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The heating of high-Ni cathode materials under low O2 partial pressures has generally been considered undesirable. Contrary to this general understanding, this study reports the postheating of LiNi...

A strategy for the syntheses of benzofuranoquinolines and its analogues via the irradiation of o-phenylfuranyl/thienylpyridines/pyrimidines in DCM with UV light at rt under an argon atmosphere is described. The mechanism of this reaction through the process of 6π-electrocyclization, [1,5]-hydrogen shift, and 1,3-eneamine tautomerism leading to H2 evolution was elucidated. Notably, the syntheses of cis-8b-methyl-8b,13a-dihydrobenzo[f]benzofuro[3,2-h]quinolone via the photoinduced rearrangement of 2-(3-methylbenzofuran-2-yl)-3-phenylpyridine relevant to the mechanism of this reaction highlights the importance of the developed methodology.

Evolution of hydrogen during the plastic state is a key parameter in coke making for the production of quality coke. Based on this phenomenon, a new devolatilization method has been developed for accessing the coking property of coals using the evolution of H2 during thermogravimetric–mass spectrometer (TG-MS) analysis. Four coals having different coking potentials, commonly used in steel industries, were considered. The investigation was performed at temperatures up to 1100 °C in an argon atmosphere under a constant heating rate of 3 °C/min to simulate the coking environment. Nonisothermal kinetics is considered as a good indication of different reaction regimes during pyrolysis, which is generally done through TGA alone. In this study evolution of H2 is used to develop nonisothermal kinetics through a new quantification approach. Finally, a definite and more generic correlation was established, based on H2 enrichment in volatiles around specific temperature zones, for measuring the exact coking behavior...

Cu2SnTe3 nanocrystals with a cubic structure are prepared by reacting stoichiometric amounts of Cu(acac)2 and Ph4Sn in presence of oleylamine (argon atmosphere, 130 °C, 30 min) followed by injection of a TeO2 solution in 1-dodecanethiol (210 °C, 90 min).

With rapid growth in the use of NdFeB magnets and growing concerns for environmental protection as well as conservation of rare earths (REs), the recycling of NdFeB magnet scrap is becoming a hot issue for current society. In this study, it is demonstrated that the rare earths in a NdFeB magnet can be selectively extracted using molten MgCl2–KCl salts at temperatures of 600–1200 °C. After crushing to granules, the scrap was subjected to molten chlorides in a dry argon atmosphere. The reaction process between NdFeB scrap and molten MgCl2–KCl was directly observed using a high-temperature contact angle measuring instrument to clarify the phenomena that occur when rare earth chlorides are formed in situ. Furthermore, the effects of reaction temperature, holding time, and mass ratio of MgCl2/NdFeB were investigated to transform REs in the scrap to RECl3 as completely as possible. The reaction products were examined with the necessary analytical techniques including SEM, EDS, XRD, and ICP. The overall extracti...

Reactions of α- and β-pinenes in pressurized hot water were examined in a batch reactor made of a SS316 1/2-in. tube at temperatures of 250–400 °C, pressures of 4–30 MPa, and reaction times of 1–30 min in the absence of any additive under an argon atmosphere. The maximum yields of limonene from α-pinene were ca. 70% in 20 min at 300 °C or 1 min at 400 °C. Limonene was obtained from β-pinene in ca. 16% yield for 30 min at 300 °C and 1 min at 400 °C. Reversible production of myrcene in 14% yield and formation of unidentified C20 dimer fractions were noted for 1 min at 370 °C from β-pinene. The conversion of α-pinene to limonene took place under anhydrous conditions, albeit at slightly lower yield of 65% compared to processes conducted in the presence of water, where increased limonene yield of 70% was observed for 1 min at 400 °C. The conversion of β-pinene to limonene under anhydrous conditions was limited to 6.1% in contrast to 11.9% in the presence of water for 7 min at 370 °C. In the presence of oxygen,...

We previously reported that holes opened at the tips of conical single-graphenes of single-wall carbon nanohorns were closed during heat treatment at 1200 °C in an argon atmosphere. Here, we report phenomena related to the behavior of these holes: the holes closed quickly at first, then reopened, and then slowly closed again as the heat treatment period increased. This close−open−close evolution occurred only when the initial hole size was medium (0.7−0.9 nm). Smaller and larger holes did not reopen after they thermally closed. We discuss the close−open−close mechanism by considering the functions of oxygenated groups existing at the edges of the holes.

