scholarly journals The Monomeric Alanediyl :AlAriPr8 (AriPr8 = C6H-2,6-(C6H2-2,4,6-Pri3)2-3,5-Pri2): An Organoaluminum(I) Compound with a One-Coordinate Aluminum Atom

2020 ◽  
Vol 142 (49) ◽  
pp. 20554-20559 ◽  
Author(s):  
Joshua D. Queen ◽  
Annika Lehmann ◽  
James C. Fettinger ◽  
Heikki M. Tuononen ◽  
Philip P. Power
Keyword(s):  
Aluminum Atom

THE USE OF THE COMBINATION OF FTIR, PYRIDINE ADSORPTION, 27Al AND 29Si MAS NMR TO DETERMINE THE BRÖNSTED AND LEWIS ACIDIC SITES

2016 ◽  
Vol 78 (6) ◽  
Author(s):  
Djoko Hartanto ◽  
Lai Sin Yuan ◽  
Sestriana Mutia Sari ◽  
Djarot Sugiarso ◽  
Irmina Kris Murwarni ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Aluminum Atom ◽  
Xrd Analysis ◽  
Acid Sites ◽  
Mas Nmr ◽  
Molar Ratio ◽  
Pyridine Adsorption ◽  
Lewis Acid Sites ◽  
27Al Mas Nmr ◽  
Pre Treatment

Lewis and Brönsted acidity were studied on ZSM-5 with combination of pyridine adsorption and FTIR vibration, ZSM-5 synthesized using kaolin Bangka Indonesia with an increase in the molar ratio of Si/Al 30-60 without pre-treatment and without organic templates and with seeds silicalite. Interestingly, the intensity of the infrared showed an increase of band vibration pyridine as absorbed Brönsted and Lewis acid sites in a molar ratio increase of Si/Al in ZSM-5, indicating an increase in the number of silanol (Brönsted acid) and deformed silica (Lewis acid) because the amount of Aluminum in ZSM-5 decrease with increase Si/Al but amount acidity increase. 29Si and 27Al MAS NMR analysis was supported by the results of infrared to indicate that all of the aluminum atom is coordinated with their neighbors are the same in ordering the ZSM-5 framework and 27Al MAS NMR showed a sharp peak of all the variations of Si/Al except the Si/Al 30 shows a low peak area. XRD analysis supported that the ZSM-5 structure formed is pure and crystal and a decrease in crystallinity proven for more than Si/Al 50, that defects silica occurs in ZSM-5, this corresponds to the growing number of Lewis acid sites caused by defects silica described the infrared results.

scholarly journals Study on Interface Structure of Cu/Al Clad Plates by Roll Casting

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 770 ◽  
Author(s):  
Qinghua Chang ◽  
Jingpei Xie ◽  
Aixia Mao ◽  
Wenyan Wang
Keyword(s):  
Molecular Dynamics ◽  
Electron Microscope ◽  
Molecular Dynamics Simulation ◽  
Large Scale ◽  
Aluminum Atom ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Aluminum Composite ◽  
Atom Diffusion ◽  
Heating And Cooling

Large scale Atomic/Molecular dynamic Parallel Simulator (LAMMPS) molecular dynamics simulation software was used to simulate the copper and aluminum atom diffusion and changes of interface during heating and cooling process of copper and aluminum composite panels. The structures of the interface were characterized through scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM), and the mechanical properties were also tested. The simulation results show that the diffusion rate of copper atom is higher than that of aluminum atom, and that the CuAl2 radial distribution function of the interface at 300 K is consistent with that of pure CuAl2 at room temperature. At 930 K, t = 50 ps Cu atoms spread at a distance of approximately four Al lattice constants around the Al layer, and Al atoms spread to about half a lattice constant distance to the Cu layer. The experimental results show that the thickness of the interface in copper–aluminum composite plate is about 1 μm, and only one kind of CuAl2 with tetragonal phase structure is generated in the interface, which corresponds with the result of molecular dynamics simulation.

