Theoretical UV-visible Spectra Research Articles

Observations into quantum simulation, spectroscopy, electronic properties, pharmacokinetics and molecular docking analysis of lawsone against breast cancer

In this current investigation, structural and spectroscopic characteristics of the Lawsone (2-hydroxy-1,4-napthoquinone) molecule was examined by density functional theory (DFT) calculations. Lawsone's anti-cancer abilities against breast cancer proteins was investigated using molecular docking analysis. The optimization was performed through 6-311++G (d,p) basis set to determine the molecular geometry of lawsone. The vibrational frequencies of Lawsone were theoretically generated and compared to analytically determined FTIR and FT-Raman spectra. In this study, a theoretical UV–visible spectrum was generated, and experimental absorption was validated. The reactive potential of lawsone was explored further using a molecular electrostatic potential surface. The HOMO-LUMO energies and energy gap were used to evaluate the stability and molecular reactivity of the lawsone molecule. The charge distribution across the lawsone atoms was found via Mulliken and natural population analyses. The weak interactions of the lawsone molecule were analysed through RDG analysis. The topology of the lawsone molecule was explored through ELF and LOL analysis. The antioxidant potential was validated using the DPPH test. The drug-like features of lawsone were confirmed by physicochemical and pharmacokinetic tests, and molecular docking simulations revealed lawsone's binding affinity against breast cancer proteins, with the greatest affinity of –7.4 Kcal/mol observed against AKT1.

Heterojunction solar cell based on donor-acceptor pi-conjugated naphthalene bisbenzimidazole, perylene bisbenzimidazole, and naphthalene imidazole: A spectroscopic, microscopic and DFT assessment.

This study represents detailed vibrational analysis of naphthalene bisbenzimidazole (NBBI), perylene bisbenzimidazole (PBBI), and naphthalene imidazole (NI) by vibrational spectroscopic (Fourier Transform Infrared (FT-IR) and Raman), Atomic Force Microscopic (AFM) and quantum chemical studies for the first time. These sorts of compounds provide an opportunity to build potential n-type organic thin film phototransistors which can be used as organic semiconductors. Optimized molecular structures and vibrational wavenumbers of these molecules in their ground states have been calculated by Density Functional Theory (DFT) using B3LYP functional with 6-311++G(d,p) basis set. Finally, theoretical UV-Visible spectrum was predicted and Light Harvesting Efficiencies (LHE) were evaluated. AFM analysis revealed that PBBI has the highest surface roughness thus exhibits an increase in high Jsc value and high conversion efficiency.

Conformational fidelity and hydrogen bond associability of L-histidine with sulfamate anion studied through XRD, quantum chemical, spectroscopic and molecular docking simulation as a cdk-4 inhibitor against retinoblastoma

L-histidinium sulfamate, (C6H10N3O2)+.SO3NH2−,crystallizes in the orthorhombic space group, P212121, with four molecules per unit cell. The asymmetric part of unit cell comprises a diprotonated monovalent histidinium cation and a sulfamate anion. The amino nitrogen of the cation is deviated from the carboxylate group plane. The backbone conformations are observed to be cis and trans conformations. The side chain conformations are witnessed to be gauche I / gauche II / gauche I rotomers. The conformations of the cation are dominated by the three dimensional intermolecular hydrogen bonding network in the crystal packing. The classical hydrogen bonds are observed in the crystalline landscapes categorically cation-cation, anion-anion and cation-anion interactions leading to chain C(4), C(5) and C(7) motifs and ring R33(10), R33(14), R33(21) and R55(30) motifs. The molecular structure, FT-IR, FT-Raman, Frontier Molecular Orbitals (FMO), Natural Bond Orbital (NBO) analysis Mulliken charge analysis, Electrostatic potential analysis (ESP), Non-Linear Optical (NLO) properties of L-histidinium sulfamate have been evaluated using the (DFT) calculations with B3LYP/6‒311++G (d, p) basis set. TD-DFT in gas phase with the same basis set was used to analyze electronic parameters such as excitation energy, wavelength, band gap, and oscillator strength from the theoretical UV–Visible spectrum. The Fukui function was also used to investigate the molecule's local reactivity. The contribution of distinct interactions within the molecule and the strength of molecular packing in the compound have been evaluated through Hirshfeld surface (HS) analysis .Retinoblastoma is the most well-known pediatric malignant development of the eye. The protein cyclin dependent kinase (Cdk) plays a role in the phosphorylation process; its inhibition triggers the retinoblastoma protein's suppressor function, which stops tumor development. Molecular docking simulation has been performed through PyRx software and the new single crystal L-histidinium sulfamate showed effective binding to the Cdk-4 protein with the binding score of -6.7 Kcal/mol and pharmacokinetic studies showed a good safety profile of L-histidinium sulfamate.

