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Olefin polymerization is one of the most important chemical reactions in industry. This work presents a strategy that emphasizes the synergistic meta/para-steric hindrance of N-aryl groups and electronic effects in newly synthesized neutral salicylaldiminato nickel catalysts. These nickel(II) catalysts exhibit exceptional thermostability, ranging from 30 °C to 130 °C, demonstrating enhanced catalytic activities and broadly regulated polyethylene molecular weights (3–341 kg·mol−1) and controlled polymer branch density (2–102 brs/1000C). The preferred catalyst Ni3 with concerted steric and electronic effects enables the production of solid-state semi-crystalline polyethylene materials at temperatures below 90 °C. Notably, Ni3 exhibits an impressive tolerance of 110 °C and can withstand even the challenging polymerization temperature of 130 °C, leading to the production of polyethylene wax and oil. Also, functionalized polyethylene is produced. [ABSTRACT FROM AUTHOR]

Context: This study investigates the ethylene insertion reaction mechanism for polymerization catalysis, aiming to discern differences between Ni-α-imine ketone–type catalyst and their SiO2-supported counterpart. The reaction force analysis unveils a more intricate mechanism with SiO2 support, shedding light on unexplored factors and elucidating the observed lower catalytic activity. Furthermore, reactivity indexes suggest earlier ethylene activation in the supported catalyst, potentially enhancing overall selectivity. Finally, the reaction electronic flux analysis provides detailed insights into the electronic activity at each step of the reaction mechanism. In sum, this study offers a comprehensive understanding of the ethylene insertion reaction mechanism in both molecular and supported catalysts, underscoring the pivotal role of structural and electronic factors in catalytic processes. Methods: Density functional theory (DFT) calculations were conducted using the ωB97XD functional and the 6–31 + G(d,p) basis sets with Gaussian16 software. Computational techniques utilized in this study encompassed the IRC method, reaction force analysis, and evaluation of electronic descriptors such as electronic chemical potential, molecular hardness, and electrophilicity reactivity indexes. Additionally, reaction electronic flux analysis was employed to investigate electronic activity along the reaction coordinate. [ABSTRACT FROM AUTHOR]

The development of highly active, reusable catalysts for aqueous‐phase reactions is challenging. Herein, metallic nickel is encapsulated in a nitrogen‐doped carbon–silica composite (SiO2@Ni@NC) as a catalyst for the selective hydrogenation of vanillin in aqueous media. The constructed catalyst achieved 99.8% vanillin conversion and 100% 4‐hydroxymethyl‐2‐methoxyphenol selectivity at room temperature. Based on combined scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, and Raman analyses, the satisfactory catalytic performance is attributed to the composite structure consisting of an active metal, carbon, and silica. The hydrophilic silica core promoted dispersion of the catalyst in aqueous media. Moreover, the external hydrophobic NC layer has multiple functions, including preventing oxidation or leaching of the internal metal, acting as a reducing agent to reduce the internal metal, regulating the active‐site microenvironment by enriching the concentrations of H2 and organic reactants, and modifying the electronic structure of the active metal via metal–support interactions. Density functional theory calculations indicated that NC facilitates vanillin adsorption and hydrogen dissociation to promote aqueous‐phase hydrogenation. This study provides an efficient strategy for constructing encapsulated Ni‐based amphiphilic catalysts to upgrade biomass‐derived compounds. [ABSTRACT FROM AUTHOR]

Hydrocarbons, when used as the medium for transition metal catalyzed organic reactions and olefin (co‐)polymerization, are ubiquitous. Environmentally friendly water is highly attractive and long‐sought, but is greatly challenging as coordination‐insertion copolymerization reaction medium of olefin and polar monomers. Unfavorable interactions from both water and polar monomer usually lead to either catalyst deactivation or the formation of low‐molecular‐weight polymers. Herein, we develop well‐behaved neutral phosphinophenolato nickel catalysts, which enable aqueous copolymerization of ethylene and diverse polar monomers to produce significantly high‐molecular‐weight linear polar polyolefins (219–549 kDa, 0.13–1.29 mol %) in a single‐component fashion under mild conditions for the first time. These copolymerization reactions occur better in water than in hydrocarbons such as toluene. The dual characteristics of high molecular weight and the incorporation of a small amount of functional group result in improved surface properties while retain the desirable intrinsic properties of high‐density polyethylene (HDPE). [ABSTRACT FROM AUTHOR]

In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation of Ni catalysts through incipient wetness impregnation. Characterization was conducted using various techniques, including X-ray diffraction (XRD), SEM–EDS, FTIR, and temperature-programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni-based catalysts were used in reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity in the dry reforming of methane. After acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite proved to be an effective support for nickel catalysts that displayed outstanding performance, achieving high methane conversion and hydrogen yield. The acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming the Ni over alkali treated support. The prepared catalysts were also evaluated in ethanol steam reforming under various conditions including temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts confirming the best performance. [ABSTRACT FROM AUTHOR]

This study describes a method to synthesize compounds with an arylidene group at the alpha position of N‐methyl‐2‐pyrrolidone (NMP) and an alcohol group at the gamma position in a single‐step reaction using NMP and aldehyde. The highest yields were obtained with Ni(glyme)Cl2 as a nickel catalyst and tert‐butyl hydroperoxide as the oxidant, and various aryl aldehydes reacted under optimal conditions to yield the target compounds. [ABSTRACT FROM AUTHOR]

An efficient and versatile synthesis of alcohols via transfer hydrogenation from ketones with isopropanol, utilizing [Ni(6,6′‐(OH)2‐2,2′‐bpy)][Br2] under alkaline conditions, has been documented. It was noteworthy that many readily reducible or labile functional groups such as nitro, cyano, and halide, within the same molecular framework, did not undergo any change under the standard reaction conditions. Furthermore, the gram scale transfer hydrogenation reaction was successfully carried out with good yield using a common route with only a single purification by column chromatography. [ABSTRACT FROM AUTHOR]

