“(Diphosphine)Nickel”‐Catalyzed Negishi Cross‐Coupling: An Experimental and Theoretical Study

The use of a strongly donating “(bis‐dialkylphosphine)Ni” fragment promotes the catalytic coupling of a large range of ArCl and ArZnCl derivatives under mild conditions. Stoichiometric mechanistic investigations and DFT calculations prove that a Ni⁰/Ni^II cycle is operative in this system.     

Novel flame retardant paint based on Co(II) and Ni(II) metal complexes as new additives for surface coating applications

The study is focused on the synthesis of a new Co(II) and Ni(II) metal complexes, which is synthesized by the reaction of the isatin 4‐aminoantipyrine Schiff base ligand with selected divalent Co(II) and Ni(II) ions and their possible applications as flame retardant additives in paint formulations for surface coating application. The prepared metal complexes were characterized using a combination of Fourier transform infrared, elemental analysis, proton nuclear magnetic resonance, ¹³C‐NMR spectra, and mass spectroscopy. The prepared Schiff base ligand metal complexes were physically added to alkyd paint formulation to give coating formulations at a laboratory scale and then applied onto plywood and steel panels using a brush. The ignitability and oxygen index values obtained indicated that the paint which contained the prepared Co(II) and Ni(II) metal complexes as additives exhibited very good flame retardant. The physical and mechanical characteristics of the coatings were studied in order to estimate any disadvantages due to the incorporation of the additives. It was discovered that the added substances did not impact the hardness, flexibility, and adhesion of the prepared coating films. The gloss of the paint formulation film was improved due to the incorporation of the aromatic ring into the formulation and the level of the oil percent.     

Caesium carbonate supported on hydroxyapatite‐encapsulated Ni0.5Zn0.5Fe2O4 nanocrystallites as a novel magnetically basic catalyst for the one‐pot synthesis of pyrazolo[1,2‐b]phthalazine‐5,10‐diones

A novel nanomagnetic basic catalyst of caesium carbonate supported on hydroxyapatite‐coated Ni_0.5Zn_0.5Fe₂O₄ magnetic nanoparticles (Ni_0.5Zn_0.5Fe₂O₄@HAP‐Cs₂CO₃) was prepared. This new catalyst was fully characterized using Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, X‐ray diffraction and vibrating sample magnetometry techniques, and then the catalytic activity of this catalyst was investigated in the synthesis of 1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives. Also, Ni_0.5Zn_0.5Fe₂O₄@HAP‐Cs₂CO₃ could be reused at least five times without significant loss of activity and could be recovered easily by applying an external magnet. Thus, the developed nanomagnetic catalyst is potentially useful for the green and economic production of organic compounds. Copyright © 2015 John Wiley & Sons, Ltd.     

Highly selective hydrogenation of acetophenone over supported amorphous alloy catalyst

Alpha-phenylethanol (PE) is an essential chemical in the field of medicine and synthetic perfumery. Therefore, in this work, we used a supported Ni–B–P amorphous alloy catalyst (Ni–B–P/SiO₂) in the hydrogenation of acetophenone (AP) to α-PE, which demonstrated excellent catalytic activity and selectivity, compared with Ni–B/SiO₂ (KBH₄ reduction of nickel salt). Ni–B–P/SiO₂ exhibited a high AP hydrogenation conversion of approximately 99%, whereas the PE selectivity reached up to 94%, which is approximately 1.4-fold higher than that of Ni–B/SiO₂ (about 69%), thereby directly proving the unique inhibition of AP hydrogenation over hydrogenation of P in the Ni–B catalytic system. The doped P in Ni–B–P/SiO₂ enhances the oxidation resistance and maintains the valence stability of Ni and B. Furthermore, sufficient experimental data were collected to determine the kinetic parameters. Based on the Langmuir–Hinshelwood model, we assumed that (i) AP and H₂ compete for adsorption on Ni–B–P/SiO₂; (ii) AP has strong adsorptive capacity on Ni–B–P/SiO₂; and (iii) PE coverage on the catalyst was negligible. Then, the dynamic equation was derived, which indicated that experimental data agree well with the dynamic model. Finally, the activation energy was confirmed to be 50.73 KJ/mol. This report will open up an avenue for the industrialization of amorphous alloy catalysts.     

Improvement of capacitance activity for Cu‐doped Ni‐based metal–organic frameworks by adding potassium hexacyanoferrate into KOH electrolyte

Cu‐doped Ni‐based metal–organic frameworks (MOFs) nanomaterials fabricated through a one‐pot hydrothermal reaction were characterized, and their performance as supercapacitor electrode materials was further studied for the first time. The results indicated that the doping of foreign metals and the introduction of K₃[Fe(CN)₆] in the KOH electrolyte significantly improve the performance of the supercapacitor. The results indicated that the Ni_2.6Cu_0.4 MOFs material shows the highest specific capacitance (1282 F g^?1 at 1 A g^?1 in mixed 2 M KOH and 0.1 M K₃[Fe(CN)₆]) and optimal capacitance retention (85.7% after 2000 cycles). This work provides a feasible optimization strategy for the construction of MOFs‐based supercapacitor electrode materials with excellent performance, and also provides a reliable experimental and theoretical basis for practical industrial production.     

