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[Display omitted] • The stannate salts are versatile precursors to explore hydrolysis chemistry and dismutation reactions. • Tetra(aqua) diorganotin dications are stabilized as multicomponent molecular crystals. • Structural chemistry reveals the role of alkanesulfonates as both coordinating and non-coordinating ligands. The reactions between diphenyl/di- n -butyltin oxide, dialkyl sulfite, and tetra- n -butylammonium iodide (120 °C, 20 h) proceed via isomerization of the sulfite to sulfonate anion and afford the stannate salts, [ n -Bu 4 N][Ph 2 Sn(OSO 2 Et) 3 ] (1) and [ n -Bu 4 N][ n -Bu 2 Sn(OSO 2 n -Pr) 3 ] (2). The solutions of 1 and 2 in acetonitrile upon exposure to atmospheric conditions resulted in the isolation of multicomponent molecular crystals, [Ph 2 Sn(H 2 O) 4 ][ n -Bu 4 N] 3 [OSO 2 Et] 5 ·3H 2 O (3), [ n -Bu 2 Sn(H 2 O) 4 ][ n -Bu 4 N] 2 [OSO 2 n -Pr] 4 ·H 2 O (4) and [ n -Bu 2 Sn(μ -OH)(H 2 O) 2 ] 2 [ n - Bu 4 N ] 2 [ OSO 2 n - Pr ] 4 (5). In the solid state, the diorganotin cations in 3 – 5 owe their stability to O H---O hydrogen bonds with non-coordinating sulfonate anions. Reactions of the previously reported stannate salt, [ n -Bu 4 N][Ph 2 Sn(OSO 2 Me) 3 ] (6) with N -donor ligands provide a manifestation of phenyl group dismutation to afford new coordination assemblies, [Ph 3 Sn(OSO 2 Me)H 2 O][4,4′-bipy] (7) and [Ph 3 Sn(OSO 2 Me)] (8). X-ray crystallographic studies reveal affinity of the alkanesulfonates to function in both primary and secondary coordination sphere that enables the formation of anionic, cationic, and neutral organotin frameworks. [ABSTRACT FROM AUTHOR]

The disproportionation of ethylbenzene and toluene have been compared on two zeolites, H-mordenite and HY. The online examination of products as a function of time on stream reflect the different processes occurring on the two zeolites. The relative activities expressed on a unit aluminium center basis, are in line with their relative cracking (n-heptane) activities reported by others, showing that no extraneous factors affect activity. The data set provides a baseline for the activity of these two zeolites for future use in comparing other more complex alkylation reactions involving mononuclear and binuclear aromatic molecules. [ABSTRACT FROM AUTHOR]

Hydrogenation reactions of some polycyclic aromatic hydrocarbons (PAHs), including anthracene, 9-phenylanthracene (9-PA) and 9,10-diphenylanthracene (9,10-DPA), were carried out under moderate reaction conditions (with the initial hydrogen pressure of 5 MPa at room temperature, reaction temperature was 300 °C) over a solid superacid (SSA). The results showed that the reactivity of the PAHs decreased in the order of anthracene > 9-PA > 9,10-DPA. It was found that not only the hydrogenation and the reversible dehydrogenation through hydrogen atom transfer, but also disproportionation reaction by intermolecular hydrogen transfer took place in the process of PAHs reactions. The catalyst proved to be versatile for the hydrogenation of anthracene and 9-PA through biatomic hydrogen transfer (BAHT) and for the hydrocraking of 9,10-DPA by monatomic hydrogen transfer (MAHT). The SSA is able to catalyze the cleavage of the C ar C ar bridge bond in 9,10-DPA to produce 9-PA and benzene, in which the key step is the generation of the mobile H + as well as the H + transferring to the ipso-position of anthracene ring in 9,10-DPA. The SSA has the selectivity to catalyze the hydrogenation or hydrocracking of different PAHs. [ABSTRACT FROM AUTHOR]