The physical properties of traditional polyolefin materials can be significantly improved by introducing polar groups, especially polar aromatic groups. However, it remains a major challenge to realize the highly effective copolymerization of ethylene with styrene derivatives. In this study, the direct copolymerization of ethylene with various polar styrene monomers bearing functional groups (o‐OMe, m‐OMe, p‐OMe, o‐Cl, m‐Cl, p‐ClSt, o‐F, o‐Br, p‐Me, p‐Ph, p‐Vinyl, p‐COOH, and C6F5) was achieved using phosphino‐dihydronaphtholate neutral nickel catalysts Ni1‐Ni3. Additionally, the catalytic behavior and the applicability of the polar monomer were evaluated in detail by copolymerization results. Catalysts Ni1‐Ni3 demonstrated inactivity towards the polymerization of polar styrene monomers but exhibited moderate catalytic activities in the copolymerization of ethylene with polar styrene monomers, yielding moderate‐molecular‐weight (Mw > 10 kDa) copolymers with the polar monomer contents ranging from 1.32 to 4.16 mol%. The steric and electronic effects of the substituent depending on the types and position in the phenyl ring considerably influenced the copolymerization behavior. Furthermore, comprehensive NMR analyses of the produced copolymers revealed that the polar monomers formed in‐chain insertions, saturated chain ends, and unsaturated chain ends after incorporation. [ABSTRACT FROM AUTHOR]

In the presented work, the catalytic performance of a nickel catalyst, in CO2 hydrogenation to methane, within a ZrO2 open-cell foam (OCF)-based catalyst was studied. Two series of analogous samples were prepared and coated with 100–150 mg of a Mg-Al oxide interface to stabilize the formation of well-dispersed Ni crystallites, with 10–15 wt% of nickel as an active phase, based on 30 ppi foam or 45 ppi foam. The main factor influencing catalytic performance was the geometric parameters of the applied foams. The series of catalysts based on 30 ppi OCF showed CO2 conversion in the range of 30–50% at 300 °C, while those based on 45 ppi OCF resulted in a significantly enhancement of the catalytic activity: 90–92% CO2 conversion under the same experimental conditions. Calculations of the internal and external mass transfer limitations were performed. The observed difference in the catalytic activity was primarily related to the radial transport inside the pores, confirmed with the explicitly higher conversions. [ABSTRACT FROM AUTHOR]

Solar‐driven photothermal conversion of carbon dioxide (CO2) to methane (CH4) is a promising approach to remedy energy shortage and climate changes, where highly efficient photothermal catalysts for CO2 methanation urgently need to be designed. Herein, nickel‐based catalysts (Ni/ZrO2) derived from metal–organic frameworks (MOFs) are fabricated and studied for photothermal CO2 methanation. The optimized catalyst 50Ni/ZrO2 achieves a stable CH4 production rate of 583.3 mmol g−1 h−1 in a continuous stability test, which is almost tenfold higher than that of 50Ni/C‐ZrO2 synthesized via commercial ZrO2. Physicochemical properties indicate that 50Ni/ZrO2 generates more tetragonal ZrO2 and possesses more oxygen vacancies (OVs) as well as enhanced nickel‐ZrO2 interaction. As a result, 50Ni/ZrO2 exhibits the strong abilities of light absorption and light‐to‐heat conversion, superior adsorption capacities of reactants (H2, CO2), and an intermediate product (CO), which finally boosts CH4 formation. This work provides an efficient strategy to design a photothermocatalyst of CO2 methanation through utilizing MOFs‐derived support. [ABSTRACT FROM AUTHOR]

This study investigates the effect of cerium–zirconium supported nickel catalyst (Ni/CeZr(x)) on the dry reforming reaction of methane (CH4) and carbon dioxide (CO2) to produce hydrogen (H2) and carbon monoxide (CO) for use in petrochemical processes. CeZr supports were synthesized via template-assisted co-precipitation using CTAC as a template with varying pH values (5, 7, 8.5, and 10) and underwent hydrothermal processing. Nickel (10% by weight) was then loaded onto the support through incipient wetness impregnation. The dry reforming reaction was performed at 700 °C. Results revealed that as the pH increased from acidic to basic conditions, the precipitation and integration of ZrO2 and CeO2 improved, leading to the formation of CeZr(x) composite supports. The Ce/Zr ratio in Ni/CeZr(x) catalysts influenced the generation of oxygen vacancies (OV) on the catalyst surface, affecting CO2 and CH4 conversions and the H2/CO ratio. The Ni/CeZr(8.5) catalyst exhibited the highest activity and stability due to its high surface oxygen vacancy and the number of basic sites on the CeZr(8.5) surface. Moreover, this catalyst reduced coke formation by promoting CO2 adsorption and dissociation, which facilitated the formation of surface-bound oxygen species that reacted with the surface carbon species. [ABSTRACT FROM AUTHOR]

A major cause of premature catalyst deactivation in the catalytic hydrogenation of fatty acids is the presence of impurities in the feedstock. With more oleochemical plants shifting to opportunistic crude palm oil (CPO) as their feedstock, the feedstock quality becomes an important factor in their procurement process. For CPO, the impurities level can be coarsely estimated by the deterioration of bleaching index (DOBI). A high DOBI value (e.g. DOBI > 2.99) indicates good quality CPO and ease in processing, while low DOBI value implies low level of carotene and/or high level of oxidised sludge oil, both of which could be detrimental to the processing of CPO. In our work, unsplit CPO feedstocks with varying DOBI value were directly hydrogenated in a laboratory‐scale pressure reactor with the presence of commercial nickel catalysts. Experimental results showed that catalyst deactivation was linked to DOBI value, where decreasing DOBI led to faster catalyst deactivation. For example, iodine value (IV) < 1.0 can be achieved for CPO with high DOBI value (2.97) after 150 min, and IV of 5–7 and IV > 20 were achieved for medium DOBI value (2.57–2.68) and low DOBI value (2.24), respectively. For CPO with low DOBI value (2.24), doubling the catalyst dosage ensured that the hydrogenated product met the low IV specification. This work showed that identifying the CPO with DOBI value presents an indicator to the manufacturer to find the right CPO tailored to the existing processes to maximise profitability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two fluorinated and one non–fluorinated complex of the type [(NHC)Ni(Cp)(Br)] were synthesized and characterized. • The non–fluorinated complex showed higher catalytic activity than the fluorinated ones in the C–S cross–coupling reaction. • The catalytic reaction mechanism was studied by theoretical calculations. • Strong nucleophilic substrates quenched the C–S cross–coupling by forming a stable intermediate complex. The catalytic activities of three Ni(II) complexes with fluorinated and non–fluorinated N–heterocyclic carbene (NHC) ligands were evaluated in the C–S cross–coupling reaction between iodobenzene and thiophenol. The complexes with fluorinated–NHC ligands exhibited lower catalytic activities compared to the non–fluorinated derivative. This can be attributed to the lower electron–donating character of the fluorinated ligands in comparison to the non–fluorinated ligand. Complex 3–Ni was tested towards different substrates, achieving moderate to good conversions. Additionally, the reaction mechanism of the C–S cross–coupling using two substrates, tert–butylthiol and 2,4–dichlorobenzenethiol, was determined. Tert–butylthiol produced a stable intermediate that inhibited the last step of the reaction mechanism (reductive elimination). On the other hand, 2,4–dichlorobenzenethiol formed a less stable intermediate, favoring the reductive elimination. This observation aligns with the lower yield observed when using tert–butylthiol compared to 2,4–dichlorobenzenethiol (20% vs 99%). [ABSTRACT FROM AUTHOR]

