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  Subjects -> CHEMISTRY (Total: 838 journals)
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CHEMISTRY (587 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: 10)
Journal of Chemical and Biological Interfaces     Full-text available via subscription  
Journal of Chemical Education     Full-text available via subscription   (Followers: 16)
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: 16)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 12)
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: 51)
Journal of Chromatography Library     Full-text available via subscription   (Followers: 5)
Journal of Clinical Toxicology     Open Access  
Journal of Colloid and Interface Science     Hybrid Journal   (Followers: 13)
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: 5)
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: 4)
Journal of Mass Spectrometry     Hybrid Journal   (Followers: 23)
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: 9)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 5)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 91)
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: 2)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 4)
Journal of Molecular Recognition     Hybrid Journal   (Followers: 2)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 6)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
Journal of Nanoparticles     Open Access  
Journal of Nanostructure in Chemistry     Open Access   (Followers: 4)
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: 12)
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: 3)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 1)
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 118)
Journal of Polymers     Open Access   (Followers: 1)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 3)
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   (Followers: 1)
Journal of Taibah University for Science     Open Access  
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 217)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 20)
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: 2)
Journal of the Iranian Chemical Society     Hybrid Journal   (Followers: 1)
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: 6)
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: 40)
Latvian Journal of Chemistry     Open Access   (Followers: 1)
Lebensmittelchemie     Hybrid Journal   (Followers: 1)
Lipid Insights     Open Access   (Followers: 1)
Luminescence     Hybrid Journal   (Followers: 1)
Macromolecular Materials & Engineering     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]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [2812 journals]
  • A combined experimental and theoretical study of the tautomeric and
           conformational properties of (5-phenyl-tetrazol-2-yl)-acetic acid methyl
           ester
    • Abstract: Publication date: 5 November 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 150
      Author(s): Aamer Saeed , Muhammad Qasim , Majid Hussain , Ulrich Flörke , Mauricio F. Erben
      The tautomeric and conformational properties of a new tetrazole derivative are studied in a combined approach that includes the analysis of the experimental vibrational data together with theoretical calculation methods, especially in terms of natural bond orbital (NBO) population analysis. Moreover, the molecular and crystal structure was determined by single crystal X-ray diffraction. The compound crystallized as the 2-tautomeric form, monoclinic space group P21/c with Z =4, a =10.0630(14), b =8.2879(11), c =12.8375(18)Å, β =105.546(3)°, V =1031.5(2)Å3. The tetrazole and phenyl rings are coplanar with the acetate group oriented perpendicular to the plane. The NBO analysis showed that delocalizing interactions of the lpp(N2) lone pair orbital contributes to a strong resonance interactions with both adjacent π∗(N3N4) and π∗(N1C5) antibonding orbitals of the tetrazole group.
      Graphical abstract image

      PubDate: 2015-05-24T16:04:02Z
       
  • Vibrational spectra, powder X-ray diffractions and physical properties of
           cyanide complexes with 1-ethylimidazole
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Güneş Süheyla Kürkçüoğlu , Fulya Çetinkaya Kiraz , Elvan Sayın
