Efficient bi-directional OER/ORR catalysis of metal-free C6H4NO2/g-C3N4: Density functional theory approaches

2020 ◽  
Vol 531 ◽  
pp. 147292
Author(s):  
Haoli Pan ◽  
Yong Wu ◽  
Can Li ◽  
Huanhuan Li ◽  
Yinyan Gong ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Metal Free

scholarly journals A computational study for the reaction mechanism of metal-free cyanomethylation of aryl alkynoates with acetonitrile

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Computational Study ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Metal Free ◽  
Coupled Cluster Methods ◽  
High Level ◽  
Cluster Methods

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].

Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory

2010 ◽  
Vol 53 (8) ◽  
pp. 1746-1753 ◽  
Author(s):  
Xue Wang ◽  
Gang Sun ◽  
ShiLing Sun ◽  
ChunGuang Liu ◽  
YongQing Qiu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Metal Free ◽  
Structures And Properties

scholarly journals Elusive Metal-Free Primary Amination of Arylboronic Acids: Synthetic Studies and Mechanism by Density Functional Theory

2012 ◽  
Vol 134 (44) ◽  
pp. 18253-18256 ◽  
Author(s):  
Chen Zhu ◽  
Gongqiang Li ◽  
Daniel H. Ess ◽  
John R. Falck ◽  
László Kürti
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Metal Free ◽  
Arylboronic Acids ◽  
Synthetic Studies

Pyridine derivative/graphene nanoribbon composites as molecularly tunable heterogeneous electrocatalysts for the oxygen reduction reaction

2016 ◽  
Vol 18 (6) ◽  
pp. 5040-5047 ◽  
Author(s):  
Huiying Zhang ◽  
Jingxiang Zhao ◽  
Qinghai Cai
Keyword(s):  
Density Functional Theory ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Density Functional ◽  
Reduction Reaction ◽  
Pyridine Derivative ◽  
Functional Theory ◽  
Metal Free ◽  
Dft Computations ◽  
New Class

In this study, a strategy to design a new class of metal-free electrocatalysts for the oxygen reduction reaction (ORR) was proposed by means of density functional theory (DFT) computations.

scholarly journals A Theoretical Evaluation of the Efficiencies of Metal-Free 1,3,4-Oxadiazole Dye-Sensitized Solar Cells: Insights From Electron-Hole Separation Distance Analysis.

2021 ◽  
Author(s):  
Louis-Charl Coetzee ◽  
Adedapo Adeyinka ◽  
Nomampondo Magwa
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Density Functional ◽  
Dye Sensitized Solar Cells ◽  
Separation Distance ◽  
Electron Hole ◽  
Functional Theory ◽  
Metal Free ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Abstract Herein, some novel metal-free 1,3,4-oxadiazole compounds O1-O7 were evaluated for Photovoltaic properties using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations to determine if they can serve as metal-free organic dyes for the use of dye-sensitized solar cells (DSSCs). To understand the trends in the relative efficiencies of the investigated compounds as dyes in DSSCs, their electron contributions, hole contributions, and electron-hole overlaps for each respective atom and fragment within the molecule were analyzed with a particular focus on the electron densities on the anchoring segments. As transition density matrices (TDM) provide details for the departure of each electron from its corresponding hole during excitations, which results in charge transfer (CT), the charge separation distance (Δr) between the electron and its corresponding hole was studied as well as the degree of electron-hole overlap (Ʌ). The latter, single-point excitation energy of each electron, the percentage electron contribution to the anchoring segments of each compound, the incident-photon-conversion-efficiency (IPCE), charge recombination, light harvesting efficiency (LHE) electron injection (Φinj) and charge collection efficiency (ncollect) were then compared to Δr to determine whether the expected relationships hold. Moreover, parameters such as diffusion constant (Dπ) and electron lifetime (t), amongst others, were also used to describe electron excitation processes. Since IPCE is the key parameter in determining the efficiency, O3 was found to be the best dye due to its highest value.

Optical Properties of Metal Free and Metal Phthalocyanine by Molecular Band Calculation

2008 ◽  
Vol 55-57 ◽  
pp. 677-680
Author(s):  
S. Pengmanayol ◽  
Tanakorn Osotchan
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Total Energy ◽  
Density Functional ◽  
Polymorphic Form ◽  
Density Of State ◽  
Metal Phthalocyanine ◽  
Peak Wavelength ◽  
Functional Theory ◽  
Metal Free

The optical properties of metal-free and metal phthalocyanine were calculated by using density functional theory with various metals including copper, zinc, cobalt, iron and manganese. The polymorphic form of these crystals was employed only for β from. The molecules were optimized with the symmetry of D4h. For the alignments of the molecule in the crystal structures of this polymorphic form which have not been reported in detail, the variation of total energy was examined as a function of the align angles. The align angle at minimum total energy was used for the band calculation. The density functional theory and plane-wave pseudopotential method were used to calculate the energy band structure and electron density of state. The calculated band structures of various metal phthalocyanines can be divided in two groups according to the peak wavelength of the maximum absorption. The first group with the peak wavelength at about 230 nm consists of β-CuPc, β-H2Pc, and β-MnPc while the wavelength of another group for β-CoPc, β-FePc, and β-ZnPc occurs at 350 nm. From the density of state calculation, it indicates that these two transitions originate from the different band and the ratio of the absorption between these states depending on the type of metal in phthalocyanine. The optical absorption was derived to examine the absorption spectra for various metal compositions while the variation in intrinsic electrical conductivity can be estimated from the shape of the band. The phonon and infrared spectra were also determined in order to investigate the vibration mode of molecule in the crystals

scholarly journals Chemoselective catalytic hydrodefluorination of trifluoromethylalkenes towards mono-/gem-di-fluoroalkenes under metal-free conditions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingjing Zhang ◽  
Jin-Dong Yang ◽  
Jin-Pei Cheng
Keyword(s):  
Density Functional Theory ◽  
Fluorine Atom ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Reaction Conditions ◽  
Functional Theory ◽  
Stepwise Mechanism ◽  
Metal Free ◽  
Great Demand ◽  
Good Group

AbstractFluorine-containing moieties show significant effects in improving the properties of functional molecules. Consequently, efficient methods for installing them into target compounds are in great demand, especially those enabled by metal-free catalysis. Here we show a diazaphospholene-catalyzed hydrodefluorination of trifluoromethylalkenes to chemoselectively construct gem-difluoroalkenes and terminal monofluoroalkenes by simple adjustment of the reactant stoichiometry. This metal-free hydrodefluorination features mild reaction conditions, good group compatibility, and almost quantitative yields for both product types. Stoichiometric experiments indicated a stepwise mechanism: hydridic addition to fluoroalkenes and subsequent β-F elimination from hydrophosphination intermediates. Density functional theory calculations disclosed the origin of chemoselectivity, regioselectivity and stereoselectivity, suggesting an electron-donating effect of the alkene-terminal fluorine atom.

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