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  Subjects -> CHEMISTRY (Total: 831 journals)
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    - CHEMISTRY (584 journals)
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CHEMISTRY (584 journals)            First | 1 2 3 4 5 6 | Last

Journal of Catalysts     Open Access  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 11)
Journal of Chemical and Biological Interfaces     Full-text available via subscription  
Journal of Chemical Education     Full-text available via subscription   (Followers: 18)
Journal of Chemical Health Risks     Open Access   (Followers: 2)
Journal of Chemical Information and Modeling     Full-text available via subscription   (Followers: 6)
Journal of Chemical Research     Full-text available via subscription   (Followers: 5)
Journal of Chemical Science and Technology     Open Access   (Followers: 3)
Journal of Chemical Sciences     Partially Free   (Followers: 17)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 13)
Journal of Cheminformatics     Open Access   (Followers: 1)
Journal of Chemistry     Open Access   (Followers: 3)
Journal of Chemometrics     Hybrid Journal   (Followers: 10)
Journal of Chromatography A     Hybrid Journal   (Followers: 54)
Journal of Clinical Toxicology     Open Access   (Followers: 1)
Journal of Colloid and Interface Science     Hybrid Journal   (Followers: 14)
Journal of Computational Chemistry     Hybrid Journal   (Followers: 15)
Journal of Coordination Chemistry     Hybrid Journal   (Followers: 1)
Journal of Dispersion Science and Technology     Hybrid Journal  
Journal of Encapsulation and Adsorption Sciences     Open Access   (Followers: 4)
Journal of Environmental Chemistry and Ecotoxicology     Open Access   (Followers: 2)
Journal of Flow Chemistry     Full-text available via subscription   (Followers: 1)
Journal of Fluorescence     Hybrid Journal   (Followers: 4)
Journal of Fluorine Chemistry     Hybrid Journal   (Followers: 6)
Journal of Fuel Chemistry and Technology     Full-text available via subscription   (Followers: 5)
Journal of Great Lakes Research     Hybrid Journal   (Followers: 7)
Journal of Heterocyclic Chemistry     Hybrid Journal   (Followers: 5)
Journal of Immunoassay and Immunochemistry     Hybrid Journal   (Followers: 3)
Journal of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (Followers: 1)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 2)
Journal of Labelled Compounds and Radiopharmaceuticals     Hybrid Journal   (Followers: 1)
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry     Hybrid Journal   (Followers: 3)
Journal of Mass Spectrometry     Hybrid Journal   (Followers: 26)
Journal of Materials Chemistry A : Materials for Energy and Sustainability     Full-text available via subscription   (Followers: 23)
Journal of Materials Chemistry B : Materials for Biology and Medicine     Full-text available via subscription   (Followers: 5)
Journal of Materials Chemistry C : Materials for Optical, Magnetic and Electronic Devices     Full-text available via subscription   (Followers: 6)
Journal of Materials Physics and Chemistry     Open Access  
Journal of Materials Research     Full-text available via subscription   (Followers: 10)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 6)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 85)
Journal of Membrane and Separation Technology     Hybrid Journal  
Journal of Membrane Science     Hybrid Journal   (Followers: 11)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 3)
Journal of Molecular Graphics and Modelling     Hybrid Journal   (Followers: 4)
Journal of Molecular Liquids     Hybrid Journal   (Followers: 1)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 3)
Journal of Molecular Recognition     Hybrid Journal   (Followers: 2)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 7)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
Journal of Nanoparticles     Open Access  
Journal of Nanostructure in Chemistry     Open Access   (Followers: 3)
Journal of Natural Gas Chemistry     Full-text available via subscription   (Followers: 2)
Journal of Nepal Chemical Society     Open Access  
Journal of Nucleic Acids Investigation     Open Access   (Followers: 2)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 1)
Journal of Organometallic Chemistry     Hybrid Journal   (Followers: 13)
Journal of Photochemistry and Photobiology A: Chemistry     Hybrid Journal   (Followers: 4)
Journal of Photochemistry and Photobiology C: Photochemistry Reviews     Full-text available via subscription   (Followers: 3)
Journal of Polymer & Composites     Full-text available via subscription   (Followers: 4)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 2)
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 123)
Journal of Polymers     Open Access   (Followers: 1)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 2)
Journal of Pure and Applied Chemistry Research     Open Access   (Followers: 1)
Journal of Raman Spectroscopy     Hybrid Journal   (Followers: 11)
Journal of Research Updates in Polymer Science     Hybrid Journal  
Journal of Saudi Chemical Society     Open Access  
Journal of Solid State Chemistry     Hybrid Journal   (Followers: 14)
Journal of Solution Chemistry     Hybrid Journal   (Followers: 4)
Journal of Structural Chemistry     Hybrid Journal  
Journal of Sulfur Chemistry     Hybrid Journal   (Followers: 2)
Journal of Superhard Materials     Hybrid Journal   (Followers: 1)
Journal of Surfactants and Detergents     Hybrid Journal   (Followers: 5)
Journal of Systems Chemistry     Open Access  
Journal of Taibah University for Science     Open Access  
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 218)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 23)
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 1)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Chilean Chemical Society     Open Access   (Followers: 1)
Journal of the Iranian Chemical Society     Hybrid Journal  
Journal of the Korean Society for Applied Biological Chemistry     Hybrid Journal   (Followers: 1)
Journal of the Mexican Chemical Society     Open Access   (Followers: 1)
Journal of Theoretical and Computational Chemistry     Hybrid Journal   (Followers: 8)
Journal of Theoretical Chemistry     Open Access  
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
JPC - Journal of Planar Chromatography - Modern TLC     Full-text available via subscription   (Followers: 5)
Jurnal Penelitian Sains (JPS)     Open Access  
Jurnal Teknologi Informasi     Open Access   (Followers: 3)
Karbala International Journal of Modern Science     Open Access  
Kinetics and Catalysis     Hybrid Journal   (Followers: 3)
Korea-Australia Rheology Journal     Hybrid Journal  
Langmuir     Full-text available via subscription   (Followers: 42)
Latvian Journal of Chemistry     Open Access   (Followers: 1)
Lebensmittelchemie     Hybrid Journal   (Followers: 1)
Lipid Insights     Open Access  
Luminescence     Hybrid Journal   (Followers: 1)
Macromolecular Materials & Engineering     Hybrid Journal   (Followers: 5)
Macromolecular Rapid Communications     Hybrid Journal   (Followers: 5)

  First | 1 2 3 4 5 6 | Last

Journal Cover   Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.628]   [H-I: 64]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [2800 journals]
  • Preparation, regulation and biological application of a Schiff base
           fluorescence probe
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Ninghua Yin, Haipeng Diao, Wen Liu, Jingru Wang, Liheng Feng
      A facile fluorescence switch with Schiff base units was designed and achieved by nucleophilic addition and dehydration reaction. The fluorescence of the probe can be regulated by metal ions (Al3+ and Cu2+). The whole process shows that the weak fluorescence of the probe enhances with the addition of Al3+, and then the strong fluorescence of the probe/Al3+ ensemble reduces by introducing Cu2+. Meanwhile, the solution color changes of the probe with metal ions can be observed under 365nm UV–vis light from weak light, pale green, green, pale green to weak light. Noticeably, the photo regulation processes of the probe by metal ions can be realized in the biological system and applied in cells imaging. The work provides a new strategy for designing facile regulation probe and develops a new application for Schiff base derivatives.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Computational insights into the molecular interaction and ion-pair
           