Pincer-type complexes [OsH2(CO){PyCH2NHCH2CH2NHP tBu2}] and [OsH2(CO){HN(CH2CH2P iPr2)2}] catalyze the disproportionation reaction of aldehydes via an outer-sphere bifunctional mechanism achieving turnover frequencies up to 14 000 h−1. The N−H group of the catalysts is a key player in this process, elucidated with the help of DFT calculations. [ABSTRACT FROM AUTHOR]

The principles of mass and charge conservation apply simultaneously to the disproportionation reactions of plutonium. New formulas for the Pu oxidation number can be generated from a bilinear equation. The new formulas are applied to the analysis of experimental errors in reported oxidation-state distributions for plutonium. Three methods of error analysis are illustrated by examples. [ABSTRACT FROM AUTHOR]

We confirmed the existence of LiO 2 by electrochemical quartz crystal microbalance (EQCM) in TEGDME based Li-O 2 batteries. Our results indicated that Li 2 O 2 is generated through stepwise electrochemical reactions rather than disproportionation. We report for the first time that the formed Li 2 O 2 oxidizes to LiO 2 at relative negative potential and O 2 at positive potential respectively. Our conclusions were based on both experimental observations and quantitative analysis. This may enlighten us to reconsider the Li-O 2 batteries mechanisms in a quantitative way. [ABSTRACT FROM AUTHOR]

The synthesis of the first linear coordinated CuII complex Cu{N(SiMe3)Dipp}2 ( 1 Dipp=C6H5-2,6Pr i2) and its CuI counterpart [Cu{N(SiMe3)Dipp}2]− ( 2) is described. The formation of 1 proceeds through a dispersion force-driven disproportionation, and is the reaction product of a CuI halide and LiN(SiMe3)Dipp in a non-donor solvent. The synthesis of 2 is accomplished by preventing the disproportionation into 1 by using the complexing agent 15-crown-5. EPR spectroscopy of 1 provides the first detailed study of a two-coordinate transition-metal complex indicating strong covalency in the Cu−N bonds. [ABSTRACT FROM AUTHOR]

Triethoxysilane disproportionation was carried out over anion exchange resins in quantitative conversion under mild conditions (40-55 °C). Using solvent, the reaction afforded only tetraethoxysilane (75 %) and monosilane (25 %) as products, in a reaction time of 3 h. The reaction under solvent-free conditions resulted in 100 % conversion after 2 h at a reduced temperature of 40 °C. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Ischemia impairs the adenine nucleotide translocase (ANT), which transports ADP and ATP across the inner mitochondrial membrane. We investigated whether ANT1 overexpression has protective effects on ischemic hearts. Myocardial infarction was induced in wild-type (WT) and heart-specific ANT1-transgenic (ANT1-TG) rats, and hypoxia was set in isolated cardiomyocytes. ANT1 overexpression reduced the myocardial infarct area and increased the survival rate of infarcted rats. Reduced ANT1 expression and increased 4-hydroxynonenal modification of ANT paralleled to impaired ANT function in infarcted WT hearts. ANT1 overexpression improved ANT expression and function. This was accompanied by reduced mitochondrial cytochrome C release and caspase-3 activation. ANT1-TG hearts suffered less from oxidative stress, as shown by lower protein carbonylation and 4-hydroxynonenal modification of ANT. ANT1 overexpression also increased cell survival of hypoxic cardiomyocytes and attenuated reactive oxygen species (ROS) production. This was linked to higher stability of mitochondrial membrane potential and lower activity of ROS detoxifying catalase. ANT1-TG cardiomyocytes also showed higher resistance against HO treatment, which was independent of catalase activity. In conclusion, ANT1 overexpression compensates impaired ANT activity under oxygen-restricted conditions. It reduces ROS production and oxidative stress, stabilizes mitochondrial integrity, and increases survival, making ANT1 a component in ROS management and heart protection during ischemia. Key messages: [ABSTRACT FROM AUTHOR]

