scholarly journals Mechanistic Studies for Palladium Catalyzed Copolymerization of Ethylene with Vinyl Ethers

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2401
Author(s):  
Andleeb Mehmood ◽  
Xiaowei Xu ◽  
Waseem Raza ◽  
Ki-Hyun Kim ◽  
Yi Luo
Keyword(s):  
Density Functional ◽  
Dft Calculation ◽  
Palladium Complex ◽  
Chain Termination ◽  
Strong Interactions ◽  
Mechanistic Studies ◽  
Cationic Complex ◽  
Functional Theory ◽  
Hydrogen Interaction ◽  
Palladium Catalyzed

The mechanism of ethylene with vinyl ether (VE, CH2=CHOEt) copolymerization catalyzed by phosphine-sulfonate palladium complex (A) was investigated by density functional theory (DFT) calculation. On achieving an agreement between theory and experiment, it is found that the favorable 1,2-selective insertion of VE into the complex A originates from stronger hydrogen interaction between the oxygen atom of VE and the ancillary ligand of catalyst A. Additionally, VE insertion is easier into the ethylene pre-inserted intermediate than that into the catalyst to form the resultant copolymers with the major units of OEt in chain and minor units of OEt at the chain end. The effect of β-OEt and β-H elimination was explored to elucidate chain termination and the molecular weight of copolymers. Furthermore, a family of cationic catalysts has been demonstrated to copolymerize ethylene with VE along with our modified cationic complex B with higher incorporation of VE and reactivity in comparison with complex A, which was modelled computationally by increasing the strong interactions between the catalyst and monomer moiety. Other than VE, the activity of cationic complex B for copolymerization of vinyl chloride and methacrylate is also computed successfully.

Oxidation of Pd(II) with Disilane in a Palladium-Catalyzed Disilylation of Aryl Halides: A Theoretical View

2021 ◽  
Author(s):  
Jing Zhang ◽  
Shihan Liu ◽  
Tao Zhang ◽  
Tao Liu ◽  
Yu Lan
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Dft Calculation ◽  
Aryl Halide ◽  
Oxidative Addition ◽  
Aryl Halides ◽  
Functional Theory ◽  
Theoretical View ◽  
Palladium Catalyzed

Density functional theory (DFT) calculation has been used to reveal the mechanism of Pd-catalyzed disilylation reaction of aryl halide. The DFT calculations indicate that the reaction starts with oxidative addition...

scholarly journals Structural and computational investigation of an imine-based propeller-shaped macrocyclic cage

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Sriram Srinivasa Raghvan ◽  
Suresh Madhu ◽  
Velmurugan Devadasan ◽  
Gunasekaran Krishnasamy
Keyword(s):  
Band Gap ◽  
Density Functional ◽  
Strain Tensor ◽  
Strong Interactions ◽  
Soft Condensed Matter ◽  
Functional Theory ◽  
Self Assembling ◽  
Phenyl Rings ◽  
Crystal Volume

AbstractIn this study, we present the synthesis, spectroscopic and structural characterization of self-assembling gem-dimethyl imine based molecular cage (IMC). Self-assembling macrocycles and cages have well-defined cavities and have extensive functionalities ranging from energy storage, liquid crystals, and catalysts to water splitting photo absorber. IMC has large voids i.e., 25% of the total crystal volume thus could accommodate wide substrates. The synthesized imine-based molecular cages are stabilized by coaxial π bonded networks and long-range periodic van der Waal and non-bonded contacts as observed from the crystal structure. IMC also has typical properties of soft condensed matter materials, hence theoretical prediction of stress and strain tensor along with thermophysical properties were computed on crystal system and were found to be stable. Molecular dynamics revealed IMC is stabilized by, strong interactions between the interstitial phenyl rings. Density functional theory (DFT) based physicochemical properties were evaluated and has band gap of around 2.38ev (520 nm) similar to various photocatalytic band gap materials.

scholarly journals Synthesis and Characterization of the Germathioacid Chloride Coordinated by an N-Heterocyclic Carbene §

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 76 ◽  
Author(s):  
Yasunobu Egawa ◽  
Chihiro Fukumoto ◽  
Koichiro Mikami ◽  
Nobuhiro Takeda ◽  
Masafumi Unno
Keyword(s):  
Carboxylic Acid ◽  
Density Functional ◽  
Dft Calculation ◽  
Acid Chlorides ◽  
Carboxylic Acid Chloride ◽  
Functional Theory ◽  
Nitrogen Ligands ◽  
Bond Property ◽  
Nitrogen Bonds

Carboxylic acid chlorides are useful substrates in organic chemistry. Many germanium analogues of carboxylic acid chloride have been synthesized so far. Nevertheless, all of the reported germathioacid chlorides use bidentate nitrogen ligands and contain germanium-nitrogen bonds. Our group synthesized germathioacid chloride, Ge(S)Cl{C6H3-2,6-Tip2}(Im-i-Pr2Me2), using N-heterocyclic carbene (Im-i-Pr2Me2). As a result of density functional theory (DFT) calculation, it was found that electrons are localized on sulfur, and the germanium-sulfur bond is a single bond with a slight double bond property.

