FT-Raman Spectra Research Articles

Spectroscopic characterization, quantum chemical and molecular docking investigations on methyl indole-3-carboxylate: A potent cervical cancer drug

Bioactive indole derivatives had great importance in recent years due to their numerous biological and pharmaceutical applications. In the present work, the vibrational, electronic, physicochemical, and inhibitory properties of the Methyl Indole-3-Carboxylate (MIC) molecule were predicted and analyzed. Initially, the molecular structure of the title molecule was optimized and its structural parameters were calculated, which were highly correlated with the previous reports. The simulated infrared and Raman spectra of the molecule were in good agreement with the FT-IR and FT-Raman spectra that were observed via the experiment. The observed UV–Visible spectrum validates the MIC molecule's π→π* electronic transition, which was also well matched with the simulated UV–Visible spectrum. The investigation of frontier molecular orbitals highlights intramolecular charge transfer across the molecule, establishing the bioactivity of the MIC molecule. The electron transport from the methyl group hydrogen atom H22 to the oxygen atom O11 is confirmed by Mulliken atomic charge distribution analysis and molecular electrostatic potential surface analysis. The calculated Fukui functions values validated the FMOs and Mulliken atomic charge distribution results. The natural bond orbital study further confirms the MIC molecule's intramolecular charge transfer and bioactivity. Molecular docking investigation results that the MIC molecule hinders the function of an enzyme known as Mitogen-activated protein kinase 14, which has been linked to cervical cancer. As a result, the present study provides the possibility towards the development of innovative to treat cervical cancer.

Crystal growth and vibrational spectroscopic studies on the novel NLO active 2-amino-4-methylpyridinium fluoroborate single crystal by experimental and computational technique

A semi-organic non-linear optical (NLO) single crystal of 2-amino-4-methylpyridinum fluoroborate(2AFB) to be synthesized and characterized via single crystal X-ray diffraction technique (SXRD), UV–Vis, FTIR and FT-Raman spectra. The quantum chemical calculations were carried out using density functional method (DFT) with B3LYP/6–31+G(D) basis set. The intermolecular interaction and stability of the title molecule have been obtained by NBO analysis. The molecular electrostatic potential and frontier molecular orbital analysis give a visual representation of charge distribution of the title molecule. The N-H…F interaction within 2AFB molecule was investigated via AIM and RDG analysis. The optical quality and energy band gap of 2AFB single crystal were found out using UV–visible spectral analysis. The emission spectra of the grown 2AFB single crystal has been examined by fluorescence spectral analysis. 2D fingerprint plot confirms the H…F and H…H interactions that exhibit the most significant contribution in crystal packing. The outcome of SXRD, UV-visible, HOMO-LUMO, NLO and Z-scan values were compared with earlier reported compounds and amongst which the analysed compound 2AFB shows good NLO activity. The NLO activity of the title molecule was confirmed theoretically and experimentally by DFT method and Z-scan technique.

Effect of molar concentration on optoelectronic properties of NiO nanoparticles for p-n junction diode application

In this work, fine nickel oxide nanoparticles (NiO NPs) were successfully made utilizing a straightforward co-precipitation approach at low temperature. The effects of precursor concentration on the structural, optical, and electrical characteristics of NiO nanoparticles were investigated. All indexed diffraction peaks in XRD demonstrate the production of NiO with cubic structure. An increase in NiO crystallite size above 16.8 nm was observed when the precursor concentration exceeds 2 M, suggesting the presence of nanostructure in the final product. In FT-Raman spectra, the band centered at ∼ 500 cm–1 is due to Ni-O stretching (LO) mode, and two-magnon (2 M) scattering mode causes the band at 1514 cm–1. The synthesized product is composed of almost rod-shaped particles with a size range of 10–20 nm, according to FESEM pictures. The UV absorption studies showed a high absorption at the fundamental absorption edges originating at 332 nm, which gradually shifted to a lower energy region up to 400 nm with increasing precursor concentration, which means a reduction in bandgap values. The effect of precursor concentration associated with the electrical characteristics of the produced NiO nanoparticles has been investigated for the temperature range 30 to 130 °C. The I-V characterization was used to compute the different photo-diode parameters including n, ФB, Io, PS, R, QE, and D* . The remarkable high photosensitivity of 1100% and specific detectivity of 4.324 × 10−10 Jones for the diode evaluated at 120 mW/cm2 was observed in a 2 M fabricated diode. These findings imply that all the fabricated diodes are exceptionally light-sensitive and are well-suited for upcoming UV photodetector applications.