      The heteronuclear tetracyanonickelate(II) complexes of the type [M(etim)Ni(CN)4] n (hereafter, abbreviated as M–Ni–etim, M=Mn(II), Fe(II) or Co(II); etim=1-ethylimidazole, C5H8N2) were prepared in powder form and characterized by FT-IR and Raman spectroscopy, powder X-ray diffraction (PXRD), thermal (TG; DTG and DTA), and elemental analysis techniques. The structures of these complexes were elucidated using vibrational spectra and powder X-ray diffraction patterns with the peak assignment to provide a better understanding of the structures. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from powder X-ray diffraction measurements. Vibrational spectra of the complexes were presented and discussed with respect to the internal modes of both the etim and the cyanide ligands. The C, H and N analyses were carried out for all the complexes. Thermal behaviors of these complexes were followed using TG, DTG and DTA curves in the temperature range 30–700°C in the static air atmosphere. The FT-IR, Raman spectra, thermal and powder X-ray analyses revealed no significant differences between the single crystal and powder forms. Additionally, electrical and magnetic properties of the complexes were investigated. The FT-IR and Raman spectroscopy, PXRD, thermal and elemental analyses results propose that these complexes are similar in structure to the Hofmann-type complexes.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Identification of solid state fermentation degree with FT-NIR
           spectroscopy: Comparison of wavelength variable selection methods of CARS
           and SCARS
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Hui Jiang , Hang Zhang , Quansheng Chen , Congli Mei , Guohai Liu
      The use of wavelength variable selection before partial least squares discriminant analysis (PLS-DA) for qualitative identification of solid state fermentation degree by FT-NIR spectroscopy technique was investigated in this study. Two wavelength variable selection methods including competitive adaptive reweighted sampling (CARS) and stability competitive adaptive reweighted sampling (SCARS) were employed to select the important wavelengths. PLS-DA was applied to calibrate identified model using selected wavelength variables by CARS and SCARS for identification of solid state fermentation degree. Experimental results showed that the number of selected wavelength variables by CARS and SCARS were 58 and 47, respectively, from the 1557 original wavelength variables. Compared with the results of full-spectrum PLS-DA, the two wavelength variable selection methods both could enhance the performance of identified models. Meanwhile, compared with CARS-PLS-DA model, the SCARS-PLS-DA model achieved better results with the identification rate of 91.43% in the validation process. The overall results sufficiently demonstrate the PLS-DA model constructed using selected wavelength variables by a proper wavelength variable method can be more accurate identification of solid state fermentation degree.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Tetradentate metal complexes derived from cephalexin and
           2,6-diacetylpyridine bis(hydrazone): Synthesis, characterization and
           antibacterial activity
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): J.R. Anacona , Victor Rangel , Marcos Loroño , Juan Camus
      Metal(II) coordination compounds of a hydrazone ligand (HL) derived from the condensation of cephalexin antibiotic with 2,6-diacetylpyridine bis(hydrazone) were synthesized. The hydrazone ligand and mononuclear [ML(H2O)2][PF6] (M(II)=Mn, Co, Ni, Zn) complexes were characterized by several techniques, including elemental and thermal analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR, EPR and 1H NMR spectral studies. The cephalexin 2,6-diacetylpyridine bis(hydrazone) ligand HL behaves as a monoanionic tetradentate NNNO chelating agent. The biological applications of complexes have been studied on two bacteria strains (Escherichia coli and Staphylococcus aureus) by agar diffusion disc method.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • TDDFT study on the sensing mechanism of a fluorescent sensor for fluoride
           anion: Inhibition of the ESPT process
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Guang-Yue Li , Dong Liu , Hang Zhang , Wei-Wei Li , Feng Wang , Ying-Hua Liang
      The fluoride-sensing mechanism of a reported salicylaldehyde-based sensor (J. Photochem. Photobiol. B 2014, 138, 75) has been investigated by the TDDFT method. The present theoretical study indicates that there is an excited-state proton transfer (ESPT) process from the phenolic O–H moiety to the neighbor N atom in the sensor. The added fluoride anion could capture the proton in the O–H moiety and the corresponding phenolic anion is formed, which could inhibit the ESPT process. The experimental UV/Vis and fluorescence spectra are well reproduced by the calculated vertical excitation energies. Frontier molecular orbital analysis indicates that the local excited state of phenolic anion is responsible for its enhanced fluorescence. Due to this reason, the sensor can be used to sense fluoride anion by monitoring the fluorescent change.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Synthesis of two new silver(I) complexes with 3-bromoquinoline: Molecular
           structure, spectroscopic characterizations and DFT studies
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Saied M. Soliman , Morsy A.M. Abu-Youssef , Taher S. Kassem , Rania Assem