Investigation on Quantum Computational Analysis and Toxicity Prediction of 4-Nitrophenylisocyanate

The compound 4-nitrophenylisocyanate is known for its various biological properties and class of compounds in medicinal chemistry. In this paper, we are reporting the DFT studies of 4-nitrophenylisocyanate (NPIC). To better understand molecular properties, the computational study, optimized molecular geometry, and reactive parameters were investigated and calculated by employing the method of DFT and B3LYP/6-311++G(d, p) basis set. The DFT calculations were performed to analyze the frontier molecular orbitals (HOMO-LUMO). The energy difference between HOMO - LUMO is 4.516 eV, and the MEP was traced to find the reactive sites of the compound. In addition, theoretical UV-visible spectrum and vibrational spectra (FT-IR) were obtained in the gas phase using the TD-DFT method. By using pkCSM toxicity of the compound was also predicted. The Quantum Theory of Atoms in Molecules (QTAIM) framework is used to calculate topological parameters. Different intermolecular interactions are described using terms like Reduced Density Gradient (RDG), Non-Covalent Interactions (NCI), electron density, and electron localization function and electron cloud present in the NPIC molecule.

Conformational stability, quantum computational, spectroscopic, molecular docking and molecular dynamic simulation study of 2-hydroxy-1-naphthaldehyde

Experimental FTIR, NMR and UV-visible spectrum analyses were used to describe the title compound 2-Hydroxy-1-Naphthaldehyde. The optimized molecular geometry and vibrational wave numbers were determined by using the DFT approach and B3LYP/6-311++G(d, p) basis set. VEDA was used to determine the vibrational assignments. The GIAO technique was used to compute carbon and proton NMR chemical shifts in CDCl3. The most reactive location of the 2H1NA molecule, according to MEP map analysis, is the site containing the oxygen atom. TD-DFT approach was used to produce the theoretical UV-visible spectrum in MeOH and gas phase. HOMO-LUMO and Donor-Acceptor (NBO) interactions were investigated for the title compound. In addition, nonlinear optical characteristics, ELF and Fukui activity were investigated. Temperature-dependent thermodynamic characteristics were also computed. The 3D intermolecular interactions of the crystal surface were characterised using Hirshfeld surface analysis, whereas the 2D interactions were explained using fingerprint plots. 2H1NA was stabilized by the development of H—H/H—C/H—O contacts. The bioactive probability of the title molecule was theoretically demonstrated by computing the electrophilicity index. In a biological study six different receptors, molecular docking was performed to evaluate the best ligand-protein interactions and likeness to the active substance. Biomolecular stability was investigated using a molecular dynamics simulation.

Exploration of electron transport behaviour of a push-push anil for possible application as an optical material

Abstract The present work delineates the relationship between the structural and spectral parameters of an anil, salicylidene-orthochloroaniline through the determination of its optimized structure, and consequential theoretical parameters using Density Functional Theory (B3LYP/6-311G (d, p) level) and spectral characteristics through UV–visible studies. The time-dependent DFT was used to calculate the theoretical UV–visible spectra and compared with the experimental spectra. The different frontier molecular orbitals and their energy gaps were elucidated and correlated with the experimentally determined values. Cyclic voltammetry confirmed the electron transport characteristics of the molecule. The anil followed a single electron transport process, which is irreversible, and diffusion-controlled. The overall study indicated that the anil could be suitably exploited as an optical material for electronic devices.

DFT/TDDFT studies of the structural, electronic and NBO properties of some complexes with the tetrathiafulvalene-1,3-benzothiazole ligand

In this work, the electronic structures and derived properties (UV, NBO and more) of the three know and relevant Cu-based complexes of tetrathiafulvalene (TTF) are reported. The experimentally available structures of formulas [Cu(hfac)2(L)2]0,2+ and [Cu(L)2]2+ (L = TTF-1,3-benzothiazole and hfac = hexafluoroacetylacetonate are characterized by variable π-π stacking in the crystals. Since the latter depends on the spin unpairing at the TTF portions of L, we have optimized with the DFT method the single units as potential building blocks of the solid state compounds. The geometric parameters appear to be in a satisfactory agreement with the available experimental data and, by taking into account the various spin distributions (possible ground states), we analyzed the corresponding MO features. The APT atomic charges were evaluated and the coordination bond strengths were evaluated by the Natural Bond Orbital (NBO) analysis, which also confirmed the π electron delocalization at the TTF portion of L. The theoretical UV–visible spectra, computed with the time-dependent DFT/TDDFT method, show that the charge transfer bands in all complexes are red-shifted with respect to the corresponding free ligand.