Spectroscopic, computational, cytotoxicity, and docking studies of 6-bromobenzimidazole as anti-breast cancer agent.

6-Bromobenzimidazole (6BBZ) has been calculated in this study utilizing the 6-311++G(d,p) basis set and the Becke-3-Lee-Yang-Parr density functional approaches. The basic frequencies and geometric optimization are known. FTIR, FT-Raman, and UV-Vis spectra of the substance are compared between its computed and observed values. The energy gap between highest occupied molecular orbital-lowest unoccupied molecular orbital and molecule electrostatic potentials has been represented by charge density distributions that may be associated with the biological response. Time-dependent density functional theory calculations in the gas phase and dimethyl sulfoxide were carried out to ascertain the electronic properties and energy gap values using the same basis set. Molecular orbital contributions are investigated using the overlap population, partial, and total densities of states. Natural bond analysis was found to have strong electron delocalization by means of π(C4-C9) → π*(C5-C6), LP (N1) → π*(C7-C8), and LP(Br12) → π*(C5-C6) interactions. The Fukui function and Mulliken analysis have been explored on the atomic charges of the molecule. The nuclear magnetic resonance chemical shifts for 1 H and 13 C have been computed using the gauge-independent atomic orbital technique. With the highest binding affinity (-6.2 kcal mol-1 ) against estrogen sulfotransferase receptor (PDB ID: 1AQU) and low IC50 value of 17.23 μg/mL, 6BBZ demonstrated potent action against the MCF-7 breast cancer cell line. Studies on the antibacterial activity and ADMET prediction of the molecule have also been carried out.

Ambipolar conjugated ladder polymers by room-temperature Knoevenagel polymerization.

Two soluble conjugated ladder polymers (cLPs), decorated with multiple electron-poor species (i.e., cyano groups, fused pentagons, and N-heterocyclic rings), have been synthesized from the newly developed tetraketo-functionalized double aza[5]helicene building blocks using a single-step Knoevenagel polycondensation strategy. This facile approach features mild conditions (e.g., room temperature) and high efficiency, allowing us to quickly access a nonalternant ladder-like conjugated system with the in situ formation of multicyano substituents in the backbone. Analysis by 1H NMR, FT-Raman, and FT-IR spectra confirms the successful synthesis of the resulting cLPs. The combination of theoretical calculations and experimental characterizations reveals that the slightly contorted geometry coupled with a random assignment of trans- and cis-isomeric repeating units in each main chain contributes to improving the solubility of such rigid, multicyano nanoribbon systems. Apart from outstanding thermal stability, the resulting cLPs exhibit attractive red fluorescence, excellent redox properties, and strong π-π interactions coupled with orderly face-on packing in their thin-film states. They are proven to be the first example of ambipolar cLPs that show satisfactory hole and electron mobilities of up to 0.01 and 0.01 cm2 V-1 s-1, respectively. As we demonstrate, the Knoevenagel polycondensation chemistries open a new window to create complex and unique ladder-like nanoribbon systems under mild reaction conditions that are otherwise challenging to achieve.

A determination of the composition and structure of the polysaccharides fractions isolated from apple cell wall based on FT-IR and FT-Raman spectra supported by PCA analysis

