Basis set dependence of the molecular electrostatic potential topography. A case study of substituted benzenes

The binding, interaction and distortion energies between the main triglycerides, palmitic-oleic-stearic (POS) in cocoa butter versus palmitic-oleic-palmitic (POP) in refined, bleached and deodorized (RBD) palm oil with cocoa′s methylxanthines (caffeine, theobromine, and theophylline) during the production of chocolate were theoretically studied and reported. The quantum mechanical software package of Gaussian09 at the theoretical level of density functional theory B3LYP/6-31G(d,p) was employed for all calculations, optimization, and basis set superposition errors (BSSE). Geometry optimizations were carried out to the minimum potential energy of individual species and binary complexes formed between the triglycerides, methylxanthines and polyphenols. The interaction energies for the optimized complexes were then corrected for the BSSE using the counterpoise method of Boys and Bernardi. The results revealed that the binding energy and interaction energy between methylxanthine components in cocoa powder with triglycerides were almost of the same magnitude (13.6-14.5 and 3.4-3.7 kJ/mol, respectively), except for the binary complex of POS-caffeine (25.1 and 10.7 kJ/mol, respectively). Based on the molecular geometry results, the hydrogen bond length and angle correlated well with the interaction energies. Meanwhile, the POS-caffeine complex with two higher and almost linear bond angles showed higher binding and interaction energies as compared to the other methylxanthines. Therefore, a donor-acceptor analysis showed that the hydrogen bond strength was proven using the molecular electrostatic potential (MEP), which resulted in parallel outcomes. The research results were believed to be one of the factors that contributed to the rheological behaviour and sensory perception of cocoa products, especially chocolate.

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A Look at the Spatial Confining Effect on the Molecular Electrostatic Potential (MEP)—A Case Study of the HF and BrCN Molecules

Molecules ◽

10.3390/molecules26195924 ◽

2021 ◽

Vol 26 (19) ◽

pp. 5924

Author(s):

Paweł Lipkowski ◽

Justyna Kozłowska ◽

Wojciech Bartkowiak

Keyword(s):

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Theoretical Study ◽

Cylindrical Symmetry ◽

Spatial Confinement ◽

Molecular Systems ◽

Confining Effect ◽

Repulsive Potentials ◽

Preliminary Study

In this theoretical study, we report on the molecular electrostatic potential (MEP) of titled molecules confined by repulsive potentials of cylindrical symmetry mimicking a topology. Our calculations show that the spatial restriction significantly changes the picture of the MEP of molecules in a quantitative and qualitative sense. In particular, the drastic changes in the MEP as a function of the strength of spatial confinement are observed for the BrCN molecule. This preliminary study is the first step in the investigation of the behavior of the MEP of molecular systems under orbital compression.

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Efficient Evaluation of Molecular Electrostatic Potential in Large Systems

Computation ◽

10.3390/computation7040064 ◽

2019 ◽

Vol 7 (4) ◽

pp. 64

Author(s):

Rafael Lopez ◽

Frank Martinez ◽

Ignacio Ema ◽

Jose Manuel Garcia de la Vega ◽

Guillermo Ramirez

Keyword(s):

Electron Density ◽

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Computation Time ◽

Basis Set ◽

Efficient Computation ◽

Multipole Moments ◽

Atomic Orbitals ◽

Electron Density Matrix ◽

Large Systems

An algorithm for the efficient computation of molecular electrostatic potential is reported. It is based on the partition/expansion of density into (pseudo) atomic fragments with the method of Deformed Atoms in Molecules, which allows to compute the potential as a sum of atomic contributions. These contributions are expressed as a series of irregular spherical harmonics times effective multipole moments and inverse multipole moments, including short-range terms. The problem is split into two steps. The first one consists of the partition/expansion of density accompanied by the computation of multipole moments, and its cost depends on the size of the basis set used in the computation of electron density within the Linear Combination of Atomic Orbitals framework. The second one is the actual computation of the electrostatic potential from the quantities calculated in the first step, and its cost depends on the number of computation points. For a precision in the electrostatic potential of six decimal figures, the algorithm leads to a dramatic reduction of the computation time with respect to the calculation from electron density matrix and integrals involving basis set functions.