      Two new Ag+ complexes with 3-bromoquinoline (3BrQ) have been synthesized and characterized using elemental analysis, FTIR, NMR and mass spectra. The studied complexes have the formula [Ag(3BrQ)(OAC)]; 1 and [Ag(3BrQ)3(TCA)]; 2 where OAC and TCA are acetate and trichloroacetate, respectively. Based on the DFT calculations, 1 and 2 showed distorted trigonal planar and distorted tetrahedral coordination geometry. The electronic properties such as dipole moment (μ), polarizability (α 0), HOMO and LUMO energies are calculated using the same level of theory. These electronic parameters were used to predict the nonlinear optical properties of the studied compounds. The studied silver complexes were predicted to be better nonlinear optical materials than urea. The electronic spectra of these complexes are calculated using the TD–DFT calculations. The infrared vibrational spectra were assigned based on the potential energy distribution (PED) analysis. The calculated 1H NMR chemical shift values using GIAO approach showed good agreement with the experimental data. The intramolecular charge transfer interactions of the title molecules were studied by natural bond orbital (NBO) analysis.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Optical properties of Lead bismuth borate glasses doped with neodymium
           oxide
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): M. Farouk , A. Abd El-Maboud , M. Ibrahim , A. Ratep , I. Kashif
      Neodymium doped Lead bismuth borate glasses with the composition of 25PbO–25Bi2O3–50B2O3:xNd2O3, where x =0.5, 1, 1.5 and 2mol%, have been prepared by melt quenching technique. The behavior of the density and molar volume allows concluding that, addition of Nd2O3 leads to the formation of non-bridging oxygen. Rare earth ion parameters have been calculated and studied. The optical band gap (E g), and band tails (E e) were determined. Judd–Ofelt theory for the intensity analysis of induced electric dipole transitions has been applied to the measured oscillator strengths of the absorption bands to determine the three phenomenological intensity parameters Ω 2, Ω 4 and Ω 6 for glass. It was observed that the deviation parameters, rms, was found to be 0.56:0.58(×10−6). The estimated Judd–Ofelt parameters were found to be Nd2O3concentration dependent. The hypersensitive transition, 4I9/2 → 4G5/2 + 2G7/2, is closely related to Ω 2 parameter.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Vibrational spectra, HOMO, LUMO, MESP surfaces and reactivity descriptors
           of amylamine and its isomers: A DFT study
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Apoorva Dwivedi , Ambrish Kumar Srivastava , Abhishek Bajpai
      Amylamine constitutes an important class of organic compounds which exists in a variety of ammonia derivatives. In present study, a comparative analysis of amylamine and its two potential isomers, iso-amylamine and tert-amylamine, has been performed using density functional theory with B3LYP method and 6-311G(d,p) as the basis set. The equilibrium structures of amylamine as well as its iso and tert forms have been obtained. The vibrational spectroscopic analysis has been carried out for the three molecules and complete assignments to all possible modes have been offered. The HOMO, LUMO and MESP surfaces are analyzed to discuss the chemical reactivity patterns in the molecules. A number of reactivity parameters have been calculated to further explain their chemical reactivity. The thermodynamic and nonlinear optical parameters are also calculated and discussed.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Scanning electron microscopy with energy dispersive spectroscopy and Raman
           and infrared spectroscopic study of tilleyite Ca5Si2O7(CO3)2-Y
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Ray L. Frost , Andrés López , Ricardo Scholz , Fernando A.N. de Oliveira
      The mineral tilleyite-Y, a carbonate-silicate of calcium, has been studied by scanning electron microscopy with chemical analysis using energy dispersive spectroscopy (EDX) and Raman and infrared spectroscopy. Multiple carbonate stretching modes are observed and support the concept of non-equivalent carbonate units in the tilleyite structure. Multiple Raman and infrared bands in the OH stretching region are observed, proving the existence of water in different molecular environments in the structure of tilleyite. Vibrational spectroscopy offers new information on the mineral tilleyite.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Study of chemical bonding, physical and biological effect of metformin
           drug as an organized medicine for diabetes patients with chromium(III) and
           vanadium(IV) ions
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Abdel Majid A. Adam , T. Sharshar , Mahmoud A. Mohamed , Omar B. Ibrahim , Moamen S. Refat