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Ian Harvey Arellano, Junhua Huang, Phillip Pendleton
      The ion pair structures of a novel CO2 capture material in the form of a metal chelate anion-containing room temperature ionic liquid (IL), 1-ethyl-3-methylimidazolium tri[bis(trifluoromethylsulfonyl)imide]zincate(II), [Emim][Zn(TFSI)3], were elucidated by correlating the infrared spectra generated using density functional theory (DFT) calculations with the experimental spectrum derived from a room temperature infrared spectroscopic measurement. A free volume energy minimization algorithm revealed stable structures where the zinc ion forms an octahedral, homoleptic complex with the ligand bis(trifluoromethylsulfonyl)imide through coordination with the oxygen of the sulfone group, with 1-ethyl-3-methylimidazolium acting as the counterion. The method of analysis was built around 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [Emim][TFSI], involving direct comparison with published data, and extended to the more complex [Emim][Zn(TFSI)3] system. The DFT calculations reproduced the vibrational spectra of [Emim][Zn(TFSI)3] and [Emim][TFSI] using their optimized geometries, with correlation slopes of 0.9996 and 1.0022, respectively. Comparison of the vibrational modes of [Emim][TFSI] and [Emim][Zn(TFSI)3] provided insights into the ion pair structure of, and molecular interactions in the ILs analyzed.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Unidirectional growth of large size urea doped l-cysteine hydrochloride
           monohydrate NLO organic crystal and investigations of its crystalline and
           optical properties
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Sunil Verma, K. Ramachandra Rao, S. Kar, K.S. Bartwal
      Organic crystals of urea doped l-cysteine hydrochloride monohydrate have been grown by unidirectional solution growth technique. The crystal grown by this technique has high growth rate as compared to the crystals grown using conventional slow cooling method. This method is ideally suited to grow crystals along a specific direction. The growth process was monitored at regular intervals of time in a time-lapsed manner to estimate the growth rate and also monitor its quality visually. The grown crystal was subjected to different characterizations in order to confirm the phase of the grown crystal, its crystalline perfection and optical properties. The X-ray diffraction confirmed the phase of the crystal. The rocking curve recorded using high resolution X-ray diffraction (HRXRD) technique reveals that the crystal grown using conventional slow cooling method has internal gain boundaries whereas that grown by unidirectional technique has high degree of crystalline perfection. The bonding environment present in the crystal was characterized by FTIR spectroscopy where vibrational frequencies of the different functional groups present were identified. The optical quality of the crystal was characterized using UV–vis-NIR spectrophotometer and Mach–Zehnder interferometer. The nonlinear optical response of the crystal was measured using Kurtz–Perry method and found to be 1.4 times that of a KDP crystal.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Spectroscopic studies of porphyrin functionalized multiwalled carbon
           nanotubes and their interaction with TiO2 nanoparticles surface
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Marco Zannotti, Rita Giovannetti, Chiara Anna D'Amato, Elena Rommozzi
      UV–vis and fluorescence investigations about the non-covalent interaction, in ethanolic solutions, of multi-wall carbon nanotube (MWCNT) with Coproporphyrin-I, and its Cu(II) and Zn(II) complexes (MCPIs) have been reported. Evidence of binding between MWCNTs and porphyrins was discovered from spectral adsorption decrease with respect to free porphyrins and by the exhibition of photoluminescence quenching with respect to free porphyrins demonstrating that MWCNT@MCPIs are potential donor–acceptor complexes. Equilibrium and kinetic aspects in the interactions with monolayer transparent TiO2 thin films with the obtained MWCNT@MCPIs are clarified showing their effective adsorption by porphyrin links on the TiO2 monolayer support, with respect to not only MWCNTs, according to the Langmuir model and with pseudo-first-order kinetics. Morphological description of the adsorption of MWCNT@MCPIs on TiO2 with scanning electron microscopy has been reported. The obtained experimental evidences describe therefore MWCNT@MCPIs as potential sensitizers in the DSSC (Dye-Sensitized Solar Cell) applications.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Accurate predictions of spectroscopic and molecular properties of 27
           Λ-S and 73 Ω states of AsS radical
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Deheng Shi, Ziyue Song, Xianghong Niu, Jinfeng Sun, Zunlue Zhu
      The PECs are calculated for the 27 Λ-S states and their corresponding 73 Ω states of AsS radical. Of these Λ-S states, only the 22Δ and 54Π states are replulsive. The 12Σ+, 22Σ+, 42Π, 34Δ, 34Σ+, and 44Π states possess double wells. The 32Σ+ state possesses three wells. The A2Π, 32Π, 12Φ, 24Π, 34Π, 24Δ, 34Δ, 16Σ+, and 16Π states are inverted with the SO coupling effect included. The 14Σ+, 24Σ+, 24Σ-, 24Δ, 14Φ, 16Σ+, and 16Π states, the second wells of 12Σ+, 34Σ+, 42Π, 44Π, and 34Δ states, and the third well of 32Σ+ state are very weakly-bound states. The PECs are extrapolated to the CBS limit. The effect of SO coupling on the PECs is discussed. The spectroscopic parameters are evaluated, and compared with available measurements and other theoretical ones. The vibrational properties of several weakly-bound states are determined. The spectroscopic properties reported here can be expected to be reliably predicted ones.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Synthesis, characterization and application of ion imprinted polymeric
           nanobeads for highly selective preconcentration and spectrophotometric
           determination of Ni2+ ion in water samples
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Hamid Reza Rajabi, Saham Razmpour
      Here, the researchers report on the synthesis of ion imprinted polymeric (IIP) nanoparticles using a thermal polymerization strategy, and their usage for the separation of Ni2+ ion from water samples. The prepared Ni-IIP was characterized by colorimetry, FT-IR spectroscopy, and scanning electron microscopy. It was found that the particle size of the prepared particle to be 50–70nm in diameter with the highly selective binding capability for Ni2+ ion, with reasonable adsorption and desorption process. After preconcentration, bound ions can be eluted with an aqueous solution of hydrochloric acid, after their complexation with dimethylglyoxime, these ions can be quantified by UV–Vis absorption spectrophotometry. The effect of various parameters on the extraction efficiency including pH of sample solution, adsorption and leaching times, initial sample volume, concentration and volume of eluent were investigated. In selectivity study, it was found that imprinting causes increased affinity of the prepared IIP toward Ni2+ ion over other ions such as Na+, K+, Ag+, Co2+, Cu2+, Cd2+, Hg2+, Pb2+, Zn2+, Mn2+, Mg2+, Cr3+, and Fe3+. The prepared IIP can be used and regenerated for at least eight times without any significant decrease in binding affinities. The prepared IIP is considered to be promising and selective sorbent for solid-phase extraction and preconcentration of Ni2+ ion from different water samples.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Development of molecular photoswitch with very fast photoresponse based on
           asymmetrical bis-azospiropyran
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Farahnaz Nourmohammadian, Ali Ashtiani Abdi
      To study the effects of an extended bis-azo conjugated bridge with two different photochemical functions on a molecule in photochromic responses, a novel asymmetrical bifunctional bis-azo spiropyran photochromic dye was designed and synthesized. The obtained photoresponses were compared with symmetrical bifunctional bis-azo spiropyran analogues, and relative mono-azo and simple spiropyrans. Colourimetric behaviour, luminescence, and switching kinetics of all the dyes were studied. The largest molar absorption coefficient in merocyanine form, quickest response to light, and highest fluorescence quantum yield of the spiropyran form with a superior ratio of emission intensities of spiropyran to merocyanine form were achieved for the asymmetric bis-azospiropyran. Solvatochromic effect was studied to observe the solvent effects on non-irradiation colouration of the photochromic dyes. Furthermore, The molecular energy levels for optimized geometries of the synthesized bis-azospiropyrans and their probable photochemical products were obtained at the B3LYP/6-31G(d) level of theory.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Application of FTIR spectroscopy to the characterization of archeological
           wood
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Mohamed Traoré, Joeri Kaal, Antonio Martínez Cortizas
      Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR–ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P=0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR–ATR.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Electrochemical and spectroelectrochemical properties of thiadiazole
           substituted metallo-phthalocyanines
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Ümit Demirbaş, Duygu Akyüz, Burak Barut, Rıza Bayrak, Atıf Koca, Halit Kantekin
      4-Thiadiazole substituted phthalonitrile and peripherally tetra-substituted phthalocyanine Cu(II), Fe(II) and Ti(IV)O complexes have been synthesized for the first time. Electrochemical properties of these complexes were determined with voltammetric and in situ spectroelectrochemical measurements. CuPc has redox inactive Cu2+ center, therefore it gave three Pc based reduction and two Pc based oxidation processes. TiOPc and FePc complexes gave metal based redox processes in addition to Pc based redox reactions due to the redox activity of Ti4+O and Fe2+ metal centers. Although FePc also gave three reduction and two oxidation reactions, peak potentials of these processes are different than those of CuPc due to the different assignments of the redox reactions. TiOPc went to five reduction and one oxidation reactions. Assignments of the redox processes were carried out with in situ spectroelectrochemical measurements. Spectra and color of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements. Distinct color differences between the electrogenerated redox species were observed, which indicated their possible electrochromic usages.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Evaluation of chemical components and properties of the jujube fruit using
           near infrared spectroscopy and chemometrics
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Ying Guo, Yongnian Ni, Serge Kokot
      Near-infrared spectroscopy (NIRS) calibrations were developed for the discrimination of spectra of the jujube (Zizyphus jujuba Mill.) fruit samples from four geographical regions. Prediction models were developed for the quantitative prediction of the contents of jujube fruit, i.e., total sugar, total acid, total phenolic content, and total antioxidant activity. Four pattern recognition methods, principal component analysis (PCA), linear discriminant analysis (LDA), least squares-support vector machines (LS-SVM), and back propagation-artificial neural networks (BP-ANN), were used for the geographical origin classification. Furthermore, three multivariate calibration models based on the standard normal variate (SNV) pretreated NIR spectroscopy, partial least squares (PLS), BP-ANN, and LS-SVM were constructed for quantitative analysis of the four analytes described above. PCA provided a useful qualitative plot of the four types of NIR spectra from the fruit. The LS-SVM model produced best quantitative prediction results. Thus, NIR spectroscopy in conjunction with chemometrics, is a very useful and rapid technique for the discrimination of jujube fruit.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Prediction of P-branch emission spectral lines of NaF and 63Cu35Cl
           molecules
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Yonghong Jiang, Weiguo Sun, Yi Zhang, Jia Fu, Qunchao Fan, Huidong Li, Hao Feng
      The analytical formula derived by Sun et al. in 2011 and used to predict the rotational lines for rovibrational diatomic systems is improved in this study. The new formula is obtained by adding a higher order spectral term H υ that is neglected in our previous expression. A physical requirement is also added to the converging process to minimize the possible error of the predicted rotational line. All these are applied to study some rovibrational transition systems of 63Cu35Cl and NaF molecules. The results indicate that the accuracy of the P-branch rotational lines predicted by this new formula is about one order of magnitude better than the results obtained using the previous formula, and that both the small H υ contribution and the improved converging requirement may play a vital role in predicting the high-lying rovibrational energies and the rotational lines. Comparisons between physical predictions and mathematical extrapolations on the rotational lines are also given.


