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Fourier transform infrared spectra, for 2-((2-aminopyridin-3-yl) methylene) hydrazinecarbothioamide (APHT) and 2((2-aminopyridin-3-yl) methylene)-N-methylhydrazinecarbothioamide (APMHT), were recorded in the spectral range 4000–400 cm−1. Their Raman counterparts were measured in the spectral region 4000–50 cm−1. Preliminary values of dihedral angles around five rotating bonds C–NH2 pyridyl C–CN, N–N, N–CS and C–NH2 aliphatic in APHT, required for initiating geometry optimization, were obtained by pairing successive bonds and evaluating torsional potential energy for various values of dihedral angle around these bonds in the entire conformational space spanning 0° to 360°. Barrier heights, around five rotating bonds in APHT and six rotating bonds in APMHT were computed, making torsional scans in conformational space from 0° to 360°. This indicated existence of two rotational isomers for APMHT. General valence force field, harmonic vibrational fundamentals, potential energy distribution (PED), along with infrared and Raman intensities were determined using DFT/B3LYP/6-311++G(d,p) level of theory for both the molecules. Good agreement was found between measured and simulated spectra, for APHT and APMHT. This was also true for corresponding Raman spectra. The rms error between experimental and theoretical vibrational frequencies was 9.00 and 6.70 cm−1, for APHT and APMHT, respectively. All vibrational fundamentals were assigned unambiguously, on the basis of computed PED, eigenvectors, and literature range for the first time. These assignments were further supported by comparing with attribution of corresponding bonds in the parent molecule pyridine and a related molecule 2-((2-aminopyridin-3-yl)methylene)-N-ethylhydrazinecarbothioamide, wherever possible. [ABSTRACT FROM AUTHOR]

An organic crystalline salt − 2,4-Diamino-6-methyl-1,3,5-triazin- 1-ium hydrogen oxalate (DMTO) has hydrogen interactions viz. NH⋯O, CH⋯O, NH⋯N and OH⋯O gives interesting vibrational effect. X-ray diffraction study reveals that DMTO is crystallized in triclinic centrosymmetric space group P-1 as expected. Structural as well as the vibrational spectra have been discussed on the basis of density functional theory (DFT) using B3LYP hybrid functional with the basis set 6–311++G(d,p). Acidic proton of the oxalic acid (OA) is transferred to 2,4-diamino-6-methyl-1,3,5-triazine (DAMT) and giving rise to singly protonated 2,4-diamino-6-methyl-1,3,5-triazinium ion.

The vibrational, electronic and charge transfer studies on 2-bromo-6-methoxynaphthalene (2BMN) were done using DFT method with B3LYP/6-311++G(d,p) theory using GAUSSIAN 09W software. Theoretical and experimental investigations on FT-IR and FT Raman were executed on 2BMN. The calculated vibrational wavenumbers were scaled using suitable scaling factors and vibrational assignments were done to all modes of vibrations using Potential Energy Distribution (PED). Frontier Molecular Orbitals were calculated using TD-DFT method and the HOMO-LUMO energy gap was also obtained. Other electronic properties and global parameters for 2BMN were found using the HOMO-LUMO energy values. An energy gap of 4.208 eV shows the stability of the molecule. The reactive sites were predicted using Molecular Electrostatic Potential (MEP), Electron Localization Function (ELF) and Fukui calculations. Hence all electrophilic sites and nucleophilic areas of the molecule were determined. The delocalization of electron density was studied using NBO calculations. The intramolecular transitions and stability of structure were explained using in detail using the former. As the compound satisfies drug-like properties and has a softness value (indicating its less toxic nature), it may be used as a pharmaceutical product. Molecular docking studies were made and the protein-ligand binding properties were discussed. It was found out that title compound exhibits anti-cancer activities. The low binding energy predicts that the compound may be modified as a drug for treating Cancer.