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Application of bioisostere plays an important role in drug discovery. α‐Aminoboronic acid is the familiar bioisostere of α‐amino acid. Developing reactions for the synthesis of a wide variety of α‐aminoboronic acid is one important task for synthetic chemistry. Herein, we report the development of nucleophilic C‐borylation chemistry for N‐arylimines catalyzed by nickel. The reaction proceeds through the insertion of a borylnickel species into the C=N bond to afford the corresponding α‐aminoboronate, which was isolated as acetamide after trapping with acetic anhydride. N‐Benzyl imine is also tolerated by the developed reaction. [ABSTRACT FROM AUTHOR]

Cellulose is one of the main components of plant matter, which makes it a viable target for biomass conversion to fuels. The direct conversion of cellulose to methane utilizing nickel‐based catalysts often has challenges associated with it. Carbon agglomeration creating nickel‐carbon nanoparticles deactivating catalytic hydrogenation of cellulose has been well reported. Utilizing rare‐earth metals as promoters increases the conversion of cellulose to methane, albeit with deactivation of the catalyst in the form of nickel‐rare‐earth‐carbon nanoparticles. Adding an additional zinc metal promoter eliminates the carbon agglomeration and allows for increased methane yields. Herein, we report an 81 % methane yield from cellulose in 48 hours utilizing a Ni/Zn/Y/Al2O3 catalyst at 225 °C and under 50 bar H2 pressure. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of nitroarenes using hydrogen gas as reducing agent to form substituted aniline derivates is an important reaction in industry and academic research. Here, we report on the nitroarene hydrogenation capability of a nanostructured nickel catalyst synthesized from a nickel salen complex and a commercially available porous silica support. Our catalyst allows the selective hydrogenation of nitroarenes under mild conditions while tolerating various functional groups and hydrogenation‐sensitive examples such as iodine, nitrile or olefinic groups. The use of the nickel salen complex as metal precursor is crucial for the high activity and selectivity observed. [ABSTRACT FROM AUTHOR]

This study focuses on the development and optimization of nanostructured anode electrodes for solid oxide fuel cells (SOFCs) by infiltration method. Ni (nickel) catalyst in the form of a nickel nitrate solution is infiltrated into porous YSZ (yttria stabilized zirconia) backbone fabricated by tape casting. Numerous electrolyte-supported cells are fabricated to investigate the effects of several significant infiltration fabrication parameters such as catalyst loading and infiltration sintering temperature. Conventional cell with screen printed Ni-YSZ anode is also fabricated for comparison. Electrochemical performances and microstructural properties of the cells are examined and evaluated. The best peak performance of 0.398 W/cm2 at 800 °C is obtained from the cell, which is infiltrated 9 times with 2 M solution followed by firing at 800 °C. The conventional cell, on the hand, exhibits only 0.174 W/cm2 under the same testing conditions in spite of the relatively higher Ni catalyst content in the anode. Furthermore, the optimized cell produces 0.169 W/cm2 maximum power density at 700 °C. The overall results reveal that nickel catalyst infiltration is a very effective method to improve the cell performance by providing increased number of electrochemical reaction zones within the anode electrode due to nanostructured nickel catalyst formed around the main YSZ phase. [ABSTRACT FROM AUTHOR]

An efficient temperature control C−S and C−N bond formation under mild nickel‐catalysed domino cross‐coupling conditions is described. The advantages of this approach are good functional group compatibility, cheaper nickel catalyst, and use of mild base. In addition, to the best of our knowledge this methodology is the first successful example of nickel‐catalysed synthesis of 2‐Arylsulfonyl Aryl cyanamides and 2‐Aminophenyl Benzothiazole. [ABSTRACT FROM AUTHOR]

Copper and iron-based bimetallic nickel catalysts supported on Mesostructured Silica Nanoparticles (MSNs) with compositions of 50% Ni–5% Cu/MSN and 50% Ni–5% Fe/MSN were prepared using an impregnation method, and they were compared with a monometallic 50% Ni–MSN catalyst for their activity and stability in methane decomposition reaction. The influence of promoters, such as Cu and Fe, at different reaction temperatures (700 °C, 800 °C and 900 °C) was investigated. The results revealed that the Cu and Fe-promoted catalysts significantly increased the hydrogen yield in methane decomposition compared with the unpromoted catalyst. This could be attributed to the formation of Ni–Cu and Ni–Fe bimetallic alloys in the catalysts, respectively, and this favored the stability of the catalysts. With increasing reaction temperature, the hydrogen yield also increased. However, the hydrogen yield and the lifetime of the nickel catalyst were enhanced upon the addition of iron compared to copper at all the reaction temperatures. The analysis conducted over the spent catalysts validated the formation of multi-walled carbon nanotubes with a bamboo-like internal channel over the catalysts along with a high crystallinity and graphitization degree of the carbon produced. [ABSTRACT FROM AUTHOR]