Generally in plants, cell wall polysaccharides are the main determinants of tissue properties and contents of an essential part of dietary fiber, prebiotics, or cosmetic ingredients. Therefore, evaluation of the content and structure of polysaccharides is crucial to understanding and controlling their functionality. Vibrational spectroscopy has already proven to be very useful in studying wall-based compounds. Here, it was proposed to use the FT-IR and FT-Raman spectra combined with PCA analysis to discriminate and distinguish pectic and hemicellulosic fractions isolated from apple parenchyma as an example. Reference measurements have been done on commercially available polysaccharides in order to identify relevant fingerprint bands. The similarities of different polysaccharide fractions from apple: water, imidazole, dilute alkali-soluble polysaccharides (WSP, ISP, DASP, respectively), and polysaccharides soluble in three potassium hydroxide concentration (KOHs) to the reference polysaccharides were found. In the case of both types of spectroscopy, the region below 1800 cm−1 was used to differentiate the samples. The results showed that the WSP, ISP, and DASP fractions have band patterns similar to the pectic polysaccharides, but also contain bands characteristic of polysaccharides containing arabinan and galactan. While the KOH fractions showed the greatest similarities to the hemicellulose polysaccharides, especially the glucomannan and xyloglucan. The results showed that FT-IR and FT-Raman spectra supported by PCA can be useful for studying the structure of polysaccharide fractions directly isolated from plant cell wall material.

Structural, optical, and thermoluminescence characterizations of 1 mol% Dy3+ion-activated Fluro Boro-phosphate glass for photonic devices

A novel Fluro boro-phosphate host matrix doped with the 1 mol% of Dy3+ ions (50B2O3 + 20P2O5 + 10TiO2 + 10SrCO3 + 4BaF2 + 5BaCO3 + 1Dy2O3) was prepared using a conventional melt-quenching mechanism, and its structural characteristics were explored through the Powder-XRD, FT-IR, FT-Raman, EDAX and SEM spectroscopic analysis. The XRD spectrum of the glass confirmed its non-crystalline or amorphous structure. FT-IR and FT-Raman spectrum studies revealed that various borate and phosphate groups present with a variety of stretching and bending vibrations. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray analysis (EDAX) analysis have been used to examine the surface morphology and the presence of elements, respectively in the prepared glass. The optical absorption spectrum was used to explore the electronic band structure through the measurements of optical band-gap energy and Urbach energy. The luminescence spectrum reveals the emission characteristics of Dy3+ ions due to the electric-dipole and magnetic-dipole transitions. It is found that the decay time of the 4F9/2 excited level at a concentration of 1 mol% Dy3+ in the glass matrix is tri-fit non-exponential. The CIE chromaticity coordinates and the concentration influence on Y/B intensity ratios were computed for the creation of white light from the luminescence spectrum. The present work also discusses the findings after figuring out the correlated color temperature associated (CCT) with the color purity (Pe). The Thermoluminescence (TL) characteristics and the kinetic parameters of the glass were studied after the γ-irradiation with a dose of 2 kGy. EPR investigation revealed the paramagnetic characteristics through the hyperfine structure of Dy3+ ions and the electron-hole pair formation upon irradiation in the glass matrix.

Impact of modifiers on structural and optical properties of Dy3+doped different lithium tetraborate glasses for W-LED applications

The melt quenching technique achieved the synthesis of multiple samples of glasses were prepared, each containing Dy3+ ions as dopants and containing alkali and alkaline earth metals. Subsequently, several physical properties of these samples were assessed. The current investigation covers the characterization of Dy3+ doped lithium tetraborate glasses with varying compositions using powder X-Ray Diffraction (PXRD), FTIR, FT-Raman spectroscopy, optical absorption, and photoluminescence spectroscopy. The X-ray powder diffraction (PXRD) analysis indicates that the glass specimens exhibit an amorphous structure. The elemental composition of these materials has been determined using EDS. The utilization of FTIR and FT-RAMAN spectra is employed for the purpose of identifying distinct structural groups. J-O theory is employed to obtain J-O Intensity parameters and radiative parameters based on the absorption spectra. The photoluminescence spectra were utilized to determine the experimental branching ratios (βexp), effective bandwidths (Δʋeff), and stimulated emission cross-sections (σP) for all of the glass matrices that were prepared. The bi-exponential decay profiles of the 4F9/2 state were obtained and analyzed for all glass specimens containing Dy3+ ions. The lifetimes (τ) and quantum efficiencies (η) were determined by measuring decay profiles. Emission spectra are used to calculate correlated color temperatures (CCTs), CIE chromaticity coordinates and yellow-to-blue intensity ratios (Y/B).

Synthesis, crystal structures, spectroscopy, and quantum chemical studies on the 4-dimethylaminopyridinium-2,4-dinitrophenolate: an organic NLO material for optoelectronics.

