (VBNC). It was observed that an irradiation at a sensitive dose of 1.2 kGy caused a significantly increase in the protein with molecular weight (MW) of 17.7 kDa (from 0.61% to 1.2%). This treatment also caused decreases in the expressed proteins with the MWs of 16.3 kDa (from 6.2% to 5.3%) and of 23.4 kDa (from 4.0% to 2.30%). Irradiation at a VBCN dose of 2.9 kGy caused increases in expressed proteins with the MWs of 17.7 kDa (from 0.61% to 3.43%), 18.7 kDa (from 1.04% to 4.30%), 19.5 kDa (from 0.71% to 2.30%), 21.1 kDa (from 1.20% to 3.80%). Moreover, this treatment (2.9 kGy) also caused significantly decreases (P≤0.05) in the expressed proteins with the MW of 30.7 kDa (from 8.6% to 5.15%), 36.3 kDa (from 3.1% to 2.7%) and 40.5 kDa (from 11.3% to 8.5%). Finally, for the irradiation at a lethal dose of 3.5 kGy, it can be found that the expressed proteins with the MW of 17.7 kDa, 18.7 kDa and 19.5 kDa were increased less than that of expressed proteins at the VCNC dose (2.9 kGy) and these might be the very important proteins which are responsible for the survival of the S. aureus. Further, there were also the decreases in expressed proteins with the MW of 30.7 kDa, 36.3 kDa and 75.1 kDa at this dose of treatment (3.5 kGy) which can be expected that these proteins are seriously affected at high dose of γ-irradiation treatment.     

Complexation thermodynamics between butyl rhodamine B and calix[n]arenesulfonates (n = 4, 6, 8)

The characteristics of host–guest complexation between water-soluble calix[n]arenesulfonates (CnS, n = 4, 6, 8) and butyl rhodamine B (BRB) were investigated by fluorescence spectrometry. Fluorescence spectroscopy experiments were performed in pH 8.0 Tris(3-aminomethane)–HCl buffer solution at different temperature to calculate the stability constants (K_S) for the stoichiometric 1:1 inclusion complexes of C4S, C6S, and C8S with BRB. The complex stability constant monotonically increased with the number of phenolic units in the calixarene ring. The thermodynamic parameters at T = 298 K for the inclusion complexes were calculated through Van’t Hoff analysis. The inclusion complexes of CnS with BRB were driven by the favorable enthalpic changes, accompanying negative entropy changes. The stability constants were affected by the acidity of the solution. When pH was 8.0, the stability constants reached the maximum. The complex interaction was mainly attributed to the weak forces including electrostatic interaction and hydrogen bonding.     

Preparation and magnetic properties of 4,6-bis(imino nitroxide)-substituted resorcinol and its Cu-complex

A novel bis(imino nitroxide)-substituted resorcinol 3H, that has two metal-binding sites with two pairs of the phenolate anion and the imino nitrogen atom, was prepared. The powdered sample of 3H showed an intramolecular ferromagnetic interaction (J/k_B = +5 K) between two (imino nitroxide)s through a m-phenylene bridge and a weak intermolecular antiferromagnetic interaction (J/k_B = − 0.9 K). The reaction of 3H with copper acetate in methanolic ammonia was examined to give a hardly soluble Cu-complex that exhibited ferromagnetic behavior in relatively high temperatures (298–55 K).     

Electrochemical characterization on cobalt sulfide for electrochemical supercapacitors

High capacitance at a high charge–discharge current density of 50 mA/cm² for a new type of electrochemical supercapacitor cobalt sulfide (CoS_x) have been studied for the first time. The CoS_x was prepared by a very simply chemical precipitation method. The electrochemical capacitance performance of this compound was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests with a three-electrode system. The results show that CoS_x has excellent electrochemical capacitive characteristic with potential range −0.3 ∼ 0.35 V (versus SCE) in 6 M KOH solution. Charge–discharge behaviors have been observed with the highest specific capacitance values of 475 F/g at the current density of 5 mA/cm², even at the high current density of 50 mA/cm², CoS_x also shows the high specific capacitance values of 369 F/g.     