Catalytic methane (CH4) dry reforming (MDR) reaction proceeds with the formation of carbon; hence the effects of the catalyst preparation method on the type of carbon are worth investigating. This study investigated the performance of 20 wt% nickel praseodymium (III) oxide (20 wt% Ni/Pr2O3) catalysts prepared by incipient wetness impregnation (IWI), ultrasonic wet impregnation (US-WI), and Pechini sol–gel (PSG) methods. The catalysts crystallite size was approximately 21.3 nm, 21.3 nm, and 10.6 nm, for IWI, US-WI, and PSG catalysts, respectively. Study of the temperature effecton the MDR system showed that higher temperatures favored the MDR reaction with the side reaction playing vital roles. The catalyst synthesized by the PSG method showd higher carbon gasification rate with the stability up to 24 h, whereas catalysts from other synthesis methods were only active for less than 2 h, which could be due to the formation of higher amount of filamentous carbon, balance in oxygen species, and the smaller crystallite size of the PSG-20 wt% Ni/Pr2O3. The PSG-20 wt% Ni/Pr2O3 catalyst accumulated more filamentous carbon than graphitic carbon. In contrast, the IWI and US-WI catalysts accumulated mainly graphitic carbon which encapsulated the Ni0 sites, resulting in excess carbon deposition and reactor clogging within 2 h on stream. [ABSTRACT FROM AUTHOR]

This study aims to utilize biochars derived from residual biomass as supports for Ni-based catalysts. For the preparation of the biochars, byproducts of agro-industrial activities were used, such as espresso coffee residue (C) and rice husks (R). Sufficient quantities of the respective biochars (BioC and BioR) were prepared via pyrolysis at 850 °C of the aforementioned materials under limited oxygen conditions. The biochars were further treated with hot water (WBioC, WBioR), H3PO4 or H2SO4 solution (BioC-P, BioC-S, BioR-P, BioR-S), and NaOH solution (BioC-A and BioR-A), and the obtained solids were characterized using various physicochemical techniques. The biochars produced were microporous with high surface areas (367–938 m2g−1). The most promising biochars were selected as supports for the preparation of nickel catalysts (10 wt.% Ni) with high Ni dispersion (mean crystal size: 8.2–9.8 nm) and suitable acidity. The catalysts were evaluated in a high-pressure semi-batch reactor for the transformation of waste cooking oil (WCO) into green diesel. The 10Ni_BioC-P catalyst exhibited the best performance, resulting in a complete conversion of the WCO but a low hydrocarbon yield (7.5%). Yield improvement was achieved by promoting this catalyst with molybdenum. The addition of Mo increased the hydrocarbon yield by almost three times (19.5%). [ABSTRACT FROM AUTHOR]

Barium doping effect on the activity and stability of nickel‐based catalysts, supported on yttria‐stabilized zirconia (Ni‐YZr), was investigated in dry reforming of methane. Catalysts were characterized by several techniques (nitrogen sorption, X‐ray diffraction [XRD], scanning electron microscopy with energy dispersive X‐ray, transmission electron microscopy [TEM], thermogravimetric analysis [TGA], temperature programmed oxidation, CO2‐TPD, H2‐TPR) and were tested in a fixed‐bed reactor at 800°C and 42,000 mL/h gcat. Barium played a crucial role in enhancing catalyst reducibility and CO2 adsorption at high temperatures, as indicated by the activity and stability of the Ni‐YZr catalyst. The addition of 4.0 wt% of barium appeared to be the optimal loading, allowing for CH4 conversion of 82%, which remained constant for 7 h of reaction, compared with 72% of barium‐unpromoted Ni‐YZr at 800°C. TEM images of the spent catalysts revealed the formation of multiwalled carbon nanotubes on all samples. The TGA analysis showed, however, that an increase in baria loading significantly reduced the coke formation amount, indicating the inhibition of coke formation and the enhancement of the catalytic activity. Such improvement in activity and stability was attributed to the incorporation of barium into YZr support, as revealed by XRD analysis, which inhibited the sintering of the catalysts support. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel N^N-bidentate chelate nickel catalyst skeleton with imidazolidin-2-imine/guanidine motif. • High activity and good thermal stability in norbornene (co)polymerization. • Good capacity of norbornene with long-chain-branched 1-alkenes. • Adjustable 1-alkene contents and T g values of cyclic olefin copolymer. • Polar functionalized cyclic olefin copolymer with reasonable incorporations The development of late transition metal catalysts bearing novel ligand platforms is a convenient pathway to obtain prospective systems with enhanced catalytic performance, however, it remains a challenge in the field of olefin (co)polymerizations. In this contribution, a new family of [N,N]-type of bidentate aldimine imidazolidin-2-imine/guanidine ligands and their nickel complexes Ni1 – Ni7 bearing a distinct six-membered chelate ring were successfully synthesized, and characterized. All of the nickel catalysts were active for norbornene polymerization with high activity of up to 7.44 × 105 g mol–1 h−1. These catalysts also copolymerized norbornene and 1-alkenes (1-dodecene and 1-octadecene) while keeping high activities to produce various norbornene-based high-molecular-weight (M n = 5.75–36.0 kg mol−1) cyclic olefin copolymers (COCs) with adjustable 1-alkene incorporations (1.44–13.30 mol%) and a wide range of T g values (102.2–271.4 °C). Moreover, with the decoration of bulky N-aryl substituents, these nickel catalysts exhibited strong tolerance towards polar monomer to promote the direct copolymerization of norbornene and methyl 10-undecenoate with high activity (up to 9.88 × 104 g mol–1 h−1), and furnished polar functionalized COCs with a high molecular weight (M n up to 72.4 kg mol−1) and reasonable polar monomer incorporations (0.19–0.45 mol%). These nickel complexes are rare examples and also promising candidates as catalysts for the efficient synthesis of various COCs. [ABSTRACT FROM AUTHOR]