      PubDate: 2015-08-25T15:32:31Z
       
  • Development of methodology for identification the nature of the
           polyphenolic extracts by FTIR associated with multivariate analysis
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Fábio dos Santos Grasel, Marco Flôres Ferrão, Carlos Rodolfo Wolf
      Tannins are polyphenolic compounds of complex structures formed by secondary metabolism in several plants. These polyphenolic compounds have different applications, such as drugs, anti-corrosion agents, flocculants, and tanning agents. This study analyses six different type of polyphenolic extracts by Fourier transform infrared spectroscopy (FTIR) combined with multivariate analysis. Through both principal component analysis (PCA) and hierarchical cluster analysis (HCA), we observed well-defined separation between condensed (quebracho and black wattle) and hydrolysable (valonea, chestnut, myrobalan, and tara) tannins. For hydrolysable tannins, it was also possible to observe the formation of two different subgroups between samples of chestnut and valonea and between samples of tara and myrobalan. Among all samples analysed, the chestnut and valonea showed the greatest similarity, indicating that these extracts contain equivalent chemical compositions and structure and, therefore, similar properties.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • A DFT study of infrared spectra and Monte Carlo predictions of the
           solvation shell of Praziquantel and β-cyclodextrin inclusion complex
           in liquid water
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): C.X. de Oliveira, N.S. Ferreira, G.V.S. Mota
      In this paper, we report a theoretical study of the inclusion complexes of Praziquantel (PZQ) and β-cyclodextrin (β-CD) in liquid water. The starting geometry has been carried out by molecular mechanics simulations, and afterwards optimized in B3LYP level with a 6-311G(d) basis set. Monte Carlo simulations have been used to calculate the solvation shell of the PZQ/β-CD inclusion complexes. Moreover, the vibrational frequencies and the infrared intensities for the PZQ/β-CD complex were computed using the B3LYP method. It is demonstrated that this combined model can yield well-converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly adequate for understanding the solute–solvent interaction used for generating the liquid structures of one solute surrounded by solvent molecules. The complex solvation shell showed an increase of the water molecule level in relation to the isolated PZQ molecule because of the hydrophilic effect of the CD molecule. The infrared spectra showed that the contribution that originated in the PZQ molecule was not predominant in the upper-wave number region in the drug/β-CD. The movement that purely originated in the PZQ molecule was localized in the absorption band, ranging from 1328 to 1688cm−1.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Chemometrics-assisted excitation–emission fluorescence analytical
           data for rapid and selective determination of optical brighteners in the
           presence of uncalibrated interferences
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Ali Gholami, Saeed Masoum, Atefeh Mohsenikia, Saleheh Abbasi
      This study describes a novel approach for the simultaneous determination of CBS-X and CXT as widely used optical brighteners in household detergent, by combining the advantage of the high sensitivity of molecular fluorescence, and the selectivity of second-order chemometric methods. The proposed method is assisted by second-order chemometric analyses employing the PARAFAC, SWATLD and APTLD that help us to determine CBS-X and CXT in laundry powders and environmental samples, through the unique decomposition of the three-way data array. Proposed method can provide the extraction of relative concentrations of the analytes, as well as the spectral profiles. This approach achieves the second-order advantage and in principle could be able to overcome the spectral uncalibrated interference problems in the determination of CBS-X and CXT at the ng g−1 level. By spiking the known concentrations of these compounds to the real samples, the accuracy of the proposed methods was validated and recoveries of the spiked values were calculated. High recoveries (90.00%–113.33%) for the spiked laundry powders and real environmental samples indicate the present method successfully faces this complex challenge without the necessity of applying separation and preconcentration steps in environmental contaminations.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Synthesis and spectroscopic characterization of fluorescent
           4-aminoantipyrine analogues: Molecular docking and in vitro cytotoxicity
           studies
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): D. Premnath, P. Mosae Selvakumar, P. Ravichandiran, G. Tamil Selvan, M. Indiraleka, J. Jannet Vennila
      Two substituted aromatic carbonyl compounds (compounds 1 and 2) of 4-aminoantipyrine were synthesized by condensation of fluorine substituted benzoyl chlorides and 4-aminoantipyrine. The structures of synthesized derivatives were established on the basis of UV–Vis, IR, and Mass, 1H, 13C NMR and Fluorescence spectroscopy. Both compounds showed significant fluorescence emission and two broad emission bands were observed in the region at 340nm and 450nm on excitation at 280nm. Theoretically to prove that the molecule has anticancer activity against cervical cancer cells, the compounds were analyzed for molecular docking interactions with HPV16-E7 target protein by Glide protocol. Furthermore, 4-aminoantipyrine derivatives were evaluated for their in vitro cytotoxic activity against human cervical cancer cells (SiHa) by MTT assay. Compound 1 showed two fold higher activity (IC50 =0.912μM) over compound 2, and its activity was similar to that of Pazopanib, suggesting that although the two compounds were chemically very similar the difference in substituent on the phenyl moiety caused changes in properties.
      Graphical abstract image