      New vanadium(IV) and chromium(III) complexes of metformin (MFN) were synthesized upon the chemical interaction between vanadyl(II) sulfate monohydrate or chromium(III) chloride hexahydrate with metformin diabetic drug in the media of a pure grade of methanol solvent. The [(VO)2(MFN)2(SO4)2]2H2O and [Cr(MFN)3]·Cl3·6H2O complexes were discussed using microanalytical measurements, molar conductance, spectroscopic (infrared, ESR, XRD, and UV–vis), effective magnetic moment, scanning electron microscopy (SEM), and thermal analyses (TG/DTG). The elemental analysis shows that VO(II) and Cr(III) complexes were associated with 1:1 and 1:3M ratios, respectively. The infrared spectroscopic results data received from the comparison between free MFN free ligand and their vanadyl(II) and chromium(III) complexes were proven that metformin reacted with respected metal ions as a bidentate ligand through its two imino groups. The kinetic thermodynamic parameters were estimated from the DTG curves. The microstructure changes of the VO(II) and Cr(III) complexes have been probed using positron annihilation lifetime (PAL) and positron annihilation Doppler broadening (PADB) techniques. The PAL and PADB line-shape parameters were found to be dependent on the structure, electronic configuration and molecular weight of metal complexes. Antimicrobial activity of the metformin free ligand and its vanadyl(II) and chromium(III) complexes were evaluated against the gram negative and gram positive bacteria strains and different fungal strains. Moderate antimicrobial activity recorded by disk diffusion inhibition growth zone method in vanadyl(II) and chromium(III) complexes compared to metformin free ligand.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Raman spectroscopic study of phosphogypsum thermal reduction with the
           carbonaceous material
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Xolani Msila , Werner Barnard , Dave G. Billing
      Elemental sulphur (S) can be produced from hydrogen sulphide (H2S) in a PiPco or Iron process. In turn H2S can be stripped with carbon dioxide (CO2) from calcium sulphide (CaS) obtained from the thermal reduction of phosphogypsum with carbon. The reaction pathway for the thermal reduction of the phosphogypsum with graphite was studied using thermogravimetric analysis and in situ Raman spectroscopy. The dehydration of the phosphogypsum to anhydrite was completed at about 142°C. The dehydration was followed by the formation of the intermediate compound at about 860°C which is characterised by a mass loss of about 11%. The intermediate compound, identified using the in situ Raman spectroscopy to be a dehydrated orschallite-type compound (Ca3[SO4][SO3]2), converted to CaS at about 935°C. The presence of the metal impurities in the phosphogypsum: Ni2+(4mgkg−1); Co2+(2mgkg−1); Mn2+(5mgkg−1); Cu2+(14mgkg−1); Fe2+(200mgkg−1) and Mg2+(300mgkg−1) showed no influence the onset temperature for the reduction reaction.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       

  •        (2E)-1-(5-Chlorothiophen-2-yl)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-en-1-one:
           Synthesis, XRD, FT-IR, Raman and DFT studies
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Cemal Parlak , Ponnadurai Ramasami , Chandraju Sadolalu Chidan Kumar , Mahir Tursun , Ching Kheng Quah , Lydia Rhyman , Metin Bilge , Hoong-Kun Fun , Siddegowda Chandraju
      A novel (2E)-1-(5-chlorothiophen-2-yl)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-en-1-one [C21H15ClOS] compound has been synthesized and its structure has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the compound have been examined by means of HF, MP2, BP86, BLYP, BMK, B3LYP, B3PW91, B3P86 and M06-2X functionals. Reliable vibrational assignments and molecular orbitals have been investigated by the potential energy distribution and natural bonding orbital analyses, respectively. The compound crystallizes in the triclinic space group P-1 with the cis–trans–trans form. There is a good agreement between the experimentally determined structural parameters and vibrational frequencies of the compound and those predicted theoretically using the density functional theory with the BLYP and BP86 functionals.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Spectrophotometric determination of basic fuchsin from various water
           samples after vortex assisted solid phase extraction using reduced
           graphene oxide as an adsorbent
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Şerife Tokalıoğlu , Emre Yavuz , Ayşe Aslantaş , Halil Şahan , Ferhat Taşkın , Şaban Patat
      In this study, a fast and simple vortex assisted solid phase extraction method was developed for the separation/preconcentration of basic fuchsin in various water samples. The determination of basic fuchsin was carried out at a wavelength of 554nm by spectrophotometry. Reduced graphene oxide which was used as a solid phase extractor was synthesized and characterized by X-ray diffraction, scanning electron microscopy and the Brunauer, Emmett and Teller. The optimum conditions are as follows: pH 2, contact times for adsorption and elution of 30s and 90s, respectively, 10mg adsorbent, and eluent (ethanol) volume of 1mL. The effects of some interfering ions and dyes were investigated. The method was linear in the concentration range of 50–250μgL−1. The adsorption capacity was 34.1mgg−1. The preconcentration factor, limit of detection and precision (RSD, %) of the method were found to be 400, 0.07μgL−1 and 1.2%, respectively. The described method was validated by analyzing basic fuchsin spiked certified reference material (SPS-WW1 Batch 114-Wastewater) and spiked real water samples.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Synthesis, spectral, computational and thermal analysis studies of