A spatial heterodyne Raman spectrometer (SHRS), constructed using a modular optical cage and lens tube system, is described for use with a commercial silica and a custom single-crystal (SC) sapphire fiber Raman probe. The utility of these fiber-coupled SHRS chemical sensors is demonstrated using 532 nm laser excitation for acquiring Raman measurements of solid (sulfur) and liquid (cyclohexane) Raman standards as well as real-world, plastic-bonded explosives (PBX) comprising 1,3,5- triamino- 2,4,6- trinitrobenzene (TATB) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) energetic materials. The SHRS is a fixed grating-based dispersive interferometer equipped with an array detector. Each Raman spectrum was extracted from its corresponding fringe image (i.e., interferogram) using a Fourier transform method. Raman measurements were acquired with the SHRS Littrow wavelength set at the laser excitation wavelength over a spectral range of ∼1750 cm−1 with a spectral resolution of ∼8 cm−1 for sapphire and ∼10 cm−1 for silica fiber probes. The large aperture of the SHRS allows much larger fiber diameters to be used without degrading spectral resolution as demonstrated with the larger sapphire collection fiber diameter (330 μm) compared to the silica fiber (100 μm). Unlike the dual silica fiber Raman probe, the dual sapphire fiber Raman probe did not include filtering at the fiber probe tip nearest the sample. Even so, SC sapphire fiber probe measurements produced less background than silica fibers allowing Raman measurements as close as ∼85 cm−1 to the excitation laser. Despite the short lengths of sapphire fiber used to construct the sapphire probe, well-defined, sharp sapphire Raman bands at 420, 580, and 750 cm−1 were observed in the SHRS spectra of cyclohexane and the highly fluorescent HMX-based PBX. SHRS measurements of the latter produced low background interference in the extracted Raman spectrum because the broad band fluorescence (i.e., a direct current, or DC, component) does not contribute to the interferogram intensity (i.e., the alternating current, or AC, component). SHRS spectral resolution, throughput, and signal-to-noise ratio are also discussed along with the merits of using sapphire Raman bands as internal performance references and as internal wavelength calibration standards in Raman measurements. [ABSTRACT FROM AUTHOR]

Organic arylidene crystal of 2,6-bis(2,6-dichloro benzylidene)cyclohexanone was synthesized by Claissen-Schmidt condensation reaction. Crystals were grown by slow evaporation technique by using the solvent DMF. Its functional groups were identified by FT-IR and they were affirmed by FT-Raman studies. Lattice parameters were confirmed by powder X-ray diffraction method. Optical transparency was calculated by UV-visible-IR studies. Melting point was measured by DSC. Variations of dielectric constant and dielectric loss with frequency were measured by dielectric meter. SHG was measured by Kurtz-Perry method. [ABSTRACT FROM AUTHOR]

The post-polymerization modification of porous glycidyl methacrylate – ethylene glycol dimethacrylate microspheres was subsequently achieved firstly by reacting the glycidyl functionalities with sodium cyclopentadienide and secondly by the Diels-Alder click reaction with maleic anhydride. Analysis of the surface-decorated spherical polymeric materials was performed using the Fourier transform vibrational (Raman), and infrared (attenuated total reflectance) spectroscopies. In addition, the FT-IR photoacoustic spectroscopy as an alternative, and interesting tool in the chemical analysis of modified polymers was used. The results from those three non-destructive complementary spectroscopic methods providing important molecular structural information were compared together. • The solid copolymers were characterized by non-destructive spectroscopic techniques. • The FT-IR/PAS technique provides broader representation of characteristic bands for a greater variety of functional groups. • The photoacoustic spectroscopy is a supplementary technique for the solid state studies. • PAS technique proved to be very useful tool in confirmation of surface functionalization. [ABSTRACT FROM AUTHOR]