DFT computational insights into structural, electronic and spectroscopic parameters of 2-(2-Hydrazineyl)thiazole derivatives: a concise theoretical and experimental approach

ABSTRACT It has been uncovered that compounds containing thiazole moiety display noteworthy biological properties, which have attracted the attention of many researchers in chemical biology as well as in medicinal chemistry. In the current examination, ten 2-(2-hydrazineyl)thiazole derivatives were studied using density functional theory (DFT). The geometry of all ten molecules was optimized by employing the DFT method with the B3LYP/6-311G (d,p) basis set. For the detailed structural and spectroscopic examination, the (E)-4-phenyl-2-(2-(1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-ylidene)hydrazineyl)thiazole (PIFHT) was studied as a representative molecule. The bond lengths and bond angles of the PIFHT molecule were discussed for the detailed understanding of the structural entities. The electronic parameters of all ten molecules were analyzed by computing HOMO and LUMO pictures. Using frontier molecular orbital analysis, spectroscopic and quantum chemical parameters were evaluated and discussed to explore the chemical reactivity of the molecules. Besides, absorption energies, oscillator strength, and electronic transitions of PIFHT molecule were explored using time-dependent density-functional theory (TD-DFT) at the B3LYP/6-311G (d,p) level of theory in the gas phase, dichloromethane, and dimethyl sulfoxide solvents. The TD-DFT computed theoretical UV-Visible spectra of the PIFHT molecule were compared with the experimental UV-Visible spectra. The scaled vibrational frequencies were compared with the experimental frequencies for the assignment of the vibrational bands. The comparisons between computed and experimental UV-Visible and IR spectral results are gratifying. The molecular electrostatic surface potential plots were computed for locating the reactivity sites. Mulliken atomic charges were also studied for acquiring insights into charge density.

Molecular Structure, Frontier Molecular Orbitals, MESP and UV–Visible Spectroscopy Studies of Ethyl 4-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate: A Theoretical and Experimental Appraisal

n the current investigation, we wish to report a combined study on the theoretical and experimental investigation of structural, molecular, and spectral properties of ethyl 4-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (EDMT). The EDMT molecule is synthesized and characterized by UV-Visible, FT-IR, 1H NMR, 13C NMR, DEPT, and mass spectral techniques. The density functional theory (DFT) investigation was performed by using the B3LYP level of theory at 6-311++G (d,p) basis set. Frontier molecular orbital (FMO) analysis is likewise examined. An TD-DFT method was used for the UV-Visible spectral analysis by using the B3LYP level and 6-311++G (d,p) basis set in the DMSO solvent. Experimental and theoretical UV-Visible spectra were compared in the present study. Various reactivity descriptors are discussed. Besides, Mulliken atomic charges, molecular electrostatic surface potential (MESP), and some valuable thermodynamic functions are studied.

Spectral, DFT and molecular docking investigations on Etodolac

The title compound (RS) -2- (1, 8-Diethyl- 4, 9-dihydro-3H- pyrano [3, 4-b] indol-1-yl) acetic acid (Etodolac) was characterized by experimental FTIR, FT-Raman, NMR and UV-Visible spectral analysis. The optimized molecular geometry and vibrational wave numbers were calculated by employing the method of DFT and B3LYP/6-311++G(d, p) basis set. The vibrational assignments were calculated using VEDA program. Carbon and Proton NMR chemical shifts were calculated in different solvents by GIAO method. Theoretical UV-Visible spectrum was obtained in DMSO and in gas phase using TD-DFT method. For the title compound, HOMO-LUMO and Donor- Acceptor (NBO) interactions were studied. In addition, MEP map was traced to find the reactive sites of Etodolac. Further, NLO properties such as dipole moment, linear and first order hyperpolarizabilities have been studied to reveal NLO nature of the title compound. Also the thermodynamic properties with respect to temperature were calculated. All the theoretical predictions were carried out by using DFT-B3LYP method at the level of 6–311++G(d, p). Finally to find its biological importance, the molecular docking interaction was studied to reveal that Etodolac is a selective inhibitor of COX (cyclooxygenase) enzyme.

Synthesis, characterization, spectroscopy, X-ray structure and gaussian hybrid computational investigation of (−)-(S)-1-[2-(benzenesulfonamido)-3-phenylpropanoyl]-4-[(4-methyl)phenyl]thiosemicarbazide

The molecule (−)-(S)-1-[2-(benzenesulfonamido)-3-phenylpropanoyl]-4-[(4-methyl)phenyl] thiosemicarbazide was synthesized and its structure analyzed by X-ray diffraction to understand its geometry, and inter/intra-molecular interactions. Theoretical calculations were carried out using DFT and TD-DFT methods with B3LYP/6-31G(d, p) and B3LYP/6-31G + (d, p) basis sets. Theoretical bond parameters, harmonic vibration frequencies, and chemical shifts are in good agreement with the experimental results. Electronic properties of the molecule derived from frontier orbitals, molecular electrostatic potential, and theoretical UV-Visible spectrum are validated experimentally.