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Chemical Reactivity, Dipole Moment and First Hyperpolarizability of Aristolochic Acid I

Journal of Institute of Science and Technology ◽

10.3126/jist.v21i1.16030 ◽

2016 ◽

Vol 21 (1) ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Bhawani Datta Joshi

Keyword(s):

Dipole Moment ◽

Electrostatic Potential ◽

Density Functional ◽

Molecular Electrostatic Potential ◽

Aristolochic Acid ◽

Chemical Reactivity ◽

Basis Set ◽

Non Linear ◽

Linear Optical ◽

Aristolochic Acid I

Aristolochic acids (AAs) have been used in the treatment of oedema in Chinese herb medicine since long ago. In this paper, molecular electrostatic potential, chemical reactivity and non linear optical properties of aristolochic acid I (AA I) have been analyzed using density functional theory employing 6-311++G(d,p) basis set. The chemical reactivity of the molecule has been explained with the help of chemical reactivity descriptors, molar refractivity and the molecular electrostatic potential surface (ESP). The calculated dipole moment and first order hyperpolarizability show that the molecule possesses non-linear optical property.Journal of Institute of Science and TechnologyVolume 21, Issue 1, August 2016, page: 1-9

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Molecular Electrostatic Potential-Based Atoms in Molecules: Shielding Effects and Reactivity Patterns

Australian Journal of Chemistry ◽

10.1071/ch16226 ◽

2016 ◽

Vol 69 (9) ◽

pp. 975 ◽

Cited By ~ 4

Author(s):

Anmol Kumar ◽

Shridhar R. Gadre

Keyword(s):

Present Article ◽

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Atoms In Molecules ◽

Basis Set ◽

Nucleophilic Attack ◽

Nmr Data ◽

Electronic Distribution ◽

Molecular Charge ◽

Shielding Effects

The Atoms in Molecules (AIM) concept based on the zero-flux surface (ZFS) of the gradient of molecular electrostatic potential (MESP) has been recently proposed by the present authors. The nature of MESP-based atomic basins brings out the asymmetric electronic distribution in a molecule. An electron-rich atom among the two bonded atoms is seen to possess a completely closed MESP-based atomic basin. The present article illustrates the nature of atomic basins for a variety of molecules such as BF, BH3, AlCl3, B2H6, and Al2Cl6, and a Lewis acid–base pair, viz. NH3BH3 wherein the electronic distribution is not merely guided by difference in the electronegativity of the atoms. The study also explores some transition metal complexes, viz. Ni(CO)4, Fe(CO)5, Cr(CO)6, Mn2(CO)10, Co2(CO)8, Fe(η5-C5H5)2, Co(η3-C3H5), and Co(η3-C3H5)(CO)3, which show a similar phenomenon of intricate charge transfer among the ligands and the metal centre. The present article employs MESP-based AIM for a qualitative explanation of the shielding or deshielding effects revealed by NMR data as well as susceptibility of an atomic region towards an electrophilic or nucleophilic attack. Because the topographical features of MESP and thus the nature of atomic basins are not very sensitive to the level of theory and basis set, the present article demonstrates the capability of MESP as a consistent and simple tool for the portrayal of asymmetry in molecular charge distribution.

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Computational Insights on Molecular Structure, Electronic Properties, and Chemical Reactivity of (E)-3-(4-Chlorophenyl)-1-(2-Hydroxyphenyl)Prop-2-en-1-one

Material Science Research India ◽

10.13005/msri.17.special-issue1.06 ◽

2020 ◽

Vol 17 (SpecialIssue1) ◽

pp. 41-53

Author(s):

Vishnu A. Adole ◽

Prashant B. Koli ◽

Rahul A. Shinde ◽

Rohit S. Shinde

Keyword(s):