      PubDate: 2015-08-25T15:32:31Z
       
  • Characterization of novel perylene diimides containing aromatic amino acid
           side chains
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Mohammed J. Farooqi, Mark A. Penick, Jessica Burch, George R. Negrete, Lorenzo Brancaleon
      Perylene diimide derivatives have attracted initial interest as industrial dyes. Recently, much attention has been focused on their strong π− π stacks resulting from the large PDI aromatic core. These PDI stacks have distinct optical properties, and provide informative models that could mimic light-harvesting systems and initial charge transfer typical of photosynthetic systems. The absorption property of PDI derivatives may be tuned from visible to near-infrared region by peripheral substitution. We have studied a new class of PDI derivatives with aryl substituents derived from the side chains of aromatic aminoacids (Tyrosine, Tryptophan and Phenylalanine). We have investigated their absorption and the fluorescence properties in a set of organic solvents and established their different tendencies to aggregate in solution despite their solubility. Most aggregation appears to be unordered. One PDI analogue (the one formed from Tyr) in Methanol, however, appears to form J-type aggregates. Based on our results the compounds appear to be promising for future investigations regarding the interaction of these dyes with biomolecules.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Mean centering of double divisor ratio spectra, a novel spectrophotometric
           method for analysis of ternary mixtures
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Said A. Hassan, Eman S. Elzanfaly, Maissa Y. Salem, Badr A. El-Zeany
      A novel spectrophotometric method was developed for determination of ternary mixtures without previous separation, showing significant advantages over conventional methods. The new method is based on mean centering of double divisor ratio spectra. The mathematical explanation of the procedure is illustrated. The method was evaluated by determination of model ternary mixture and by the determination of Amlodipine (AML), Aliskiren (ALI) and Hydrochlorothiazide (HCT) in laboratory prepared mixtures and in a commercial pharmaceutical preparation. For proper presentation of the advantages and applicability of the new method, a comparative study was established between the new mean centering of double divisor ratio spectra (MCDD) and two similar methods used for analysis of ternary mixtures, namely mean centering (MC) and double divisor of ratio spectra-derivative spectrophotometry (DDRS-DS). The method was also compared with a reported one for analysis of the pharmaceutical preparation. The method was validated according to the ICH guidelines and accuracy, precision, repeatability and robustness were found to be within the acceptable limits.
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      PubDate: 2015-08-25T15:32:31Z
       
  • A highly selective and sensitive fluorescent sensor for the rapid
           detection of Hg2+ based on phenylamine-oligothiophene derivative
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Qingfen Niu, Xingxing Wu, Shanshan Zhang, Tianduo Li, Yuezhi Cui, Xiaoyan Li
      A fast-responsive fluorescent phenylamine-oligothiophene sensor 3TDDA was reported. This sensor exhibited highly selective and sensitive detection of Hg2+ ion in aqueous solution (THF/CH3CN/H2O, 45/50/5, v/v) through fluorescence quenching. The detection was not affected by the coexistence of other competitive metal ions such as Na+, K+, Ag+, Ca2+, Fe3+, Al3+, Co2+, Ni2+, Zn2+, Pb2+, Cd2+, Fe2+ and Cr3+. A stoichiometric ratio (1:1) of the sensor and Hg2+ was determined by a Job's plot and mole-ratio curves. The binding of sensor 3TDDA and Hg2+ was also chemically reversible with EDTA. The detection limit was calculated as low as 4.392×10−7 M.
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      PubDate: 2015-08-25T15:32:31Z
       