Binding energies for aluminum atom association complexes with dimethyl ether, diethyl ether and tetrahydrofuran

1988 ◽  
Vol 92 (13) ◽  
pp. 3869-3874 ◽  
Author(s):  
J. Mark Parnis ◽  
S. A. Mitchell ◽  
David M. Rayner ◽  
Peter A. Hackett
Keyword(s):  
Dimethyl Ether ◽  
Diethyl Ether ◽  
Aluminum Atom ◽  
Binding Energies

scholarly journals Влияние водорода на флуктуационное охрупчивание алюминия

2019 ◽  
Vol 45 (17) ◽  
pp. 31
Author(s):  
Д.А. Индейцев ◽  
Е.В. Осипова
Keyword(s):  
Activation Energy ◽  
Hydrogen Embrittlement ◽  
Ab Initio ◽  
Aluminum Atom ◽  
Interstitial Site ◽  
Ab Initio Methods ◽  
Hydrogen Atoms ◽  
Vacancy Generation ◽  
Tetrahedral Voids ◽  
Kinetic Concept

The main processes occurring during vacancy generation in aluminum in the presence of hydrogen are described on the base of ab initio methods using the meta-functional SCAN. It was shown that hydrogen reduces the vacancy generation energy from 2.8 eV to 0.8 eV. In this case, eight hydrogen atoms located in the tetrahedral voids of the lattice around one aluminum atom make it much easier for it to move to the interstitial site. In accordance with the kinetic concept of embrittlement the dependence of the activation energy of hydrogen embrittlement of aluminum is calculated on the concentration of hydrogen and temperature. It is shown that hydrogen reduces the time of aluminum embrittlement only if its concentration in aluminum is more than critical one (~3⋅〖10〗^(-4) at T=293 K).

scholarly journals Analysis of Pyridine, Picoline and Lutidine’s Adsorption Behavior on The Al (111)-lattice

2021 ◽  
Vol 12 (3) ◽  
pp. 3225-3237
Keyword(s):  
Pyridine Ring ◽  
Aluminum Atom ◽  
Adsorption Behavior ◽  
Basis Sets ◽  
Frontier Orbitals ◽  
Protonated Forms ◽  
Molecular Reactivity ◽  
Organic Inhibitors ◽  
Derivatives Of ◽  
Organic Inhibitor

The reactivity and adsorption behavior of five organic inhibitors of pyridine and its derivatives of 2-picoline, 3-picoline, 4-picoline, and 2,4-lutidine at the Al(111) lattice in hydrochloric acid was studied by the principle of the HF and B3LYP level using the 6-31G and LANL2DZ basis sets from the program package gaussian 03. The compound was adsorbed on the metal lattice based on the calculated results, mainly in their protonated forms. In the Al (111)-lattice, the charge is transferred to the inhibitor, and the organic inhibitor is adsorbed at the Al (111)-lattice in an inclined state. The quantum chemical calculations of molecular reactivity show that the frontier orbitals of the four additives are distributed around the nitrogen atom of the pyridine ring, the aluminum atom of Al (111)-lattice, and active electrophilic centers are located on the nitrogen atoms of the pyridine ring. All five molecules were adsorbed with the chemical adsorption on the Al (111)-lattice, and the order of adsorption was 2-picoline>2, 4-lutidine> 4-picoline> 3-picoline> pyridine. The N atoms of four derivatives form N-Al bonds with the Al atoms of the Al (111)-lattice, which makes derivatives stably adsorb on the Al lattice.

Density Functional Theory Study of the Adsorption of Metal Adatoms on Graphene

2021 ◽  
Vol 1016 ◽  
pp. 1863-1868
Author(s):  
Norio Nunomura ◽  
Jun Yamashita ◽  
Satoshi Sunada
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Copper Atom ◽  
First Principles ◽  
Density Functional ◽  
Aluminum Atom ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Nanocarbon Materials ◽  
The Difference

In this study, we investigated the influence of the interaction between graphene and other materials as a basis for controlling the electronic structure of nanocarbon materials. First-principles calculations based on density functional theory (DFT) were performed on the optimized structure, adsorption energies and electronic states when copper and aluminum atoms were placed on graphene. As a result, we found that copper and aluminum are stable at the bridge and the hollow site, respectively. It was found that the adsorption energy of aluminum atom on graphene is larger than that of copper atom. It is considered that the difference in adsorption energy is caused by the difference in the dominant electron orbitals of the copper atom and the aluminum atom.