In this work, the 4-dimethylaminopyridinium-2,4-dinitrophenolate (4DMAP + 2,4DNP) by slow evaporation solution growth method has been presented. The Fourier transform infrared (FT-IR) (4000-400cm-1) and FT-Raman (4000-50cm-1) spectra were recorded for the grown crystal. The computational calculation has been carried out with density functional theory (DFT) in ground state with Gaussian program package. Optimized geometrical parameters (bond distances, bond angles, and dihedral angles) have been obtained and compared with X-ray crystallography data. The calculated fundamental vibrational frequencies from DFT/B3LYP with 6-311 + + G(d,p) level of theory were scaled so as to agree with the observed results, and the scaling factors were reported. Experimental and computed ultraviolet-visible (UV-Vis) spectra in acetone and methanol solvents were found comparable to each other. Furthermore, the frontier molecular orbitals (FMOs) energies, molecular electrostatic potential (MEP), nonlinear optical (NLO), hirshfeld surface (HS), and global chemical descriptors of the molecule were also calculated. The thermal stability and the melting point of the title compound were analyzed by the thermogravimetric analysis/differential thermal analysis (TGA/DTA) techniques. The mechanical behavior of the organic single crystal was measured by Vickers micro-hardness method. The third-order nonlinear optical properties such as nonlinear refractive index (n2), nonlinear absorption coefficient (β), optical nonlinear susceptibility Reχ(3), and optical nonlinear susceptibility Imχ(3) were calculated by using the open and closed aperture Z-scan technique. The theoretical and experimental NLO values clearly proposed that the nonlinearity of 4DMAP + 2,4DNP molecule could be helped as a potential candidate for optical limiting, frequency doubling, and optical switching applications.

Study of different interactions in piperazine benzoate and its effect on biological properties: Experimental and theoretical approach

Piperazine benzoate (PPB), an antibacterial molecule, was synthesized and characterized using FT-IR, FT-Raman, UV, and NMR spectra as well as biological research. The optimized geometry of the molecule was performed using Gaussian'09w programme at B3LYP with 6–311G++(d,p) basis set. Hyper conjugative interaction σ(CH) → σ*(OH) enhances NH…O interaction and C-H…O interaction arises mainly from charge transfer between the molecules. The electronic transitions in the molecule were exhibited by comparing the UV–vis spectrum with the observed spectrum using the TD-DFT method in gaseous phase. FMO analysis, natural charge analysis, and global chemical reactivity descriptors methods were investigated. PPB is a soft molecule with significant polarizability and chemical reactivity because of its low molecular orbital energy gap. Normal coordinate analysis (NCA) was used to determine the detailed interpretation of the fundamental modes. The chemical shifts of the molecule were determined from the recorded 13C and 1H NMR spectra using the gauge independent atomic orbital (GIAO) method. Using NBO analysis, concerns related to molecular stability and bond strength have been presented. The topological properties were studied using MEP, ELF, and LOL maps. From AIM findings, the PPB is defined by two BCPs, one each for an ON…H and CO…H type hydrogen bond. Through RDG investigation, the interactions inside the PPB molecule were examined. The interaction areas in the molecular structure of PPB are confirmed by the RDG graph data. PPB's absorption rate was 78.18 percent. This figure led to the conclusion that PPB had the highest percentage of absorption. Bacterial proteins were used for molecular docking, and docking parameters were derived. Based on Lipinski's rule of five, drug similarity was determined, and the ADMET variables were also predicted.

Monohalogenated methyl- and methoxy-benzoic acids: A combined experimental and quantum chemical theoretical study on their structure, vibrational analysis and molecular parameters