  • The investigation of excited state proton transfer mechanism in
           water-bridged 7-azaindole
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Yong-Jia Zhang, Jin-Feng Zhao, Yong-Qing Li
      Based on the time-dependent density functional theory (TDDFT), the excited-state intermolecular proton transfer (ESIPT) mechanism of water-bridged 7-azaindole has been investigated theoretically. The calculations of primary bond lengths and the IR vibrational spectra between the S0 state and the S1 state that verified the intramolecular hydrogen bond were strengthened. The fact that reproduced experimental absorbance and fluorescence emission spectra well theoretically demonstrate that the TDDFT theory we adopted is reasonable and effective. In addition, intramolecular charge transfer based on the frontier molecular orbitals demonstrated the indication of the ESIPT reaction. The constructed potential energy curves of ground state and the first excited state based on keeping the H2···O3 and H6···N7 distances fixed at a series of values have been used to illustrate the ESIPT process. A relative lower barrier of 5.94kcal/mol in the S1 state potential energy curve for type II (lower than that of 9.82kcal/mol in the S1 state for type I) demonstrates that type II ESIPT process occurs firstly in 7Al-2H2O complex.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Study of the decomposition pathway of 12-molybdophosphoric acid in aqueous
           solutions by micro Raman spectroscopy
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): D. Bajuk-Bogdanović, S. Uskoković-Marković, R. Hercigonja, A. Popa, I. Holclajtner-Antunović
      Micro Raman spectroscopy was applied to investigate the speciation of heteropoly and isopoly molybdates in 0.05 and 0.005M aqueous solutions of 12-molybdophosphoric acid at pH values between 1 and 6. For comparative purposes, 31P NMR spectroscopy was applied too. It is shown that stability of Keggin anion is influenced both by pH and concentration of solution. The Keggin structure is stable in acidic solutions (pH<1.6) while defective Keggin structures are formed with further alkalization (up to pH5.6). Monolacunary anion PMo11O39 7− is the main component in the pH region from 1.6 to 3.4. Further removal of molybdenyl species causes the appearance of other vacant Keggin structures such as PMo9O31(OH)3 6− and PMo6O25 9− at about pH4. At pH5.0, anion PMo6O25 9− is the main species. In solutions with pH greater than 5.0, heteropolymolybdates disappear completely and isopolymolybdates Mo7O24 6− and MoO4 2− are formed in higher amounts. In more diluted solution of 0.005M, the decomposition scheme of 12-molybdophosphoric acid solution with increasing of pH takes place without observation of significant amounts of Mo7O24 6− species. If alkalinization is performed with 0.5M instead of 5M NaOH, there are no significant changes in the Raman spectra of solutions. It is shown that the spectra of evaporated samples may be used for the identification of molecular species in corresponding concentrated solutions. However, Raman spectra of dry residues of more diluted solutions differ from spectra of corresponding solutions due to the reactions performed during the process of drying and cannot be used for unambiguous identification of species in solution. Acidification of 0.05M solution of Na2MoO4 shows that at pH>5.6, molybdate anion MoO4 2− dominates, while in the pH range between 5.6 and 1, heptamolybdate anion Mo7O24 6− is preferentially formed.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Influence of CeO2 content on complex optical parameters of phosphovanadate
           glass system
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): R.V. Barde
      In the present work, glass system of the compositions of 60V2O5–5P2O5–(35-x)B2O3–xCeO2 is prepared by modified melt-quenching method. The conformation of amorphous phase in sample was done through X-ray diffraction analysis. Optical studies were carried out at room temperature and direct and indirect band gap energy, refractive index, Urbach energy, molar refractivity and polarizability have been determined. The values of indirect band gap are lower than the corresponding values of direct band gap. Urbach energy is observed between 0.58 and 0.48eV. The samples show gradual increase in absorption around the 225nm, which results in increase of refractive index and optical conductivity. The real and imaginary dielectric constants show good agreement with each other.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Elemental analysis-aided Raman spectroscopic studies on Chinese
           cloisonné wares and painted enamels from the Imperial Palace
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Yan Su, Liang Qu, Hongying Duan, Nicolae Tarcea, Aiguo Shen, Jürgen Popp, Jiming Hu
      Two kinds of enamels, including Chinese cloisonné wares from Fuwang chamber and gourd-shaped painted enamels decorations from the Forbidden City, in the Imperial Palace of China, are investigated by micro-Raman spectroscopy in combination with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy-dispersive X-ray fluorescence (EDXRF) in order to examine and analyze the composition of the glaze layer in each case. In this study the excitation is employed with either a NIR laser (785nm) or a red laser (632.8nm) in order to effectively eliminate the interference of background fluorescence and resonance effect. We have identified that the major matrix ingredients of the cloisonné wares are lead-based potash-lime silicate glasses while lead-potash silicate glass matrix is the main constituent for the painted enamels. Eight different colored areas of glaze layer also have been discussed in detail due to the distinct colors including turquoise, deep blue, yellow, white, red, pink, deep green and pale green. Their identification based on Raman data will be useful with regard to rapid and on site analysis and the restoration of the enamel decorations.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic
           diphosphonates based on multinuclear units
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Chen Zhao, Kui-Rong Ma, Yu Zhang, Yu-He Kan, Rong-Qing Li, Hua-You Hu
      Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2′-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2′-bipyridine/1,10-phenanthroline (2,2′-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O–P–O)8] built through single/double O–P–O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O–P–O)4] n . Then H-bonding and π–π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1–2 are centered at 423nm, mainly deriving from intraligand π*–π transition state of N-heterocyclic ligand 2,2′-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Spectroscopic analysis of aluminum chloride phthalocyanine in binary
           water/ethanol systems for the design of a new drug delivery system for
           photodynamic therapy cancer treatment
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Cristiano Ceron Jayme, Italo Rodrigo Calori, Antonio Claudio Tedesco
      This study evaluated the behavior of aluminum chloride phthalocyanine in a binary water/ethanol mixture using electronic absorption spectroscopy and static and time-resolved fluorescence spectroscopy. The electronic absorption spectra, resonance light scattering and fluorescence quenching of aluminum chloride phthalocyanine in water/ethanol mixtures were studied at several concentrations. The electronic absorption spectra and fluorescence quenching changed significantly at approximately 50% water (v/v). Below 50% water, the dimerization constant values were negative (−2609.2M−1 and −506.5M−1 at 30% and 40% of water, respectively), indicating that the formation of aggregates under these conditions is not favored. However, at 50% water, the dimerization constant value was estimated to be 559.7M−1, which indicates the presence of dimers. Above 60% water, the aggregation process was responsible for the balance between large complexes (such as trimers, tetramers or oligomers) formed in the medium under these conditions. The appearance of new absorption bands at 387nm and 802nm and their bathochromic shift relative to the monomer bands suggested that some J-type aggregates form. These results are relevant to understanding the behavior and use of aluminum chloride phthalocyanine in the design of new drug delivery systems for clinical application in photodynamic therapy as a new approach to treat skin cancer.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Spectroscopic, microchemical and petrographic analyses of plasters from
           ancient buildings in Lamezia Terme (Calabria, Southern Italy)
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Raffaella De Luca, Valentina Gigliotti, Mario Panarello, Andrea Bloise, Gino M. Crisci, Domenico Miriello
      This work shows the results of the spectroscopic, microchemical and petrographic study carried out on six plasters coming from three important residential buildings of the 18th century, located in Lamezia Terme (Catanzaro, Southern Italy). To study the provenance of the raw materials used to make the plasters, one sample of limestone and two samples of sand were also collected from the quarries near Lamezia Terme and compared with the historical plasters. Samples were studied by polarized optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. The results of these analyses allowed to determine the mineralogical, petrographical and chemical characteristics of the plasters, identify the pigments used for their coloration and provide useful information about the building techniques, the raw materials employed and the production technology of plasters during the 18th century in Lamezia Terme. SEM–EDS microanalysis also revealed the presence of gold and silver on the surface of two samples.
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      PubDate: 2015-08-25T15:32:31Z
       
  • A simple ratiometric and colorimetric chemosensor for the selective
           detection of fluoride in DMSO buffered solution
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Hu Niu, Qinghai Shu, Shaohua Jin, Bingjun Li, Jiaping Zhu, Lijie Li, Shusen Chen
      A derivative of squaramide (cyclobuta[b]quinoxaline-1, 2(3H, 8H)-dione) has been synthesized for the ratiometric and colorimetric sensing of F− in aqueous solution in competitive fashion. With F−, probe 1 showed a highly selective naked-eye detectable color change along with a characteristic UV–Vis absorbance over other tested ions, which probably originates from the deprotonation occurred between 1 and F−, as proved by the 1H NMR titration experiments and DFT calculations.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Design, synthesis and 1H NMR study of C3v-symmetric anion receptors with
           urethane-NH as recognition group
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Jin-Oh Park, Suban K. Sahoo, Heung-Jin Choi
      C 3v-Symmetric anion receptors 3 and 4 with urethane groups were synthesized by using trindane triol as tripodal molecular framework. In 1H NMR titration study, the receptors showed noticeable downfield shift/disappearance of the urethane-NH peak in presence of H2PO4 − and F− due to the host–guest complexation occurred through multiple hydrogen bonding and/or the deprotonation of urethane-NH groups. Other tested anions such as Cl−, Br−, HSO4 −, and NO3 − showed either no or negligible chemical shift of the urethane groups. The deprotonation event in 4 allowed selective detection of F− by perceptible color change from colorless to yellowish-red with the appearance of a new charge transfer absorption band at 450nm.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Microwave-assisted ultrafast synthesis of silver nanoparticles for
           detection of Hg2+
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Yun Ma, Yuehong Pang, Fei Liu, Hanqi Xu, Xiaofang Shen
      Silver nanoparticles (AgNPs) were successfully prepared in aqueous solution by a one-pot procedure based on a rapid microwave-assisted green approach. l-Cysteine acted as a capping agent in the process of AgNP formation. The structural and morphological characteristics of the l-cysteine-capped AgNPs were investigated by the UV–vis, CD, FL, FTIR, XRD, TEM and EDX analysis. It was found that the well-dispersed crystalline AgNPs were formed after irradiation for 90s and had sphere-like morphology. Such strategy may facilitate new ways to the synthesis of other metal nanoparticles, such as Au, Pt and Pd. In addition, the synthesized AgNPs were developed as a platform for the detection of Hg2+ and showed a high sensitivity on the order of 1×10−8 M. This sensing system could discriminate Hg2+ from a wide range of cations (Ca2+, Ba2+, Mn2+, etc.). The selectivity and sensitivity of AgNPs indicated its potential use as a sensor for Hg2+ detection in the ecosystems.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Development of new UV–vis spectroscopic microwave-assisted method
           for determination of glucose in pharmaceutical samples
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Fazal Mabood, Z. Hussain, H. Haq, M.B. Arian, R. Boqué, K.M. Khan, K. Hussain, F. Jabeen, J. Hussain, M. Ahmed, A. Alharasi, Z. Naureen, H. Hussain, A. Khan, S. Perveen
      A new UV–Visible spectroscopic method assisted with microwave for the determination of glucose in pharmaceutical formulations was developed. In this study glucose solutions were oxidized by ammonium molybdate in the presence of microwave energy and reacted with aniline to produce a colored solution. Optimum conditions of the reaction including wavelength, temperature, and pH of the medium and relative concentration ratio of the reactants were investigated. It was found that the optimal wavelength for the reaction is 610nm, the optimal reaction time is 80s, the optimal reaction temperature is 160°C, the optimal reaction pH is 4, and the optimal concentration ratio aniline/ammonium molybdate solution was found to be 1:1. The limits of detection and quantification of the method are 0.82 and 2.75ppm for glucose solution, respectively. The use of microwaves improved the speed of the method while the use of aniline improved the sensitivity of the method by shifting the wavelength.
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      PubDate: 2015-08-25T15:32:31Z
       
