•The experimental structure was characterized by FT-IR, UV-Vis and NMR.•The optimized geometry is computed and spectroscopic properties of NBCA were examined•The nonlinear optical properties have ...been evaluated for the different conformations.•MEP and energy gaps of frontier orbital (HOMO–LUMO) have been calculated.•Hirshfeld surface analysis and fingerprint plots were carried out.
In this research, we have compared theoretical and experimental results such as the molecular structure, vibration frequencies, UV-Vis, chemical shift values of 1H and 13C NMR of (E)-N-(4-nitrobenzylidene)-3-chlorobenzenamine (NBCA). The experimental data have been collected from a high-resolution X-ray diffraction pattern and the theoretical analyses have been carried out using the density functional theory (DFT) based on B3LYP level at 6-31++G (d, p) by Gaussian program, knowing that every single vibration frequency is awarded on the potential energy distribution (PED) base and electronic transitions are computed according to the time-dependent density functional theory (TD-DFT). The non-linear optical parameters (NLO) have similarly been investigated at the same level theory. The energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and the global chemical reactivity descriptors (GCRD) of the title molecule were investigated by using DFT/B3LYP/6-311++G (d, p) method. Molecular electrostatic potential (MEP) is simulated to look for better reactive sites for electrophilic and nucleophilic attacks. To ascertain the contribution of intermolecular interactions, Hirshfeld surface analysis and fingerprint plots were carried out. To determine the biological activity of NBCA molecule, the basic prediction of substance activity spectra (PASS) and molecular docking are studied.
•A series of 2-mercapto-1,3,4-oxadiazole has been successfully synthesized.•All compounds underwent characterization using IR, NMR and Mass spectrometry.•These compounds were evaluated as urease ...inhibitors.•DFT used to predict the electronic, structural and spectroscopic properties.•The docking study contributed to the analysis of urease protein binding.
In the present work seven derivatives (5a-5d and 6a-6c) of 2-mercapto-1,3,4-oxadiazole were synthesized by multistep reactions. After characterization through IR, EI-MS, 1H-, and 13C NMR spectroscopy, the synthesized compounds were screened in vitro against urease enzyme. Among the series, five derivatives 6c (IC50 = 9.90 ± 1.92 µM), 6a (IC50 = 10.65 ± 1.80 µM), 6b (IC50 = 12.30 ± 0.99 µM), 5c (IC50 = 12.57 ± 0.41 µM), and 5d (IC50 = 16.96 ± 0.64 µM) attributed excellent inhibition effect excellent than the standard thiourea (IC50 = 22.80 ± 2.20 µM). In addition, the remaining four compounds 5a, 5b, 4, and 3 were found good inhibitors against the urease enzyme with IC50 values of 23.23 ± 0.17, 25.20 ± 0.90, 31.40 ± 1.18, and 36.77 ± 1.03 µM respectively. The cytotoxicity assay revealed that the synthetic derivatives did not show any cytotoxic effect. DFT used to calculate frontier molecular orbital including; HOMO and LUMO to indicate the charge transfer from molecule to biological media, and MEP map to indicate the chemically reactive zone suitable for drug action. The results of docking and MD simulation indicate that most active mercapto-1,3,4-oxadiazoles have high binding efficiency to urease. The In silico ADMET indicated that 5a-d and 6a-c compounds did not exhibit carcinogenicity, mutagenicity or tumorigenicity.
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Using molecular docking and multispectral analytical techniques, the present work investigates the binding characteristics between hexanal and β-lactoglobulin at near neutral pH and ambient ...temperature. Fluorescence quenching demonstrates that binding between β-lactoglobulin and hexanal is of low to medium strength, having a KA ranging from 9.6 × 102 to 4.0 × 104 M−1, with UV–vis and MALDI-TOF analysis suggesting that interactions are non-covalent in nature. Analysis of secondary structure using both FTIR and CD, shows that the complexation of the ligand with the protein induces an increase in β-sheet structure and a corresponding decrease in α-helical components. The method of continuous variation reveals a 1:1.5 (2:3) binding ratio under the present experimental conditions, suggesting that each β-lactoglobulin dimer may bind 3 hexanal molecules. Molecular docking simulations were consistent with these findings, showing three potential binding locations with distinct binding energies for the dimer. One binding site is located within the hydrophobic calyx of each monomer, while the third site is located at the interface between the two monomers. Knowledge achieved presently may advance our understanding of the fate of flavour compounds in dairy based beverage formulations.