In this paper, the molecules 3-fluoro-2-methylbenzoic acid; 3-chloro-2-methoxybenzoic acid; and 3-bromo-2-methylbenzoic were investigated using experimental and quantum chemical theoretical approach for vibrational and electronic properties from the optimized structure. Becke three parameter Lee–Yang–Parr density functionals along with 6-311++G(d,p) basis set were employed to compute their geometric optimization, fundamental frequencies and molecular parameters. The detected FT-IR and FT-Raman spectra were compared with their simulated spectra and the rms error between the detected and simulated vibrational frequencies was found at 6.17, 7.22 and 6.76 cm−1 for FMA, CMA and BMA, respectively. All the vibrational fundamentals were assigned unequivocally using potential energy distribution (PED) obtained in the computations. 1H and 13C NMR chemical shifts were evaluated by integrating the gauge-independent atomic orbital (GIAO) method with DFT and compared with corresponding experimental values. TD-DFT approach was followed to compare the simulated absorption maxima (λmax) in DMSO-d6 solvent with observed values and interpreted in terms of HOMO and LUMO. The global reactive descriptors were estimated from the associated energies of HOMO and LUMO which describe the reactivity and stability of the molecules. Molecular electrostatic potential (MEP) surface has been determined using the charge density distributions to demonstrate electrophilic and nucleophilic nature of the molecules. DFT computations also ascertained the applicability of the titled molecules as NLO materials from the computed values of dipole moment and hyperpolarizability. Thermodynamic parameters and rotational constants were also evaluated employing rigid rotor harmonic oscillator approximation. Natural bond orbital (NBO) analysis confirmed the charge delocalization due to intra-molecular interactions.

Molecular structural analysis, conformers and spectral (FT-IR, FT-Raman, NMR and UV-Visible), Importance of solvent role in molecular, ADME and molecular docking investigation on alpha-cyano-4-hydroxycinnamic acid

The primary objective of research to reveals the effective drug treatment for corona virus disease (COVID-19). The current study on alpha-cyano-4-hydroxycinnamic acid (ACHC), the theoretical predictions were done by using Gaussian 09 W software on the basis of DFT/ TDFT/B3LYP methods with basis set of 6–311++G (d, p). The vibrational wavenumbers were obtained from the observed FT-IR and FT-Raman spectra and these vibrations were assigned on the basis of their potential energy distribution (PED) contribution. 1H and 13C NMR chemical shift of the molecule were computed by using Gauge independent atomic orbital (GIAO) method. In UV-Visible analysis the electronic transition was predicted by Time-dependent self-consistent field (TD-SCF)/DFT method. NBO analysis was done to understand the possible the intermolecular interaction, electron transition within the donor and acceptor orbitals of the molecule. The HOMO and LUMO indicates the prominent charge transfer possibilities and its energy gap shows stability of the molecule. A molecular electrostatic potential (MEP) image shows the electrophilic and nucleophilic sites of the molecule. Molecular docking analysis was carried out against Agaricus bisporus tyrosinase (2Y9X) and severe acute respiratory syndrome corona virus 2 (6LZG).

FT-Raman Methodology Applied to Study the Effect of Time and Type of Seasoning in the Crafting of Sherry Casks® Used in the Aging of Brandy De Jerez.

Brandy de Jerez is a grape-derived spirit produced in Southern Spain with specific characteristics that come from the casks where it is produced, which must have previously contained some type of Sherry wine for at least 12 months. These casks are known as Sherry Cask®. In this work, Brandies de Jerez aged for different aging times (0, 3, 6 and 12 months) in casks seasoned with three different types of Sherry wines (Fino, Oloroso and Amontillado) have been studied. The samples have been analyzed using FT-Raman spectroscopy, and their chemical characterization has also been realized by studying their total content of organic acid, volatile compounds, and phenolic and furanic compounds. Their chemical study showed that the main differences between the studied samples were due to the duration and the type of seasoning performed. However, the spectra obtained through FT-Raman presented noticeable differences according to cask seasoning time and the Sherry wine used for the process. A PCA (Principal Component Analysis) confirmed that the Brandies de Jerez presented significant differences depending on the seasoning time and type that the casks were subjected to. A PLS-R (Partial Least Squares Regression) study enabled establishing a close correlation between specific regions of the FT-Raman spectra and cask seasoning time.