Nickel-based catalysts used for dry reforming of methane (DRM) suffer from coking and sintering, which hinders the broad application of the process in the industry. Thermogravimetric analysis was employed to investigate coking on a commercial nickel catalyst with an anti-coking additive (CaO). It was found that the catalyst sintered at temperatures between 850 and 900 °C, which resulted in permanent catalyst deactivation. For the tested Ni/CaO–Al 2 O 3 catalyst, the coking and carbon gasification rates are equal at the temperatures of 796–860 °C, depending on the heating rate (5–20 K/min). Significant differences in the temperatures related to the maxima on TG curves for various heating rates follow from DRM kinetics. This work reveals that the coking rate is lower at higher temperatures. After 50 min, the weight gains amount to about 20% and 40% at 800 °C and 600 °C, respectively. Lower sample weight gains were observed at higher temperatures for a methane decomposition reaction over the Ni/CaO catalyst, unlike for the second tested catalyst – activated carbon. For the nickel catalyst, the reaction order for methane decomposition is 0.6 in the temperature range 640–800 °C, while the sign of the activation energy changes at 700 °C. The elaborated kinetic equation predicts the initial CH 4 decomposition rate with 15% accuracy. [Display omitted] • Thermogravimetric analysis of dry reforming of CH 4 on a commercial Ni/CaO catalyst. • The higher the temperature, the lower the coking rate on the Ni/CaO catalyst. • Reaction order for CH 4 decomposition on the Ni/CaO catalyst is 0.6. • The sign of the activation energy for CH 4 decomposition reaction changes at 700 °C. • Elaborated kinetic equation predicts CH 4 decomposition rate with 15% accuracy. [ABSTRACT FROM AUTHOR]

The dry reforming of methane (DRM) was studied for seven hours at 800 °C and 42 L/(g·h) gas hourly space velocity over Ni-based catalysts, promoted with various amounts of gadolinium oxide (x = 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 wt.%) and supported on mesoporous yttrium-zirconium oxide (YZr). The best catalyst was found to have 4.0 wt.% of gadolinium, which resulted in ∼80% and ∼86% conversions of CH4 and CO2, respectively, and a mole ratio of ∼0.90 H2/CO. The addition of Gd2O3 shifted the diffraction peaks of the support to higher angles, indicating the incorporation of the promoter into the unit cell of the YZr support. The Gd2O3 promoter improved the catalyst basicity and the interaction of NiO with support, which were reflected in the coke resistance (6.0 wt.% carbon deposit on 5Ni+4Gd/YZr; 19.0 wt.% carbon deposit on 5Ni/YZr) and the stability of our catalysts. The Gd2O3 is believed to react with carbon dioxide to form oxycarbonate species and helps to gasify the surface of the catalysts. In addition, the Gd2O3 enhanced the activation of CH4 and its conversion on the metallic nickel sites. [ABSTRACT FROM AUTHOR]

This work investigated the influence of the catalytic support precursor on the activity of nickel catalysts 20%Ni/5%La2O3–95%Al2O3 in the mixed methane reforming process. The activity tests were carried out at a temperature of 750 °C. The research showed that the catalyst prepared from the precursor containing chloride exhibited very low conversions of methane and carbon dioxide. The poisoned catalyst system before and after the calcination process was subjected to Temperature Programmed Surface Reaction tests to determine whether the thermal treatment causes a decrease in the amount of chlorine in the system. To determine the decomposition temperature of the LaCl3 precursor and the nickel chloride NiCl2 compound, the samples were analyzed by Thermogravimetry. Finally, the catalytic samples were tested by Time-of-Flight Secondary Ion Mass Spectrometry analysis to confirm the presence of nickel–chlorine bonds on the surface of the catalytic system. [ABSTRACT FROM AUTHOR]

A nickel‐catalyzed transfer hydrogenation of aryl alkenes has been developed using hydrosilane as the hydrogen source. Sterically hindered disubstituted or trisubstituted alkenes were employed to test the efficiency of this transformation. Mechanism studies showed that hydrogenation took place smoothly with more sterically‐hindered trans‐alkenes. While uncongested cis‐alkenes could hardly convert to the alkanes but hydrosilylation products were generated instead. Moreover, certain amount of water was found to be a promotion for the protonation process and could partly serve as the hydrogen source. Not only for simple stilbenes, this easy handle protocol also showed tolerance for substrates involving other unsaturated groups as well as heterocycles. [ABSTRACT FROM AUTHOR]

Chlorine- and nitrogen-containing carbon nanofibers (CNFs) were obtained by combined catalytic pyrolysis of trichloroethylene (C2HCl3) and acetonitrile (CH3CN). Their efficiency in the adsorption of 1,2-dichlorobenzene (1,2-DCB) from water has been studied. The synthesis of CNFs was carried out over self-dispersing nickel catalyst at 600 °C. The produced CNFs possess a well-defined segmented structure, high specific surface area (~300 m2/g) and high porosity (0.5–0.7 cm3/g). The addition of CH3CN into the reaction mixture allows the introduction of nitrogen into the CNF structure and increases the volume of mesopores. As a result, the capacity of CNF towards adsorption of 1,2-DCB from its aqueous solution increased from 0.41 to 0.57 cm3/g. Regardless of the presence of N, the CNF samples exhibited a degree of 1,2-DCB adsorption from water–organic emulsion exceeding 90%. The adsorption process was shown to be well described by the Dubinin–Astakhov equation. The regeneration of the used CNF adsorbent through liquid-phase hydrodechlorination was also investigated. For this purpose, Pd nanoparticles (1.5 wt%) were deposited on the CNF surface to form the adsorbent with catalytic function. The presence of palladium was found to have a slight effect on the adsorption capacity of CNF. Further regeneration of the adsorbent-catalyst via hydrodechlorination of adsorbed 1,2-DCB was completed within 1 h with 100% conversion. The repeated use of regenerated adsorbent-catalysts for purification of solutions after the first cycle of adsorption ensures almost complete removal of 1,2-DCB. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient and straightforward protocol for the synthesis of thioesters-functionalized 2 H -pyrones. • A nickel-catalyzed thiocarbonylation reaction with sulfonyl chlorides as the sulfur sources. • A diverse set of thioesters-containing 2 H -pyrones have been obtained in moderate to good yields. • Mo(CO) 6 has been used as convenient CO source and reductant. An efficient and straightforward protocol for the synthesis of thioesters-functionalized 2 H -pyrones has been explored through a nickel-catalyzed thiocarbonylation reaction with sulfonyl chlorides as the sulfur sources. By using Mo(CO) 6 as both CO source and reductant, a diverse set of thioesters-containing 2 H -pyrones have been obtained in moderate to good yields. This reaction provides a good supplement for the carbonylative synthesis of thioesters-functionalized 2 H -pyrones via a Ni/Mo(CO) 6 catalytic system. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiAl catalyst to H 2 was prepared with NiAl LDHs precursor. • The effects of preparation methods and Ni/Al molar ratios on the H 2 yield were investigated. • Transition state evolution of Ni nanoparticles during methane decomposition was studied. • The Ni 3 Al catalyst was stabilized for 75 min at near 90 % H 2 yield at 700 °C. Designing nickel-based methane cracking catalysts with excellent catalytic activity and surveying their transition during the catalytic process with varied reaction condition have been challenge. In this paper, NiAl catalysts were prepared by reduced hydrotalcite precursor for efficient catalytic methane cracking to produce hydrogen. The catalysts were characterized by XRD, N 2 physisorption, XPS, SEM, TEM, Raman and TGA. The effects of preparation method, Ni/Al ratio and reaction temperature on methane cracking performance were revealed and the transformation for the Ni particles during the reaction process was analyzed. The results indicated that the catalyst performance of hydrotalcite-derived NiAl catalysts is superior to Ni/Al 2 O 3 catalysts prepared by the conventional impregnation method, which maybe due to the better Ni dispersion and uniform average particle size distribution with around 12.7 nm compared with the agglomeration of the Ni/Al 2 O 3 particles for up to 53.2 nm. The catalyst with a Ni/Al molar ratio of 3 exhibited the optimal catalytic activity with a stability for 75 min at nearly 90 % hydrogen yield at 700 °C. The reaction temperature also suggested a positive correlation between the hydrogen yield and the reaction temperature from 600 °C to 800 °C. Moreover, based on the investigation of the catalysts during the reaction transition state, Ni particles sintered rapidly from 10.2 nm to 31.2 nm at the beginning reaction time with the high hydrogen yield and then tended to be stable, which may be correlated well with the degree of graphitization of the deposited carbon. This paper provides a valuable design for efficient methane cracking catalysts. [ABSTRACT FROM AUTHOR]

