scholarly journals Quantum Chemical Studies of Structural Parameters and Molecular Properties  of Pigment 2-[(2-methoxy-4-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-butanamide 

2021 ◽  
Vol 31 (1) ◽  
pp. 6-10
Keyword(s):  
Energy Surface ◽  
Energy Gap ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Molecular Properties ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Paint Industry ◽  
Trans Structure ◽  
Homo Lumo

Pigments play an important role in the paint industry. The structural parameters and molecular properties of 2-[(2-methoxy-4-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-Butanamide (pigment P.Y.74) has been determined by quantum calculation at the B3LYP/6-31+G(d) level of theory. Our results show that the trans – trans structure of pigment P.Y.74 is the most stable. The 46th orbital is the HOMO orbital when the 47th orbital is the LUMO orbital and the HOMO-LUMO energy gap of the title molecule is found to be 0.067815 a.u. Besides, the potential energy surface for its decomposition has been investigated at the same level of theory. The results may be helpful for experimental studies in the future.

scholarly journals Diradicalar Character and Ring Stability of Mesoionic Heterocyclic Oxazoles and Thiazoles by Ab Initio Mono and Multi-Reference Methods

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4524
Author(s):  
Antonio João da Silva Filho ◽  
Lucinêz da Cruz Dantas ◽  
Otávio Luís de Santana
Keyword(s):  
Ab Initio ◽  
Energy Gap ◽  
Experimental Studies ◽  
Energy Difference ◽  
Basis Sets ◽  
Neutral Compounds ◽  
Diradical Character ◽  
Electronic Configurations ◽  
Homo Lumo

Mesoionics are neutral compounds that cannot be represented by a fully covalent or purely ionic structure. Among the possible mesomeric structures of these compounds are the diradical electronic configurations. Theoretical and experimental studies indicate that some mesoionic rings are unstable, which may be related to a significant diradical character, that until then is not quantified. In this work, we investigated the diradical character of four heterocycles: 1,3-oxazol-5-one, 1,3-oxazol-5-thione, 1,3-thiazole-5-one, and 1,3-thiazole-5-thione. The oxazoles are known to be significatively less stable than thiazoles. DFT and ab initio single (B3LYP, MP2, CCSD, and QCISD) and ab initio multi-reference (MR-CISD) methods with three basis sets (6-311+G(d), aug-cc-pVDZ, and aug-cc-pVTZ) were employed to assess the diradical character of the investigated systems, in gas phase and DMSO solvent, from three criteria: (i) HOMO-LUMO energy gap, (ii) determination of energy difference between singlet and triplet wave functions, and (iii) quantification of the most significant diradical character (y0, determined in the unrestricted formalism). All of the results showed that the diradical character of the investigated systems is very small. However, the calculated electronic structures made it possible to identify the possible origin of the oxazoles instability, which can help the design of mesoionic systems with the desired properties.

scholarly journals Molecular Structure and Quantum Chemical Calculations of 2, 4-difluoroanisole

2020 ◽  
Vol 8 (4S4) ◽  
pp. 125-130
Keyword(s):  
Molecular Structure ◽  
Quantum Chemical ◽  
Chemical Shifts ◽  
Vibrational Analysis ◽  
1H And 13C Nmr ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Homo Lumo ◽  
Orbital Analysis ◽  
Ft Raman

FTIR / FT-Raman spectra in the regions 4000-400 cm-1 /3500-50 cm-1 are utilized for studying the molecular vibrations of 2,4-difluoroanisole (DFA). The optimized molecular structure and vibrational analysis of the DFA were estimated with the experimental as well as quantum chemical studies from ab initio and DFT calculations. The chemical shifts of 1H and 13C NMR were calculated. In addition, the thermodynamic and important electronic properties like HOMO-LUMO, NPA charge analyses have been examined. With the aid of NBO (Natural Bond Orbital) analysis, inter and intra molecular interactions are also illustrated.

scholarly journals Inhibition Effect of Atenolol on Copper Corrosion in 1M HNO3: Experimental Study and DFT

2021 ◽  
pp. 1-13
Author(s):  
Ehouman Ahissan Donatien ◽  
Bamba Kafoumba ◽  
Kogbi Guy Roland ◽  
Bamba Amara ◽  
Kouakou Adjoumani Rodrigue ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Quantum Chemical ◽  
Density Functional ◽  
Energy Gap ◽  
Copper Surface ◽  
Thermodynamic Quantities ◽  
Copper Corrosion ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Lowest Unoccupied Molecular Orbital

