scholarly journals Optimization and Computational Approach to Understand the Adsorption Behavior of Alizarine Red S on the Surface of Fish Scales

2021 ◽  
Vol 11 (6) ◽  
pp. 14918-14934
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Fish Scales ◽  
Functional Theory ◽  
Normal Probability ◽  
The Density Functional Theory ◽  
Metropolis Monte Carlo ◽  
Dyes Adsorption ◽  
Factorial Design Analysis ◽  
Natural Composite

The key components of fish scales are hydroxyapatite and collagen, which form a natural composite. In this present study, fish scales were used as biosorbent to uptake Alizarine Red S dyes from the wastewaters. Here, dye concentration, adsorbent amount, pH, and temperature were optimized using complete factorial design analysis. Sixteen experiments were required, and a linear mathematical model representing the influence of the different variables and their interactions was obtained. The discussion covered analysis of variance (ANOVA), normal probability plots of residuals, and surface plots. Theoretical calculations by Metropolis Monte Carlo (MC) methods, the density functional theory (DFT), and the electrostatic potential surface (ESP) analysis were achieved to obtain a more understanding of the dyes adsorption mechanism on both collagen and hydroxyapatite (HDA) surfaces. The findings results exhibited that the ARS dye presents more tendency of adsorption on the collagen than on the HDA surface.

scholarly journals Theoretical Calculations on the Mechanism of Enantioselective Copper(I)-Catalyzed Addition of Enynes to Ketones

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 359 ◽  
Author(s):  
Hanwei Li ◽  
Mingliang Luo ◽  
Guohong Tao ◽  
Song Qin
Keyword(s):  
Density Functional Theory ◽  
Steric Hindrance ◽  
Phenyl Ring ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
Catalytic Cycle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Chiral Systems

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.

scholarly journals Optical Properties of DMA-π-DCV Derivatives: A Theoretical Inspection under the DFT Microscope

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Joaquín Calbo
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Test System ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Donor Acceptor ◽  
Derivatives Of ◽  
Bridge Length ◽  
Theory Framework

The optical properties of a series of donor-acceptor N,N-dimethylaniline-π-dicyanovinylene (DMA-π-DCV) chromophores have been investigated under the density functional theory framework. Focus has been made on the low-lying charge-transfer (CT) electronic transitions for which experimental data is available. The effect of theπ-conjugated bridge length and type was analysed between the families of oligoene and oligoyne derivatives of increasing size. Theoretical calculations demonstrate that the ethylene bridge is a betterπ-communicator and allows for more delocalized frontier molecular orbitals compared to the acetylene spacer. TheΛdiagnostic test allowed rationalization of the orbital spatial overlap in the main CT excitations. The performance of different density functional rungs was assessed in the prediction of the lowest-lying CT electronic transition. Surprisingly, most modern long-range corrected functionals demonstrated to provide among the largest errors, whereas hybrid functionals showed the best performance. Solvatochromism was confirmed in both oligoene and oligoyne compounds. A donor-acceptor-donor triad based on tetrathiafulvalene was utilised as a test system for the prediction of its two CT bands of different nature, energy, and intensity. The hybrid PBE0 (or a similar hybrid analogue) consolidates as the best choice for the prediction of CT excitations in the DMA-π-DCV push-pull family.

A theoretical investigation on promising acceptor groups for POM-based dyes: from electronic structure to photovoltaic conversion efficiency

2020 ◽  
Vol 8 (1) ◽  
pp. 219-227 ◽  
Author(s):  
Yu Gao ◽  
Wei Guan ◽  
Li-Kai Yan ◽  
Zhong-Min Su
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Photovoltaic Conversion Efficiency ◽  
Acceptor Group ◽  
The Density Functional Theory ◽  
Td Dft

Theoretical calculations based on the density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to screen efficient acceptor group candidates for POM-based dyes.

