Reactivity Indices for ortho/para Monosubstituted Phenols

2007 ◽  
Vol 10 (1) ◽  
Author(s):  
Nevim San ◽  
Murat Kılıç ◽  
Zekiye Çınar
Keyword(s):  
Photocatalytic Degradation ◽  
Density Functional ◽  
Reaction Rates ◽  
Chemical Hardness ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Degradation Reactions ◽  
The Density Functional Theory ◽  
Local Softness ◽  
Soft Interactions

AbstractThe kinetics of the photocatalytic degradation reactions of twelve ortho/para mono-substituted phenols containing electron-donating or -withdrawing groups have been investigated experimentally. With the intention of determining the most suitable DFT reactivity descriptors, geometry optimizations of the compounds have been performed with the Density Functional Theory DFT at B3LYP/6-31G* level. In order to take the effect of solvent water into account, the calculations have been repeated for the optimized structures by using COSMO as the solvation model. Chemical hardness, softness, electronegativities, Fukui functions, local hardness and softness, local electrophilicities and softness differences for all phenol molecules have been calculated. Correlations between the apparent initial first-order rate constants determined in the experiments and the calculated DFT reactivity descriptors have been examined. Results show that the reactions investigated are electrophilic in nature. The local softness and softness differences correlate well with the reaction rates indicating that soft-soft interactions dominate in the photocatalytic degradation reactions of phenols.

scholarly journals DFT investigations on arylsulphonyl pyrazole derivatives as potential ligands of selected kinases

2020 ◽  
Vol 18 (1) ◽  
pp. 857-873
Author(s):  
Kornelia Czaja ◽  
Jacek Kujawski ◽  
Radosław Kujawski ◽  
Marek K. Bernard
Keyword(s):  
Free Energy ◽  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Chemical Hardness ◽  
Free Energy Of Solvation ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Condensed Fukui Functions ◽  
Charge Partitioning

AbstractUsing the density functional theory (DFT) formalism, we have investigated the properties of some arylsulphonyl indazole derivatives that we studied previously for their biological activity and susceptibility to interactions of azoles. This study includes the following physicochemical properties of these derivatives: electronegativity and polarisability (Mulliken charges, adjusted charge partitioning, and iterative-adjusted charge partitioning approaches); free energy of solvation (solvation model based on density model and M062X functional); highest occupied molecular orbital (HOMO)–lowest occupied molecular orbital (LUMO) gap together with the corresponding condensed Fukui functions, time-dependent DFT along with the UV spectra simulations using B3LYP, CAM-B3LYP, MPW1PW91, and WB97XD functionals, as well as linear response polarisable continuum model; and estimation of global chemical reactivity descriptors, particularly the chemical hardness factor. The charges on pyrrolic and pyridinic nitrogen (the latter one in the quinolone ring of compound 8, as well as condensed Fukui functions) reveal a significant role of these atoms in potential interactions of azole ligand–protein binding pocket. The lowest negative value of free energy of solvation can be attributed to carbazole 6, whereas pyrazole 7 has the least negative value of this energy. Moreover, the HOMO–LUMO gap and chemical hardness show that carbazole 6 and indole 5 exist as soft molecules, while fused pyrazole 7 has hard character.

scholarly journals Conceptual DFT as a Novel Chemoinformatics Tool for Studying the Chemical Reactivity Properties of the Amatoxin Family of Fungal Peptides

2019 ◽  
Vol 17 (1) ◽  
pp. 1133-1139 ◽  
Author(s):  
Norma Flores-Holguín ◽  
Juan Frau ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Density Functional ◽  
Chemical Reactivity ◽  
Active Regions ◽  
Chemical Hardness ◽  
Conceptual Density Functional Theory ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Molecular Systems ◽  
Chemical Structures ◽  
Simple Protocol

AbstractThe chemical structures and molecular reactivities of the Amatoxin group of fungi-derived peptides have been determined by means of the consideration of a model chemistry that has been previously validated as well-behaved for our purposes. The reactivity descriptors were calculated on the basis of a methodological framework built around the concepts that are the outcome of the so called Conceptual Density Functional Theory (CDFT). This procedure in connection with the different Fukui functions allowed to identify the chemically active regions within the molecules. By considering a simple protocol designed by our research group for the estimation of the pKa of peptides through the information coming from the chemical hardness, these property has been established for the different molecular systems explored in this research. The information reported through this work could be of interest for medicinal chemistry researchers in using this knowledge for the design of new medicines based on the studied peptides or as a help for the understanding of the toxicity mechanisms exerted by them.

scholarly journals Chemical-Reactivity Properties, Drug Likeness, and Bioactivity Scores of Seragamides A–F Anticancer Marine Peptides: Conceptual Density Functional Theory Viewpoint