Abstract The single crystals of p-nitroanilinium p-toluene sulphonate have been grown by slow solvent evaporation method at room temperature. X-Ray diffraction data have been collected from single crystal X-ray diffraction analysis and reveals that the crystal crystallizes in monoclinic system with centro symmetric space group P 21/n. The lattice parameters are calculated to be a = 6.2189 (14)Å, b = 30.7201 (36)Å, c = 7.4080 (12) Å, α = γ = 90° and β = 97.25 (3)o. The volume of the unit cell is calculated to be = 1404.0 (4) (Å)3. The hydrogen bond interactions between the singly protonated 4-nitroanilinium cation and single dissociated toluene sulphonate (1-) anions forms a three dimensional network. The crystallite size is calculated to be 14.264 μm from powder X-ray diffraction spectrum by using Debye-Scherrer's formula. The vibrational spectra provide the presence of NH 3 , CH 3 , SO 3 and NO 2 group of the title molecule. Further the 3D Hirshfeld surface analysis and 2D fingerprint maps were used for quantitative mapping out of the intermolecular interactions. Graphical abstract Image 10471 Highlights • p-nitroanilinium p-toluene sulphonate (PNAPTS) crystal synthesized at room temperature. • X-ray crystallographic analysis has been carried out for PNAPTS. • Obtained PNAPTS crystallizes in monclinic system with space group P 21/n. • Characterized by FT-IR and FT Raman spectral analysis. • Hirshfeld surface analysis has been reported. [ABSTRACT FROM AUTHOR]

The present work reports a simple coprecipitation adapted method for the synthesis of stable Ce substituted to Ca hydroxyapatite (HAp) nanoparticles. The structural and morphological properties of Ce doped hydroxyapatite (Ce:HAp) were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDAX). The optical properties of Ce doped hydroxyapatite were also investigated using Fourier Transform Infrared (FTIR) spectroscopy, FT Raman spectroscopy and photoluminescence analysis. The results of the XRD studies revealed the progressive increase in the a- and c-axes with increasing of Ce concentrations. In the FTIR studies of Ce:HAp powders a similar structure to hydroxyapatite was observed. IR and Raman wavenumbers and the peak strength of the bands associated to the P-O and O-H bonds decreases progressively with the increase of Ce concentration. All the emission maxima could be attributed to the 5d-4f transitions of Ce ions. The displacement of maximum emission bands with the increase of Cerium in the samples is in agreement with the results obtained by XRD studies. The Ce:HAp samples with xCe =0.03 and 0.05 exhibited significant antibacterial activity against Staphylococcus aureus ATCC 6538 and E. coli 714 bacterial strains compared to Ce:HAp samples with xCe =0 (pure HAp) and 0.01.

This review presents some applications of proteomics and selected spectroscopic methods to validate certain aspects of seafood traceability. After a general introduction to traceability and the initial applications of proteomics to authenticate traceability information, it addresses the application of proteomics to trace seafood exposure to some increasingly abundant emergent health hazards with the potential to indicate the geographic/environmental origin, such as microplastics, triclosan and human medicinal and recreational drugs. Thereafter, it shows the application of vibrational spectroscopy (Fourier-Transform Infrared Spectroscopy (FTIR) and Fourier-Transform Raman Spectroscopy (FT Raman)) and Low Field Nuclear Magnetic Resonance (LF-NMR) relaxometry to discriminate frozen fish from thawed fish and to estimate the time and temperature history of frozen fillets by monitoring protein modifications induced by processing and storage. The review concludes indicating near future trends in the application of these techniques to ensure seafood safety and traceability.