Disproportionation reactions can noticeably change the acidity of a plutonium solution. The estimation of the pH change depends on the the Pu concentration, the initial oxidation-state distribution, the initial pH of the solution, and the values of three equilibrium constants. The method can be used to estimate the minimum Pu concentration that produces a specified change in the solution acidity. The results can be checked. [ABSTRACT FROM AUTHOR]

We studied the chemical processes that take place during hydrothermal gelation of graphene oxide (GO), quantifying the reaction products generated during hydrothermal reduction. The gelation proceeds with disproportionation of GO yielding a large amount of CO2 (about a quarter of the original mass of GO), organic acidic fragments, and CO. The CO2 that is formed is trapped in the hydrogel creating macroscopic voids which can lead to cracking of the hydrogel during compression. We were able to quantify the amount of CO2 produced in situ by adding ammonia during the synthesis, and converting CO2 into ionic carbonate species that we could easily quantify by titration. We used titration to evaluate the formation of organic acidic fragments too and evaluated the amount of H2O and CO produced by thermogravimetric analysis and mass balance. The conversion of CO2 into ionic species allowed us to produce void-free hydrogels which remain structurally stable after extensive compression. However, such hydrogels on average showed lower mechanical strength and electrical conductivity than the hydrogels with voids. This is a result of the difference in chemistry and morphology between hydrogels reduced under acidic pH and basic pH. Our work provides for the first time a clear quantitative estimate of CO2 evolution and organic fragment formation during hydrothermal reduction of GO, an overall picture of the reaction products, and a deepened understanding of the conditions that can be used to prepare stronger and more conductive graphene hydrogels and aerogels. [ABSTRACT FROM AUTHOR]

The termination mechanism of the radical polymerization of acrylates, namely the selectivity of disproportionation (Disp) and combination (Comb) between polymer end radicals, is unambiguously determined by the reaction of polyacrylate end radicals generated from corresponding 'living' organotellurium ω-end polymer. While textbooks describe the occurrence of Comb, the reaction at 25 °C exclusively gives the Disp products. Ab initio molecular dynamics suggests that the products form by two pathways: The direct disproportionation reaction and a novel stepwise process that involves the initial formation of the C-O coupling product followed by intramolecular rearrangement. The termination at high temperature and low radical concentration increases the contribution of back-biting reaction giving mid-chain radicals, and complex reaction pathways of the mid-chain radicals are clarified for the first time. [ABSTRACT FROM AUTHOR]

During investigating water-compatible Lewis acids catalyzed etherifications using alcohols as alkylating reagents directly, we developed Fe(III)-catalyzed trityl benzyl ether formations irradiated by microwave. Then an in situ trityl benzyl ether formation and disproportionation cascade reaction was achieved to yield the benzaldehyde products with good functional group tolerances under neat conditions at relative higher temperatures. The substituent effects of the substrates on the etherification and disproportionation were explored by changing the substitutions on benzyl alcohols and triarylmethanols using chemical kinetic plots methods and the mechanism of the transformation was studied by crossover experiments. The etherification and disproportionation cascade process could be conveniently scaled up in laboratory without losing much efficiency. [ABSTRACT FROM AUTHOR]

Sulfur dioxide disproportionation is one of three reaction steps that make up the sulfur based thermochemical cycle used for thermal energy storage of concentrated solar power. The characteristics of this reaction were studied using thermodynamic modeling and laboratory measurements. Modeling results showed full disproportionation can only be achieved at pressure. The reaction driving force is enhanced by system pressure but declines with increasing temperature. Appropriate water to sulfur dioxide ratio also drives disproportionation. Batch experiments showed that reaction rate increases with temperature. A catalyst survey identified homogenous iodides as catalysts that can improve the reaction rate by up to twenty times while increasing the apparent extent of disproportionation. The dependence of disproportionation rate on sulfuric acid concentration was established via constant pressure experiments. Means to recover the iodide catalyst from sulfuric acid and molten sulfur for reuse were demonstrated. Modeling and test results were used to establish a design concept for a sulfur dioxide disproportionation reactor system capable of rapidly generating sulfur as required for the sulfur based thermochemical energy storage technology. [ABSTRACT FROM AUTHOR]