  • Theoretical and experimental NMR studies on muscimol from fly agaric
           mushroom (Amanita muscaria)
    • Abstract: Publication date: 15 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 153
      Author(s): Teobald Kupka, Piotr P. Wieczorek
      In this article we report results of combined theoretical and experimental NMR studies on muscimol, the bioactive alkaloid from fly agaric mushroom (Amanita muscaria). The assignment of 1H and 13C NMR spectra of muscimol in DMSO-d6 was supported by additional two-dimensional heteronuclear correlated spectra (2D NMR) and gauge independent atomic orbital (GIAO) NMR calculations using density functional theory (DFT). The effect of solvent in theoretical calculations was included via polarized continuum model (PCM) and the hybrid three-parameter B3LYP density functional in combination with 6-311++G(3df,2pd) basis set enabled calculation of reliable structures of non-ionized (neutral) molecule and its NH and zwitterionic forms in the gas phase, chloroform, DMSO and water. GIAO NMR calculations, using equilibrium and rovibrationally averaged geometry, at B3LYP/6-31G* and B3LYP/aug-cc-pVTZ-J levels of theory provided muscimol nuclear magnetic shieldings. The theoretical proton and carbon chemical shifts were critically compared with experimental NMR spectra measured in DMSO. Our results provide useful information on its structure in solution. We believe that such data could improve the understanding of basic features of muscimol at atomistic level and provide another tool in studies related to GABA analogs.
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      PubDate: 2015-08-25T15:32:31Z
       
  • In-situ synthesis of high stable CdS quantum dots and their application
           for photocatalytic degradation of dyes
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Abdolraouf Samadi-Maybodi, Mohammad-Rasool Sadeghi-Maleki
      Photocatalysis based on semiconductor quantum dots, which utilize the solar energy can be used for elimination of pollutants from aqueous media and applied for water purification. In this paper, high stable CdS quantum dots (QDs) with good optical properties were successfully synthesized in a facile in-situ method, using Na2S2O3 as precursor and thioglycolic acid (TGA) as a catalyst, as well as capping agent in aqueous media. The synthesis process was optimized with a 2 IV 7 – 3 fractional factorial design method. Then, we studied the degradation of some industrial dyes including: alizarin, acid violet, mordant red and thymol blue as a tool to check the photocatalytic activity of synthesized CdS QDs. Results specified that the synthesized CdS QDs are capable for degradation of organic dyes under visible light irradiation with good recycling stability during photocatalytic experiments. Structural and spectroscopic properties of the synthesized CdS QDs were studied by TEM, XRD and absorption and fluorescence spectroscopy techniques. The synthesized TGA-capped CdS QDs have sizes in the range of 2.65–2.93nm with cubic crystalline structures.
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      PubDate: 2015-07-25T04:41:57Z
       
  • Fingerprints of polycyclic aromatic hydrocarbons (PAHs) in infrared
           absorption spectroscopy
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Matteo Tommasini, Andrea Lucotti, Michela Alfè, Anna Ciajolo, Giuseppe Zerbi
      We have analyzed a set of 51 PAHs whose structures have been hypothesized from mass spectrometry data collected on samples extracted from carbon particles of combustion origin. We have obtained relationships between infrared absorption signals in the fingerprint region (mid-IR) and the chemical structures of PAHs, thus proving the potential of IR spectroscopy for the characterization of the molecular structure of aromatic combustion products. The results obtained here for the spectroscopic characterization of PAHs can be also of interest in Materials Science and Astrophysics.
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      PubDate: 2015-07-25T04:41:57Z
       
  • Solvent scales used to study the intermolecular interactions in binary
           solutions of two p-aryl-pyridazinium methylids
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Daniela Babusca, Dana Ortansa Dorohoi
      The visible electronic absorption band with intramolecular charge transfer of two pyridazinium ylids having common carbanion and different heterocycles is recorded in solutions and its position is correlated to parameters of some empirical scales of solvents. The nature of the intermolecular interactions in pyridazinium ylid solutions is discussed and the supply of each type of interaction is established based on solvatochromic study.
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      PubDate: 2015-07-25T04:41:57Z
       
  • Polarized Raman spectroscopy unravels the biomolecular structural changes
           in cervical cancer
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Amuthachelvi Daniel, Aruna Prakasarao, Koteeswaran Dornadula, Singaravelu Ganesan
      Polarized Raman spectroscopy has emerged as a promising technique giving a wealth of information about the orientation and symmetry of bond vibrations in addition to the general chemical information from the conventional Raman spectroscopy. In this regard, polarized Raman Spectroscopic technique was employed to study the changes in the orientation of biomolecules in normal and cancerous conditions. This technique was compared to the conventional Raman spectroscopic technique and was found to yield additional information about the orientation of tyrosine, collagen and DNA. The statistically analyzed depolarization ratios by Linear Discriminant Analysis yielded better accuracy than the statistical results of conventional Raman spectroscopy. Thus, this study reveals that polarized Raman spectroscopy has better diagnostic potential than the conventional Raman spectroscopic technique.
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      PubDate: 2015-07-21T03:23:55Z
       
  • Role of SrO on the bioactivity behavior of some ternary borate glasses and
           their glass ceramic derivatives
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): A.M. Abdelghany, M.A. Ouis, M.A. Azooz, H.A. ElBatal, G.T. El-Bassyouni
      Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass–ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550–680cm−1 after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.
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      PubDate: 2015-07-21T03:23:55Z
       
  • A rapid and sensitive assay for determination of doxycycline using
           thioglycolic acid-capped cadmium telluride quantum dots
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Javad Tashkhourian, Ghodratollah Absalan, Marzieh Jafari, Saber Zare
      A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of <10s. The results revealed that doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism. The sensor permitted determination of doxycycline in a concentration range of 1.9×10−6–6.1×10−5 molL−1 with a detection limit of 1.1×10−7 molL−1. The sensor was applied for determination of doxycycline in honey and human serum samples.
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      PubDate: 2015-07-21T03:23:55Z
       
