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Spectroscopic analysis, DFT studies and surface enhanced Raman scattering of antimicrobial bioactive (Z)-2-[5-(5-bromo-2-hydroxybenzylidene)-4-oxo-2-thioxothiazolidin-3-yl]acetic acid (BPTA) have been studied on different silver sols. Very large changes are observed for Raman and SERS bands. Observed variations in the ring modes may be due to surface π-electron interactions and presence of this indicated that molecule is inclined with respect to the metal surface. Changes in orientation are seen in SERS spectra depending on concentration. The molecular docking results show that binding affinity and interactions with the receptors may be supporting evidence for further studies in design further BPTA pharmaceutical applications. Reactivity properties are obtained from DFT and MD simulations. The quantum-mechanical level of theory has been applied to obtain information about the MEP and ALIE surfaces. These calculations give sensitivity of BPTA towards autoxidation mechanism. An influence of water has been studied computationally, via the MD simulations and RDF analysis. This level of theory was also used to identify possible excipient substance for this molecule. more...

Spectroscopic analysis, density functional theory (DFT) studies and surface enhanced Raman scattering (SERS) of (E)-N’-(5-chloro-2-hydroxybenzylidene)-4-trifluoromethyl) benzohydrazide (CHTB) have ... more...

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

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

Spectroscopic analysis, DFT studies and surface enhanced Raman scattering of antimicrobial bioactive 4-[(2‑hydroxy-3,5-diiodobenzylidene)amino]-N-(5-methylisoxazole-3-yl)benzenesulfonamide (HDMB) have been studied. Changes in intensity and enhancement variations are observed for Raman and SERS bands. Changes observed in the ring mode vibrations may be due to surface π-electron interactions which means molecule is orientated in a tilted position with respect to metal surface. Changes in orientation are seen in SERS spectra depending on concentration. The molecular docking results show that binding affinity and interactions with the receptors may be supporting evidence for further studies in design further HDMB pharmaceutical applications. Reactivity properties are obtained from DFT analysis. more...

Spectroscopic analysis, DFT studies and surface enhanced Raman scattering (SERS) of antimicrobial bioactive 4-[(5-tert-butyl)2-hydroxybenzylidene]amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (THPB) have been studied on different silver sols. Intensity and hence enhancement variations are observed for Raman and SERS bands. Observed changes in the ring modes may be due to surface π-electron interactions and presence of this indicated that molecule is inclined with respect to the metal surface. Changes in orientation are seen in SERS spectra depending on concentration. The molecular docking results show that binding affinity and interactions with the receptors may be supporting evidence for further studies in design further THPB pharmaceutical applications. Reactivity properties are obtained from DFT analysis. more...

In the present work the structural and spectral characteristics of acetazolamide have been studied by methods of infrared, Raman spectroscopy and quantum chemistry. Electrostatic potential surface, optimized geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by density functional theory (DFT) employing B3LYP with complete relaxation in the potential energy surface using 6-311++G(d,p) basis set. Based on these results, we have discussed the correlation between the vibrational modes and the structure of the dimers of acetazolamide. The calculated vibrational spectra of three dimers of acetazolamide have been compared with observed spectra, and the assignment of observed bands was carried out using potential energy distribution. The observed spectra agree well with the values computed from the DFT. A comparison of observed and calculated vibrational spectra clearly shows the effect of hydrogen bonding. The frequency shifts observed for the different dimers are in accord with the hydrogen bonding in acetazolamide. Natural bond orbital (NBO) analyses reflect the charge transfer interaction in the individual hydrogen bond units and the stability of different dimers of acetazolamide. more...

Nine black powders found in Pompeii houses in three different types of bronze vessels (cylindrical theca atramentaria, unguentaries, and aryballoi) were characterized in order to assess a correspondence between the composition and the type of vessel and, possibly, to verify if these powders were inks or not. For the compositional characterization, a multi-analytical approach was adopted, which involved the use of scanning electron microscopy-energy dispersive X-ray, Fourier-transformed infrared spectroscopy, Raman, X-ray diffraction, electron paramagnetic resonance spectroscopy, thermogravimetric analysis, gas chromatography coupled with mass spectrometry (GC/MS), and pyrolysis GC/MS. Powders contained in cylindrical theca atramentaria form a homogeneous group, and their organic and inorganic compositions suggest that they were writing inks, while powders contained in unguentaries and aryballoi could have had several different uses, including writing inks and cosmetics. Furthermore, the composition profile of the powders found in cylindrical cases shows that, at 79 AD: , in Pompeii, carbon-based inks were still used for writing, and iron gall inks had not been introduced yet. more...

A selection of samples, obtained from a particular copper-alloy domestic artefact of Roman style from Pompeii, has been analysed by using different techniques (IR, Raman, SEM-EDX, FAAS), in order to investigate the chemical nature and composition of the metals utilised for such manufacturing pieces. The surface analysis of the bright red metallic microfragments conducted by different analytical techniques, emphasises the presence of pure unalloyed copper and confirms the absence of other metallic species on the upper layers. On the contrary, the mapping analysis of the section of the laminar metal of the investigated sample shows a consistent enrichment in tin content. Finally, destructive analysis by FAAS confirms that the artefact looks like a bronze metal alloy, with a medium Sn content of about 6.5%. more...

Natural organic materials used to prepare pharmaceutical mixtures including ointments and balsams have been characterized by a combined non-destructive spectroscopic analytical approach. Three classes of materials which include vegetable oils (olive, almond and palm tree), gums (Arabic and Tragacanth) and beeswax are considered in this study according to their widespread use reported in ancient recipes. Micro-FTIR, micro-Raman and fluorescence spectroscopies have been applied to fresh and mildly thermally aged samples. Vibrational characterization of these organic compounds is reported together with tabulated frequencies, highlighting all spectral features and changes in spectra which occur following artificial aging. Synchronous fluorescence spectroscopy has been shown to be particularly useful for the assessment of changes in oils after aging; spectral difference between Tragacanth and Arabic gum could be due to variations in origin and processing of raw materials. Analysis of these materials using non-destructive spectroscopic techniques provided important analytical information which could be used to guide further study. more...

A pharmaceutical active compound, chloramphenicol palmitate, appears in three polymorphic forms, that can be observed at room temperature. The stable form A (biologically inactive modification), the meta-stable form B (active modification) and unstable form C were found to have distinct Raman spectra, with bands attributable to the different polymorphs. The use of hot-stage Raman microscopy (the direct coupling of Raman microscopy and hot-stage) is demonstrated for the drug substance chloramphenicol palmitate form C. All modifications of form C were produced and identified by hot-stage Raman microscopy. A close correlation of thermal and spectroscopic information was achieved by this combination of techniques. As reported in several pharmacopoeias, the content of form A should be less than 10%; therefore, a mixture of 10% (w/w) A in B was prepared, and the presence of the characteristic bands of form A after subtraction of the pure B was revealed. Moreover, mixtures between 2 and 12% (w/w) A in B were investigated and the intensity ratio (as peak area) I413–435/I1035–1158 as a function of A percentage has been demonstrated to show a linear trend. Other methods for the characterization of polymorphs were used: Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). more...