Spectroscopic investigation, HOMO–LUMO energies, natural bond orbital (NBO) analysis and thermodynamic properties of two-armed macroinitiator containing coumarin with DFT quantum chemical calculations

2016 ◽  
Vol 94 (6) ◽  
pp. 583-593 ◽  
Author(s):  
Feride Akman
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Dft Method ◽  
Basis Set ◽  
Orbital Method ◽  
Functional Theory ◽  
Homo Lumo

In the present work, two-armed macroinitiator containing coumarin were synthesized, characterized by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance techniques and investigated theoretically using density functional theory (DFT) calculations. The molecular geometry, fundamental vibrational frequencies, atomic charges obtained from atomic polar tensors and Mulliken were analyzed by means of structure optimizations based on the DFT method with 6-31G+(d, p) as a basis set. The 1H chemical shifts were calculated by the gauge-including atomic orbital method and compared with available experimental data. The electronic properties, such as highest occupied molecular orbital – lowest unoccupied molecular orbital (HOMO–LUMO) energies, electron affinity, electronegativity, ionization energy, hardness, chemical potential, global softness, and global electrophilicity were calculated by using the DFT method. The electrostatic potential and molecular electrostatic potential surfaces were performed to predict the reactive sites of the two-armed macroinitiator. The energy difference between acceptor and donor and stabilization energy were determined using natural bond orbital analysis. The results show that the occurrence of intramolecular charge transfers within the polymer. Time-dependent density functional theory calculations of visible spectra were analyzed at different solvents. Finally, thermodynamic functions, such as enthalpy, heat capacity, and entropy, of the two-armed macroinitiator at different temperatures were calculated and the relationship with temperature was investigated.

SOLVENT EFFECTS ON THE ELECTRONIC STRUCTURE AND NON-LINEAR OPTICAL PROPERTIES OF PYRENE AND SOME OF ITS DERIVATIVES BASED ON DENSITY FUNCTIONAL THEORY

2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Lumo Energy ◽  
Functional Theory ◽  
Organic Optoelectronic ◽  
Homo Lumo

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.

scholarly journals Substitution Effects on the Optoelectronic Properties of Coumarin Derivatives

2019 ◽  
Vol 10 (1) ◽  
pp. 144
Author(s):  
Amit Kumar ◽  
Roberto Baccoli ◽  
Antonella Fais ◽  
Alberto Cincotti ◽  
Luca Pilia ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Molecular Orbital ◽  
Density Functional ◽  
Optoelectronic Properties ◽  
Exciton Binding Energy ◽  
Basis Set ◽  
Substitution Effects ◽  
Coumarin Derivatives ◽  
Functional Theory

Coumarin derivatives have gathered major attention largely due to their versatile utility in a wide range of applications. In this framework, we report a comparative computational investigation on the optoelectronic properties of 3-phenylcoumarin and 3-heteroarylcoumarin derivatives established as enzyme inhibitors. Specifically, we concentrate on the variation in the optoelectronic characteristics for the hydroxyl group substitutions within the coumarin moiety. In order to realize our aims, all-electron density functional theory and time dependent density functional theory calculations were performed with a localized Gaussian basis-set matched with a hybrid exchange–correlation functionals. Molecular properties such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, vertical ionization (IEV) and electron affinity energies, absorption spectra, quasi-particle gap, and exciton binding energy values are examined. Furthermore, the influence of solvent on the optical properties of the molecules is considered. We found a good agreement between the experimental (8.72 eV) and calculated (8.71 eV) IEV energy values for coumarin. The computed exciton binding energy of the investigated molecules indicated their potential optoelectronics application.

scholarly journals Molecular Geometry, NLO, MEP, HOMO-LUMO and Mulliken Charges of Substituted Piperidine Phenyl Hydrazines by Using Density Functional Theory