Entecavir, a new deoxyguanine nucleoside analogue, is a selective inhibitor of the replication of the hepatitis B virus. In the present study, Quantum mechanical approach was carried out on the title compound to study the vibrational spectrum, the stability of the compound, the intermolecular and intramolecular interactions by using Density Functional Theory (DFT) with B3LYP 6-311++G(d,p) basis set. The B3LYP/DFT method was chosen because diverse studies have shown that the results obtained with it are in good agreement with those determined by other costly computational methods. The computational methods were aided by the experimental spectroscopic techniques, namely FTIR and FT Raman spectroscopies. The optimized molecular geometry, vibrational wavenumbers, infrared intensities and Raman scattering activities were calculated. The calculated HOMO and LUMO energies were found to be −6.397 eV and −1.504 eV which indicate the charge transfer within the molecule. The maximum absorption wavelength and the band gap energy of the title compound were obtained from the UV absorption spectrum computed theoretically. Natural Bond Orbital analysis has been carried out to explain the charge transfer (or) delocalization of charge due to the intra molecular interactions. The molecule orbital contributions are studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. Molecular electrostatic potential (MEP), First order hyperpolarizability, Hirshfield surface analysis and Fukui functions calculation were also performed. From the calculations the first order hyperpolarizability was found to be 2.3854 × 10 −30  esu. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures have been calculated. Molecular docking studies were made on the title compound to study the hydrogen bond interactions and the minimum binding energy was calculated. [ABSTRACT FROM AUTHOR]

The bioactivity of compounds is mainly dependent on molecular structure and the present work aims to explore the bonding features responsible for biological activity of novel anticancer drug N -(6-ferrocenyl-2-naphthoyl)-gamma-amino butyric acid ethyl ester (FNGABEE). In the present study, we investigate the molecular structural properties of newly synthesized title compound through experimental and quantum chemical studies. The detailed vibrational analysis has been performed using FT IR and FT Raman spectrum, aided by DFT computed geometry, vibrational spectrum, Eigen vector distribution and PED, at B3LYP/6-311 ++G(d,p) level. The resonance structure of naphthalene, different from that of benzene, revealed by molecular structure has been investigated using C C and C C stretching modes. The proton transfer in amide has been analyzed to obtain spectral distinction between different carbonyl and C N groups which point to the reactive sites responsible for binding with DNA and bovine serum albumin (BSA). The spectral distinction between eclipsed and staggered form of ferrocene has been analyzed. The molecular docking of FNGABEE with BSA and DNA has been performed to find the strength of binding and the moieties responsible for the interactions. The experimental binding studies of FNGABEE with BSA and DNA has been performed using UV absorption spectroscopy and fluorometric assay, to find the nature and strength of binding. [ABSTRACT FROM AUTHOR]

In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter. Ultraviolet Raman measurements were performed using a SHRS modified to use the plate beam splitter and a matching compensator plate and compared to the previously described cube beam splitter setup. Raman spectra obtained using the modified SHRS exhibit much higher signals and signal-to-noise (S/N) ratio and show fewer spectral artifacts. In this paper, we discuss the plate beam splitter SHRS design features, the advantages over previous designs, and discuss some general SHRS issues such as spectral bandwidth, S/N ratio characteristics, and optical efficiency. [ABSTRACT FROM AUTHOR]

A spatial heterodyne Raman spectrometer (SHRS) was used to measure transmission Raman spectra of highly scattering compounds. Transmission Raman spectral intensities of ibuprofen were only 2.4 times lower in intensity than backscatter Raman spectra. The throughput was about eight times higher than an f/1.8 dispersive spectrometer, and the width of the area viewed was found to be seven to nine times higher, using 50.8mm and 250mm focal length collection lenses. However, the signal-to-noise (S/N) ratio was two times lower for the SHRS than the f/1.8 dispersive spectrometer, apparently due to high levels of stray light. [ABSTRACT FROM AUTHOR]