3D image of best binding pose between hexanal (in yellow circles) and β-lactoglobulin as a dimer (each monomer denoted as A and B) under ambient conditions at neutral pH, with arrows depicting 2D images of the interactions with amino acids of each protein monomer and interface as well as the binding distances, where green lines represent hydrogen bonds, purple lines represent pi-alkyl bonds, pale purple lines represent pi-alkyl bonds and unbound amino acids interact via non van der Waals interactions. Display omitted
•Three binding locations for hexanal on dimeric β-lactoglobulin at neutral pH are proposed.•Binding sites are within the calyx of each monomer and at the interface of the dimer.•Interaction within the calyx possesses the highest binding energy.•Binding between hexanal and β-lactoglobulin is non-covalent in nature.
Mixed halide hybrid perovskites, CH
NH
Pb(I
Br
)
, represent good candidates for low-cost, high efficiency photovoltaic, and light-emitting devices. Their band gaps can be tuned from 1.6 to 2.3 eV, ...by changing the halide anion identity. Unfortunately, mixed halide perovskites undergo phase separation under illumination. This leads to iodide- and bromide-rich domains along with corresponding changes to the material's optical/electrical response. Here, using combined spectroscopic measurements and theoretical modeling, we quantitatively rationalize all microscopic processes that occur during phase separation. Our model suggests that the driving force behind phase separation is the bandgap reduction of iodide-rich phases. It additionally explains observed non-linear intensity dependencies, as well as self-limited growth of iodide-rich domains. Most importantly, our model reveals that mixed halide perovskites can be stabilized against phase separation by deliberately engineering carrier diffusion lengths and injected carrier densities.Mixed halide hybrid perovskites possess tunable band gaps, however, under illumination they undergo phase separation. Using spectroscopic measurements and theoretical modelling, Draguta and Sharia et al. quantitatively rationalize the microscopic processes that occur during phase separation.
Vibrational Spectroscopy of Ionic Liquids Paschoal, Vitor H; Faria, Luiz F. O; Ribeiro, Mauro C. C
Chemical reviews,
05/2017, Volume:
117, Issue:
10
Journal Article
Peer reviewed
Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of ...publications in the 1990’s. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.
Higgs and Goldstone modes are collective excitations of the amplitude and phase of an order parameter that is related to the breaking of a continuous symmetry. We directly studied these modes in a ...supersolid quantum gas created by coupling a Bose-Einstein condensate to two optical cavities, whose field amplitudes form the real and imaginary parts of a U(1)-symmetric order parameter. Monitoring the cavity fields in real time allowed us to observe the dynamics of the associated Higgs and Goldstone modes and revealed their amplitude and phase nature. We used a spectroscopic method to measure their frequencies, and we gave a tunable mass to the Goldstone mode by exploring the crossover between continuous and discrete symmetry. Our experiments link spectroscopic measurements to the theoretical concept of Higgs and Goldstone modes.
Atomic force microscopy-based infrared spectroscopy (AFM-IR) is a rapidly emerging technique that provides chemical analysis and compositional mapping with spatial resolution far below conventional ...optical diffraction limits. AFM-IR works by using the tip of an AFM probe to locally detect thermal expansion in a sample resulting from absorption of infrared radiation. AFM-IR thus can provide the spatial resolution of AFM in combination with the chemical analysis and compositional imaging capabilities of infrared spectroscopy. This article briefly reviews the development and underlying technology of AFM-IR, including recent advances, and then surveys a wide range of applications and investigations using AFM-IR. AFM-IR applications that will be discussed include those in polymers, life sciences, photonics, solar cells, semiconductors, pharmaceuticals, and cultural heritage. In the Supporting Information, the authors provide a theoretical section that reviews the physics underlying the AFM-IR measurement and detection mechanisms.
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