The syntheses of the chloro complexes [Ru(η5-C5R5)Cl(L)] (R = H, Me; L = phosphinoamine ligand) (1a−d) have been carried out by reaction of [(η5-C5H5)RuCl(PPh3)2] or {(η5-C5Me5)RuCl}4 with the corresponding phosphinoamine (R,R)-1,2-bis((diisopropylphosphino)amino)cyclohexane), R,R-dippach, or 1,2-bis(((diisopropylphosphino)amino)ethane), dippae. The chloride abstraction reactions from these compounds lead to different products depending on the starting chlorocomplex and the reaction conditions. Under argon atmosphere, chloride abstraction from [(η5-C5Me5)RuCl(R,R-dippach)] with NaBAr‘4 yields the compound [(η5-C5Me5)Ru(κ3P,P‘-(R,R)-dippach)][BAr‘4] (2b) which exhibits a three-membered ring Ru−N−P by a new coordination form of this phosphinoamine. However, under the same conditions the reaction starting from [(η5-C5Me5)RuCl(dippae)] yields the unsaturated 16 electron complex [(η5-C5Me5)Ru(dippae)][BAr‘4] (2d). The bonding modes of R,R-dippach and dippae ligands have been analyzed by DFT calculations. The p...

In terms of standard addition method, the density and surface tension of an amino acid ionic liquid EMIGly(1-ethyl-3-methylimidazolium aminoacetate) were measured under dry argon atmosphere in the temperature range of 288.15-343.15 K. The properties of volume and surface for pure EMIGly were discussed in terms of the interstice model and Glasser's theory. The thermal expansion coefficient alpha = 5.03 x 10(-4) K(-1) calculated using interstice model is in good agreement with alpha (experimental) = 5.20 x 10(-4) K(-1).

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are shown to be globally distributed, environmentally persistent, and bioaccumulative. Although the toxicities of these compounds were reported, the cleanup procedure from the environment is not developed because of their inertness. In this report the sonochemical degradations of PFOS and PFOA to the products through the fission of the perfluorocarbon chains were observed and the half-life times of the PFOS and PFOA degradations under an argon atmosphere determined to be 43 and 22 min, respectively. The shortening of perfluorocarbon chain of PFOS and PFOA leads to the lowering of the toxicity in view of the decrease of the persistence, and the technique would contribute to the remediation of the environmental pollution by these compounds.

Thermal analysis on two coals (semi-anthracite and high-volatile coking coal), iron ore, and their corresponding mixtures was performed using a computer-aided thermal analysis technique. Samples were heated to 1000 °C at a typical rate of 10 °C/min under an argon atmosphere. It was found that the iron ore undergoes several reactions prior to its reduction, which resulted in an endothermic heat effect. The iron ore reduction commenced at temperatures as low as 580 °C and progressively increased at higher temperatures. Coal devolatilization was found to play an important role in iron ore reduction for the coal−ore mixtures at temperatures below 920 °C, while the effect of char gasification resulting in CO as a reducing gas was dominant at higher temperatures. No apparent difference in the effect of coal devolatilization on reduction reactions was observed when low- and high-volatile matter coal was mixed with the iron ore. The main difference was detected only in the temperature range where char gasificatio...

The new ternary selenostannates Sr(4)Sn(2)Se(9) and Sr(4)Sn(2)Se(10) have been synthesized by heating the elements at 1023 K in an argon atmosphere. Their structures were determined by single-crystal X-ray methods. Sr(4)Sn(2)Se(9) crystallizes in a new structure type (Pbam, a = 12.042(2) A, b = 16.252(3) A, c = 8.686(2) A, Z = 4) with Sn(2)Se(6)(4-), SnSe(4)(4-), and Se(2)(2-) subunits. Sr(4)Sn(2)Se(10) (P2(1)2(1)2, a = 12.028(2) A, b = 16.541(3) A, c = 8.611(2) A, Z = 4) has a similar structure with Se(3)(2-) triangles instead of Se(2)(2-) dumbbells. Strontium is 8-fold-coordinated by selenium in both cases. The opening angles between tin and the terminal selenium atoms in the Sn(2)Se(6) subunits are close to 160 degrees , which is nearer a typical Sn(2+) coordination geometry than classical SnSe(4) tetrahedra. This result suggests the tin oxidation state in the Sn(2)Se(6) units to be lower than the expected Sn(4+). This question is examined by self-consistent LMTO and LAPW band structure calculations expanded by the Bader analysis of the charge density to assign reliable atomic charges.

The hexahydride complex OsH6(PiPr3)2 (1) reacts with 2-vinylpyridine to give the trihydride derivative (2). The β- and γ-positions of the pyridine ring are quantitatively and selectively deuterated by addition of 1 (5%) to toluene-d8 and benzene-d6 solutions of 2. Under hydrogen atmosphere, 2 reacts with HBF4·OEt2 to afford [HNC5H4-o-Et]BF4 and regenerate 1. Under argon atmosphere, the addition of HBF4·OEt2 to dichloromethane solutions of 2 leads to the hydride-dihydrogen (3), which catalyzes the hydrogenation of 2-vinylpyridine to 2-ethylpyridine. In dichloromethane 3 evolves into the neutral chloro-dihydrogen compound (4). Complex 1 also reacts with N-methylene-2-pyridinamine and (E)-N-(phenylmethylene)-2-pyridinamine. The reaction with the first pyridinamine leads to a 3:1 mixture of the trihydride complexes (5) and (6), while the reaction with the second one selectively affords (7). Similarly to 2, the addition of 1 (5%) to toluene-d8 and benzene-d6 solutions of 6 produces the quantitative and selecti...