Computation ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 52 ◽  
Author(s):  
Norma Flores-Holguín ◽  
Juan Frau ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Density Functional Theory ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Drug Repurposing ◽  
Chemical Hardness ◽  
Conceptual Density Functional Theory ◽  
Functional Theory ◽  
Fukui Functions ◽  
Reactivity Descriptors

A methodology based on concepts that arose from Density Functional Theory (CDFT) was chosen for the calculation of global and local reactivity descriptors of the Seragamide family of marine anticancer peptides. Determination of active sites for the molecules was achieved by resorting to some descriptors within Molecular Electron Density Theory (MEDT) such as Fukui functions. The pKas of the six studied peptides were established using a proposed relationship between this property and calculated chemical hardness. The drug likenesses and bioactivity properties of the peptides considered in this study were obtained by resorting to a homology model by comparison with the bioactivity of related molecules in their interaction with different receptors. With the object of analyzing the concept of drug repurposing, a study of potential AGE-inhibition abilities of Seragamides peptides was pursued by comparison with well-known drugs that are already available as pharmaceuticals.

Tautomeric transformations and reactivity of isoindole and sila-indole: A computational study

2014 ◽  
Vol 13 (05) ◽  
pp. 1450041 ◽  
Author(s):  
Reza Ghiasi ◽  
Morteza Zaman Fashami
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Polarizable Continuum Model ◽  
Band Gap Energy ◽  
Reaction Field ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Quadrupole Resonance ◽  
Local Softness ◽  
Polarizable Continuum

In this work, the tautomeric transformations and reactivity of isoindole and sila-isoindole molecules has been explored using the B3LYP/6-311G(d,p) level of theory in gas and solution phases. These calculations show that isoindole isomer has more stability rather than 1-h-isoindole. There is identical trend in silated species. The frontier molecular orbitals (FMO) and band gap energy calculations were performed at the B3LYP/6-311G(d,p) level in gas and various solvent. Solvent effects have been analyzed by using the self-consistent reaction field (SCRF) method based on polarizable continuum model (PCM) in chloroform, chlorobenzene, dichloromethane and tetrahydrofurane. Thermodynamic parameters calculated at room temperature have been analyzed. Also, electron affinities were computed. Local reactivity descriptors as Fukui functions [Formula: see text] local softness [Formula: see text] and electrophilicity indices [Formula: see text] analyses are performed to find out the reactive sites within molecule. Density functional theory (DFT) calculations were performed to compute nitrogen-14 nuclear quadrupole resonance (NQR) spectroscopy parameters.

Study of the Stability and Chemical Reactivity of a Series of Tetrazole Pyrimidine Hybrids by the Density Functional Theory Method (DFT)

2021 ◽  
Vol 37 (4) ◽  
pp. 805-812
Author(s):  
Ahissandonatien Ehouman ◽  
Adjoumanirodrigue Kouakou ◽  
Fatogoma Diarrassouba ◽  
Hakim Abdel Aziz Ouattara ◽  
Paulin Marius Niamien
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Chemical Reactivity ◽  
Density Functional Theory Method ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global Reactivity Descriptors

Our theoretical study of stability and reactivity was carried out on six (06) molecules of a series of pyrimidine tetrazole hybrids (PTH) substituted with H, F, Cl, Br, OCH3 and CH3 atoms and groups of atoms using the density function theory (DFT). Analysis of the thermodynamic formation quantities confirmed the formation and existence of the series of molecules studied. Quantum chemical calculations at the B3LYP / 6-311G (d, p) level of theory determined molecular descriptors. Global reactivity descriptors were also determined and analyzed. Thus, the results showed that the compound PTH_1 is the most stable, and PTH_5 is the most reactive and nucleophilic. Similarly, the compound PTH_4 is the most electrophilic. The analysis of the local descriptors and the boundary molecular orbitals allowed us to identify the preferred atoms for electrophilic and nucleophilic attacks.

New molecular target insights about protein kinases of the Plasmodium falciparum. Using molecular docking and DFT-based reactivity descriptors

2017 ◽  
Vol 16 (08) ◽  
pp. 1750076 ◽  
Author(s):  
Alejandro Morales-Bayuelo
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Kinases ◽  
Density Functional ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Binding Pocket ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Chemical Reactivity Descriptors ◽  
Hinge Zone

Currently, there is increasing interest in the potential of malaria inhibitors in Plasmodium falciparum activity. In this work, is propose a possible alternative to classifying 154 antimalarials, with P. falciparum activity. These antimalarials were synthesized by the Chibale’s group ( http://www.kellychibaleresearch.uct.ac.za/ ), with the goal of finding new insights on the binding pocket of the protein kinase PfPK5, PfPK7, PfCDPK1, PfCDPK4, PfMAP1, and PfPK6 of the malaria parasite. However, there is only information about crystallography of PfPK5 and PfPK7. The protein kinases PfCDPK1, PfCDPK4, PfMAP1, and PfPK6 were modeled using molecular homology. The validation used shows that our homology models can be an alternative for the protein kinases from P. falciparum, unknown today. The antimalarials were classified by taking into account the interactions in the hinge zone. These ligands bind to the kinase through the formation of one of two hydrogen bonds, with the backbone residues of the hinge region connecting the kinase N- and C-terminal loops. These interactions were supported by a reactivity chemistry analysis, using global chemical reactivity descriptors such as chemical potential, hardness, softness, electrophilicity, and the Fukui functions as local reactivity descriptors, within the Density Functional Theory (DFT) context.