• Structural and Spectroscopic studies were carried out using XRD and Spectroscopic techniques. • NBO and HOMO-LUMO energies were estimated. • DFT calculations were accomplished by using B3LYP with 6-311++G(d,p) basis set. • The intermolecular interaction has been evaluated by Hirshfeld surface analysis. The detailed investigation of the structural and spectroscopic characterization of the products formed in aqueous solution of hydrazine and maleic acid is studied in the current research. Single crystal X-ray diffraction inquiry concedes that obtained crystal hydrazinium fumarate (1) crystallises in the centrosymmetric space group P2 1 /c of the monoclinic system with four molecules per unit cell, whereas maleic hydrazide in the monolactim form (2) crystallises in the triclinic system with centrosymmetric space group and possess two molecules per unit cell. Further the structure of hydrazinium fumarate is optimized by using density functional theory with B3LYP/6-311++G(d,p) level. Structural and vibrational spectral analysis has been established by both experimental and theoretical method. B3LYP exchange correlational hybrid with 6-311++G (d, p) basis sets are used to assign all modes of vibration and analyse the structure of the molecule in terms of parameters like bond length, bond angle, and dihedral angle. The charge transfer between localised bonds and lone pairs is visualised via NBO analysis. The HOMO–LUMO mappings are presented, revealing the molecule's many charge transfer possibilities. The non-linear attribute of the molecule is described using the dipole moment (μ), polarizability (α), and hyperpolarizability (β) values of the molecule. The Crystal Explorer Ver. 3.1 tool is used to calculate Hirshfeld surface analyses, 2D fingerprint plots, and percentage contributions for several intermolecular interactions in the examined crystal hydrazinium fumarate (1). [Display omitted] [ABSTRACT FROM AUTHOR]

A spatial heterodyne Raman spectrometer (SHRS) is evaluated for stand-off Raman measurements in ambient light conditions using both ultraviolet (UV) and visible pulsed lasers with a gated ICCD detector. The wide acceptance angle of the SHRS simplifies optical coupling of the spectrometer to the telescope and does not require precise laser focusing or positioning of the laser on the sample. If the laser beam wanders or loses focus on the sample, as long as it is in the field of view of the SHRS, the Raman signal will still be collected. The SHRS is not overly susceptible to vibrations, and a vibration isolated optical table was not necessary for these measurements. The system performance was assessed by measuring stand-off UV and visible Raman spectra of a wide variety of materials at distances up to 18 m, using 266 nm and 532 nm pulsed lasers, with 12.4 in. and 3.8 in. aperture telescopes, respectively. [ABSTRACT FROM AUTHOR]

Lornoxicam is a non steroidal anti inflammatory drug (NSAID). Modern spectroscopic methods are very effective and sensitive tool for the qualitative and quantitative analysis of many drugs and the results are well employed in the quality control laboratories of pharmaceutical firm. In the present work, the FTIR and Raman spectra of the drug was recorded in the solid state. The fundamental modes of vibration were assigned based on the position, shape and relative intensity of the recorded spectra and in correlation with the vibrational bands of structurally related molecules. The stability of the drug under different environmental conditions is one of the quality assurance method undertaken in the pharmaceutical laboratory. By employing FTIR spectral technique the quality of the drug under various storage conditions has been studied. The assay of the tablet of the title drug was done using UV-visible spectroscopy and compared with the labelled amount. [ABSTRACT FROM AUTHOR]

• The synthesized compound Zn(II)2A3PC was characterized using experimental and theoretical tools. • Complete vibrational assignments were made unambiguously. • HOMO and LUMO energies are evaluated. • Studied MESP, NBO, QTAIM analysis, anti-inflammatory activity and molecular docking studies. • Exhibit NLO characteristics. As a continuation of the work in the present article, we described the spectroscopic and physicochemical properties of the synthesized Zn(II)-2-amino-3-pyridinecarboxaldehyde complex was investigated experimentally and theoretically. The zinc(II) complex was optimized with B3LYP and B3PW91 functional with 6–311++G(d,p) basis set. Fourier transform infrared spectrum of zinc(II) complex was recorded in the spectral range 4000–400 cm−1 and Raman counterparts were measured in the spectral region 4000–50 cm−1. The experimental FTIR and Raman results are compared to theoretical geometrical parameters. The rms error between experimental and theoretical vibrational frequencies of the titled compound was found to be 8.9 cm−1. The HOMO-LUMO energy gap demonstrates the compound is highly chemically reactive. The Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analyses were employed to obtain a precise picture of the conjugative and hyper conjugative interactions within the structure of the investigated molecule. Additionally, zinc(II) complex was also screened for their anti-inflammatory activity, using the carrageenan-induced rat paw edema method. The investigated complex exhibited significant anti-inflammatory potencies compared to standards. Furthermore, the compound was also assessed for their molecular docking studies against protein receptor cyclooxygenase COX-2 (PDBID: 5IKT) and showed their binding energy value of −7.98 kcal/mol, towards the anti-inflammatory activity. [ABSTRACT FROM AUTHOR]