The transamination reaction of Sm{N(SiMe3)2}2(THF)2 with two dipyrrole ligands of formula RR‘C(α-C4H3NH)2 (R = R‘ = Et; R = Me, R‘ = Ph) has been examined. The reactions in THF and under N2 gave two similar tetranuclear dinitrogen complexes, {[Et2C(α-C4H3N)2Sm}4(THF)2](μ-N2)·2THF and [{[(C6H5)(CH3)C(α-C4H3N)2]Sm}4(DME)2](μ-N2), where the dinitrogen unit has undergone a four-electron reduction via cooperative attack of four divalent samarium atoms and remained coordinated both side-on and end-on between the four coplanar metal centers. The same reaction carried out with diethyldipyrrolylmethane under an argon atmosphere afforded the divalent samarium macrocyclic cluster {[Et2C(α-C4H3N)2]Sm}8(THF)4·4THF. In the case of the reaction with the methylphenyldipyrrolylmethane ligand under N2, the unprecedented hexanuclear mixed-valence SmII/SmIII cluster [([(C6H5)(CH3)C(α-C4H3N)2][(C6H5)(CH3)C(α-C4H3N)(β-C4H3N)]{[(C6H5)(CH3)C]2(α-C4H3N)2(α,α‘-C4H2N)}Sm3)(THF)3]2, containing tripyrrolide, “N-confused”, and regular...

A novel intramolecular cyclization reaction mediated by dicobalt octacarbonyl (Co(2)(CO)(8)) is reported. Thermolysis in an argon atmosphere transforms the cobalt complex of 1-trimethylsilyl-6-hepten-1-ynes into 1-trimethylsilyl-5-vinylcyclopentenes in good yield and in a highly diastereoselective manner. This formal 5-endo-dig cyclization is proposed to proceed via an allylic C-H oxidative addition.

Reaction of a large excess of H2S with 2 mol of •Cr(CO)3C5Me5 yields HCr(CO)3C5Me5 and HSCr(CO)3C5Me5. Kinetic studies of this reaction show two reaction pathways are followed. At pressures of CO above 10−15 atm and temperatures ≤10 °C, a third-order rate law d[P]/dt = k3rd order[•Cr(CO)3C5Me5]2[H2S] is followed. The value of the third-order rate constant 70 ± 5 M-2 s-1 is essentially independent of temperature in the range −30 to +10 °C. As the pressure of CO is reduced, mixed-order kinetics is followed, and under argon atmosphere the reaction obeys the following second-order rate law: d[P]/dt = k2nd order[•Cr(CO)3C5Me5][H2S]. The value of k2nd order was found to be 0.20 ± 0.05 M-1 s-1 at 1 °C and 0.30 ± 0.05 M-1 s-1 at 10 °C. This reaction channel is proposed to proceed by rate-determining ligand substitution and formation of the hydrogen sulfide substituted radical complex •Cr(H2S)(CO)2C5Me5. The rate of ligand substitution of •Cr(CO)3C5Me5 by PMe2Ph yielding the phosphine-substituted radical •Cr(PMe2...

The origin of the previously observed unusual photostability of 2,4,6-triisopropyl-4‘-(methoxycarbonyl)benzophenone (1-p-CO2Me) in the solid state was investigated. 1-p-CO2Me was found to photocyclize normally to produce the corresponding benzocyclobutenol 2-p-CO2Me when its solid-state photolysis was carried out either (a) after thorough grinding, (b) after solid−solid mixing with 2,4,6-triisopropyl-4‘-(ethoxycarbonyl)benzophenone (1-p-CO2Et), or (c) at elevated temperatures (an estimated energy barrier of 20 kcal/mol). Furthermore, when the photolysis was performed under more carefully deoxygenated conditions (closed argon atmosphere), formation of blue species that are persistent in the absence of oxygen was observed. On the basis of oxygen trapping and ESR experiments, the blue species are regarded as a mixture of a diradical intermediate DR and monoradicals derived thereof. The X-ray study of 1-p-CO2Me had revealed that the distances between the carbonyl oxygen and the o-i-Pr methine hydrogens are wi...