Vibrational and Electronic Spectra of 2-Phenyl-2-Imidazoline: A Combined Experimental and Theoretical Study

The structural properties and vibrational frequencies of 2-phenyl-2-imidazoline have been investigated using theoretical and techniques by which a good correlation was observed. The assignments of the vibrational modes were performed with the help of normal co-ordinate analysis following the Scaled Quantum Mechanical Force Field methodology. Natural bond orbital analysis and the highest occupied molecular orbital-lowest unoccupied molecular orbital gap analysis have been carried out. UV-visible spectrum of the compound was recorded and compared with the theoretical UV-visible spectrum of the title molecule using Symmetry Adapted Cluster-Configuration Interaction method which yielded good agreement. Our results reflect that the title compound can be used as good source of UV light.

Theoretical investigation of oligomer structure and optoelectronic properties for [4-(methoxyphenyl)acetonitrile]n (n=1-5).

Experimental measurement on oligomeric 4-(methoxyphenyl)acetonitrile (OMPA) synthesized via an electrochemical method indicated that the average chain length for OMPA was around 5 units (5-MPA) [J Mol Struct 1031:186 (2013)], but did not provide enough information to completely characterize the chemical structure of the molecule. Nevertheless a possible structure was proposed on the basis of 13C NMR and the spin density hypothesis for radical polymerization. A more complete validation of the resultant structure is needed to show the extent to which the structure is consistent with a variety of measured properties. This is done here for the infrared (IR), ultraviolet-visible (UV-vis), and photoluminescence (PL) spectra of 5-MPA which are found to agree reasonably well with the experimentally measured spectra of OMPA. Electronic structure information regarding the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) energies, ionization potentials and electron affinities, as well as optical properties (UV-vis, PL) is also provided. Graphical Abstract Comparison of theoretical and experimental UV-visible absorption and photoluminescence spectra of oligomeric 4-(methoxyphenyl)acetonitrile.

Spectroscopic Aspects, Structural Elucidation, Vibrational and Electronic Investigations of 2-Methoxy-1,3-Dioxolane: An Interpretation Based on DFT and QTAIM Approach

Extensive vibrational spectroscopic investigations along with theoretical quantum chemical studies on 2-methoxy-1,3-dioxolane (MDOL) have been consummated. The experimentally observed spectral data (FT-IR and FT-Raman) of the title compound were compared with the spectral data obtained by DFT/B3LYP method. The 1H and 13C nuclear magnetic resonance (NMR) spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The theoretical UV-Visible spectrum of the title compound was measured in different solvent and the electronic properties, such as excitation energies, oscillator strength and wavelengths were performed by time-dependent density functional theory (TD-DFT) approach. The kinetic stability of the molecule has been determined from the frontier molecular orbital (FMO) energy gap. Total density of state (TDOS) and partial density of state (PDOS) of the MDOL in terms of Mulliken population analysis Topological parameters at bond critical point have been analyzed in MDOL by Bader’s were calculated and analyzed. Reduced density gradient (RDG) of the MDOL was given to investigate interactions of the molecule. ‘Atoms in molecules’ (AIM) theory in detail. In addition, the temperature dependence thermodynamic properties and magnetic susceptibility of MDOL were calculated with the help of DFT/ B3LYP method using 6-311++G(d,p) basis set.

Free radical scavenging properties of phytofluene and phytoene isomers as compared to lycopene: a combined experimental and theoretical study.

Free radical scavenging properties of Lycopene (LYC), Phytofluene (PF), and Phytoene (PE) are studied experimentally, considering the electron transfer mechanism and using the ABTS(•+) decolouration assay. Density Functional Theory is used to obtain the theoretical UV-visible spectra of ABTS (neutral and cation) and to determine the free radical scavenger capacity in terms of the electron donor mechanism and the deactivation of singlet oxygen. The experimental data agreed very well with the theoretical results. Considering both mechanisms, LYC, PF, and PE can be considered good free radical scavengers, with LYC turning out to be the best and PE the worst antiradical. However, the triplets that formed following the deactivation of singlet oxygen presented similar capacity for donating electrons. In the case of triplets, the antiradical capacity of LYC, PF, and PE is similar in terms of the electron donor mechanism. Although the results indicated that PF and PE are not as effective antiradicals as LYC, which is to be expected due to the number of conjugated double bonds, they do present a higher antioxidant capacity than expected considering the small number of conjugated double bonds.