Atenolol was examined as a copper corrosion inhibitor in 1M nitric acid solution using the mass loss technique and quantum chemical studies, based on density functional theory (DFT) at the B3LYP level with the base 6-311G (d,p). The inhibitory efficiency of the molecule increases with increasing concentration and temperature. The adsorption of the molecule on the copper surface follows the modified Langmuir model. The thermodynamic quantities of adsorption and activation were determined and discussed. The calculated quantum chemical parameters related to the inhibition efficiency are the energy of the highest occupied molecular orbital E(HOMO), the energy of the lowest unoccupied molecular orbital E(LUMO), the HOMO-LUMO energy gap, the hardness (η), softness (S), dipole moment (μ), electron affinity (A), ionization energy (I), absolute electronegativity (χ),absolute electronegativity (χ), fraction (ΔN) of electrons transferred from Atenolol to copper and electrophilicity index(ω). The local reactivity was analyzed through the condensed Fukui function and condensed softness indices to determine the nucleophilic and electrophilic attack sites. There is good agreement between the experimental and theoretical results.

Quantum chemical, experimental exploration of biological activity and inhibitory potential of new cytotoxic kochiosides from Kochia prostrata (L.) Schrad

2020 ◽  
Vol 19 (05) ◽  
pp. 2050012
Author(s):  
Ahmad Irfan ◽  
Muhammad Imran ◽  
Abdullah G. Al-Sehemi ◽  
Mohammed A. Assiri ◽  
Ajaz Hussain ◽  
...  
Keyword(s):  
Active Sites ◽  
Energy Gap ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Standard Drug ◽  
Steroidal Glycoside ◽  
Reactivity Descriptors ◽  
Whole Plant ◽  
Active Nature ◽  
Inhibitory Potential

New cytotoxic steroidal glycoside of methanol extract from Kochia prostrata ([Formula: see text]) Schrad was investigated in this study. Bio-guided isolation from ethylacetate fraction of whole plant afforded steroidal glycosides named as 5-ene-dimethylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 1A1), 5-ene-methylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 2A1) and 4-ene-dimethylcholest3-O-[Formula: see text]-D-glucoside (Kochioside 3A1). Their structures were assigned by physical and spectroscopic methods. Kochiosides 1A1–3A1 showed inhibitory potential against brine shrimp lethality bioassay with etoposide standard drug. The new steroidal glycoside kochiosides 1A1–3A1 showed inhibition values of 8.3201, 8.8205 and 8.2310[Formula: see text][Formula: see text]g/mL, respectively with [Formula: see text] compared to standard etoposide [Formula: see text] (7.4625[Formula: see text][Formula: see text]g/mL) drug. Moreover, six new derivatives were designed by substituting the –NH2 and –OCH3 at R1, R2 and R3 positions in the isolated compounds. Herein, various molecular descriptors, frontier molecular orbitals (FMO), electron affinity, ionization potential and molecular electrostatic potential (MEP) were carried out to understand the active sites and biological active nature of the new cytotoxic steroidal glycoside kochiosides. The effect of electron donating groups (–NH2 and –OCH3) was also investigated on the structural parameters and electronic properties in gas and solvent (DMSO) phases. The energy gap, MEP and reactivity descriptors values demonstrate that the kochioside 3A1 retains good reactivity, which is in good agreement with current experimental studies.

scholarly journals Theoretically studying the optoelectronic properties of oligomers based on 2.7-divinyl-cabazole

2022 ◽  
Vol 47 (1) ◽  
pp. 40-54
Author(s):  
Mohamed Jabha ◽  
Abdellah El Alaoui ◽  
Abdellah Jarid ◽  
El Houssine Mabrouk
Keyword(s):  
Density Functional ◽  
Energy Surface ◽  
Energy Gap ◽  
Dft Method ◽  
Photovoltaic Cell ◽  
Organic Photovoltaic ◽  
Functional Theory ◽  
Total Potential ◽  
The Density Functional Theory ◽  
Homo Lumo

This work consists of theoretically studying the electronic and optical properties of 9-(4-octyloxyphenyl)-2.7-divinyl-carbazole (PCrV) oligomers. This study has been undertaken using the density functional theory (DFT) method at the B3LYP/6-31G (d,p) level and BP86/6-31G (d,p) level of theory. To evaluate the PCrV-basis systems properties, the structural optimization without geometrical restrictions was performed on the total potential energy surface (TPES). In order to ensure good absorption of radiation, the interest was in increasing the efficiency of the organic photovoltaic cell. For this effect, the (HOMO-LUMO) gap energy of such compounds was reduced in terms of geometric and electronic structure. The BP86 functional gives good results at the energy gap level, while other parameters using the B3LYP functional give the best results.

Quantum Chemical Studies of Hole Transfer in Liquid Hexane

2017 ◽  
Vol 137 (7) ◽  
pp. 435-441
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka ◽  
Toshiyuki Hirano ◽  
Fumitoshi Sato
Keyword(s):  
Quantum Chemical ◽  
Hole Transfer ◽  
Chemical Studies ◽  
Quantum Chemical Studies
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