Phase equilibrium for ozone-containing hydrates formed from an (ozone + oxygen) gas mixture coexisting with gaseous carbon dioxide and liquid water

The paper reports the three-phase (gas + aqueous liquid + hydrate) equilibrium pressure (p) versus temperature (T) data for a (O₃ + O₂ + CO₂ + H₂O) system and, for comparison, corresponding data for a (O₂ + CO₂ + H₂O) system for the first time. These data cover the temperature range from (272 to 279) K, corresponding to pressures up to 4 MPa, for each of the three different (O₃ + O₂)-to-CO₂ or O₂-to-CO₂ mole ratios in the gas phase, which are approximately 1:9, 2:8, and 3:7, respectively. The mole fraction of ozone in the gas phase of the (O₃ + O₂ + CO₂ + H₂O) system was from ∼0.004 to ∼0.02. The modified pressure-search method, developed in our previous study [S. Muromachi, T. Nakajima, R. Ohmura, Y.H. Mori, Fluid Phase Equilib. 305 (2011) 145–151] for p–T measurements in the presence of chemically unstable ozone, was applied, having been further modified for dealing with highly water-soluble CO₂, for the (O₃ + O₂ + CO₂ + H₂O) system, while the conventional temperature-search method was used for the (O₂ + CO₂ + H₂O) system. The measurement uncertainties (with 95% coverage) were ±0.11 K for T, ±6.0 kPa for p, and ±0.0015 for the mole fraction of each species in the gas phase. It was confirmed that, at a given CO₂ fraction in the gas phase, p for the (O₃ + O₂ + CO₂ + H₂O) system was consistently lower than that for the (O₂ + CO₂ + H₂O) system over the entire T range of the present measurements, indicating a preference of O₃ to O₂ in the uptake of guest-gas molecules into the cages of a structure I hydrate.     

Chemical composition,antibacterial and antioxidant activities of essential oils from leaves of three Melaleuca species of Pakistani flora

This study presents essential oil composition of three Melaleuca species namely, Melaleuca bracteata F. Muell, Melaleuca fulgens R. Br. subsp. steedmanii and Melaleuca leucadendron (L.) L. collected from different regions of Pakistan. The chemical composition of essential oils was analyzed by GC-FID and GC–MS. Eugenol methyl ether was identified as a principal component in M. bracteata (82.3%), M. fulgens (87.8%) and M. leucadendron (95.4%) oils. In vitro antibacterial studies were done by agar well diffusion and microdilution method and the tested essential oils exhibited bacteriostatic and bactericidal effects against the tested foodborne pathogens at 4–8 µg/ml. Time kill assay showed significant bactericidal effect of oils for four weeks. The antioxidant potential was assessed by free radical scavenging activity and reducing power assay. The oils showed strong antioxidant activity with approximately 89.0–89.5% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical and ferric reducing power in the range of 1.94 ± 0.007–2.04 ± 0.04% at 100 µg/ml.     

Influence of the structure of medium-sized aromatic precursors on the reactivity of their dications towards rare gases

The gas-phase reactivity of dications generated by dissociative electron ionization of several aromatic C_mH_nN_o precursors with 4 ≤ m ≤ 13, 4 ≤ n ≤ 21, and 0 ≤ o ≤ 2 with rare gases is investigated. Whereas most of these reactions lead to monocations via simple electron transfer, proton transfer, or Coulomb explosion, the formation of organo rare-gas dications is observed in a few cases. Specifically, dications generated from 2,4,6-trimethylpyridine react with krypton and xenon to form organo rare-gas species as major products and under maintenance of the two-fold positive charge. Such a reactivity is not observed in the presence of lighter rare gases. The formation of organo rare-gas dications are also observed for dications generated from 3-vinylpyridine, N,N-dimethylaniline, isopropylbenzene, and 4-ethyltoluene as neutral precursors. In some cases, isomeric dications are characterized by very different reactivity toward rare gases, suggesting that the structure of the precursors is crucial and that electron ionization does not lead to a total scrambling of the structures of the doubly charged ions obtained.     

Chemical composition and antioxidant, α-glucosidase inhibitory and antibacterial activities of three Echeveria DC. species from Mexico

Three Echeveria species from Sinaloa, Mexico (Echeveria craigiana, Echeveria kimnachii and Echeveria subrigida) were analyzed for their content of antioxidant compounds (β-carotene, ascorbic acid, α-tocopherol, total phenolics and flavonoids) and the in vitro antioxidant (DPPH, ABTS, ORAC and β-carotene bleaching [β-CBM]), α-glucosidase inhibitory and antibacterial activities. The studied Echeveria species showed high α-tocopherol content (2.9–9.0 mg/100 g f.w.) and total phenolics as Gallic Acid Equivalents (GAE) (152.2–400.5 mg GAE/100 g f.w.). Antioxidant activities of the three Echeveria methanol extracts (ME) were higher than those of other well-known plants with this property; the activities of E. craigiana (ABTS, 65.91 μmol ET/g f.w.) and E. subrigida (β-CBM, 79.3%) were remarkable. The Echeveria ME showed stronger α-glucosidase inhibition (IC₅₀ 25.21–50.57 μg/mL) than acarbose (IC₅₀ 3.59 mg/mL) as well as high antibacterial activity (Minimal Inhibitory Concentrations, MICs ⩽ 1 mg/mL), mainly against Gram positive bacteria. The results showed the three Echeveria species had components/biological activities with high potential for food/pharmacological uses and could be exploited by sustainable management schemes.     