The pseudo-equilibrium concentrations of the H, IO, and HOI ions, kinetically very important species in the disproportionation reaction of iodous acid, have been determined from the equilibrium dissociation reactions of sulfuric and iodous acids in the quasi-stationary state. The values observed were higher than the concentration of the protonated ion of hypoiodous acid. [ABSTRACT FROM AUTHOR]

Disulfide bonds have frequently been incorporated into synthetic materials to promote sensitivity of the systems towards different redox environments. Although many strategies have been developed to rationally tune the stability of disulfide linkers, methods to tune their responsiveness towards different redox environments remain elusive. In this work we have developed and explored a disulfide linker bearing two independent disulfide bonds, referred to as a twin-disulfide linker. We have demonstrated that the twin-disulfide linker displays an ultrahigh stability at lower concentrations of reducing agent or in weakly reducing environments without a significant compromise in the sensitivity of its response to highly reducing environments such as cytoplasm, a feature that is in remarkable contrast to the traditional single disulfide bonds. Such an extraordinary responsiveness arises from the cooperativity of the twin-disulfide bonds, which should be of particular interest for applications such as controlled drug delivery and sensing, because relatively large differences in disulfide stability in different redox environments is desired in these applications. [ABSTRACT FROM AUTHOR]

Two π-conjugated dimethyldihydropyrene (DHP)-bis-terpyridine ligands (2 and 3) were prepared, in which two terpyridine moieties were connected at the 4 and 9 positions of DHP (1) via phenyl and ethynyl linkers, respectively. The nature of the π-conjugated linkers influenced the valence orbitals of the DHP moiety, which shifted the redox potentials of the DHP moiety and the absorption spectra. In 3 with an ethynyl linker, the redox potentials of the DHP moiety were shifted in the positive direction and the absorption band was largely red-shifted compared with 1. In 2 with a phenyl linker, the shifts in the redox potentials of the DHP moiety and in the absorption band were moderate. These results were supported by valence orbital energies calculated using time-dependent density functional theory, which enabled the assignment of the four main transitions in each spectrum for the first time. The fluorescence intensity of 3 was larger than that of 2, which was photoisomerisable. Two dinuclear Ru(bis-terpyridine) complexes (4 and 5) were prepared from 2 and 3, and their redox and photochemical properties were investigated. [ABSTRACT FROM AUTHOR]

Supported gold nanoparticles are highly effective for a range of redox reactions. In these reactions the activity is often enhanced by the addition of a second or indeed a third metallic component. A model reaction that is often investigated is the selective oxidation of benzyl alcohol using molecular oxygen as terminal oxidant. In the presence of a solvent the complexity of this reaction can often be missed. However, in the solvent-free oxidation of benzyl alcohol to benzaldehyde using supported gold palladium nanoparticles as catalysts, there are two pathways to the principal product, benzaldehyde. One is the direct catalytic oxidation of benzyl alcohol to benzaldehyde by O 2 , while the second is the disproportionation of two molecules of benzyl alcohol to give equal amounts of benzaldehyde and toluene. The formation of toluene is an unwanted side reaction. In this paper the research on this reaction will be reviewed and two strategies described that can be used to switch off the formation of the non desired toluene. The first involves the use of basic supports for the gold palladium nanoparticles, which is highly effective in suppressing the formation of toluene and this may be related to the morphology of the gold palladium nanoparticles and their interaction with the support. The second involves the introduction of platinum to the gold palladium nanoparticles which also switches off toluene formation on supports that permit toluene formation in the absence of platinum. This effect may be related to the relative stability of platinum hydride. [ABSTRACT FROM AUTHOR]

Equations representing disproportionation reactions should be numerically verifiable. Comprehensive, balanced equations for plutonium disproportionation reactions can be verified in several ways. Overall equations for Pu disproportionation reactions do not meet all the requirements. [ABSTRACT FROM AUTHOR]