Vibrational assignments of cyclic dimers and inter-monomers of adenine relating FT-IR, FT-Raman and UV spectra with SQMFF and DFT calculations

In this work, three different cyclic dimers and a tetramer of adenine taken from the experimental structure determined by X-ray diffraction have been studied by combination of experimental FT-IR, FT-Raman and UV–Visible spectra with hybrid B3LYP/6–311++G** and scaled quantum mechanical force field (SQMFF) calculations in order to perform the complete assignments of bands observed in the vibrational spectra. The characteristics of different N-H···N interactions of those three cyclic structures together with the group of IR bands observed between 2865 and 2599 cm−1 have been elucidated considering the tetrameric structure. The cyclic dimers and the tetramer of adenine confirm that the bands observed between 2865 and 2599 cm−1 are not due to N-H···N interactions but to bands of combination, as was previously suggested. The experimental available deuterated IR and terahertz spectra have allowed the complete assignments of regions of higher and lower wavenumbers. Good correlations were acquired comparing the theoretical IR, Raman and UV spectra of three species and the tetramer with the analogous experimental ones, suggesting the presence of all species in both phases. Vibronic bands are observed in the electronic spectra when adenine concentration is increased in aqueous solution evidencing the presence of monomer, tautomers and dimers, as reported by different studies. Similar characteristics of H bonds interactions are predicted for dimers 1 and 2 but different from the dimer 3, as revealed by using NBO and AIM calculations. Different scaled force constants values were found for the cyclic dimers 1 and 2, as compared to the corresponding to dimer 3.

The experimental and theoretical spectroscopic elucidation of molecular structure, electronic properties, thermal analysis, biological evaluation, and molecular docking studies of isococculidine

Experimental techniques, such as vibrational spectroscopy (FT-IR and FT-Raman), UV–visible, thermal analysis (DSC), along with quantum chemical calculations based on density functional theory (DFT) were conducted to explore the physicochemical properties of a plant-derived natural product, isococculidine. The potential energy distribution (PED) has been assigned to each of the vibrational bands observed in FT-IR and FT-Raman spectra. The reduced density gradient (RDG) analysis was used to demonstrate the non-covalent interactions (NCI). Natural bond orbital (NBO) study revealed that the benzene ring's hyper-conjugative interactions were primarily responsible for the molecular stability. The intramolecular charge transfer has been further verified by the HOMO-LUMO analysis. The molecular electrostatic potential (MEP) analysis signifies that the nucleophilic and electrophilic interaction sites are prone to oxygen of O1-CH3 and hydrogens of O2-CH3, respectively. The chemical activity and the toxicity of the molecule have been examined based on the calculated Mulliken charges, softness, hardness, and local reactivity parameters. The thermal properties like specific heat capacity, entropy and enthalpy which affect the drug's activities were studied. The large value of the first hyperpolarizability indicates its significant nonlinear optical (NLO) property. The molecular docking of isococculidine has been performed with nicotinic acetylcholine protein which deliberates the significant biological activity of the molecule.

Spectroscopic, quantum chemical investigation and molecular docking studies on N-(2-benzoylamino) phenyl benzamide: A novel SARS-CoV-2 drug.

The present work describes the structural and spectral properties of N-(2-benzoylamino) phenyl benzamide (NBPB). The geometrical parameters of NBPB molecule such as bond lengths, bond angles and dihedral angles are calculated and compared with experimental values. The assigned vibrational wave numbers are in good agreement with the experimental FTIR and FT Raman spectra. The vibrational frequency of C=O stretching was downshifted to a lower wave number (red shift) due to mesomeric effect. The UV-Vis spectrum of the title compound was simulated and validated experimentally. The energy gap and charge transfer interaction of the title molecule were studied using frontier molecular orbital analysis. The electrophilic and nucleophilic reactivity sites of NBPB were investigated through the analysis of the molecular electrostatic potential surface and the Fukui function. An assessment of the intramolecular stabilization interactions of the molecule was performed using natural bond orbital analysis. The drug-likeness parameter was calculated. To investigate the inhibitory potential of the molecule, molecular docking analysis was conducted against SARS-CoV-2 proteins, revealing its capability to serve as a novel inhibitor against SARS-CoV-2. The high binding affinity of NBPB molecule was due to the presence of hydrogen bonds along with different hydrophobic interactions between the drug and the SARS-CoV-2 protein receptor. Hence, the title molecule is identified to be a potential candidate for SARS-CoV-2.