Theoretical study of 11-thiocyanatoundecanoic acid phenylamide derivatives on corrosion inhibition efficiencies

2014 ◽  
Vol 92 (9) ◽  
pp. 876-887 ◽  
Author(s):  
Seda Sagdinc ◽  
Yesim Kara ◽  
Filiz Kayadibi
Keyword(s):  
Density Functional ◽  
Corrosion Inhibitors ◽  
Energy Gap ◽  
Basis Set ◽  
Inhibitor Molecule ◽  
Functional Theory ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Hartree Fock ◽  
Adsorption Sites

Ab initio Hartree–Fock (HF) and Density Functional Theory (DFT) B3LYP methods with the 6-311G(d,p) basis set were applied to the three 11-thiocyanatoundecanoic acid phenylamide derivatives as corrosion inhibitors. Inhibition efficiency obtained experimentally followed the following order: N-(4-methoxyphenyl)-11-thiocyanatoundecanamide (N3MPTUA) > N-phenyl-11-thiocyanatoundecanamide (NPTUA) > N-(3-nitrophenyl)-11-thiocyanatoundecanamide (N3NPTUA). The molecular parameters most relevant to their potential action as corrosion inhibitors have been calculated in the neutral and protonated forms: EHOMO, ELUMO, energy gap (ΔE), dipole moment (μD), electronegativity (χ), global hardness (η), and the fraction of electrons transferred from the inhibitor molecule to the metallic atom (ΔN). The results of most of the global reactivity descriptors show that the experimental and theoretical studies agree well, and confirm that N3MPTUA is a better inhibitor than NPTUA or N3NPTUA. In addition, the local reactivity, analyzed through Fukui functions, show that the oxygen and nitrogen atoms will be the main adsorption sites.

scholarly journals Conceptual DFT-based Computational Peptidology of Marine Natural Compounds: Discodermins A–H

2020 ◽  
Author(s):  
Norma Flores-Holguín ◽  
Juan Frau ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Density Functional Theory ◽  
Active Sites ◽  
Density Functional ◽  
Homology Model ◽  
Conceptual Density Functional Theory ◽  
Functional Theory ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Qsar Studies ◽  
Biological Targets

A methodology based on the concepts that arise from Density Functional Theory named Conceptual Density Functional Theory (CDFT) was chosen for the calculation of some global and local reactivity descriptors of the Discodermins A-H family of marine peptides through the consideration of the KID (Koopmans in DFT) technique that was successfully used in previous studies of this kind of molecular systems. The determination of active sites of the studied molecules for different kind of reactivities was achieved by resorting to some CDFT-based descriptors like the Fukui functions as well as the Parr functions derived from Molecular Electron Density Theory (MEDT). A few properties identified with their ability to behave as a drug and the bioactivity of the peptides considered in this examination were acquired by depending on a homology model by studying the correlation with the known bioactivity of related molecules in their interaction with various biological receptors. With the further object of analyzing their bioactivity some parameters of usefulness for future QSAR studies, their predicted biological targets and the the ADME (Absorption, Distribution, Metabolism, and Excretion) parameters related to the Discodermins A-H pharmacokinetics are also reported.

A Density Functional Theory Study on the Structures and Electronic Properties of XAln (X = Br, I; n = 3–15) Clusters

2019 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Ming Hui ◽  
Qing-Huai Zhao ◽  
Zhi-Peng Wang ◽  
Shuai Zhang ◽  
Gen-Quan Li
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Chemical Hardness ◽  
Geometrical Structures ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractThe effects of halogen element X (X = Br, I) doping on the geometrical structures and electronic properties of neutral aluminium clusters are systematically studied by utilising the density functional theory calculations. The structures of X-doped clusters show the three-dimensional forms with increasing atomic number except for n = 3 and X (X = Br, I) atom prefer to occupy the surface site of the host Aln clusters. BrAl7 and IAl7 clusters are the most stable geometries. The HOMO-LUMO energy gap and chemical hardness show an odd–even alternative phenomenon. The charges always transfer from the Al atoms to the X (X = Br, I) atom. Finally, the dipole and polarisability are discussed.

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