Ethylene formation by methane dehydrogenation and C–C coupling reaction on a stoichiometric IrO2 (110) surface – a density functional theory investigation

2015 ◽  
Vol 5 (8) ◽  
pp. 4064-4071 ◽  
Author(s):  
T. L. M. Pham ◽  
E. G. Leggesse ◽  
J. C. Jiang
Keyword(s):  
Density Functional ◽  
Catalyst Surface ◽  
Coupling Reaction ◽  
Direct Conversion ◽  
Efficient Catalyst ◽  
Functional Theory ◽  
Elementary Reactions ◽  
Ethylene Formation ◽  
Conversion Of Methane ◽  
Mild Temperature

The capability to activate methane at mild temperature and facilitate all elementary reactions on the catalyst surface is a defining characteristic of an efficient catalyst especially for the direct conversion of methane to ethylene.

scholarly journals Cu2O-Ag Tandem Catalysts for Selective Electrochemical Reduction of CO2 to C2 Products

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2175
Author(s):  
Di Niu ◽  
Cong Wei ◽  
Zheng Lu ◽  
Yanyan Fang ◽  
Bo Liu ◽  
...  
Keyword(s):  
Density Functional ◽  
Catalyst Surface ◽  
Coupling Reaction ◽  
Reduction Reaction ◽  
Functional Theory ◽  
Faradaic Efficiency ◽  
Barrier Energy ◽  
Co Concentration ◽  
Reduction Of Co2 ◽  
Partial Current

The electrochemical carbon dioxide reduction reaction (CO2RR) to C2 chemicals has received great attention. Here, we report the cuprous oxide (Cu2O) nanocubes cooperated with silver (Ag) nanoparticles via the replacement reaction for a synergetic CO2RR. The Cu2O-Ag tandem catalyst exhibits an impressive Faradaic efficiency (FE) of 72.85% for C2 products with a partial current density of 243.32 mA·cm−2. The electrochemical experiments and density functional theory (DFT) calculations reveal that the introduction of Ag improves the intermediate CO concentration on the catalyst surface and meanwhile reduces the C-C coupling reaction barrier energy, which is favorable for the synthesis of C2 products.

scholarly journals Decomposition of Formic Acid over Orthorhombic Molybdenum Carbide

2021 ◽  
Author(s):  
Kushagra Agrawal ◽  
Alberto Roldan ◽  
Nanda Kishore ◽  
Andrew J Logsdail
Keyword(s):  
Formic Acid ◽  
Density Functional ◽  
Molybdenum Carbide ◽  
Catalyst Surface ◽  
Energy Landscape ◽  
Functional Theory ◽  
Potential Energy Landscape ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Dehydrogenation Mechanism

The decomposition of formic acid is investigated on the β-Mo<sub>2</sub>C (100) catalyst surface using density functional theory. The dehydration and dehydrogenation mechanism for the decomposition is simulated, and the thermochemistry and kinetics are discussed. The potential energy landscape of the reaction shows a thermodynamically favourable cleavage of H-COOH to form CO; however, the kinetics show that the dehydrogenation mechanism is faster and CO<sub>2</sub> is continuously formed. The effect of HCOOH adsorption on the surface is also analysed, in a temperature-programmed reaction, with the decomposition proceeding at under 350 K and desorption of CO<sub>2</sub> observed.

scholarly journals A novel selective fluorescent chemosensor for Fe3+ ions based on phthalonitrile dimer: synthesis, analysis, and theoretical studies

2020 ◽  
Vol 44 (5) ◽  
pp. 1254-1264
Author(s):  
Shaya AL-RAQA ◽  
İpek ÖMEROĞLU ◽  
Doğan ERBAHAR ◽  
Mahmut DURMUŞ
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Interaction Mechanism ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Density Functional Theory Calculations ◽  
Theoretical Studies ◽  
Functional Theory ◽  
Cross Coupling Reaction ◽  
Ft Ir