Ultrafiltration of mixed protein solutions of lysozyme and lactoferrin: role of modified inorganic membranes and ionic strength on the selectivity

Ultrafiltration of either single protein solutions (lysozyme 14,300 g mol⁻¹, pI=11; lactoferrin 80,000 g mol⁻¹, pI=8–9) or mixed protein solution was performed with inorganic membranes (MMCO 300,000 g mol⁻¹, pore radius 14 nm) chemically modified in order to bear either pyrophosphate (PP, anionic) or ethylenediamine (EDA, cationic) groups.The electrophoretic mobility of modified and unmodified zirconia particles fouled with proteins was similar whatever the grafted groups, meaning that the membrane surface was always made of adsorbed proteins during UF. In spite of that, for the UF of lysozyme/lactoferrin mixed solution, the maximum selectivity (S=lysozyme transmission/lactoferrin transmission=165) was observed with the EDA membrane and allowed an instantaneous purity of lysozyme in the permeate close to 100% to be achieved. Such high selectivitiy was mainly due to the negligible transmission of lactoferrin with the membrane modified with the EDA groups in the ionic strength range 0–100 mmol l⁻¹ of NaCl at pH 7 (achieved either for mixed and single solutions).     

Use of γ-irradiation to produce films from whey,casein and soya proteins: structure and functionals characteristics

γ-irradiation and thermal treatments have been used to produce sterilized cross-linked films. Formulations containing variable concentrations of calcium caseinate and whey proteins (whey protein isolate (WPI) and commercial whey protein concentrate) or mixture of soya protein isolate (SPI) with WPI was investigated on the physico-chemical properties of these films. Results showed that the mechanical properties of cross-linked films improved significantly the puncture strength for all types of films. Size-exclusion chromatography showed for no cross-linked proteins, a molecular mass of around 40 kDa. The soluble fractions of the cross-linked proteins molecular distributions were between 600 and 3800 kDa. γ-irradiation seems to modify to a certain extent the conformation of proteins which will adopt structures more ordered and more stable, as suggested by X-ray diffraction analysis. Microstructure observations showed that the mechanical characteristics of these films are closely related to their microscopic structure. Water vapor permeability of films based on SPI was also significantly decreased when irradiated. Microbial resistance was also evaluated for cross-linked films. Results showed that the level of biodegradation of cross-linked films was 36% after 60 d of fermentation in the presence of Pseudomonas aeruginosa.     

Self-diffusion coefficient measurements at high temperature by PFG NMR

We have developed a new experimental setup for the measurement of self-diffusion coefficients at high temperature (up to 1500 K) in corrosive liquids. It is based on pulsed field gradient NMR using a 10 mm liquid probe with two channels F-H/X modified and coupled with laser heating. The values obtained thanks to this setup are in good agreement with the available data obtained using the reference method, i.e., the capillary method. We present here results on ¹⁹F, ⁷Li, ²³Na, ²⁷Al in molten fluorides. In alkali fluoride mixtures, the self-diffusion coefficients depend weakly on the composition (nature and concentration of the different alkali) but mainly on temperature. In cryolite (Na₃AlF₆), the diffusion evidences AlF_x^3 ? x species.     

Synthesis and structures of N,N,O-scorpionatoruthenium(II) complexes featuring “non-innocent” o-benzoquinonediimines

A series of ruthenium(II) complexes bearing redox-active o-benzoquinonediimines (o-bqdi) was synthesized and characterized. Reactions of [RuCl(bdmpza)(η⁴-cod)] (bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetato; cod = 1,5-cyclooctadiene) and 1,2-benzenediamines such as o-phenylenediamine (o-pdaH₂), 4,5-difluoro-1,2-benzenediamine (o-pdaF₂), 4,5-dichloro-1,2-benzenediamine (o-pdaCl₂), and 4,5-dimethoxy-1,2-benzenediamine (o-pda(OMe)₂) afforded [RuCl(bdmpza)(o-bqdiX₂)] (X = H, 1; X = F, 2; X = Cl, 3; X = OMe, 4).