Theoretical calculations of stability, mechanical and thermodynamic properties of IVA group Willemite-II nitrides

2015 ◽  
Vol 14 (04) ◽  
pp. 1550024 ◽  
Author(s):  
Ying-Chun Ding ◽  
Min Chen ◽  
Wen-Juan Wu
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Mechanical Anisotropy ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Good Agreement

The structural stability and mechanical and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are calculated by first-principles calculations based on the density functional theory. The calculated lattice parameters and elastic constants of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are in good agreement with the experimental data and previously calculated values. WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds are also found to be thermodynamically and mechanically stable. The results suggest that hardness of WII- C 3 N 4 is the hardest of these C 3 N 4 polymorphs. The hardness of WII- Sn 3 N 4 is the smallest among WII- A 3 N 4 ( A=C , Si , Ge and Sn ). Furthermore, the mechanical anisotropy, Debye temperature, the minimum thermal conductivity and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds can be investigated.

F2 storage by confinement inside carbon nanotubes

2016 ◽  
Vol 94 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Wiem Felah Gtari ◽  
Bahoueddine Tangour
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Density Functional Theory Method ◽  
Van Der Waals Interactions ◽  
Basis Set ◽  
Basis Sets ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Walled Carbon Nanotubes

Theoretical calculations have been achieved to study the interaction between the confined F2 molecule along the nanotube axis and perpendicular to it and armchair (n,n) single-walled carbon nanotubes with n = 4, 5, 6, 7, and 8 and the zig-ag nanotube (9,0) using the density functional theory method with the CAM-B3LYP functional and both cc-pVQZ and STO-3G basis sets. The interaction of the F2 molecule with the nanotube is different according to the molecular orientation, the chirality of the carbon nanotube, and the confinement space extension. These results interpreted by means of van der Waals interactions reveal anisotropic and competitive behavior at the nanometric level. The π electrons of the nanotube interact with the lone pairs of F2 highlighting its lateral polarizability. The encapsulated F2 molecule is stable along and perpendicular to the nanotube (5,5) and (6,6) axis. The best stabilization energy is obtained fornanotube (5,5) at the perpendicular position using the cc-pVQZ basis set.

Phase Transition and Elastic Properties of Zinc Sulfide Under High Pressure from First Principles Calculations

2011 ◽  
Vol 66 (10-11) ◽  
pp. 656-660
Author(s):  
Dai Wei ◽  
Song Jin-Fan ◽  
Wang Ping ◽  
Lu Cheng ◽  
Lu Zhi-Wen ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Zinc Sulfide ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Structural Phase ◽  
Functional Theory ◽  
The Density Functional Theory

A theoretical investigation on structural and elastic properties of zinc sulfide semiconductor under high pressure is performed by employing the first-principles method based on the density functional theory. The calculated results show that the transition pressure Pt for the structural phase transition from the B3 structure to the B1 structure is 17:04 GPa. The calculated values are generally speaking in good agreement with experiments and with similar theoretical calculations.

Synthesis and structures of three new pyridine-containing oxazoline ligands of complexes for asymmetric catalysis

2021 ◽  
Vol 77 (9) ◽  
pp. 529-536
Author(s):  
Ewa Wolińska ◽  
Waldemar Wysocki ◽  
Danuta Branowska ◽  
Zbigniew Karczmarzyk
Keyword(s):  
Asymmetric Catalysis ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Ligand Conformation ◽  
Oxazoline Ligands

Three new chiral pyridine-containing oxazoline derivatives with fluorine and perfluoromethyl groups, namely, 2-({2-[(4S)-4-phenyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C21H16F3N3O, 2-({5-fluoro-2-[(4S)-4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C18H17F4N3O, and 2-({2-[(3aR,8aS)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C22H16F3N3O, as chiral ligands in metal-catalysed asymmetric reactions, were synthesized and characterized by spectral and X-ray diffraction methods. The conformation of the molecules is influenced by strong N—H...N hydrogen bonding and weak C—H...X (X = O and N) interactions. There are no intermolecular hydrogen bonds in the crystal structures of the analysed compounds. Hirshfeld surface analysis showed that the H...H contacts constitute a high percentage of the intermolecular interactions. The conformational analysis was performed by theoretical calculations using the density functional theory (DFT) method. The mechanism of complex formation in terms of the electron-withdrawing effect of the substituents on the oxazoline ring and the ligand conformation is discussed.

Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

2018 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Athanassis Katsenis ◽  
Novendra Novendra ◽  
Zamirbek Akimbekov ◽  
Dayaker Gandrath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Experimental Evaluation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zeolitic Imidazolate Framework ◽  
Functional Theory ◽  
Calorimetric Measurements ◽  
And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

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