Transition metal‐catalyzed copolymerization of CO and ethylene has a strong inherent propensity to produce the strictly alternating copolymer. In this work, nickel catalysts capable of both homopolymerization of ethylene and alternating copolymerization of CO and ethylene are developed to explore the possibility of non‐alternating copolymerization of CO and ethylene under the assumption that comonomer incorporation in the polymer chain can be adjusted by the concentrations of the comonomers. Both polyketones with slightly more than 50 % ethylene and "polyethylenes" with a small amount of CO incorporation are obtained but only under carefully controlled conditions and in low yields. [ABSTRACT FROM AUTHOR]

The main objective of these studies was development of competitive catalyst for the upgrading of biomass pyrolysis vapors to H 2 -rich gas. The performed experiments were devoted to determination of the effect of incorporation of zirconium into the structure of BEA zeolite on the performance of NiBEA in the mentioned process. Moreover, the most important parameters responsible for the increased activity of NiZrBEA catalyst in comparison to nickel supported on parent zeolite have been identified. The activity of synthesized catalysts was tested in two step fixed bed quartz reactor. Firstly, cellulose or pine were heated to the 500 °C in order to decompose lignocellulosic feedstock. Then, formed pyrolysis vapors were directed through catalyst bed (700 °C) where their upgrading took place. The obtained results revealed that an introduction of zirconium in the structure of BEA zeolite allowed for the increase in the efficiency of Ni catalyst in the formation of H 2 -rich gas. It was related to the increase in pore volume of the synthesized materials, formation of smaller nickel oxide crystallites and creation of the catalysts with moderate acidity. • Efficient BEA-based catalysts for upgrading of biomass pyrolysis vapors. • Modification of NiBEA by Zr enhances production of hydrogen-rich gas. • Introduction of Zr impacts porosity, acidity and Ni dispersion. [ABSTRACT FROM AUTHOR]

The CO2 reforming of methane to syngas was examined over five different supported catalysts. In this study, 5% Ni was used as the active metal part of the catalyst. To better comprehend the impact of the supports on the catalytic properties, 5% Ni-based catalysts were characterized using nitrogen adsorption–desorption isotherms, XRD, H2-TPR, CO2-TPD, TGA, TPO, FTIR, and Raman. The results showed that the catalyst support with the highest surface area provided the best catalytic activity. The acquired CH4 and CO2 conversions at 700 °C were 58.2% and 67.6%, respectively, with a hydrogen/carbon ratio of 0.85. The TGA investigation of the high-surface-area sample produced a minimum carbon deposition of 11.2 wt.%, and in the CO2-TPD investigation, the high-surface-area sample exhibited the absence of a peak in the strong-basic-sites zone. The formation of NiAl2O4 spinel, moderate basicity, and the high surface area explained the outperformance of the high-surface-area catalyst sample. [ABSTRACT FROM AUTHOR]

Living polymerization by suppressing chain transfer is a very useful method for achieving precise molecular weight and structure control. However, the suppression of chain transfer at high temperatures is extremely challenging in any catalytic polymerization. This has been a severe limitation for catalytic olefin polymerization, which is one of the most important chemical reactions. Here, we report the unprecedented living polymerization of ethylene at 130 °C, with a narrow molecular weight distribution range of 1.04 to 1.08. This is a significant increase in the reaction temperature. Tailor‐made α‐diimine nickel catalysts that exhibit both the steric shielding and fluorine effects play an essential role in this breakthrough. These nickel catalysts are even active at 200 °C, and enable the formation of semi‐crystalline, ultrahigh‐molecular‐weight polyethylene at 150 °C. Mechanistic insights into the key chain transfer reaction are elucidated by density functional theory calculations. [ABSTRACT FROM AUTHOR]