In situ green synthesis of Cu‐Ni bimetallic nanoparticles supported on reduced graphene oxide as an effective and recyclable catalyst for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles

In the present work, for the first time we have designed a novel approach for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles using reduced graphene oxide (rGO) decorated with Cu‐Ni bimetallic nanoparticles (NPs). In situ synthesis of Cu/Ni/rGO nanocomposite was performed by a cost efficient, surfactant‐free and environmentally benign method using Crataegus azarolus var. aronia L. leaf extract as a stabilizing and reducing agent. Phytochemicals present in the extract can be used to reduce Cu²⁺ and Ni²⁺ ions and GO to Cu NPs, Ni NPs and rGO, respectively. Analyses by means of FT‐IR, UV–Vis, EDS, TEM, FESEM, XRD and elemental mapping confirmed the Cu/Ni/rGO formation and also FT‐IR, NMR, and mass spectroscopy as well as elemental analysis were used to characterize the tetrazoles. The Cu/Ni/rGO nanocomposite showed the superior catalytic activity for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles within a short reaction time and high yields. Furthermore, this protocol eliminates the need to handle HN₃.     

XANES/EPR Evidence of the Oxidation of Nickel(II) Quinolinylpropioamide and Its Application in Csp3−H Functionalization

An in situ generated oxidation species of nickel quinolinylpropioamide intermediate was produced. Characterization by X-ray absorption near edge structure (XANES) and EPR provides complementary insights into this oxidized nickel species. With aliphatic amides and isocyanides as substrates, a nickel-catalyzed facile synthesis of structurally diverse five-membered lactams could be achieved.     

Measurement of the surface excitation parameter of Kapton,polyethylene (PE), polymethyl methacrylate (PMMA), polystyrene (PS) and polytetrafluoroethylene (PTFE)

Reflection electron energy loss spectra (REELS) were measured for five insulating organic compounds: Kapton, polyethylene (PE), poly(methyl methacrylate) (PMMA), polystyrene (PS) and polytetrafluoroethylene (PTFE), as well as for Ni and Si, in the energy range between 200 and 1600 eV. The average number of surface excitations for a single surface crossing were determined from the experimental data and were found to be considerably smaller than for earlier studied materials, which mainly consisted of elemental metals [Surf. Sci. 486(2001)L461]. The surface excitation parameter, a material parameter used to quantify the relative intensity of surface losses in (photo)electron spectroscopy, was extracted from the data and compared with values found in the literature. The results indicate that surface excitations only have a minor influence on quantification of XPS spectra of polymers. On the other hand, a correction for surface excitations turns out to be essential for measurements of the electron inelastic mean free path of polymers when a metal is used as reference material.     

Direct synthesis of hyperbranched ethene oligomers and ethene-MA co-oligomers using iminopyridyl systems with weak neighboring group interactions

The synthesis of hyper-branched ethene oligomers through catalytic insertion reactions with late transition metal catalysts is unique in its synthetic and practical scope. In this study, a series of iminopyridyl Ni(II) and Pd(II) complexes with electron-rich distal aryl motifs were synthesized and characterized. These complexes were very efficient in ethene oligomerization and co-oligomerization with methyl acrylate (MA). Hyperbranched ethene oligomers with different microstructures were generated using different metal species in ethene oligomerization. More importantly, hyperbranched ethene-MA co-oligomers with varying incorporation ratios were generated via ethene and MA co-oligomerization using the Pd(II) complexes. Most notably, weak neighboring group interactions of distal aryl motifs in the nickel system are more effective in influencing the microstructure of ethene oligomers than the corresponding palladium system.     

The new structure type Gd3Ni7Al14

The crystal structure of Gd₃Ni₇Al₁₄ (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two‐layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al₄Gd₂ and Al₆) are observed, the Al atoms are inside tetragonal (Ni₂Al₂Gd₄, Ni₂Al₄Gd₂, Al₄Gd₄, Ni₄Al₄ and Al₈) and pentagonal (Ni₄Al₆ and Al₁₀) prisms, while the Gd atoms are at the centres of pentagonal (Ni₄Al₆) and hexagonal (Ni₄Al₈) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd₃Ni₇Al₁₄ are similar to those of the intermetallides PrNi₂Al₃ and ZrNiAl. In all these structures, Ni‐centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three‐dimensional framework with six‐membered rings in the (001) plane in the case of the PrNi₂Al₃ and ZrNiAl types. In the case of Gd₃Ni₇Al₁₄, six‐membered rings are also observed, but only two‐thirds of the rings are interconnected via prism edges.