Abstract: The pressure-induced disproportionation reaction phase transition, mechanical, and dynamical properties of LaH2 with fluorite structure under high pressure are investigated by performing first-principles calculations using the projector augmented wave (PAW) method. The phase transition of 2LaH2 → LaH + LaH3 obtained from the usual condition of equal enthalpies occurs at the pressure of 10.38 GPa for Perdew–Wang (PW91) functional and 6.05 GPa for Ceperly–Adler (CA) functional, respectively. The result shows that the PW91 functional calculations agree excellently with the experimental finding of 11 GPa of synchrotron radiation (SR) X-ray diffraction (XRD) of Machida et al. and 10 GPa of their PBE functional theoretical result. Three independent single-crystal elastic constants, polycrystalline bulk modulus, shear modulus, Young's modulus, elastic anisotropy, Poisson's ratio, the brittle/ductile characteristics and elastic wave velocities over different directions dependences on pressure are also successfully obtained. Especially, the phonon dispersion curves and corresponding phonon density of states of LaH2 under high pressure are determined systematically using a linear-response approach to density functional perturbation theory (DFPT). Our results demonstrate that LaH2 in fluorite phase can be stable energetically up to 10.38 GPa, stabilized mechanically up to 17.98 GPa, and stabilized dynamically up to 29 GPa, so it may remain a metastable phase above 10.38 GPa up to 29 GPa, these calculated results accord with the recent X-Ray diffraction experimental finding and theoretical predictions of Machida et al. [Copyright &y& Elsevier]

The deposition of tetranuclear potassium carbonylruthenate K[Ru(CO)] onto carbon Sibunit, SiO, γ-AlO, and MgO followed by the thermal decomposition of the supported anionic cluster at 300 °C in an H or Ar flow leads to systems capable of catalyzing the disproportionation of cyclohexa-1,3-diene and cyclohexa-1,4-diene. The reactions proceed at room temperature to form mixtures of benzene and cyclohexene, benzene, cyclohexene, and cyclohexane, or benzene and cyclohexane. The catalytic systems developed are also active in cyclohexene disproportionation to benzene and cyclohexane at 100-130 °C. [ABSTRACT FROM AUTHOR]

Highlights: [•] New zeolite catalyst has been created where only a portion is developed for strong acid sites. [•] Selective creation of strong acid sites occurs via Al replacement for B in parts of the structure. [•] The novel large pore (but short path) zeolite is contrasted with ZSM-11 and SSZ-57. [•] Reactions studied are Constraint Index, hydroisomerization of n-hexane, and isomerization and disproportionation of diethylbenzene. [Copyright &y& Elsevier]

Highlights: [•] We report a new photocatalyst for aerobic oxidations using molecular oxygen and sunlight. [•] We examine the reaction conditions and explore the substrate scope. [•] We report the evidence of detecting the key oxidizing intermediate. [•] The observed oxidation photocatalysis is ascribed to a photo-disproportionation mechanism. [Copyright &y& Elsevier]

Abstract: During the reactive processing of HD Polyethylene molecules are known to form branched structures, eventually resulting in a MFI decrease. This phenomenon was studied by experiments in a twin-screw extruder and measurement of the MWD by SEC-MALS. A Monte Carlo simulation model has been setup to calculate the MWD and branching distribution. The model includes both branching and random scission. Branch points are assumed to be created by coupling of vinyl ends of linear PE to secondary radical sites on PE backbones, yielding tertiary radical sites that undergo termination by disproportionation. This mechanism was recently proposed by Camara et al. [1]. Comparing the computed MWD to SEC-MALS data allowed determining the kinetic coefficients of the branching and scission reactions. Random scission turns out to be weak but still significant to prevent the formation of an extended MWD tail. For the found parameters perfect agreement was found between measured and computed MWD for various initial peroxide concentrations. These findings contribute to a better fundamental understanding of the simultaneous branching and scission during PE modification. It forms a firm support of the vinyl end to secondary radical coupling branching mechanism. Furthermore, it is shown that the MC simulations provide explicit branching topologies as a basis for predicting, for instance, complex rheological behavior of the modified polymer melt (Read et al. [2]). [Copyright &y& Elsevier]