2019 ◽  
Vol 32 (2) ◽  
pp. 401-407
Author(s):  
M. Dinesh Kumar ◽  
P. Rajesh ◽  
R. Priya Dharsini ◽  
M. Ezhil Inban
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Molecular Geometry ◽  
Basis Set ◽  
Functional Theory ◽  
B3lyp Method ◽  
Reactivity Descriptor ◽  
Homo Lumo ◽  
Optimized Geometries

The quantum chemical calculations of organic compounds viz. (E)-1-(2,6-bis(4-chlorophenyl)-3-ethylpiperidine-4-ylidene)-2-phenyl-hydrazine (3ECl), (E)-1-(2,6-bis(4-chlorophenyl)-3-methylpiperidine-4-ylidene)-2-phenylhydrazine (3MCl) and (E)-1-(2,6-bis(4-chloro-phenyl)-3,5-dimethylpiperidine-4-ylidene)-2-phenylhydrazine (3,5-DMCl) have been performed by density functional theory (DFT) using B3LYP method with 6-311G (d,p) basis set. The electronic properties such as Frontier orbital and band gap energies have been calculated using DFT. Global reactivity descriptor has been computed to predict chemical stability and reactivity of the molecule. The chemical reactivity sites of compounds were predicted by mapping molecular electrostatic potential (MEP) surface over optimized geometries and comparing these with MEP map generated over crystal structures. The charge distribution of molecules predict by using Mulliken atomic charges. The non-linear optical property was predicted and interpreted the dipole moment (μ), polarizability (α) and hyperpolarizability (β) by using density functional theory.

scholarly journals Theoretical Study of a Class of Organic D-π-A Dyes for Polymer Solar Cells: Influence of Various π-Spacers

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 163
Author(s):  
Nguyen Van Trang ◽  
Tran Ngoc Dung ◽  
Ngo Tuan Cuong ◽  
Le Thi Hong Hai ◽  
Daniel Escudero ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Polymer Solar Cells ◽  
Basis Set ◽  
Structure Theory ◽  
Functional Theory ◽  
Alkyl Groups

A class of D-π-A compounds that can be used as dyes for applications in polymer solar cells has theoretically been designed and studied, on the basis of the dyes recently shown by experiment to have the highest power conversion efficiency (PCE), namely the poly[4,8-bis(5-(2-butylhexylthio)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-TZNT] (PBDTS-TZNT) and poly[4,8-bis(4-fluoro-5-(2-butylhexylthio)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-TZNT] (PBDTSF-TZNT) substances. Electronic structure theory computations were carried out with density functional theory and time-dependent density functional theory methods in conjunction with the 6−311G (d, p) basis set. The PBDTS donor and the TZNT (naphtho[1,2-c:5,6-c]bis(2-octyl-[1,2,3]triazole)) acceptor components were established from the original substances upon replacement of long alkyl groups within the thiophene and azole rings with methyl groups. In particular, the effects of several π-spacers were investigated. The calculated results confirmed that dithieno[3,2-b:2′,3′-d] silole (DTS) acts as an excellent π-linker, even better than the thiophene bridge in the original substances in terms of well-known criteria. Indeed, a PBDTS-DTS-TZNT combination forms a D-π-A substance that has a flatter structure, more rigidity in going from the neutral to the cationic form, and a better conjugation than the original compounds. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of such a D-π-A substance becomes smaller and its absorption spectrum is more intense and red-shifted, which enhances the intramolecular charge transfer and makes it a promising candidate to attain higher PCEs.

Protonation Effect on C-N Bond Length of Alkylamines Studied by Molecular Orbital Calculations

2000 ◽  
Vol 55 (9-10) ◽  
pp. 769-771 ◽  
Keyword(s):  
Density Functional Theory ◽  
Bond Length ◽  
Molecular Orbital ◽  
Density Functional ◽  
Second Order ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Functional Theory ◽  
Hartree Fock ◽  
Protonation Effect

