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Nanostructured Co3O4 was synthesized by a sol–gel technique while 30% & 40% Co3O4–PANI (polyaniline) nanocomposites were successfully prepared employing an in situ polymerization technique. Various characterization techniques were utilized to examine the structural, spectroscopic, topographical, elemental and chemical features of the nanostructured Co3O4 and Co3O4–PANI nanocomposites utilizing XRD, FTIR, SEM and EDX respectively. The crystallite sizes of Co3O4, 30% Co3O4–PANI and 40% Co3O4–PANI were calculated, with the aid of XRD patterns, to be 41, 30 and 22 nm, respectively. By scrutinizing the SEM results of all the materials, a nearly spherical morphology was perceived. Numerous pores were also observed in their surface morphology which shows that the prepared materials are highly advantageous for gas sensing. Further, the materials were utilized for LPG sensing. Significant parameters of LPG sensing such as response time, recovery time, sensitivity and reproducibility were calculated for both materials. LPG sensing studies indicate that the 40% Co3O4–PANI nanocomposite, which exhibits lower response and recovery times, i.e. 10 s and 32 s, might be an efficient and potential material for use as an LPG sensor. [ABSTRACT FROM AUTHOR]

The article in ChemPlusChem discusses the use of Raman optical activity spectra to monitor the conformation and protonation states of glutathione. By combining this technique with density functional theory and molecular dynamics computations, researchers can deduce potential energy maps from the spectra. These maps can be used to verify or improve common force fields. The study found that the pH had a limited effect on the backbone conformation of glutathione. The full details of the research can be found in the article by Petr Bouř and his colleagues. [Extracted from the article]

Polymorphism is an important characteristic which affects the activity, solubility and other physical properties of a compound and can be induced by varying temperature, pressure and solvent. The presence and conversion of α to β polymorphic forms of an anti-rheumatic drug leflunomide have been studied by temperature-dependent and in situ Raman observations. Both α and β polymorphs were found to co-exist in the temperature interval 367-372 K. The α form alone exists below 367 K and the β form alone above 373 K. The CO stretching band clearly demonstrates the α → β conversion because of breaking of N-H···O bond and formation of N-H···N bond. On cooling the Raman spectra suggest the irreversibility of this conversion. Thermodynamic stability, crystal parameters and surface morphology of both forms in the leflunomide powder used for the present study have been verified by differential scanning calorimetry, X-ray powder diffraction and scanning electron microscopy. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The relative structural and dynamic properties of hydrogen-bonding between Pyrimidine (Pmd)+H2O and Pmd+D2O, and 4-Methylpyrimidine (Mpmd)+H2O and Mpmd+D2O are investigated experimentally by linear Raman spectroscopy using Raman difference spectroscopic (RDS) technique. The focus has been given to the ring breathing mode (ν 1). The effect of methylation on the Pmd ring has been studied in terms of wavenumber shift (Δν), peak-position and linewidth variation with mole fraction of the solvent. The wavenumber shift has been calculated by assuming the Voigt profile of the Raman band. In order to explain our experimental results, we have optimized single Pmd and 4Mpmd molecules and their various complexes with H2O and D2O in the stoichiometric ratio of 1:1, 1:2, 1:3 and 1:4 by employing DFT/B3LYP functional with 6-311+G(d,p) basis set using Gaussian software. There is a good correspondence between experimental and theoretical results. Our result reveals that with RDS technique, Δν of a band up to 1/100th of the FWHM can be measured precisely. [Copyright &y& Elsevier]

Abstract: The relative effect of hydrogen bonding of pyrimidine (Pyr) in H2O/D2O and pyridine (Py) in CH3OH/CD3OD has been analyzed using Raman Difference Spectroscopic (RDS) technique and DFT calculations. This study is focused on analyzing the concentration dependent variation of linewidth, peak position and intensity of ring breathing mode of Py and Pyr. The ring breathing mode of Pyr in H2O and D2O has three components; due to free Pyr, lighter complexes of mPyr+ nH2O/D2O and heavier complexes of mPyr+ nH2O/D2O. The pyridine molecules, however, show only two components in CH3OH and CD3OD. Of these two components, one corresponds to free Py and the other inhomogeneously broadened profile corresponds to all mPy+ nCH3OH/CD3OD complexes. The variation of peak position and linewidth establishes the role of dipole moment of complexes and the diffusion in the mixture. In case of CD3OD solution splitting was observed in ∼1030cm−1 band of Py, where an additional band at ∼1034cm−1 appears at x(Py)⩽0.4. However, this band remains single at all concentrations in case of CH3OH solvent. [Copyright &y& Elsevier]