Interaction of NO (15NO) with amorphous layers of Ru(II) carbonyl porphyrin (Ru(TPP)(CO), TPP2- = meso-tetraphenylporphyrinato dianion) was monitored by FTIR spectroscopy from 80 K to room temperature. An intermediate spectrally characterized at very low temperatures (110 K) with ν(CO) at 2001 cm-1 and ν(NO) at 1810 cm-1 (1777 cm-1 for 15NO isotopomer) was readily assigned to the mixed carbonyl--nitrosyl complex Ru(TPP)(CO)(NO), which is the logical precursor to CO labilization. Remarkably, Ru(TPP)-mediated disproportionation of NO is seen even at 110 K, an indication of how facile this reaction is. By varying the quantity of supplied NO, it was also demonstrated that the key intermediate responsible for NO disproportionation is the dinitrosyl complex Ru(TPP)(NO)2, supporting the conclusion previously made from solution experiments. [ABSTRACT FROM AUTHOR]

The sequential reaction of tellurium with rubidium in liquid ammonia solution has been monitored by ultraviolet-visible spectroscopy. Reaction times for rubidium with tellurium in liquid ammonia were markedly slower than those of sodium and potassium, and the “yellow phase” intermediate was long lived and exhibited a peak at approximately 330 nm with a broad shoulder at about 440 nm. Species formed agree with those previously reported: Rb2Te, Rb2Te2, and Rb2Te3. Rb2Te2solution was a violet-blue with absorbance peaks at 285.8, 324.3, 358.0, and 560.0 nm. No evidence of disproportionation reactions for rubidium polytellurides in liquid ammonia was observed. [ABSTRACT FROM PUBLISHER]

Abstract: Disproportionation of benzyl alcohol has been identified as the source of toluene formation in the solvent free oxidation of benzyl alcohol using supported gold palladium catalysts. There is a slight increase in the disproportionation reaction, and hence the toluene selectivity, when this reaction is performed in a continuous mode using a micro-packed bed reactor when compared to the same reaction performed in a conventional glass stirred batch reactor. Oxidation and disproportionation reactions respond slightly differently to the changes in reaction parameters, like oxygen concentration and pressure, when a micro packed bed reactor was used instead of a conventional glass stirred reactor. When MgO supported gold–palladium catalysts were used for this reaction, the toluene selectivity reduced substantially at the cost of conversion. [Copyright &y& Elsevier]

Abstract: The sulphur-cycle processes inside constructed wetlands (CWs) and their role in the complex network of transformation processes and the long-term stability of wetland systems are still not sufficiently understood. A comprehensive review is accordingly necessary for better understanding to optimize the future design and operation of wetland systems. In this paper, the concept of sulphur cycling in CWs in principle, transformations dynamics of sulphur compounds and their interactions with other element cycles (such as carbon, nitrogen and phosphorus) and plants, as well as importance for treatment efficiencies are reviewed. The abiotic and biotic transformations of sulphur are both spatially and temporally dynamic in CWs. Next to physico-chemical processes, e.g. mineral precipitation and dissolution, biologically catalyzed redox reactions such as assimilatory and dissimilatory sulphate reduction, as well as oxidation/reduction, and disproportionation of more reduced sulphur compounds also simultaneously occur in the rooted zones of CWs. Moreover, the interactions between sulphur transformations and other processes including microbial transformations of carbon, nitrogen and phosphorus, as well as the impact of plants are discussed. Briefly, sulphide as a product of dissimilatory sulphate reduction may remove heavy metals from wastewaters via the precipitation of metal sulphide and the use of CWs in treating heavy metal containing waters (e.g. acid mine drainage) is increasing. However, high sulphide concentrations may also negatively affect growth of wetland plants and microbial activities, especially nitrification, but also influence the mobilization of iron-bound phosphorus. This information may be used to offer future design and operational methodologies that might enhance the performance of contaminants removal and drive a sustainable management of CWs for wastewater treatment. [Copyright &y& Elsevier]

