scholarly journals Carbon Dioxide Activation by a Palladium Terminal Imido Complex

2019 ◽  
Vol 72 (11) ◽  
pp. 900 ◽  
Author(s):  
Stephen J. Goodner ◽  
Annette Grünwald ◽  
Frank W. Heinemann ◽  
Dominik Munz
Keyword(s):  
Carbon Dioxide ◽  
Nitrogen Atom ◽  
Density Functional ◽  
Reaction Rate ◽  
Density Functional Theory Calculations ◽  
Nucleophilic Attack ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Nucleophilic Reactivity ◽  
Complex Features

We recently reported the first example of a palladium(ii) terminal imido complex. We proposed that this complex features exceptional high nucleophilicity at the nitrogen atom and a peculiar zwitterionic electronic structure with an anti-bonding highest-occupied molecular orbital (HOMO). This complex swiftly activated moderately acidic CH, OH, and NH bonds and also reacted with dihydrogen. However, unambiguous nucleophilic reactivity with substrates not featuring a hydrogen atom could not be observed. Herein, we now show that this nucleophilic complex also reacts with CO2 to give a ring-strained four-membered palladium(ii) carbamate complex. Remarkably, the same product is obtained in the reaction of the related bisamido complex, albeit at a slower reaction rate. Density functional theory calculations indicate that the addition of CO2 does not proceed via initial 1,2-addition across the Pd–N bond, but instead through nucleophilic attack by the imido (amido respectively) nitrogen atom.

scholarly journals Direct carbon-carbon coupling of furanics with acetic acid over Brønsted zeolites

2016 ◽  
Vol 2 (9) ◽  
pp. e1601072 ◽  
Author(s):  
Abhishek Gumidyala ◽  
Bin Wang ◽  
Steven Crossley
Keyword(s):  
Acetic Acid ◽  
Density Functional ◽  
Reaction Rate ◽  
Activation Barrier ◽  
Density Functional Theory Calculations ◽  
Step Change ◽  
Functional Theory ◽  
Transportation Fuels ◽  
Bond Forming ◽  
Direct Acylation

Effective carbon-carbon coupling of acetic acid to form larger products while minimizing CO2emissions is critical to achieving a step change in efficiency for the production of transportation fuels from sustainable biomass. We report the direct acylation of methylfuran with acetic acid in the presence of water, all of which can be readily produced from biomass. This direct coupling limits unwanted polymerization of furanics while producing acetyl methylfuran. Reaction kinetics and density functional theory calculations illustrate that the calculated apparent barrier for the dehydration of the acid to form surface acyl species is similar to the experimentally measured barrier, implying that this step plays a significant role in determining the net reaction rate. Water inhibits the overall rate, but selectivity to acylated products is not affected. We show that furanic species effectively stabilize the charge of the transition state, therefore lowering the overall activation barrier. These results demonstrate a promising new route to C–C bond–forming reactions for the production of higher-value products from biomass.

scholarly journals A computational study of the competing reaction mechanisms of the photo-catalytic reduction of CO2 on anatase(101)

2016 ◽  
Vol 18 (36) ◽  
pp. 25010-25021 ◽  
Author(s):  
Chung Man Ip ◽  
Alessandro Troisi
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Reaction Mechanisms ◽  
Density Functional ◽  
Catalytic Reduction ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Reaction Pathways ◽  
Functional Theory ◽  
Reduction Of Co2

Three reaction pathways for the photocatalytic reduction of carbon dioxide to methane are investigated with density functional theory calculations.

Nb2BN2− cluster anions reduce four carbon dioxide molecules: reactivity enhancement by ligands

2020 ◽  
Vol 49 (40) ◽  
pp. 14081-14087 ◽  
Author(s):  
Hai-Yan Zhou ◽  
Ming Wang ◽  
Yong-Qi Ding ◽  
Jia-Bi Ma
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Cluster Anions ◽  
Gas Phase Reactions ◽  
Functional Theory ◽  
Flight Mass Spectrometry

The thermal gas-phase reactions of Nb2BN2− cluster anions with carbon dioxide have been explored by using the art of time-of-flight mass spectrometry and density functional theory calculations.

scholarly journals Surprisingly facile CO2 insertion into cobalt alkoxide bonds: A theoretical investigation

2015 ◽  
Vol 11 ◽  
pp. 1340-1351 ◽  
Author(s):  
Willem K Offermans ◽  
Claudia Bizzarri ◽  
Walter Leitner ◽  
Thomas E Müller
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Density Functional Theory ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Activation Barrier ◽  
Density Functional Theory Calculations ◽  
Reaction Energy ◽  
Reaction Step ◽  
Functional Theory