Electronic Properties ◽

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Chemical Reactivity ◽

Basis Set ◽

Group Symmetry ◽

Ir Absorption ◽

Hydrogen Atoms ◽

Ft Ir ◽

Title Molecule

In the current examination, (E)-3-(4-chlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one has been studied to investigate geometrical entities, electronic properties, and chemical reactivity viewpoints. To inspect structural, spectroscopic, and chemical reactivity aspects, density functional theory method (DFT) at B3LYP/6-311G(d,p) basis set has been employed. The (E)-3-(4-chlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one has been synthesized and characterized by FT-IR, 1HNMR, and 13C NMR spectral techniques. The detailed investigation of bond lengths and bond angles is discussed to comprehend the geometrical framework. To explore its chemical behaviour, Mulliken atomic charges, molecular electrostatic potential surface, and electronic parameters are introduced. The imperative exploration of the electronic properties, such as HOMO and LUMO energies, was studied by the time-dependent DFT (TD-DFT) method. The dipole moment of the title molecule is 2.57 Debye with C1 point group symmetry. The most electropositive carbon and hydrogen atoms in the title molecule are C14 and H27 respectively. Amongst aromatic C=C, the C16-C18 is the longest, and C17-C19 is the shortest bond. The molecular electrostatic potential plot predicts the positive electrostatic potential is around hydrogen atoms. The vibrational assignments were made by comparing the experimental FT-IR absorption peaks with the scaled frequencies obtained using computational work. Besides, some significant thermochemical information is obtained using the same basis set using frequencies.

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Molecular structure, HOMO, LUMO, MEP, natural bond orbital analysis of benzo and anthraquinodimethane derivatives

Pharmaceutical and Biological Evaluations ◽

10.26510/2394-0859.pbe.2018.04 ◽

2018 ◽

Vol 5 (2) ◽

pp. 27 ◽

Cited By ~ 2

Author(s):

Tahar Abbaz ◽

Amel Bendjeddou ◽

Didier Villemin

Keyword(s):

Electrostatic Potential ◽

Density Functional ◽

Molecular Electrostatic Potential ◽

Natural Bond Orbital ◽

Molecular Structures ◽

Basis Set ◽

Frontier Molecular Orbital ◽

Charge Delocalization ◽

B3lyp Method ◽

Optimized Geometries

Objective: Optimized molecular structures have been investigated by DFT/B3LYP method with 6-31G (d,p) basis set. Stability of Benzo and anthraquinodimethane derivatives 1-4, hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed by using natural bond orbital (NBO) analysis. Electronic structures were discussed and the relocation of the electron density was determined. Molecular electrostatic potential (MEP), local density functional descriptors has been studied. Nonlinear optical (NLO) properties were also investigated. In addition, frontier molecular orbitals analyses have been performed from the optimized geometries. An ionization potential (I), electron afﬁnity (A), electrophilicity index (ω), chemical potential (µ), electronegativity (χ), hardness (η), and softness (S), have been investigated. All the above calculations are made by the method mentioned above.Methods: The most stable optimized geometries obtained from DFT/B3LYP method with 6-31G(d,p) basis set were investigated for the study of molecular structures, nonlinear properties, natural bond orbital (NBO), molecular electrostatic potential (MEP) and frontier molecular orbital of Benzo and anthraquinodimethane derivatives.Results: Reactive sites of electrophilic and nucleophilic attacks for the investigated molecule were predicted using MEP at the B3LYP/6-31G(d,p). Compound 4 possesses higher electronegativity value than all compounds so; it is the best electron acceptor; the more reactive sites for electrophilic attacks are shown in compounds 1 and 4, for nucleophilic attacks are indicated in compounds 2 and 3 and the more reactive sites in radical attacks are detected in compounds 2 and 4.Conclusions: Compound 1 is softest, best electron donor and more reactive than all compounds. The calculated ﬁrst order hyperpolarizability was found much lesser than reported in literature for urea.

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Look at the Spatial Confining Effect on the Molecular Electrostatic Potential (Mep). A Case Study of the Hf and Brcn Molecules

10.20944/preprints202108.0500.v1 ◽

2021 ◽

Author(s):

Paweł Lipkowski ◽

Justyna Kozłowska ◽

Wojciech Bartkowiak

Keyword(s):

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Theoretical Study ◽

Cylindrical Symmetry ◽

Spatial Confinement ◽

Molecular Systems ◽

Confining Effect ◽

Repulsive Potentials ◽

Preliminary Study

In this theoretical study we report on molecular electrostatic potential (MEP) of titled molecules confined by repulsive potentials of cylindrical symmetry mimicking a topology. Our calculations show that the spatial restriction significantly changes the picture of MEP of molecules in quantitative and qualitative sense. In particular, the drastic changes of MEP as a function of the strength of spatial confinement are observed for the BrCN molecule. This preliminary study is the first step in the investigations of the behavior of MEP of molecular systems under the orbital compression.

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