In this work, electrochemical studies on the seven-coordinate iron complex (FeIII/IIdapsox), a functional model for the superoxide dismutase enzyme (SOD mimetic), were performed in an aqueous solution over the pH range 1-12 (with and without buffers) to conceive the underlying heterogeneous proton-coupled electron transfer (PCET) processes of various complex species. The thermodynamics of the corresponding proton transfer, electron transfer, and PCET processes have been evaluated as well as the kinetics of related heterogeneous electrode reactions of all complex species in solution. Measurements in D2O have also been carried out for selected redox couples to assess a possible kinetic isotope effect (KIE). In the case of a two-proton one-electron transfer process in the absence of a buffer, the KIE was found to be 4.8, whereas in the case of a one-proton one-electron transfer process in buffered solutions, an inverse KIE was observed. The overall data suggest the operation of a concerted PCET mechanism for the two-proton one-electron transfer process, whereas involvement of an H-bonded precursor adduct formed between the buffer components, and the complex species within a one-proton one-electron transfer mechanism is feasible. These results shed light on both the enzymatic and the mimetic SOD mechanisms, speaking in favor of the two-proton one-electron transfer process as a desirable mechanism for efficient catalytic superoxide dismutation. [ABSTRACT FROM AUTHOR]

Abstract: H-ZSM-5 zeolite catalysts were doped with 2%, 3% and 4%HF to be used for investigating their activities and selectivities for xylenes production and for para-xylene maximization at temperatures of 300–500°C via toluene disproportionation. This doping caused pore size modification of the H-ZSM-5 catalyst. The reaction was carried out in a fixed bed flow type reactor. The ratio of produced para-xylene relative to its thermodynamic composition reached as high as 3.29 at 300°C on the 4%HF doped H-ZSM-5 catalyst although this catalyst possessed the lowest amount of the largest pores (3.0–5.7nm) and the smallest pores (0.4–1.7nm). The overall activities of the catalysts were decreased with an increase in HF doping because of diffusion restriction. The kinetics of the reaction were simply treated and found to give E a and ΔS ∗ values compatible with the characterization data of the catalysts. [Copyright &y& Elsevier]

The first empirical method for preparing a plutonium predominance-region diagram used horizontal lines to locate the boundaries of the regions of forbidden, unique, and ambiguous oxidation-state distributions. A second approach changes the procedure by using vertical lines to illustrate these regions. In both cases, the boundary lines are determined by the Pu oxidation number and the equilibrium fraction of one oxidation state. [ABSTRACT FROM AUTHOR]

Abstract: A new MnIV dinuclear complex [MnIV 2(μ-O)2(L′)4].2CH3OH (HL′=(E)-N′-(1-(thiophen-2-yl)ethylidene)benzohydrazide) was obtained from MnIII(acetate)3.2H2O by an unusual MnIII disproportionation reaction. This compound exhibits a strong antiferromagnetic coupling with a J value of −149(5) cm−1. Moreover, a new MnIII mononuclear complex bearing L′ named [MnIII(acac)(L′)2] (acac = acetylacetonate) was obtained from [MnIII(acac)3] and is described as a part of a systematic research work around manganese complexes of magnetic interest. [Copyright &y& Elsevier]