Phenyl-4,4-di(3,6-dibutoxyphthalonitrile) (3) was synthesized by the reaction of 1,4-phenylenebisboronic acid (1) and 4-bromo-3,6-dibutoxyphthalonitrile (2), using Suzuki cross-coupling reaction. The newly synthesized compound (3) was characterized by FT-IR, MALDI-MS, ESI-MS, 1H-NMR, 13C-NMR, and 13C-DEPT-135-NMR. The fluorescence property of phenyl-4,4-di(3,6- dibutoxyphthalonitrile) (3) towards various metal ions was investigated by fluorescence spectroscopy, and it was observed thatthe compound (3) displayed a significantly ‘turn-off’ response to Fe3+, which was referred to 1:2 complex formation between ligand (3) and Fe3+. The compound was also studied via density functional theory calculations revealing the interaction mechanism of the molecule with Fe3+ ions.

scholarly journals Zn(II)-to-Cu(II) Transmetalation in an Amide Functionalized Complex and Catalytic Applications in Styrene Oxidation and Nitroaldol Coupling

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2644 ◽  
Author(s):  
Anup Paul ◽  
Luísa M. D. R. S. Martins ◽  
Anirban Karmakar ◽  
Maxim L. Kuznetsov ◽  
M. Fátima C. Guedes da Silva ◽  
...  
Keyword(s):  
Density Functional ◽  
Coupling Reaction ◽  
X Ray Diffraction ◽  
Styrene Oxidation ◽  
Aqueous Hydrogen Peroxide ◽  
Functional Theory ◽  
Catalytic Activities ◽  
Eds Analysis ◽  
Carboxylate Groups ◽  
Thermodynamic Feasibility

The mononuclear zinc(II) complex cis-[ZnL2(H2O)2] (1; L = 4-(pyridin-3-ylcarbamoyl)benzoate) was synthesized and characterized. By soaking crystals of 1 in a mixture of DMF-H2O solution containing a slight excess of Cu(NO3)2 × 3H2O a transmetalation reaction occurred affording the related copper(II) complex trans-[CuL2(H2O)2] (2). The structures of the compounds were authenticated by single crystal X-ray diffraction revealing, apart from a change in the isomerism, an alteration in the relative orientation of the chelating carboxylate groups and of the pyridine moieties. H-bond interactions stabilize both geometries and expand them into two-dimensional (2D) networks. The transmetalation was confirmed by SEM–EDS analysis. Moreover, the thermodynamic feasibility of the transmetalation is demonstrated by density-functional theory (DFT) studies. The catalytic activities of 1 and 2 for the oxidation of styrene and for the nitroaldol (Henry) C-C coupling reaction were investigated. The copper(II) compound 2 acts as heterogeneous catalyst for the microwave-assisted oxidation of styrene with aqueous hydrogen peroxide, yielding selectively (>99%) benzaldehyde up to 66% of conversion and with a turnover frequency (TOF) of 132 h−1. The zinc(II) complex 1 is the most active catalyst (up to 87% yield) towards the nitroaldol (Henry) coupling reaction between benzaldehyde and nitro-methane or -ethane to afford the corresponding β-nitro alcohols. The reaction of benzaldehyde with nitroethane in the presence of 1 produced 2-nitro-1-phenylpropanol in the syn and the anti diastereoisomeric forms, with a considerable higher selectivity towards the former (66:34).

scholarly journals Propane Fuel Cells: Selectivity for Partial or Complete Reaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shadi Vafaeyan ◽  
Alain St-Amant ◽  
Marten Ternan
Keyword(s):  
Fuel Cells ◽  
Density Functional ◽  
Catalyst Surface ◽  
Polymer Electrolyte Membrane ◽  
Platinum Group Metal ◽  
Pem Fuel Cells ◽  
Metal Catalyst ◽  
Boltzmann Factor ◽  
Functional Theory ◽  
Electrolyte Membrane

The use of propane fuel in high temperature (120°C) polymer electrolyte membrane (PEM) fuel cells that do not require a platinum group metal catalyst is being investigated in our laboratory. Density functional theory (DFT) was used to determine propane adsorption energies, desorption energies, and transition state energies for both dehydrogenation and hydroxylation reactions on a Ni(100) anode catalyst surface. The Boltzmann factor for the hydroxylation of a propyl species to form propanol and its subsequent desorption was compared to that for the dehydrogenation of a propyl species. The large ratio of the respective Boltzmann factors indicated that the formation of a completely reacted product (carbon dioxide) is much more likely than the formation of partially reacted products (alcohols, aldehydes, carboxylic acids, and carbon monoxide). That finding is evidence for the major proportion of the chemical energy of the propane fuel being converted to either electrical or thermal energy in the fuel cell rather than remaining unused when partially reacted species are formed.

