scholarly journals Antioxidant Properties of Lapachol and Its Derivatives and Their Ability to Chelate Iron (II) Cation: DFT and QTAIM Studies

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Djafarou Ngouh Pajoudoro ◽  
Daniel Lissouck ◽  
Baruch Ateba Amana ◽  
Joseph Zobo Mfomo ◽  
A. E. B. Abdallah ◽  
...  
Keyword(s):  
Metal Ion ◽  
Density Functional ◽  
Topological Analysis ◽  
Antioxidant Properties ◽  
Solution Phase ◽  
B3lyp Method ◽  
Starting Point ◽  
The Density Functional Theory ◽  
Phase Water ◽  
Two Parameters

The elucidation of the complexation of lapachol and its derivatives to Fe2+ cation has been done using the density functional theory (DFT). This complexation has been limited to bidentate and tridentate to Fe2+ cation. Geometry optimizations have been implemented in gas and solution phase (water, acetonitrile, chlorobenzene, benzene, and toluene) for ligands at B3LYP/6-311++G (d,p) level of theory using B3LYP/6-31+G(d,p) optimized data as starting point. But, the geometrical optimizations in solution phase of the 22 complexes analyzed of lapachol and its derivatives to Fe2+ cation were restricted to acetonitrile and benzene. The complexation energy and the metal ion affinity (MIA) have also been calculated using the B3LYP method. The results obtained indicated a proportionality between the MIA values and the retained charge on Fe2+ cation for k2-(O1,O2) modes. But, an inverse proportionality has been yielded between these two parameters for k3-(O2, C=C) tridentate modes. For k3-(O3,C=C) tridentate mode coordination, the higher stability has been obtained. In this latter tridentate coordination in gas phase, the topological analysis of complexes exhibits the fact that the electron density is concentrated between the O3 oxygen atom of the ligand attached to Fe2+ and this metal cation. Moreover, the hydrogen bond strength calculated for isolated ligands (situated between 23.92 and 30.15 kJ/mol) is in the range of normal HBs. Collectively, all the complexation processes have shown to be highly exothermic. Our results have also shown that the electron extraction from Fe2+...Lai complexes is more difficult compared to that from free ligands.

scholarly journals Synthesis, X-ray Crystal Structures, Computational Studies and Catechol Oxidase Activity of New Acylhydrazone Derivatives

2018 ◽  
Author(s):  
Khalid Karrouchi ◽  
Smaail Radi ◽  
Yousfi El Bekkaye ◽  
Nada Kheira Sebbar ◽  
Jamal Taoufi Taoufik ◽  
...  
Keyword(s):  
Density Functional ◽  
Low Cost ◽  
Molecular Structures ◽  
Catechol Oxidase ◽  
One Pot ◽  
X Ray ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Two Parameters ◽  
L1 And L2

To make low-cost catalytic materials that mimic the activity of tyrosinase enzymes (Catechol oxidase) is an exciting challenge of biochemical technology. Herein, we report the synthesis of a series of acylhydrazone-pyrazoles based biomolecule materials (L1-L7) with superior catecholase activity. These biomolecules were synthesized by a one pot chemical condensation between 5-methyl-1H-pyrazole-3-carbohydrazide and benzaldehyde derivatives. The X-ray single crystal diffraction (XRD) for two ligands L1 and L2 have been studied and the molecular structures were optimized and confirmed using the density functional theory (DFT/B3LYP) method. Copper (II) complexes of the biomolecules (L1-L7), generated in-situ, and were studied for their catalytic activities towards the oxidation reaction of catechol to ortho-quinone according to two parameters: the nature of the ligand and the nature of counter anion. The L7-CuSO4 was found to have an excellent catalytic activity (105.42 μmol·L−1·min−1) among the catalysts recently reported in the existing literature.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

scholarly journals DFT Studies on the Antioxidant Activity of Naringenin and Its Derivatives: Effects of the Substituents at C3

2019 ◽  
Vol 20 (6) ◽  
pp. 1450 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu
Keyword(s):  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Resonance Effect ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Dft Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Selection Of

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.

Density Functional Study on the Configurations of Nen (n=2~36) Clusters

2017 ◽  
Vol 727 ◽  
pp. 381-387
Author(s):  
Chang Ning Peng ◽  
Xing Rong Zheng
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Functional Study ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Quantum Chemistry Calculations ◽  
Average Bond

Based on the First-principles and the method of quantum chemistry calculations, using the B3LYP method and 6-31G basis set of the density functional theory (DFT), the configurations and binding energy of Nen (n=2~36) clusters are calculated and studied theoretically after the calculation of geometry optimization. By changing the atomic number n of the Nen (n=2~36) clusters, it obtained that the stable structures, the binding energy and HOMO - LUMO energy gap of the Nen (n=2~36) clusters under the same ideal conditions, and summarizes the change rule of the stable configurations, the binding energy and the average bond length of the Nen (n=2~36) clusters.