Substituted pyrroles may be synthesized from selected 1,2-pyridazines through a reductive ring contraction involving the addition of four electrons and four protons. Our density functional theory computations of this reaction mechanism show that the first reduction event must be preceded by the uptake of one proton by 1,2-pyridazine and that the reaction proceeds through a 2e-/3H+-bearing intermediate. In the absence of electron-withdrawing groups able to resonate charge away from the ring, this intermediate lies too high in energy, making the reaction sequence thermodynamically inaccessible. After another two-electron reduction and the addition of two more protons, the original 1,2-pyridazine ring opens. Ring contraction and ammonia elimination then proceed with very small barriers, irrespective of the substituents present in the original 1,2-pyridazine. By establishing the need for electron-withdrawing resonant groups in the 3- and 6-positions to stabilize the critical intermediate in the initial stages of the reaction, this work suggests that the scope of the reductive ring contraction of 1,2-pyridazines may be expanded to pyridazines bearing COCH3 groups, amides or aryls in these positions. We also explain the lack of reactivity of unsubstituted 1,2-pyridazine and analyze the feasibility of bypassing the high energy 2e-/3H+-intermediate through disproportionation of earlier 2e-/2H+-bearing intermediates. [ABSTRACT FROM AUTHOR]

Abstract: New salts C27H22N3O2BrI2 (1) and C27H19N3O2Br4I2·2CHCl3·2H2O (2) were synthesized by the iodination of derivatives of 1,3-dimethyl-2,4-dioxo-5,6,7-R-1Н,2Н,3Н,4Н-pyrido[4,3-d]pyrimidinium bromide (R=phenyl (1a), p-bromphenyl (2a)) with an equimolar amount of iodine. The positive values of enthalpy (ΔH) and entropy (ΔS) indicate that the complexation of organic bromide and iodine molecule in chloroform solution is mainly entropically driven. The molecular and crystal structures (1) and (2) are studied by X-ray diffraction analysis. The structure of diiodinebromide 1 is composed of separate almost liner and 1,3-dimethyl-2,4-dioxo-5,6,7-thriphenyl-1Н,2Н,3Н,4Н-pyrido[4,3-d]pyrimidinium cation. The crystal structure 2 is built up of alternate layers of (A) and (Br2I−)(СHСl3) (B), connected to each other by hydrogen bonds . The formation of the ions and Br2I− occurs via the disproportionation of I2Br− under the action of solvent on C27H19N3O2Br4I2·2CHCl3·2H2O (2) crystallization. [Copyright &y& Elsevier]

Selenide ions have been shown to catalyze the Tishchenko reaction for the first time. These catalysts are superior to previously reported thiolate analogues and promote the disproportionation of aldehydes with increased reaction rates and broader scope at lower catalyst loadings and temperatures. Significantly improved catalyst performance was also observed in the aryl selenide mediated crossed intermolecular Tishchenko reaction. [ABSTRACT FROM AUTHOR]

Maxima in the fractions of the trivalent and hexavalent oxidation states of plutonium are inherent in the algebra of its disproportionation reactions. The maxima do not support overall disproportionation equations as satisfactory representations of aqueous plutonium. [ABSTRACT FROM AUTHOR]

A stimuli-responsive material with AND logic function was realized by modulating sensitive Cu–Cu interactions, which is quite different from traditional photoinduced electron transfer (PET) strategies. The obtained material not only gets rid of fluid media, but also displays nondestructive, high intensity optical signals and environmentally friendly performances. [ABSTRACT FROM AUTHOR]

The reaction of benzoic acid with the uranyl(V) complex [(UO2Py5)(KI2Py2)] in pyridine leads to immediate disproportionation with formation of a hexanuclear U(IV) benzoate cluster, a bis-benzoate complex of uranyl(VI) and water. [ABSTRACT FROM AUTHOR]

Single crystals of NbF4 are prepared by disproportionation of Nb2F5 (Nb Tube in evacuated silica tubes, 1273 K, 2 d) and by solid state reaction of Nb and NbF5 (1073 K, 2 d; heating rate of 16 K/h). [ABSTRACT FROM AUTHOR]

The oxygen-stoichiometric, B-site-ordered perovskite Ca2Fe1.1Mn0.9O6 with alternate stacking of Fe and Mn layers is prepared by reaction of Ca2Fe1.1Mn0.9O5 with KClO4 in a molar ratio of 1:0.5 (gold foil, 4 GPa, 550 °C, 45 min). [ABSTRACT FROM AUTHOR]