  • Enhanced red emission on co-doping of divalent ions (M2+=Ca2+, Sr2+, Ba2+)
           in YVO4:Eu3+ phosphor and spectroscopic analysis for its application in
           display devices
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Puja Kumari, J. Manam
      This paper reports the enhancement in photoluminescence due to the alkaline ions (M2+) co-doping in YVO4:Eu3+ phosphors prepared by solid state reaction method. The as synthesized samples were found to have single phase tetragonal structure and the incorporation of dopant/codopant did not affect the crystal structure. The characteristic bands of YO and VO were located at 450cm−1 and 830cm−1, respectively. The microscopic images exhibited the irregular morphology of the synthesized phosphor consisting of μm sized particles. Upon UV excitations, all phosphors showed intense red–orange emissions corresponding to the 5D0 → 7F J =1,2:Eu3+ transitions, and the emission intensity was further enhanced due to codoping. Divalent ions introduced radiative defect centers, which enhances the PL intensity significantly. The calculation of spectral parameters was done through Judd–Ofelt theory from emission spectra. The photometric characterizations and corresponding calculations indicated the suitability of the phosphor for display devices.
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      PubDate: 2015-07-21T03:23:55Z
       
  • Experimental and theoretical study of urea and thiourea based new
           colorimetric chemosensor for fluoride and acetate ions
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Eramoni Saikia, Manash Protim Borpuzari, Bolin Chetia, Rahul Kar
      Two new anion receptors 1,1-(4-nitro-1,2-phenylene) bis(3-phenylurea) (1) and 1,1-(4-nitro-1,2-phenylene) bis(3-phenylthiourea) (2) have been reported here. The binding and colorimetric sensing properties of receptors 1 and 2 with different anions were investigated by naked-eye, 1H-NMR and UV–Vis spectroscopy. They showed effective and selective binding with two biologically important anions F− and CH3COO−, in presence of other anions, such as Cl−, Br−, I−, NO2 −, ClO4 −, HSO4 −, H2PO4 −, N3 −, CN− in acetonitrile. The relative binding mode of fluoride and acetate anions towards receptors 1 and 2 were studied using density functional theory (DFT), in gas phase and in acetonitrile solvent. Computational studies revealed that receptor 1 formed complexes by two intermolecular hydrogen bonds while receptor 2 by three intermolecular hydrogen bonds. In addition, time dependent DFT (TD-DFT) calculations qualitatively match the experimental UV–Vis spectra.
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      PubDate: 2015-07-21T03:23:55Z
       
  • The molecular structure and vibrational, 1H and 13C NMR spectra of
           lidocaine hydrochloride monohydrate
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Hassan M. Badawi, Wolfgang Förner, Shaikh A. Ali
      The structure, vibrational and NMR spectra of the local anesthetic drug lidocaine hydrochloride monohydrate salt were investigated by B3LYP/6-311G∗∗ calculations. The lidocaine·HCl·H2O salt is predicted to have the gauche structure as the predominant form at ambient temperature with NCCN and CNCC torsional angles of 110° and −123° as compared to 10° and −64°, respectively in the base lidocaine. The repulsive interaction between the two N–H bonds destabilized the gauche structure of lidocaine·HCl·H2O salt. The analysis of the observed vibrational spectra is consistent with the presence of the lidocaine salt in only one gauche conformation at room temperature. The 1H and 13C NMR spectra of lidocaine·HCl·H2O were interpreted by experimental and DFT calculated chemical shifts of the lidocaine salt. The RMSD between experimental and theoretical 1H and 13C chemical shifts for lidocaine·HCl·H2O is 2.32 and 8.21ppm, respectively.
      Graphical abstract image

      PubDate: 2015-07-21T03:23:55Z
       
  • Raman and infrared spectroscopy study on structure and microstructure of
           glass–ceramic materials from
           SiO2–Al2O3–Na2O–K2O–CaO system modified by
           variable molar ratio of SiO2/Al2O3
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Janusz Partyka, Magdalena Leśniak
      This paper is focused on the effect of the molar ratio of SiO2/Al2O3 on the microstructure and structure of the internal aluminium–silicon-oxide lattice of the glass–ceramic materials from the SiO2–Al2O3–Na2O–K2O–CaO system. In order to examine the real composition of the obtained samples, a chemical analysis was performed. Following the heat-treatment procedure, pseudowollastonite, anorthite and the vitreous phase were identified. In order to determine the microstructure, research using the scanning electron microscope (SEM) with EDS was done. For the inner structural study, X-ray diffraction (XRD), Raman spectroscopy as well as MIR and FIR spectroscopy were performed.
      Graphical abstract image

      PubDate: 2015-07-21T03:23:55Z
       
  • Quenching of fluorescence in C60 fulleropyrrolidines by chloroform
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Abdulrazack Parveen, Venkatesan Sughanya, Samuthira Nagarajan
      Functionalized [C60] fullerene, fulleropyrrolidines were synthesized and their photophysical properties are studied. The absorption and emission patterns are altered in fulleropyrrolidines, when compared with C60. Fluorescence of the molecules is quenched by CHCl3 in toluene solution at room temperature. Effect of nature and length of side chains in fulleropyrrolidine on quenching is investigated. Results suggested that the fluorescence intensity increased with increase in carbon chain length and the Stern–Volmer plot intercept values are indirectly proportional to the number of the carbons.
      Graphical abstract image Highlights

      PubDate: 2015-07-21T03:23:55Z
       
  • A new “off–on” fluorescent probe for Al3+ in aqueous
           solution based on rhodamine B and its application to bioimaging
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Qi Huang, Qingyou Zhang, Enze Wang, Yanmei Zhou, Han Qiao, Lanfang Pang, Fang Yu
      In this paper, a new fluorescent probe has been synthesized and applied as “off–on” sensor for the detection of Al3+ with a high sensitivity and excellent selectivity in aqueous media. The sensor was easily prepared by one step reaction between rhodamine B hydrazide and pyridoxal hydrochloride named RBP. The structure of the sensor has been characterized by nuclear magnetic resonance and electron spray ionization-mass spectrometry. The fluorescence intensity and absorbance for the sensor showed a good linearity with the concentration of Al3+ in the range of 0–12.5μM and 8–44μM, respectively, with detection limits of 0.23μM and 1.90μM. The sensor RBP was preliminarily applied to the determination of Al3+ in water samples from the lake of Henan University and tap water with satisfying results. Moreover, it can be used as a bioimaging reagent for imaging of Al3+ in living cells.
      Graphical abstract image

      PubDate: 2015-07-21T03:23:55Z
       
  • Chemical physics behind formation of efficient charge-separated state for
           complexation between PC70BM and designed diporphyrin in solution
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Anamika Ray, Shrabanti Banerjee, Shalini Ghosh, Ajoy K. Bauri, Sumanta Bhattacharya
      The present work reports supramolecular interaction of [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) with two designed diporphyrin molecules having dithiophene (1) and carbazole (2) spacer in solvent having varying polarity. Studies on complex formation reveal relatively higher binding constant for PC70BM/2 complex in all the solvent studied. Solvent dependence of charge separation and charge recombination processes in PC70BM/diporphyrin non-covalent complexes has been well established in present work. Donor–acceptor geometry and stabilization of the singlet excited state of the diporphyrin during charge recombination are considered to be the possible reasons for this behavior.
      Graphical abstract image

