Molecular structure, FT-IR, NBO, HOMO and LUMO, MEP and first order hyperpolarizability of (2E)-1-(2,4-Dichlorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one by HF and density functional methods

Theoretical Investigation of para Amino-Dichloro Chalcone Isomers. Part II: A DFT Structure-Stability Study of the FMO and NLO Properties

The density functional theory (DFT) method using the functional hybrid (B3LYP) and 6-311G(d,p) basis set was utilized for the geometry optimization with dispersion correction, procedure (GO + DC), for the E and Z chalcone isomers -1-(4-aminophenyl)- 3-(i,j-dichlorophenyl)prop-2-en-1-one, where (i) and (j) represent the positions of the two chlorine atoms [(2,3), (2,4),(2,5),(2,6),(3,4), and (3,5)] abbreviated (i,j)-chalcone, and 4-(x,y-dichloro-8aH-chromen-2-yl)aniline, where (x = 5,6 and y = 6,7,8,8a) abbreviated (x,y)-chromen isomers. The calculations revealed that E chalcones are the most stable and the 4-(x,y-dichloro-8aH-chromen-2-yl) aniline isomers are the least stable. The (3,5) chalcones were the most stable in both E and Z chalcone series. However, the 4-(5,8a-dichloro-8aH-chromen-2-yl) aniline is the most stable in the series. The isomer stability order is the same as in Part 1, in which the geometry optimization calculation was followed by the dispersion correction single point energy calculation (GO/SPDC) procedure. The procedures (GO + DC) and (GO/SPDC) were used to calculate energies of the highest occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) and related properties. The order of the HOMO-LUMO energy gap (ΔE gap) was chromens Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Affiliation(s)

Haval A. Hussein Department of Chemistry, College of Science, University of Duhok, Zakho Street 38, 1006AJDuhok, Kurdistan Region, Iraq
Ghazwan F. Fadhil Department of Chemistry, College of Science, University of Duhok, Zakho Street 38, 1006AJDuhok, Kurdistan Region, Iraq

Collapse

Spectroscopic, quantum chemical, molecular docking and molecular dynamics investigations of hydroxylic indole-3-pyruvic acid: a potent candidate for nonlinear optical applications and Alzheimer's drug

In this paper, a complete theoretical investigation of hydroxylic indole-3-pyruvic acid (HIPyA) molecule was performed using the DFT quantum chemical, molecular docking and molecular dynamics calculations. The conformational analysis of HIPyA molecule was carried out using density functional theory quantum chemical calculations. The most stable structure of the studied molecule was predicted by means of DFT/B3LYP method with cc-pVTZ basis set. The simulated vibrational frequencies were assigned and proved to be in agreement with the available experimental FT-IR data. The effects of gas phase and solvents on UV-visible spectra of HIPyA molecule were simulated using TD-DFT/B3LYP method with cc-pVTZ basis set. The analysis of the density of states spectrum validates the frontier molecular orbitals results, which reveals the charge transfer interaction in HIPyA molecule. The molecular electrostatic potential surface confirms the electrophilic and nucleophilic reactive sites of the studied molecule. The natural bond orbital analysis evidences the bioactivity of the studied molecule. The obtained first order hyperpolarizability value is 33.596 times greater than urea, which confirms the nonlinear optical activity of HIPyA molecule. The molecular docking analysis reveals that the studied molecule under interest can act as a potent inhibitor against the amyloid β-protein (Aβ) enzyme, which causes the Alzheimer's disease. The molecular dynamics analysis confirms the reliability of the docking results.Communicated by Ramaswamy H. Sarma.

Modeling the structural and reactivity properties of hydrazono methyl-4H-chromen-4-one derivatives-wavefunction-dependent properties, molecular docking, and dynamics simulation studies

This study explains the vibration and interaction of three pharmaceutically active hydrazine derivatives, (E)-3-((2-(2,5-difluorophenyl)hydrazono)methyl)-4H-chromen-4-one (DFH), (E)-3-((2-(4-(trifluoromethyl)phenyl)hydrazono)methyl)-4H-chromen-4-one (TMH), and (E)-3-((2-(3,5-bis(trifluoromethyl)phenyl)hydrazono)methyl)-4H-chromen-4-one (BPH) using theoretical approach. The trend in chemical reactivity and stability of the studied compounds was observed to show increasing stability and decreasing reactivity and this was obtained from orbital energies. The effect of bromine and chlorine atoms, instead of fluorine atoms, is also noted. Surface analysis on the covalent bond was attained by ELF and LOL analysis. Biological activities were predicted using molecular docking studies. Docking results were analyzed with standard drugs, 5-fluorouracil/piperine. Antitumor activity of hydrazine derivatives was found to be higher than reference ones. Molecular dynamics (MD) simulation was performed for 100 ns to validate the stability behavior of hydrazine derivatives with the dual specificity threonine tyrosine kinase (TTK) protein. RMSD, RMSF, Rg, SASA, and intermolecular analysis of DFH, TMH, and BPH with threonine tyrosine kinase forms stable ligand-protein interactions. The molecular and predictive biological properties of three pharmaceutically active hydrazine derivatives which can be helpful to researchers in future experimental validation through in vitro and in vivo studies.