Exploiting carbon dioxide as co-monomer with epoxides in the production of polycarbonates is economically highly attractive. More effective catalysts for this reaction are intensively being sought. To promote better understanding of the catalytic pathways, this study uses density functional theory calculations to elucidate the reaction step of CO2 insertion into cobalt(III)–alkoxide bonds, which is also the central step of metal catalysed carboxylation reactions. It was found that CO2 insertion into the cobalt(III)–alkoxide bond of [(2-hydroxyethoxy)CoIII(salen)(L)] complexes (salen = N,N”-bis(salicyliden-1,6-diaminophenyl)) is exothermic, whereby the exothermicity depends on the trans-ligand L. The more electron-donating this ligand is, the more exothermic the insertion step is. Interestingly, we found that the activation barrier decreases with increasing exothermicity of the CO2 insertion. Hereby, a linear Brønsted–Evans–Polanyi relationship was found between the activation energy and the reaction energy.

scholarly journals Spectroscopic Studies and Vibrational Assignments, Homo- Lumo, UV-VIS, NBO Analysis of Benzonitrile

2020 ◽  
Vol 13 (3) ◽  
pp. 225-239
Author(s):  
K. Rajalakshmi ◽  
S. Sharmila
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Studies ◽  
Nbo Analysis ◽  
Functional Theory ◽  
Vibrational Assignments ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
The Fourier Transform

The Fourier transform infrared and FT-Raman spectra of Benzonitrile have been recorded in region of 4000-400 and 4000-100 cm -1 respectively. A complete assignments and analysis of fundamental vibrational modes of the molecule have been carried out. The observed fundamental modes have been compared with harmonic vibrational frequencies computed using ab initio and density functional theory calculations by employing B3LYP functional at 6-311G(d, p) level and HF/6-311G(d, p).UV-Vis spectrum of the compound has been recorded, the natural bond orbital (NBO) electronic properties, such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been calculated with B3LYP/6-311G(d, p) level. These calculated energies show that charge transfer occurs within molecule. NBO analysis, thermodynamics properties and Mulliken charges of the title molecule are also calculated and interpreted

Modeling Reaction Kinetics of Twin Polymerization via Differential Scanning Calorimetry

2018 ◽  
Vol 43 (4) ◽  
pp. 347-357
Author(s):  
Janett Prehl ◽  
Robin Masser ◽  
Peter Salamon ◽  
Karl Heinz Hoffmann
Keyword(s):  
Reaction Mechanism ◽  
Density Functional ◽  
Reaction Rate ◽  
Density Functional Theory Calculations ◽  
Scanning Calorimetry ◽  
Functional Theory ◽  
Reaction Rate Constants ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Derivatives Of

Abstract We present a kinetic model for the reaction mechanism of acid-catalyzed twin polymerization. Our model characterizes the reaction mechanism not by the reactants, intermediate structures, and products, but via reaction-relevant moieties. We apply our model for three different derivatives of 2,2’-Spirobi[4H-1,3,2-benzodioxasiline] and determine activation energies, reaction enthalpies, and reaction rate constants for the reaction steps in our mechanism. We compare our findings to previously reported values obtained from density functional theory calculations. Furthermore, with this approach we are also able to follow the time development of the concentrations of the reaction-relevant moieties.

scholarly journals Electronic structure of porphyrin-based metal–organic frameworks and their suitability for solar fuel production photocatalysis

2015 ◽  
Vol 3 (46) ◽  
pp. 23458-23465 ◽  
Author(s):  
Said Hamad ◽  
Norge C. Hernandez ◽  
Alex Aziz ◽  
A. Rabdel Ruiz-Salvador ◽  
Sofia Calero ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Metal Organic Frameworks ◽  
Density Functional Theory Calculations ◽  
Carbon Dioxide Reduction ◽  
Fuel Production ◽  
Functional Theory ◽  
Metal Organic

Density functional theory calculations reveal that the electronic structure of a family of porphyrin-based metal–organic frameworks is suitable for the photocatalysis of water splitting and carbon dioxide reduction reactions.

scholarly journals Ab InitioDensity Functional Theory Investigation of the Interaction between Carbon Nanotubes and Water Molecules during Water Desalination Process

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Loay A. Elalfy ◽  
Walid M. I. Hassan ◽  
Wael N. Akl
Keyword(s):  
Carbon Nanotubes ◽  
Reverse Osmosis ◽  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Water Desalination ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Dynamics Simulations

Density functional theory calculations using B3LYP/3-21G level of theory have been implemented on 6 carbon nanotubes (CNTs) structures (3 zigzag and 3 armchair CNTs) to study the energetics of the reverse osmosis during water desalination process. Calculations of the band gap, interaction energy, highest occupied molecular orbital, lowest unoccupied molecular orbital, electronegativity, hardness, and pressure of the system are discussed. The calculations showed that the water molecule that exists inside the CNT is about 2-3 Å away from its wall. The calculations have proven that the zigzag CNTs are more efficient for reverse osmosis water desalination process than armchair CNTs as the reverse osmosis process requires pressure of approximately 200 MPa for armchair CNTs, which is consistent with the values used in molecular dynamics simulations, while that needed when using zigzag CNTs was in the order of 60 MPa.

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