(S)-3-aminomethyl hexonic acid (S3AMH) is a well known antiepileptic drug that controls epileptic seizures. In the present study FTIR and FT- Raman spectra of the drug S3AMH have been recorded for the identification of the functional groups. The structure, geometry optimization, vibrational frequencies and vibrational assignments have been made for the stable conformer of the molecule using semi empirical PM6 method, Abinito Restricted Hartree Fock (RHF), Density Functional theory based on Becke 3-lee-yang-parr (B3LYP) and (B3PW91) functional with standard 6-311++G(d,p) basis set. Detailed investigation of the observed fundamental vibrational frequencies of the molecule and calculated results by PM6, RHF, B3LYP and B3PW91methods indicates that B3PW91 is superior for molecular vibrational problems. The HOMO and LUMO energy level, Natural population analysis and the thermodynamic functions have also been calculated for the title molecule using the PM6, RHF, B3LYP and B3PW91methods. B3PW91 based UV and experimental spectral analysis of the molecule have been performed. The RHF, B3LYP and B3PW91methods based NMR calculation procedure has been used to assign the 1H NMR and 13C NMR chemical shift of S3AMH. [ABSTRACT FROM AUTHOR]

In this effort the alkali dopants Li, Na and K are co-doped with ZnO by solution combustion technique. This work is the production of room temperature ferromagnetism along with a rare orange emission from ZnO with equally concentrated Li, Na and K impurities. The XRD analysis reveals the hexagonal wurtzite structure and the substitution of the alkali in ZnO. The SEM and EDAX study shows the morphology and impurity free samples of ZnAO. The interstitial Zn atoms and the strain produced in the crystal structure due to alkali dopants is reflected in the FT Raman spectra. The band gap determined from the UV-Vis-NIR shows a variation that follows the variation of the grain size. The PL emission spectra brings to limelight the abundance of interstitial O atoms that involves in orange emission. The oxygen vacancies in the sample produce a weak green emission that decreases and then increases with alkali content. There is also a weak UV emission due to bound acceptor–donor recombination. The magnetometry establishes the fact that the direct bandgap semiconductor ZnO becomes magnetically sensitive due to the presence of alkali thereby making ZnO:Li + Na + K as a member of the family of dilute magnetic semiconductors. To the best of our knowledge this is the first report on the ferromagnetism observed in Li, Na and K co-doped ZnO. [ABSTRACT FROM AUTHOR]

Highlights: [•] Strong intermolecular O H⋯O H-bonding interactions enhance the stability of the molecule. [•] Hyperconjugative interactions in the phenyl ring causes more delocalization in the ring. [•] Red shift of O H stretching band in IR shows clear evidence of the occurrence of O H⋯O interaction. [•] Carboxyl-end of the molecule behaves as an active site as it is electron rich relative to the phenyl end. [ABSTRACT FROM AUTHOR]

Highlights: [•] FT-IR and FT-Raman spectra of 1RNDPA in solid phase were recorded and analyzed. [•] The vibrational wave numbers were computed using B3LYP and HF methods. [•] The vibrational assignment and spectroscopic analysis have been carried out. [•] The HOMO, LUMO energy gap were theoretically predicted. [•] The NBO analysis explained the intramolecular hydrogen bonding. [Copyright &y& Elsevier]