scholarly journals Copper-catalyzed aerobic oxidative coupling: From ketone and diamine to pyrazine

2015 ◽  
Vol 1 (9) ◽  
pp. e1500656 ◽  
Author(s):  
Kun Wu ◽  
Zhiliang Huang ◽  
Xiaotian Qi ◽  
Yingzi Li ◽  
Guanghui Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxidative Coupling ◽  
Density Functional ◽  
Coupling Reaction ◽  
Density Functional Theory Calculations ◽  
Radical Species ◽  
Functional Theory ◽  
X Ray ◽  
Oxidative Coupling Reaction ◽  
X Ray Absorption

Copper-catalyzed aerobic oxidative C–H/N–H coupling between simple ketones and diamines was developed toward the synthesis of a variety of pyrazines. Various substituted ketones were compatible for this transformation. Preliminary mechanistic investigations indicated that radical species were involved. X-ray absorption fine structure experiments elucidated that the Cu(II) species 5 coordinated by two N atoms at a distance of 2.04 Å and two O atoms at a shorter distance of 1.98 Å was a reactive one for this aerobic oxidative coupling reaction. Density functional theory calculations suggested that the intramolecular coupling of cationic radicals was favorable in this transformation.

scholarly journals Synthesis, Characterization, Catalytic Activity, and DFT Calculations of Zn(II) Hydrazone Complexes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4043 ◽  
Author(s):  
Temiloluwa T. Adejumo ◽  
Nikolaos V. Tzouras ◽  
Leandros P. Zorba ◽  
Dušanka Radanović ◽  
Andrej Pevec ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Geometry Optimization ◽  
Coupling Reaction ◽  
Functional Theory ◽  
Reactivity Descriptors

Two new Zn(II) complexes with tridentate hydrazone-based ligands (condensation products of 2-acetylthiazole) were synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction methods. The complexes 1, 2 and recently synthesized [ZnL3(NCS)2] (L3 = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium) complex 3 were tested as potential catalysts for the ketone-amine-alkyne (KA2) coupling reaction. The gas-phase geometry optimization of newly synthesized and characterized Zn(II) complexes has been computed at the density functional theory (DFT)/B3LYP/6–31G level of theory, while the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO and LUMO) energies were calculated within the time-dependent density functional theory (TD-DFT) at B3LYP/6-31G and B3LYP/6-311G(d,p) levels of theory. From the energies of frontier molecular orbitals (HOMO–LUMO), the reactivity descriptors, such as chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and electrophilicity index (ω) have been calculated. The energetic behavior of the investigated compounds (1 and 2) has been examined in gas phase and solvent media using the polarizable continuum model. For comparison reasons, the same calculations have been performed for recently synthesized [ZnL3(NCS)2] complex 3. DFT results show that compound 1 has the smaller frontier orbital gap so, it is more polarizable and is associated with a higher chemical reactivity, low kinetic stability and is termed as soft molecule.

scholarly journals Synthesis of Pyrroles Through the CuH-Catalyzed Coupling of Enynes and Nitriles

2020 ◽  
Author(s):  
Yujing Zhou ◽  
Lin Zhou ◽  
Luke T. Jesikiewicz ◽  
Peng Liu ◽  
Stephen L. Buchwald
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Efficient Method ◽  
Density Functional ◽  
Coupling Reaction ◽  
Copper Hydride ◽  
Reductive Coupling ◽  
Functional Theory ◽  
Subsequent Cyclization

<p>Herein, we describe an efficient method to prepare polysubstituted pyrroles via a copper-hydride (CuH)-catalyzed enyne-nitrile coupling reaction. This protocol accommodates both aromatic and aliphatic substituents and a broad range of functional groups, providing a variety of N-H pyrroles in good yields and with high regioselectivity. We propose that the Cu-based catalyst promotes both the initial reductive coupling and subsequent cyclization steps. Density functional theory (DFT) calculations were performed to elucidate the reaction mechanism.</p>

Sign in / Sign up

Export Citation Format

Share Document