Effect of Solute Ta on Grain Refinement of Al-7Si-0.3Mg Based Alloys

2022 ◽  
Vol 327 ◽  
pp. 54-64
Author(s):  
Ivo Spacil ◽  
David Holec ◽  
Peter Schumacher ◽  
Jiehua Li
Keyword(s):  
Grain Refinement ◽  
Density Functional ◽  
Dft Calculation ◽  
Interface Energy ◽  
Special Focus ◽  
Grain Refiner ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Sandwich Configuration ◽  
Scanning Electron

Different Ta concentrations together with stochiometric grain refiner (Al-2.2Ti-1B) in Al-Si-Mg based alloys were investigated with the aim to elucidate grain refinement mechanisms. Post-solidification microstructure was characterised using optical microscopy and scanning electron microscopy (SEM), with a special focus on the Ta-rich layer (more likely to be Al3Ta) on the basal planes (0001) of TiB2. A significant grain refinement was observed by using the solute Ta together with stochiometric grain refiner (Al-2.2Ti-1B). In order to further elucidate the formation of Ta-rich layer on the basal planes (0001) of TiB2, the Density Functional Theory (DFT) calculation were also performed to determine the interface energies of different interfaces and sandwich configurations, including Al (111), Al3Ti (112) and Al3Ta (112) at the interface of TiB2 basal plane (0001). It was found that the interface energy for Ti-terminated TiB2 at the interface throughout all configurations involved in this paper is lower than that for B-terminated TiB2, indicating that Ti-terminated TiB2 is more favourable. It was also found that the Al3Ta configuration yields the same interface energies as the Al3Ti configuration. Furthermore, the interface energy of the sandwich configuration also shows nearly identical values along the TiB2 // Al3Ti and TiB2 // Al3Ta interface energy, strongly indicating that the solute Ti can be fully replaced by the solute Ta.

scholarly journals Do two oxidants (ferric-peroxo and ferryl-oxo species) act in the biosynthesis of estrogens? A DFT calculation

RSC Advances ◽  
2018 ◽  
Vol 8 (27) ◽  
pp. 15196-15201 ◽  
Author(s):  
Xiang-Yun Wang ◽  
Hui-Min Yan ◽  
Yan-Li Han ◽  
Zhu-Xia Zhang ◽  
Xiao-Yun Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Calculation ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Two Oxidants ◽  
Ferric Peroxo

Density functional theory calculations were performed in order to reveal the mysterious catalytic step of the biosynthesis of estrogens.

Spin Alignment Studies on the Muon-Site Determination in La2CuO4

2020 ◽  
Vol 860 ◽  
pp. 154-159
Author(s):  
Muhammad Redo Ramadhan ◽  
Irwan Ramli ◽  
Dita Puspita Sari ◽  
Budhy Kurniawan ◽  
Azwar Manaf ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Potential Distribution ◽  
Density Functional ◽  
Dft Calculation ◽  
Minimum Energy ◽  
Point Dipole ◽  
Spin Alignment ◽  
Functional Theory ◽  
Muon Site ◽  
Insulating Gap

Here we report spin-alignment contributions to muon coordinate calculated utilizing density functional theory (DFT) calculation. We estimated four different antiferromagnetic (AF) spin alignments in La2CuO4. We observed small changes by adjusting spin configurations in DFT calculations. Cu-spin value of 0.61 µB is constant in all calculations. The insulating gap of 1.9 eV is unchanged in all configurations. Muon coordinate was defined as the most minimum energy in atomic potential distribution. By assuming that Cu-spin is a point dipole for each atom, internal fields for muon were calculated and compared to known experimental results.

scholarly journals Tin, The Enabler—Hydrogen Diffusion into Ruthenium

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 129 ◽  
Author(s):  
Chidozie Onwudinanti ◽  
Ionuţ Tranca ◽  
Thomas Morgan ◽  
Shuxia Tao
Keyword(s):  
Density Functional ◽  
Hydrogen Diffusion ◽  
Extreme Ultraviolet ◽  
Hydrogen Uptake ◽  
Significant Drop ◽  
Functional Theory ◽  
Euv Lithography ◽  
Hydrogen Interaction ◽  
Hydrogen Penetration ◽  
Hydride Molecule

Hydrogen interaction with ruthenium is of particular importance for the ruthenium-capped multilayer reflectors used in extreme ultraviolet (EUV) lithography. Hydrogen causes blistering, which leads to a loss of reflectivity. This problem is aggravated by tin. This study aims to uncover the mechanism via which tin affects the hydrogen uptake, with a view to mitigation. We report here the results of a study of hydrogen interaction with the ruthenium surface in the presence of tin using Density Functional Theory and charge density analyses. Our calculations show a significant drop in the energy barrier to hydrogen penetration when a tin atom or a tin hydride molecule (SnHx) is adsorbed on the ruthenium surface; the barrier has been found to drop in all tested cases with tin, from 1.06 eV to as low as 0.28 eV in the case of stannane (SnH4). Analyses show that, due to charge transfer from the less electronegative tin to hydrogen and ruthenium, charge accumulates around the diffusing hydrogen atom and near the ruthenium surface atoms. The reduced atomic volume of hydrogen, together with the effect of electron–electron repulsion from the ruthenium surface charge, facilitates subsurface penetration. Understanding the nature of tin’s influence on hydrogen penetration will guide efforts to mitigate blistering damage of EUV optics. It also holds great interest for applications where hydrogen penetration is desirable, such as hydrogen storage.

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