           metallocefotaxime antibiotics
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Mamdouh S. Masoud , Alaa E. Ali , Gehan S. Elasala
      Cefotaxime metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and two mixed metals complexes of (Fe,Cu) and (Fe,Ni) were synthesized and characterized by elemental analysis, IR, electronic spectra, magnetic susceptibility and ESR spectra. The studies proved that cefotaxime may act as mono, bi, tri and tetra-dentate ligand through oxygen atoms of lactam carbonyl, carboxylic or amide carbonyl groups and nitrogen atom of thiazole ring. From the magnetic measurements and electronic spectral data, octahedral structures were proposed for all complexes. Quantum chemical methods have been performed for cefotaxime to calculate charges, bond lengths, bond angles, dihedral angles, electronegativity (χ), chemical potential (μ), global hardness (η), softness (σ) and the electrophilicity index (ω). The thermal decomposition of the prepared metals complexes was studied by TGA, DTA and DSC techniques. Thermogravimetric studies revealed the presence of lattice or coordinated water molecules in all the prepared complexes. The decomposition mechanisms were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides and carbon residue as a final product except in case of Hg complex, sublimation occur at the temperature range 376.5–575.0°C so, only carbon residue was produced during thermal decomposition. The orders of chemical reactions (n) were calculated via the peak symmetry method and the activation parameters were computed from the thermal decomposition data. The geometries of complexes may be converted from Oh to Td during the thermal decomposition steps.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Vibrational spectroscopy, ab initio calculations and Frontier Orbital
           
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): C.E.S. Nogueira , P.E.S. Caselli , P.T.C. Freire , A.M.R. Teixeira , I.M.M. Oliveira , R.R.F. Bento , J.L.B. Faria , G.O.M. Gusmão , L.E. Silva
      In this work we present a study of the vibrational spectra of 4,5,6,8,9-pentachloropyrimido-[1,2-a][1,8]naphthyridin-10-one, C11H2Cl5N3O, a substance belonging to the important pharmacological class of 1,8-naphthyridine derivatives. The Fourier transform infrared and the Fourier transform Raman spectra of the crystal were recorded at room temperature in the regions 400–4000 and 50–4000cm−1, respectively. Vibrational wavenumbers were predicted using Density Functional Theory calculations with the B3LYP functional on 6-31G(d,p) and 6-311++G(d,p) basis sets. The descriptions of the normal modes were made after calculating the potential energy distribution. Additionally, potential reaction sites were evaluated through Mulliken population and Frontier Orbital analysis.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Cathodoluminescence properties of gadolinium-doped CaMoO4:Eu nanoparticles
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): P.V. Ramakrishna
      Gadolinium (Gd3+) doped CaMoO4:Eu nanoparticles were prepared via facile auto-combustion route and annealed at 900°C for ∼4h. X-ray diffraction study confirms the tetragonal scheelite type of CaMoO4 phase. Low voltage cathodoluminescent (CL) measurement were performed for Gd3+ (0 and 10at.%) co-doped CaMoO4:Eu as a function of accelerating voltage and filament current. CL studies confirm that Gd3+ co-doped CaMoO4:Eu has a visible emission peak centered at ∼615nm and a broad host emission band in the range 380–550nm. Commission Internationale de L’Eclairage chromaticity diagram co-ordinates of Gd3+ co-doped CaMoO4:Eu are found to be in reddish orange region as was observed through photoluminescence and CL spectra.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Insights into the new Th (IV) sulfate fluoride complex: Synthesis, crystal
           structures, and temperature dependent spectroscopic properties
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Yanyan Zhao , Chunxiang Wang , Jing Su , Yaxing Wang , Yanlong Wang , Shuao Wang , Juan Diwu , Zhihong Liu