Abstract Molecular orbital calculations were performed for the six saturated alkylamines (CH3NH2 , (CH3)2 NH, (CH 3)3 N, CH 3CH2NH2 , (CH3)2 CHNH2 , (CH3)3 CNH2), their protonated cations (CH3NH3 + , (CH3)2NH2 + , (CH3)3NH + , CH3CH2NH3 + , (CH3)2CHNH3 + , (CH3)3CNH3+), and (CH3)4 N + using the Hartree-Fock, second-order M0ller-Plesset, and density functional theory methods with the 6-311+G(d,p) basis set. Protonation lengthens the C-N bonds of the amines by 0.05 -0.08 Å and shortens the C-C bonds of CH3CH2NH2, (CH3)2CHNH2 , and (CH3)3CNH2 by ca. 0.01 Å.

scholarly journals Theoretical Evaluation on The Interaction Between Triglycerides and Methylxanthines Using Density Functional Theory B3LYP/6-31G(d,p) and Molecular Electrostatic Potential

2020 ◽  
Vol 33 (1) ◽  
pp. 171-178
Author(s):  
N.F.M. Azmi ◽  
R. Ali ◽  
A.A. Azmi ◽  
M.Z.H. Rozaini ◽  
K.H.K. Bulat ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Basis Set ◽  
Individual Species ◽  
Interaction Energies ◽  
Binding Interaction ◽  
Functional Theory

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.

Spectroscopic and Bioactivity Analysis of Naturally Occurring Methyl Ester of Chlorogenic Acid Using Density Functional Theory Based Quantum Chemical Computation

2019 ◽  
Vol 17 (10) ◽  
pp. 822-825 ◽  
Author(s):  
Ashok Kumar Mishra ◽  
Satya Prakash Tewari
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Basis Set ◽  
Theory Approach ◽  
Functional Theory ◽  
Naturally Occurring ◽  
Quantum Chemistry Calculations ◽  
Spectroscopic Characteristics ◽  
Title Molecule

The present study describes the spectroscopic characteristics like IR and Raman active vibrations, (1H, 13C) nuclear magnetic resonance (NMR) chemical shifts and UV-Visible spectra of the molecular geometry obtained using quantum chemistry calculations based on density functional theory approach via B3LYP hybrid functional at 6-31 + G(d, p) basis set of title bioactive natural compound. The calculated highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap in titled compound is –0.14327 eV which is reasonably small and may be the prime reason for its bioactivity. Theoretical IR active vibration spectra show the maximum peak at 1146 cm–1. The maximum absorption in UV-Vis spectrum has been observed to be occurred at 329 nm. The biological activity has also been examined through virtual screening using molecular docking approach. The calculated spectroscopic characteristics are well aligned with their experi- mental counterparts. The obtained docking score predicts the title molecule to be a good naturally occurring anti diabetic agent. The outcomes of our investigation would be useful for deriving the structural analog of the title molecule for developing an efficient naturopathic anti diabetic drug agent with less side effects.

scholarly journals Structure, Electronic And Vibrational Study of 7-Methyl-2,3-Dihydro-(1,3)Thiazolo(3,2-A) Pyrimidin-5-One by Using Density Functional Theory

2018 ◽  
Vol 22 (2) ◽  
pp. 1-11
Author(s):  
Bhawani Datt Joshi ◽  
Janga Bahadur Khadka ◽  
Atamram Bhatt
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Functional Theory ◽  
Hartree Fock ◽  
Solvent Phase ◽  
Lowest Unoccupied Molecular Orbital

 We have presented molecular structure and vibrational wavenumber assignments of 7-methyl-2,3-dihydro-(1,3)thiazolo(3,2-a)pyrimidin-5-one. Both ab initio Hartree-Fock and density functional theory employing 6-311++G(d,p) basis set have been used for the calculations. The scaled values of the calculated vibrational frequencies were used for assignments on the basis of potential energy distribution. The structure-activity relation has been interpreted by mapping molecular electrostatic potential surface. Electronic properties have been analyzed by using time dependent density functional theory (TD-DFT) for both gaseous and solvent phase. The calculated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values show that the charge transfer occurs within the molecule. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 1-11 

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