Deprotonative metalation of 2‐halo‐3‐substituted thiophene in a metal amide‐free manner takes place at the 5‐position smoothly in the presence of additive N,N,N′,N′‐tetramethylethylenediamine (TMEDA) at room temperature in a hexane solution. Following addition of nickel catalyst to the thus formed thiophene‐sodium species promotes cross‐coupling polymerization. When toluene was employed as a solvent in the polymerization reaction of 2‐chloro‐3‐hexylthiophene in the presence of 2 mol% of nickel catalyst bearing N‐heterocyclic carbene ligand, polythiophene was obtained in up to 86% yield with Mn of 23700 (Mw/Mn=1.98) suggesting that ca. 30% of the catalyst participated in the polymerization. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) is considered a promising reforming technology that converts natural gas in the Natuna Sea into synthesis gas, which can be further utilized to produce beneficial chemicals such as olefins, alcohols, and liquid hydrocarbons. However, the challenges in commercializing the DRM process are carbon deposition and sintering of the catalyst at high temperatures, because of which the catalyst is easily deactivated. This study aimed to test the activity and stability of MCM-41-based catalysts for the DRM; determine the effect of promoter type on the activity and stability of MCM-41-based catalysts; and determine the effect of base promoter addition on the amount of carbon deposition. MCM-41-based catalysts were synthesized using incipient wetness impregnation method. XRD, N 2 Physisorption, H 2 -TPR, CO 2 -TPD, and TGA analysis were conducted to determine the physicochemical properties of the catalysts. The catalysts activity was tested in a fixed-bed reactor, under atmospheric pressure at 700 °C. Overall, all catalysts exhibited good stability for 240 min. Moreover, catalysts with Mg and Ca promoters showed the highest CH 4 and CO 2 conversion among all catalysts. Ni–Mg/MCM-41 catalyst yielded 72% CH 4 conversion and 54% CO 2 conversion, meanwhile Ni–Ca/MCM-41 yielded 69% CH 4 conversion and 55% CO 2 conversion. Furthermore, MCM-41-based catalysts with base promoter produced small amount of carbon deposition. [Display omitted] • The effect of several base promoters (Mg, Ca, Na, and K) to Ni/MCM-41 catalyst was examined. • The 5% Ni–Mg/MCM-41 catalyst has better basicity property and yields highest conversion for both CH 4 and CO 2 conversion. • The 5% Ni–Na/MCM-41 and 5% Ni–K/MCM-41 is less active due to the severe sintering. • The 5% Ni–Mg/MCM-41 catalyst shows better activity and stability tests for dry reforming of methane. [ABSTRACT FROM AUTHOR]

The decomposition of toluene as a tar imitator in a gas composition similar to the gas after biomass pyrolysis was studied in a plasma–catalytic system. Nickel catalysts and the plasma from gliding arc discharge under atmospheric pressure were used. The effect of the catalyst bed, discharge power, initial toluene, and hydrogen concentration on C7H8 decomposition, calorific value, and unit energy consumption were studied. The gas flow rate was 1000 NL/h, while the inlet gas composition (molar ratio) was CO (0.13), CO2 (0.15), H2 (0.28–0.38), and N2 (0.34–0.44). The study was conducted using an initial toluene concentration in the range of 2000–4500 ppm and a discharge power of 1500–2000 W. In plasma–catalytic systems, the following catalysts were compared: NiO/Al2O3, NiO/(CaO-Al2O3), and Ni/(CaO-Al2O3). The decomposition of toluene increased with its initial concentration. An increase in hydrogen concentration resulted in higher activity of the Ni/(CaO-Al2O3) catalysts. The gas composition did not change by more than 10% during the process. Trace amounts of C2 hydrocarbons were observed. The conversion of C7H8 was up to 85% when NiO/(CaO-Al2O3) was used. The products of the toluene decomposition reactions were not adsorbed onto its surface. The calorific value was not changed during the process and was higher than required for turbines and engines in every system studied. [ABSTRACT FROM AUTHOR]

Because of its unique properties, polyethylene wax has been widely applied in many fields. In this contribution, several iminopyridyl nickel catalysts are designed and synthesized. The introduction of sterically bulky substituents can significantly enhance the catalytic performances during ethylene polymerization. The generated polyethylene wax is highly branched due to the chain walking characteristic for this system. To further enhance the catalytic behavior of these nickel catalysts, the corresponding supported system is prepared and investigated. The heterogeneous system presents higher activity and higher thermal stability than its homogenous counterpart. Specifically, the nickel catalyst bearing OH moiety is highly robust even at 120 °C with catalytic activity of up to 9.4 × 106 g mol−1 h−1. The molecular weight and microstructure of the generated polyethylene wax can also be affected by ligand substituents and the heterogenization process. This work demonstrates the great potentials of nickel catalysts for the synthesis of polyethylene wax. [Display omitted] • A series of iminopyridyl nickel complexes were designed and well-characterized. • The homogeneous and heterogenous systems were investigated for the synthesis of polyethylene wax. • The nickel catalyst is highly robust even at 120 °C with catalytic activity of up to 9.4 × 106 g mol−1 h−1. [ABSTRACT FROM AUTHOR]

Two series of Ce-promoted nickel catalysts were prepared by co-impregnation method using unmodified and dealuminated Beta zeolites as supports, denoted Ni10Ce#-HAlBEA and Ni10Ce#-SiBEA, respectively. Transmission electron microscopy studies of the first group of catalysts evidenced the presence of nickel nanoparticles of various size (2–20 nm) and complex morphology, decorated with CeO 2 nanoparticles, stemmed from the mutual diffusion of the corresponding species. An increase in Ce loading from 3 to 5 wt% facilitated direct interaction of metallic nickel crystallites with CeO 2 nanoparticles, leading to a decrease in Ni crystallite size. In-situ DRIFTS studies indicated an improvement of the activation of CO 2 and H 2 , formation of weakly adsorbed carbonyl groups, bicarbonate and carbonate intermediate species in the initial stages of the reaction, which increased the activity of catalysts in CO 2 methanation reaction and their resistance towards sintering and poisoning with H 2 S. Raman and FTIR-PAS spectroscopy pointed out that strongly adsorbed sites produced upon dealumination and slight structural changes Beta zeolite influenced the way of formation of nickel crystallites and their morphology, dispersion of cerium oxide nanoparticles, acid-base and redox properties of catalysts. Thus, the second group of catalysts showed higher catalytic activity at low temperatures and higher sintering and poisoning resistance, which was attributed to the presence of small, regular nickel particles of the size ca. 2 nm, located in the close proximity to the dispersed cerium oxide phases. The CO 2 methanation reaction proceeded mainly via formation of more strongly adsorbed intermediate surface carbonyl groups and carbonate species. [Display omitted] • Synthesis of Ce-promoted Ni catalysts with dealuminated BEA zeolite as support. • Dealumination of BEA zeolite alters the morphology of Ni particles. • Introduction of Ce-promoter improves the activity of BEA-supported Ni catalysts. • Introduction of Ce-promoter rises sintering and poisoning resistance of catalysts. [ABSTRACT FROM AUTHOR]