Vibrational characterization of active drug to the treatment of chagas disease, benznidazole by using force fields and internal coordinates

Two experimental structures of benznidazole active drug used to the treatment of Chagas disease have been structurally characterized and its vibrational spectra completely assigned combining B3LYP/6-311++G** calculations with the experimental FT-IR and FT-Raman spectra and the SQMFF methodology. The most stable conformer of benznidazole found in the study of the potential energy surface is in agreement with that experimentally observed by X-ray diffraction at room temperature while the other one was observed with the heating up to 195 ºC. Both differs in the positions of CH2 groups of acetamide fragment. Their structural properties in gas phase and ethanol solution were computed by using natural bond orbital (NBO), atoms in molecules (AIM), Merz-Kollman (MK) charges, molecular electrostatic potentials (MEP) and frontier orbitals calculations by using the hybrid B3LYP method and the 6-31G* and 6-311++G** basis sets. Additional WB97XD/6-311++G** calculations show that the energy values optimized for the most stable species in both media present lower values than the obtained with the B3LYP/6-31G* method. The vibrational assignments for those two conformers in both media were obtained from their corresponding harmonic force fields together with the scaled force constants.

Structures, vibrational spectra and microbiological activity of 5-methylbenzotriazole tautomers stabilized by N-H···N intermolecular hydrogen bonds

Three tautomeric forms (1H-, 2H-, 3H-) of 5-methylbenzotriazole (5MeBTA) and the tetramer, which includes the 1H-5MeBTA and 3H-5MeBTA tautomers connected by N3−H⋅⋅⋅N3 and N1−H⋅⋅⋅N2 intermolecular hydrogen bonds, have been studied by density functional theory (DFT) using B3LYP, B3LYP-D3 and ωB97XD methods combined with the 6–31++G(d,p) basis set. Calculations for the tetramer have revealed that intermolecular N3⋅⋅⋅N3 distances range from 2.881 to 2.851 Å, while the N1⋅⋅⋅N2 distances vary between 2.965 and 2.915 Å. These distances are very similar to those reported for the crystal of 5MeBTA (R. K. Belter, F. R. Fronczek, CCDC 1971683, 2019). The theoretical Raman and infrared spectra of the tetramer are in a very good agreement with the FT-Raman and FT-IR spectra of 5MeBTA in the solid state, measured in this work. A detailed interpretation of the experimental vibrational spectra has been made on the basis of the calculated potential energy distribution (PED). Microbiological studies in vitro were conducted for 5MeBTA and benzotriazole (BTA) against six bacterial strains (E. coli, K. pneumoniae, P. aeruginosa, B. subtilis, L. monocytogenes and S. aureus) and two fungal strains (A. niger and C. albicans). The results have shown that the substitution by the methyl group at the C-5 atom of BTA leads to an increase in activity against tested strains, in comparison to BTA. For 5MeBTA, the inhibition zones for bacteria and fungi range from 12 mm to 20 mm, and from 13 mm to 24 mm, respectively. The title compound has revealed particularly strong activity against A. niger, C. albicans and L. monocytogenes (with inhibition zones ≥ 20 mm).

Vibrational Spectra of the thioglycolate complexes of Zn(II) and Cd(II), structure and natural bond orbitals

The objective of this research was to characterize the vibrational spectrum of the Zn(II) and Cd(II) thioglycolate complexes, as well as their structures, vibrational analysis and the natural orbitals of bonds, through the infrared spectrum with Fourier transform (FT -IR) and Raman. The thioglycolate complexes of Zn(II) and Cd(II) were synthesized following procedures given by the graphical method, and structural analysis was performed through a theoretical-experimental method using both, the hybrid RHF/MP2:STO-3G and the experimental FT-IR and FT-Raman spectra. Calculations were performed on the optimized structure and harmonic vibrational wavenumbers for both complexes were obtained. Second derivative of the vibrational spectra and deconvolution analysis were also performed. The infrared and Raman spectra show many combination and overtone bands in both cases. Calculated and experimental spectra confirmed the structural hypothesis considering two ATG (thioglycolic acid) with two water molecules in the coordination sphere of the central atoms. The natural bond orbital analysis (NBO) was also carried out to study the Zn(II) and Cd(II) hybridization leading to a pseudo-octahedral geometry for both complexes.

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.