Concentration dependent SERS, DFT and molecular docking studies of a ureido derivative with antitubercular properties

Spectroscopic analysis, density functional theory (DFT) studies and surface enhanced Raman scattering (SERS) of antimycobactetial 4-[3-(4-acetylphenyl)ureido]-2-hydroxybenzoic acid (AUHB) have been studied on different silver sols. For Raman and SERS wavenumbers, very large changes are observed. Observed variations in the modes of ring may be due to surface π-electron interactions and presence of this indicated that poly substituted ring is more inclined than para substituted phenyl ring and assumes a inclined position for concentration 10^-3 M. Changes in orientation are seen in SERS spectra depending on concentration. In order to find electron-rich and poor sites of AUHB, molecular electrostatic potential was also constructed. The molecular docking results show that binding affinity and interactions with the receptor DprE1 may be supporting evidence for further studies in design further AUHB pharmaceutical applications. Based on antitubercular activity of 4-aminosalicylic acid (PAS) and urea derivatives we designed, synthesized and investigated mutual PAS-urea derivatives as potential antimycobacterial agents.

Spectroscopic investigations, concentration dependent SERS, and molecular docking studies of a benzoic acid derivative

Spectroscopic analysis, density functional theory (DFT) studies and surface enhanced Raman scattering of 4-((3-bromo-5-chloro-2-hydroxybenzylidene)amino)benzoic acid (BCHB) have been studied on different silver colloids concentrations in order to know the particular chemical species responsible for the spectra. For Raman and surface enhanced Raman scattering (SERS) wavenumbers, changes are observed. Observed variations in the modes of ring may be due to interaction of the π-electrons and presence of this indicated that RingII is more inclined than RingI and the BCHB assumes inclined orientation for concentration 10^-3 M. Changes in orientation are seen in SERS spectra depending on concentration. In order to determine the electron-rich and poor sites of BCHB, the molecular electrostatic potential was also constructed. The molecular docking studies show that the bindings and interactions with the receptors may be supporting evidence for further studies in design further BCHB pharmaceutical applications.

DFT and molecular docking investigations of oxicam derivatives

The organic molecule tenoxicam and similar derivatives, piroxicam and isoxicam have been studied by quantum chemical theory (DFT), FT-Raman and FT-IR. By FMOs energies the charge transfer inside the molecules are obtained. The UV-Vis spectra of the compounds are simulated to study the electronic transition in the target molecules. By using natural bond orbital (NBO), charge delocalization analyzes arising from hyper conjugative interactions and the stability of the molecules are obtained. First order hyperpolarizability of piroxicam is higher than that of isoxicam and tenoxicam. The reactive areas are thoroughly studied by MEP. Prediction of Activity Spectra gives activities, anti-inflammatory, CYP2C9 substrate and gout treatment. Docked ligands form a stable complex with the receptors.

Spectroscopic, single crystal XRD structure, DFT and molecular dynamics investigation of 1-(3-chloro-4-fluorophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea

The title compound 1-(3-chloro-4-fluorophenyl)-3-[3-(trifluoromethyl) phenyl]thiourea (ANF-2) was synthesized and structurally characterized by single crystal XRD.

Molecular structure, IR spectra, and chemical reactivity of cisplatin and transplatin: DFT studies, basis set effect and solvent effect

Three different density functional theory (DFT) methods were employed to study the molecular structures of cis-diamminedichloroplatinum(II) (CDDP) and trans-diamminedichloroplatinum(II) (TDDP). The basis set effect on the structure was also investigated. By comparing the optimized structures with the experimental data, a relatively more accurate method was chosen for further study of the IR spectra and other properties as well as the solvent effect. Nineteen characteristic vibrational bands of the title compounds were assigned and compared with available experimental data. The number of characteristic peaks for the asymmetric stretching and deformation vibrations of N-H can serve as a judgment for the isomer between CDDP and TDDP. Significant solvent effect was observed on the molecular structures and IR spectra. The reduced density gradient analysis was performed to study the intramolecular interactions of CDDP and TDDP, and the nature of changes in the structures caused by the solvent was illustrated. Several descriptors determined from the energies of frontier molecular orbitals (HOMO and LUMO) were applied to describe the chemical reactivity of the title compounds. The molecular electrostatic potential (MESP) surfaces showed that the amino groups were the most favorable sites that nucleophilic reagents tend to attack, and CDDP was easier to be attacked by nucleophilic reagents than TDDP.