An efficient method for direct thiolation of anilides with thiols using NiCl2 ·6H2 O as the catalyst is developed. Using this method, the desired products were successfully synthesized in moderate to good yields. Initial mechanistic studies suggest that this reaction proceeds through a radical pathway. [ABSTRACT FROM AUTHOR]

The α-imino-ketone nickel catalyst is an emerging versatile platform that is easy to prepare and allows for the production of branched high molecular weight functionalized polyethylenes. However, study on this catalyst system is rare thus far. In this contribution, by introducing different backbones, flexible and rigid axial substituents into the α-imino-ketone framework, a family of cationic nickel catalysts were synthesized and fully characterized. Without the addition of any activator, systematic studies on ethylene polymerization and copolymerization with polar monomers were performed to explore the influence of both backbone and axial substituent on catalytic activity, polymer molecular weight, branching density and incorporation. In particular, owing to the unique semi-opening feature of the α-imino-ketone framework, the preferred nickel catalyst exhibited high activity of 175 kg·mol−1·h−1 to produce functionalized polyethylene with molecular weight of 13.4 kg·mol−1 and comonomer incorporation of 2.9 mol%. [ABSTRACT FROM AUTHOR]

Our group introduced a green protocol for the Pd(OAc)2- or NiCl2-catalyzed P–C coupling reaction of aryl halides and various > P(O)H-compounds under MW conditions without directly added P-ligands. The reactivity of a few aryl derivatives in the Pd(OAc)2-catalyzed Hirao reaction was also studied. An induction period was observed in the reaction of bromobenzene and diphenylphosphine oxide. Finally, the less known copper(I)-promoted P–C coupling reactions were investigated experimentally. The mechanism was explored by quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Ni nanoparticle catalysts embedded in ZrO2 porous spheres and ZrO2 porous composite spheres, SiO2-ZrO2, MgO-ZrO2, and Y2O3-ZrO2, with 83−115 nm diameter and 167–269 m2/g specific surface area were prepared by a one-pot and one-step solvothermal reaction from precursor solutions consisting of Ni(NO3)2‧6H2O, Zr(OnBu)4, and acetylacetone in moist ethanol combined with either Si(OEt)4, magnesium acetylacetate, or Y(OiPr)3. The obtained Ni catalysts have high specific surface areas of 130–196 m2/g, even after high-temperature reduction by H2 at 450 °C for 2 h. They were utilized as catalysts for low-temperature dry reforming of methane (DRM) at 550 °C to suppress carbon deposition on Ni nanoparticles. The Ni catalysts embedded in SiO2-ZrO2 and Y2O3-ZrO2 demonstrated high catalytic activity and long stability in the reaction. Moreover, carbon deposition on Ni nanoparticles in the DRM reaction was effectively suppressed in when using the SiO2-ZrO2 and Y2O3-ZrO2 composites. [ABSTRACT FROM AUTHOR]

Biomass gasification gas contains hydrocarbons that must be converted to CO and H2 prior to the utilization of the gas in a synthesis unit. Autothermal or steam reforming operating with a nickel or noble metal catalyst is a feasible option to treat the gas, but the harsh reaction conditions may lead to the formation of solid carbon. This study discusses the effects of pressure, time-on-stream, and ethylene content on the carbon formation on nickel and rhodium catalysts. The experiments were carried out with laboratory-scale equipment using reaction conditions that were closely simulated after a pilot-scale biomass gasifier. The results indicated that ethylene content above 20,000 vol-ppm and the increased pressure would increase the carbon formation, although there were differences between the rhodium and nickel catalysts. However, carbon formation was significantly more pronounced on the nickel catalyst when the reaction time was increased from 5 h to 144 h. The type of carbon was found to be primarily encapsulating and graphitic. The formation of whisker carbons (also known as carbon nanotubes) was not observed, which is consistent with the literature as the feed gas contained H2S. It was concluded that utilizing a noble metal catalyst as the front layer of the catalyst bed could lower the risk for carbon formation sufficiently to provide stable long-term operation. [ABSTRACT FROM AUTHOR]

This article considers the catalytic and physicochemical properties of composite materials obtained by the heat treatment of nickel nitrate immobilized on polyvinyl alcohol (PVA). The effects of the composite formation temperature on the phase composition of the metal-containing particles and their size were studied. The composite material obtained was found to be an active catalyst for the hydrogenation of carbon monoxide without a pre-activation step. The following synthesis parameters were achieved: 29% carbon monoxide conversion under conditions for catalytic hydrogenation and 28 g/m3 methane yield. Hypotheses were offered concerning the effect of particle size on the activity of the synthesized composite and an effect of the volume velocity on the carbon monoxide hydrogenation process parameters was demonstrated. [ABSTRACT FROM AUTHOR]

A new synthetic method, which achieves regiospecific functionalization of 8-methylquinoline derivatives at C-2 and subsequent selective hydrogenation of the pyridine ring in a one-pot tandem process, has been reported. With this method, a total of thirteen new 8-methyltetrahydroquinoline derivatives with an amide side chain at C-2 were synthesized in moderate yields. The scope of substrates was investigated, and the reaction mechanism was studied and proposed. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth‐abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N‐doped carbon layer on the active carbon support. [ABSTRACT FROM AUTHOR]

Nickel-catalyzed reductive homocoupling of aryl ethers has been achieved with Mg(anthracene)(thf)3 as a readily available low-cost reductant. DFT calculations provided a rationale for the specific efficiency of the diorganomagnesium-type two-electron reducing agent. The calculations show that the dianionic anthracene-9,10-diyl ligand reduces the two aryl ether substrates, resulting in the homocoupling reaction through supply of electrons to the Ni-Mg bimetallic system to form organomagnesium nickel(0)-ate complexes, which cause two sequential C–O bond cleavage reactions. The calculations also showed cooperative actions of Lewis acidic magnesium atoms and electron-rich nickel atoms in the C–O cleavage reactions. [ABSTRACT FROM AUTHOR]