Dependence of Particle Number on Density of States of an Aluminum Nanocluster

2010 ◽  
Vol 3 (2) ◽  
pp. 88-94
Author(s):  
Natalya V. Tikhovskaya ◽  
Klimentiy N. Yugay
Keyword(s):  
Oxygen Atom ◽  
Hubbard Model ◽  
Density Of States ◽  
Lattice Site ◽  
Particle Number ◽  
Local Density ◽  
Aluminum Atom ◽  
Density Of State

On basis of the Hubbard model density of states of the 2D square nanosystem by size of N × N aluminum atoms with N = 3÷30, and also density of states of the 2D aluminum square nanocluster, where one of the aluminum atom is changed by oxygen atom, is calculated. It is shown that the local density of state depends on the total number of atoms in the cluster, and also on the location of atom in a lattice and the atom sort in a lattice site.

Alkylaluminum complexes containing pyridyl amido ligands. Syntheses and characterization of AlMe2[N(CH2-2-Py)2], Al2Me5[N(CH2-2-Py)2], and Al2Me4[2,3,5,6-tetra(2-pyridyl)piperazyl], an unusual carbon–carbon bond coupling product

1996 ◽  
Vol 74 (11) ◽  
pp. 2032-2040 ◽  
Author(s):  
Steven J. Trepanier ◽  
Suning Wang
Keyword(s):  
Nitrogen Atom ◽  
Aluminum Atom ◽  
Planar Geometry ◽  
X Ray Diffraction ◽  
Tetrahedral Geometry ◽  
Amido Ligands ◽  
Trigonal Bipyramidal Geometry ◽  
Trigonal Bipyramidal ◽  
Carbon Carbon Bond

The reactions of AlMe3 with di(2-pyridylmethyl)amine have been investigated. Two new complexes, AlMe2[N(CH2-2-Py)2] (1) and Al2Me4[2,3,5,6-tetra(2-pyridyl)piperazyl] (3), were obtained as the major and the minor product, respectively, from the reaction of AlMe3 with di(2-pyridylmethyl)amine in a 1:1 ratio in toluene at 23 °C. The reaction of AlMe3 with di(2-pyridylmethyl)amine in a 2:1 ratio yielded a dinuclear complex Al2Me5[N(CH2-2-Py)2] (2). These complexes were fully characterized by NMR, and elemental and single-crystal X-ray diffraction analyses. Crystal data: 1, C14H18N3Al, monoclinic, P21/m, a = 7.568(2), b = 7.340(1), c = 13.120(8) Å, β = 104.17(3)°, V = 706.6(4) Å3, Z = 2; 2, C14H27N3Al2, triclinic, [Formula: see text], a = 8.422(1), b = 16.711(6), c = 7.659(1) Å, α = 91.94(2)°, β = 113.08(1)°, γ = 85.17(2)°, V = 988.2(4) Å3, Z = 2; 3, C28H32N6Al2, monoclinic, P21/c, a = 7.522(8), b = 15.841(8), c = 11.584(4) Å, β = 98.53(5)°, V = 1365(1) Å3, Z = 2. Compound 1 is a mononuclear complex with the aluminum atom in an approximately trigonal bipyramidal geometry and the amido nitrogen atom in a trigonal planar geometry. Compound 2 contains two aluminum centers bridged by an amido nitrogen atom where one of the aluminum atoms has a tetrahedral geometry while the other has a trigonal bipyramidal geometry. The dinuclear compound 3 can be described as the result of two unusual C—C bonds coupling between the methylene carbon atoms of two molecules of 1. The aluminum coordination environment in 3 is similar to that of 1. Key words: aluminum, amide, pyridyl, 2,3,5,6-tetra(2-pyridyl)piperazine, structure.

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