scholarly journals Theoretical Calculations and Modeling for the Molecular Polarization of Furan and Thiophene under the Action of an Electric Field Using Quantum Similarity

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alejandro Morales-Bayuelo ◽  
Ricardo Vivas-Reyes
Keyword(s):  
Electric Field ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Point Group ◽  
Quantum Similarity ◽  
Local Similarity ◽  
Functional Theory ◽  
Effect Theory ◽  
Molecular Quantum Similarity ◽  
Euclidean Distances

A theoretical study on the molecular polarization of thiophene and furan under the action of an electric field using Local Quantum Similarity Indexes (LQSI) was performed. This model is based on Hirshfeld partitioning of electron density within the framework of Density Functional Theory (DFT). Six local similarity indexes were used: overlap, overlap-interaction, coulomb, coulomb-interaction, Euclidian distances of overlap, and Euclidean distances of coulomb. In addition Topo-Geometrical Superposition Algorithm (TGSA) was used as a method of alignment. This method provides a straightforward procedure to solve the problem of molecular relative orientation. It provides a tool to evaluate molecular quantum similarity, enabling the study of structural systems, which differ in only one atom such as thiophene and furan (point group C2v) and cyclopentadienyl molecule (point group D5h). Additionally, this model can contribute to the interpretation of chemical bonds, and molecular interactions in the framework of the solvent effect theory.

scholarly journals Scale Alpha and Beta of Quantitative Convergence and Chemical Reactivity Analysis in Dual Cholinesterase/Monoamine Oxidase Inhibitors for the Alzheimer Disease Treatment Using Density Functional Theory (DFT)

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Alejandro Morales-Bayuelo ◽  
Rosa Baldiris ◽  
Ricardo Vivas-Reyes
Keyword(s):  
Density Functional Theory ◽  
Monoamine Oxidase ◽  
Density Functional ◽  
Monoamine Oxidase Inhibitors ◽  
Quantum Similarity ◽  
Disease Treatment ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Reactivity Indexes ◽  
Molecular Quantum Similarity

Molecular quantum similarity descriptors and Density Functional Theory (DFT) based reactivity descriptors were studied for a series of cholinesterase/monoamine oxidase inhibitors used for the Alzheimer's disease treatment (AD). This theoretical study is expected to shed some light onto some molecular aspects that could contribute to the knowledge of the molecular mechanics behind interactions of these molecules with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as well as with monoamine oxidase (MAO) A and B. The Topogeometrical Superposition Algorithm to handle flexible molecules (TGSA-Flex) alignment method was used to solve the problem of the relative orientation in the quantum similarity (QS) field. Using the molecular quantum similarity (MQS) field and reactivity descriptors supported in the DFT was possible the quantification of the steric and electrostatic effects through of the Coulomb and Overlap quantitative convergence scales (alpha and beta). In addition, an analysis of reactivity indexes is development, using global and local descriptors, identifying the binding sites and selectivity in the (cholinesterase/monoamine oxidase) inhibitors, understanding the retrodonor process, and showing new insight for drugs design in a disease of difficult control as Alzheimer.

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>

Density Functional Theory Study of Antioxidant Adsorption onto Single- Wall Boron Nitride Nanotubes: Design of New Antioxidant Delivery Systems

2019 ◽  
Vol 22 (7) ◽  
pp. 470-482
Author(s):  
Samereh Ghazanfary ◽  
Fatemeh Oroojalian ◽  
Rezvan Yazdian-Robati ◽  
Mehdi Dadmehr ◽  
Amirhossein Sahebkar
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Vitamin C ◽  
Electric Field ◽  
External Electric Field ◽  
Lipoic Acid ◽  
Density Functional ◽  
Cell Interaction ◽  
Boron Nitride Nanotubes ◽  
Functional Theory

Background: Boron Nitride Nanotubes (BNNTs) have recently emerged as an interesting field of study, because they could be used for the realization of developed, integrated and compact nanostructures to be formulated. BNNTs with similar surface morphology, alternating B and N atoms completely substitute for C atoms in a graphitic-like sheet with nearly no alterations in atomic spacing, with uniformity in dispersion in the solution, and readily applicable in biomedical applications with no obvious toxicity. Also demonstrating a good cell interaction and cell targeting. Aim and Objective: With a purpose of increasing the field of BNNT for drug delivery, a theoretical investigation of the interaction of Melatonin, Vitamin C, Glutathione and lipoic acid antioxidants using (9, 0) zigzag BNNTs is shown using density functional theory. Methods: The geometries corresponding to Melatonin, Vitamin C, Glutathione and lipoic acid and BNNT with different lengths were individually optimized with the DMOL3 program at the LDA/ DNP (fine) level of theory. Results: In the presence of external electric field Melatonin, Vitamin C, Glutathione and lipoic acid could be absorbed considerably on BNNT with lengths 22 and 29 Å, as the adsorption energy values in the presence of external electric field are considerably increased. Conclusion: The external electric field is an appropriate technique for adsorbing and storing antioxidants on BNNTs. Moreover, it is believed that applying the external electric field may be a proper method for controlling release rate of drugs.

The tuning effect of the electric field on the physical properties of some typical wurtzite semiconductors

2017 ◽  
Vol 31 (33) ◽  
pp. 1750310 ◽  
Author(s):  
Jia-Ning Li ◽  
San-Lue Hu ◽  
Hao-Yu Dong ◽  
Xiao-Ying Xu ◽  
Jia-Fu Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Physical Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Great Influence ◽  
Semiconductor Materials ◽  
Functional Theory ◽  
The Stability ◽  
Wurtzite Semiconductors

Under the tuning of an external electric field, the variation of the geometric structures and the band gaps of the wurtzite semiconductors ZnS, ZnO, BeO, AlN, SiC and GaN have been investigated by the first-principles method based on density functional theory. The stability, density of states, band structures and the charge distribution have been analyzed under the electric field along (001) and (00[Formula: see text]) directions. Furthermore, the corresponding results have been compared without the electric field. According to our calculation, we find that the magnitude and the direction of the electric field have a great influence on the electronic structures of the wurtzite materials we mentioned above, which induce a phase transition from semiconductor to metal under a certain electric field. Therefore, we can regulate their physical properties of this type of semiconductor materials by tuning the magnitude and the direction of the electric field.

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