Ab Initio Study of the Structural and Mechanical Properties of Hf-Si-N

2010 ◽  
Vol 139-141 ◽  
pp. 22-25 ◽  
Author(s):  
Xin Tan ◽  
Yu Qing Li ◽  
Xue Jie Liu ◽  
De Gong Liu
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
Cohesive Energy ◽  
Density Functional ◽  
Substitutional Solid Solution ◽  
Lattice Parameter ◽  
Solution Phase ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory

The structural and elastic properties of HfN and Hf-Si-N have been studied, using first principles calculations based on the density functional theory. These calculations provide the lattice parameter, cohesive energy and elastic constants of fcc (NaCl)-HfN, the N-deficient Hf-Si-N and the Hf-deficient Hf-Si-N solution phase. In order to study the relative stability, binding energy of all configurations has been calculated. The results showed that it was difficult to add a Si atom into the center of the HfN cell because the cohesive energy decreased. However, if an Hf atom or an N atom was missing in the HfN, a silicon atom was possible to occupy the vacant site and form the Hf-Si-N substitutional solid solution. Moreover, the bulk modulus, shear modulus and elastic modulus increased accordingly, the mechanical properties were improved.

scholarly journals A combined DFT/topological analysis approach for modeling disordered solid electrolytes

2019 ◽  
Vol 201 ◽  
pp. 02005 ◽  
Author(s):  
Pavel Zolotarev ◽  
Nadezhda Nekrasova ◽  
Andrey Golov ◽  
Roman Eremin
Keyword(s):  
Density Functional ◽  
Topological Analysis ◽  
Density Functional Theory Calculations ◽  
Topological Descriptors ◽  
Elastic Band ◽  
Functional Theory ◽  
Ion Migration ◽  
Energy Characteristics ◽  
The Density Functional Theory ◽  
Band Method

In the scope of this study, the Ag2S·CdS·3SnS2 solid electrolyte disordered in the Cd/Sn sublattice is explored by means of the approach involving configurational space (CS) setting and first-principles calculations. Within the density functional theory calculations on the CS, the absolute differences in Ag vacancy formation energies up to 2.6 eV/cell were obtained for possible Cd/Sn dispositions. Subsequently, silver ion migration was modeled using the nudged elastic band method. The migration energies in the range of 0.250 to 2.993 eV/cell were obtained. By application of topological descriptors, namely, the relative disposition of Cd atoms and the number of Cd atoms in the vicinity of Ag vacancy, the reliable correlations were obtained between the Cd/Sn relative disposition and the calculated energy characteristics.

scholarly journals Noble gas cluster ions

2018 ◽  
Vol 174 ◽  
pp. 06003
Author(s):  
Yunus Kaya ◽  
Yalçin Kalkan ◽  
Rob Veenhof
Keyword(s):  
Density Functional ◽  
Noble Gas ◽  
Kinetic Studies ◽  
Basis Set ◽  
Cluster Ions ◽  
Functional Theory ◽  
B3lyp Method ◽  
Xenon Cluster ◽  
The Density Functional Theory ◽  
Potential Basis

In this work, a reaction mechanism of formation of noble gas (Ng) cluster ions has been theoretically investigated in detail. The kinetic studies of formation of Xe+Xe cluster in Xe, Ar+Ar cluster ions in Ar, and Ne+Ne cluster ions in Ne have been made as theoretically. The optimized structures in the ground state were calculated using the density functional theory (DFT) by the B3LYP method combined with the Stuttgart/Dresden effective core potential basis set (SDD). In addition, we calculated the rate constants of all cluster formations. The results are 1.15 × 10−31, 3.58 × 10−31, 0.23 × 10−31cm6/s, respectively for Neon, Argon, Xenon cluster ions.

A theoretical study on the antioxidant properties of methoxy-substituted chalcone derivatives: A case study of kanakugiol and pedicellin through their Fe (II and III) coordination ability

2016 ◽  
Vol 15 (06) ◽  
pp. 1650048 ◽  
Author(s):  
Kemoabetswe R. N. Serobatse ◽  
Mwadham M. Kabanda
Keyword(s):  
Metal Binding ◽  
Metal Ion ◽  
Density Functional ◽  
Theoretical Study ◽  
Water Solution ◽  
Antioxidant Properties ◽  
Hydroxyl Group ◽  
Chalcone Derivatives ◽  
Coordination Ability

A theoretical study on the antioxidant properties of two chalcone derivatives, kanakugiol and pedicellin, is performed by considering their Fe[Formula: see text] and Fe[Formula: see text] coordination ability. The objective of the study is to elucidate the factors influencing the stability of the isolated conformers, the nature of the complexes, metal[Formula: see text]ligand stability, metal ion affinities (MIA) and electronic properties of the cations before and after coordination to the ligand. The study is performed using the B3LYP/6–311[Formula: see text]G(2d,p)//B3LYP/6–31[Formula: see text]G(d,p) method. The LANL2DZ pseudopotential is selected to describe the Fe[Formula: see text] ions. Time-dependent density functional theory (TDDFT) method is used to assess the electronic UV–Vis spectra of the isolated chalcones and their complexes with Fe[Formula: see text] ions. The results suggest that the preferred complexes are those in which the Fe ion is coordinated at the hydroxyl-methoxy and hydroxyl-keto sites for kanakugiol and methoxy-keto site for pedicellin. Both kanakugiol and pedicellin have potential to chelate iron ions as demonstrated by their high MIA values in vacuo and in water solution. However, the ability of pedicellin to chelate iron is slightly lower than that of kanakugiol, indicating that the presence of the hydroxyl group has an effect of enhancing the metal binding abilities of the chalcone derivatives. In all the complexes obtained in vacuo, kanakugiol and pedicellin exhibit the ability to reduce the Fe[Formula: see text] ion. In water solution (which mimics the environment in biological systems or studies performed in vivo), Fe[Formula: see text] is reduced to Fe[Formula: see text] upon coordination to the ligand while the oxidation number of Fe[Formula: see text] upon coordination to the ligand remains virtually unchanged.

Sign in / Sign up

Export Citation Format

Share Document