      PubDate: 2015-07-21T03:23:55Z
       
  • Internal charge transfer based ratiometric interaction of anionic
           surfactant with calf thymus DNA bound cationic surfactant: Study I
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Abhijit Mukherjee , Tandrima Chaudhuri , Satya Priya Moulik , Manas Banerjee
      Cetyl trimethyl ammonium bromide (CTAB) binds calf thymus (ct-) DNA like anionic biopolymers electrostatically and established equilibrium both in the ground as well as in excited state in aqueous medium at pH 7. Anionic sodium dodecyl sulfate (SDS) does not show even hydrophobic interaction with ct-DNA at low concentration. On contrary, SDS can establish well defined equilibrium with DNA bound CTAB in ground state where the same CTAB–DNA isosbestic point reappears. First report of internal charge transfer (ICT) based binding of CTAB with ct-DNA as well as ICT based interaction of anionic SDS with DNA bound CTAB that shows dynamic quenching contribution also. The reappearance of anodic peak and slight increase in cathodic peak current with increasing concentration (at lower range) of anionic SDS, possibly reflect the release of CTAB from DNA bound CTAB by SDS.
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
  • Structural, optical and electrical characterization of nanostructured
           porous silicon: Effect of current density
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): K. Kulathuraan , K. Mohanraj , B. Natarajan
      In this work, an attempt has been made to fabricate porous silicon (PS) from p-type crystalline silicon (c-Si) wafers by using the electrochemical etching process at six different current densities (40, 60, 75, 100, 125 and 150mA/cm2) with constant time (30min). The influence of varying current density on morphological, structural, optical and electrical properties of PS samples were analyzed by using SEM, AFM, XRD, FT-IR, PL and electrical (I–V) techniques, respectively. Microstructural images clearly showed that the average pore diameter and thickness increase with increase current densities up to 100mA/cm2 and decrease for 125mA/cm2. It could be related to breaking of pore walls and exposing to the next layer of c-Si. Further increase the current density about 150mA/cm2, the average pore diameter increase as in the case of first layer (40–100mA/cm2) of c-Si wafer. The result is reflected in PL emission band (at 708nm) and the intensity of the emission band shifted towards red region. The X-ray diffraction pattern confirm the formation of porous silicon as appeared as a broad peak at 2θ =69.3° belongs to (400) reflection. The FTIR study supports the X-ray diffraction analysis that shows the vibrational bands of S–H2 and Si–O–Si at 2109cm−1, 915cm−1 and 615cm−1 and 1107cm−1, respectively. The I–V characteristic of PS exhibited rectifying behavior with different values of ideality factor (η) and barrier height (ϕ b). It is concluded from the experimental results that the formed pores developed up to 100mA/cm2 in the top layer of c-Si and the formed pores exposed to the next layer of c-Si when increase the high electrochemical etching process (above 100mA/cm2).
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
  • Estimation of lattice strain in nanocrystalline RuO2 by
           Williamson–Hall and size–strain plot methods
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): R. Sivakami , S. Dhanuskodi , R. Karvembu
      RuO2 nanoparticles (RuO2 NPs) have been successfully synthesized by the hydrothermal method. Structure and the particle size have been determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). UV–Vis spectra reveal that the optical band gap of RuO2 nanoparticles is red shifted from 3.95 to 3.55eV. BET measurements show a high specific surface area (SSA) of 118–133m2/g and pore diameter (10–25nm) has been estimated by Barret–Joyner–Halenda (BJH) method. The crystallite size and lattice strain in the samples have been investigated by Williamson–Hall (W–H) analysis assuming uniform deformation, deformation stress and deformation energy density, and the size–strain plot method. All other relevant physical parameters including stress, strain and energy density have been calculated. The average crystallite size and the lattice strain evaluated from XRD measurements are in good agreement with the results of TEM.
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
  • Differential identification of mushrooms sclerotia by IR macro-fingerprint
           method
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Yew Keong Choong , Jin Lan , Han Lim Lee , Xiang-dong Chen , Xiao-guang Wang , Yu-ping Yang
      Many macrofungus sclerotia are well-known medicinal herbs, health food and nutritional supplements. However, the prevalent adulterant commercial products are major hindrances to their incorporation into mainstream medical use in many countries. The mushroom sclerotia of Lignosus rhinocerotis, Poria cocos, Polyporus umbellatus, Pleurotus tuber-regium and Omphalia lapidescens are commonly used in traditional Chinese medicine. In this study, IR macro-fingerprint method was used in the identification of these sclerotia. The results showed that the spectrum of L. rhinocerotis (LR) was comparable with P. cocos with 94.4% correlation, except that the peak at 1543cm−1 of LR appeared in lower intensity. The spectrum of P. umbellatus and P. tuber-regium was also correlated (91.5%), as both spectra could be clearly discriminated in that P. umbellatus spectrum has small base peaks located at the range of 1680–1500cm−1. O. lapidescens was not comparable with all the other sclerotia as its spectrum was totally different. Its base peak was broad and derivated equally along the range. The first IR has revealed the dissimilarity among five mushrooms sclerotia. The second derivative and 2DIR further enhanced the identification in detail.
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
  • Novel coumarin-based fluorescent probe for selective detection of Cu(II)
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Ahmadreza Bekhradnia , Elham Domehri , Masome Khosravi
      We report an efficient and convenient method for preparing nitro-3-carboxamide coumarin derivatives, proposed as novel fluorescent chemosensor, through microwave irradiation. This compound can be used as fluorescent probe for Cu2+ with selectivity over other metal ions in aqueous solution. The fluorescence of 6-nitro-N-[2-(dimethylamino)ethyl]-2-oxo-2H-chromene-3-carboxamide(3) is the highest in the presence of Cu2+, with stronger excitation at λ =320nm than for the other cations tested.
      Graphical abstract image Highlights

      PubDate: 2015-07-16T02:45:07Z
       
  • Caffeine and sulfadiazine interact differently with human serum albumin: A
           combined fluorescence and molecular docking study
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): Mullah Muhaiminul Islam , Vikash K. Sonu , Pynsakhiat Miki Gashnga , N. Shaemningwar Moyon , Sivaprasad Mitra
      The interaction and binding behavior of the well-known drug sulfadiazine (SDZ) and psychoactive stimulant caffeine (CAF) with human serum albumin (HSA) was monitored by in vitro fluorescence titration and molecular docking calculations under physiological condition. The quenching of protein fluorescence on addition of CAF is due to the formation of protein–drug complex in the ground state; whereas in case of SDZ, the experimental results were explained on the basis of sphere of action model. Although both these compounds bind preferentially in Sudlow’s site 1 of the protein, the association constant is approximately two fold higher in case of SDZ (∼4.0×104 M−1) in comparison with CAF (∼9.3×102 M−1) and correlates well with physico-chemical properties like pK a and lipophilicity of the drugs. Temperature dependent fluorescence study reveals that both SDZ and CAF bind spontaneously with HSA. However, the binding of SDZ with the protein is mainly governed by the hydrophobic forces in contrast with that of CAF; where, the interaction is best explained in terms of electrostatic mechanism. Molecular docking calculation predicts the binding of these drugs in different location of sub-domain IIA in the protein structure.
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
  • Synthesis and spectroscopic characterization on
           4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid: A DFT approach
    • Abstract: Publication date: 5 January 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 152
      Author(s): M. Kurt , E. Babur Sas , M. Can , S. Okur , S. Icli , S. Demic , M. Karabacak , T. Jayavarthanan , N. Sundaraganesan
      A complete structural and vibrational analysis of the 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid (TPBA), was carried out by ab initio calculations, at the density functional theory (DFT) method. Molecular geometry, vibrational wavenumbers and gauge including atomic orbital (GIAO) 13C NMR and 1H NMR chemical shift values of (TPBA), in the ground state have been calculated by using ab initio density functional theory (DFT/B3LYP) method with 6-311G(d,p) as basis set for the first time. Comparison of the observed fundamental vibrational modes of (TPBA) and calculated results by DFT/B3LYP method indicates that B3LYP level of theory giving yield good results for quantum chemical studies. Vibrational wavenumbers obtained by the DFT/B3LYP method are in good agreement with the experimental data. The study was complemented with a natural bond orbital (NBO) analysis, to evaluate the significance of hyperconjugative interactions and electrostatic effects on such molecular structure. By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals analysis and thermodynamic properties of TPBA were investigated using theoretical calculations.
      Graphical abstract image

      PubDate: 2015-07-16T02:45:07Z
       
 
 
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