Surface characteristics of nongraphitized carbon black (S-II) and graphitized carbon black (S-III) were investigated by analyzing the adsorption isotherms of Kr, N2, and H2O. S-II was prepared by heating Spheron 6 (S-I) at 1273 K in vacuo, and S-III was prepared by graphitizing Spheron 6 (S-I) at 2973 K in an argon atmosphere. It was found from the Kr isotherms that the surface of S-II was heterogeneous, while that of S-III was homogeneous. The t-plot of the N2 isotherm showed that S-II was nonporous. However, the minute microporosity was detected in S-II from the comparison plot of the water isotherm. The size of the micropores present in S-11 may be larger than 0.22 nm (the water molecule size) and smaller than 0.43 nm (the nitrogen molecule size). The adsorption isotherms of water vapor on S-III were measured at 283, 298, and 308 K in the range of Γ = 0.0004−0.6 H2O/nm2. The differential enthalpies (ΔHS) and the differential entropies (ΔSS = SS − SL) of the water molecules adsorbed on the S-III surf...

The effect of axial ligands on the structure, oxidation state, and electronic configuration of two diruthenium(II,III) and two diruthenium(III,III) complexes is reported. The investigated compounds are represented by Ru2(dpf)4Cl (1), Ru2(dpf)4(C⋮CC6H5) (2), Ru2(dpf)4(C⋮CC6H5)2 (3), and Ru2(dpf)4(CN)2 (4), where dpf is the N,N‘-diphenylformamidinate ion. The chloro and mono(phenylacetylide) complexes, which contain a Ru25+ core, are paramagnetic and contain three unpaired electrons, while the bis(phenylacetylide) and bis(cyano) species, which contain a Ru26+ core, are diamagnetic. Compound 1, Ru2(dpf)4Cl, was prepared by heating Ru2(CH3COO)4Cl and excess molten N,N‘-diphenylformamidine (Hdpf) for 10 h at 130 °C under an argon atmosphere. Compound 2, Ru2(dpf)4(C⋮CC6H5), was prepared by reaction of purified Ru2(dpf)4Cl with LiC⋮CC6H5 (in a 1:5 ratio) in THF at room temperature (2 h). Compound 3, Ru2(dpf)4(C⋮CC6H5)2, was also obtained from Ru2(dpf)4Cl by using excess LiC⋮CC6H5. A related diruthenium(III,III) ...

Novel Fe(III)Fe(III) and Fe(II)Fe(III) complexes [Fe(2)(BBPMP)(mgr;-OAc)(mgr;-X)](n)() (1, X = OAc(-), n = 1+; 2, X = OH(-), n = 1+; 3, X = OAc(-), n = 0; 4, X = OH(-), n = 0), where BBPMP(3)(-) is the anion of 2,6-bis[(2-hydroxybenzyl)(2-pyridylmethyl)aminomethyl]-4-methylphenol, and OAc(-) is acetate, were prepared in order to provide models for the active site of purple acid phosphatases (PAPs). Complex 1 was obtained by the reaction of H(3)BBPMP with Fe(ClO(4))(2).6H(2)O in methanol and sodium acetate trihydrate under ambient conditions, while complex 3 was synthesized as described for 1, under an argon atmosphere with low levels of dioxygen. 2 was isolated from 1in acetonitrile by a substitution of the bridging acetate group by hydroxide, while 4 was generated in solution during a spectropotentiostatic experiment on 2, under argon. Complex 1, [Fe(III)(2)(BBPMP)(mgr;-OAc)(2)]ClO(4).H(2)O, has been characterized by X-ray crystallography. Crystal data: monoclinic, space group P2(1)/n, a = 14.863(5) Å, b = 12.315(3) Å, c = 20.872(8) Å, beta = 90.83(3) degrees, Z = 4. IR, Mössbauer, magnetic, electronic absorption, and electrochemical properties of 1-3 have been investigated, and some of these properties represent a contribution to the understanding of the dinuclear iron center of PAPs. Complexes 2, [Fe(III)(2)(BBPMP)(mgr;-OAc)(mgr;-OH)]ClO(4) (lambda(max) = 568 nm/epsilon = 4760 M(-)(1) cm(-)(1)), and 4 [Fe(II)Fe(III)(BBPMP)(mgr;-OAc)(mgr;-OH)] (lambda(max) = 516 nm/epsilon = 4560 M(-)(1) cm(-)(1)), constitute good synthetic analogues for the chromophoric site for the oxidized and reduced forms, respectively, of the enzyme.

The reduction of nitrobenzenes with electrogenerated nickel in DMF gave anilines without affecting the alkenyl, alkynyl, halo, acetyl, methoxy, cyano, ethoxycarbonyl, formyl, benzyloxy, and phenylsulfonylamino groups at room temperature in a short time. The nickel was easily prepared by electrolysis in 0.3 M Et4NBF4−DMF solution under an argon atmosphere at a constant current (10 mA/cm2) and can be stored under argon at −20 °C for at least a week.