      Under hydrothermal condition, the decomposition of methanesulfonic acid to sulfate anion is observed, resulting in the formation of a novel thorium sulfate fluoride compound ThF2(SO4)(H2O) (1). This complex is structurally characterized by single crystal X-ray diffraction, revealing a three-dimensional structure crystallized in the monoclinic space-group P21/n, where thorium cation is nine coordinated by four SO4 2− oxygen atoms, four bridging F−, and one H2O molecule. The crystal lattice parameters are a =6.9065(7)Å, b =6.9256(7)Å, c =10.5892(11)Å, β =96.755(2)°, V =502.98(9)Å3, Z =4. The temperature dependent UV–Vis–NIR absorption spectra and fluorescence spectra were collected from 77K to 300K, where the intensities of the peaks varied as a function of temperature. The Raman vibrational spectrum of the samples collected from 100 to 2000cm−1 shows identical SO4 2− vibration modes.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Portuguese tin-glazed earthenware from the 17th century. Part 2: A
           spectroscopic characterization of pigments, glazes and pastes of the three
           main production centers
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): L.F. Vieira Ferreira , D.P. Ferreira , D.S. Conceição , L.F. Santos , M.F.C. Pereira , T.M. Casimiro , I. Ferreira Machado
      Sherds representative of the three Portuguese faience production centers of the 17th century – Lisbon, Coimbra and Vila Nova were studied with the use of mostly non-invasive spectroscopies, namely: ground state diffuse reflectance absorption (GSDR), micro-Raman, Fourier-transform infrared (FT-IR) and proton induced X-ray (PIXE) or X-ray fluorescence emission (XRF). X-ray diffraction (XRD) experiments were also performed. The obtained results evidence a clear similarity in the pastes of the pottery produced Vila Nova and some of the ceramic pastes from Lisbon, in accordance with documental sources that described the use of Lisbon clays by Vila Nova potters, at least since mid 17th century. Quartz and Gehlenite are the main components of the Lisbon’s pastes, but differences between the ceramic pastes were detected pointing out to the use of several clay sources. The spectroscopic trend exhibited Coimbra’s pottery is remarkably different, Quartz and Diopside being the major components of these pastes, enabling one to well define a pattern for these ceramic bodies. The blue pigment from the Lisbon samples is a cobalt oxide that exists in the silicate glassy matrix, which enables the formation of detectable cobalt silicate microcrystals in most productions of the second half of the 17th century. No micro-Raman cobalt blue signature could be detected in the Vila Nova and Coimbra blue glazes. This is in accordance with the lower kiln temperatures in these two production centers and with Co2+ ions dispersed in the silicate matrix. In all cases the white glaze is obtained with the use of tin oxide. Hausmannite was detected as the manganese oxide mineral used to produce the purple glaze (wine color “vinoso”) in Lisbon.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • SEM, EDX and Raman and infrared spectroscopic study of brianyoungite
           Zn3(CO3,SO4)(OH)4 from Esperanza Mine, Laurion District, Greece
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Ray L. Frost , Andrés López , Lina Wang , Ricardo Scholz , Ney Pinheiro Sampaio
      The mineral brianyoungite, a carbonate–sulphate of zinc, has been studied by scanning electron microscopy (SEM) with chemical analysis using energy dispersive spectroscopy (EDX) and Raman and infrared spectroscopy. Multiple carbonate stretching modes are observed and support the concept of non-equivalent carbonate units in the brianyoungite structure. Intense Raman band at 1056cm−1 with shoulder band at 1038cm−1 is assigned to the CO3 2 − ν1 symmetric stretching mode. Two intense Raman bands at 973 and 984cm−1 are assigned to the symmetric stretching modes of the SO4 2 − anion. The observation of two bands supports the concept of the non-equivalence of sulphate units in the brianyoungite structure. Raman bands at 704 and 736cm−1 are assigned to the CO3 2 − ν4 bending modes and Raman bands at 507, 528, 609 and 638cm−1 are assigned to the CO3 2 − ν2 bending modes. Multiple Raman and infrared bands in the OH stretching region are observed, proving the existence of water and hydroxyl units in different molecular environments in the structure of brianyoungite. Vibrational spectroscopy enhances our knowledge of the molecular structure of brianyoungite.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Rapid analysis of diesel fuel properties by near infrared reflectance
           spectra
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Fei Feng , Qiongshui Wu , Libo Zeng
      In this study, based on near infrared reflectance spectra (NIRS) of 441 samples from four diesel groups (−10# diesel, −20# diesel, −35# diesel, and inferior diesel), three spectral analysis models were established by using partial least square (PLS) regression for the six diesel properties (i.e., boiling point, cetane number, density, freezing temperature, total aromatics, and viscosity) respectively. In model 1, all the samples were processed as a whole; in model 2 and model 3, samples were firstly classified into four groups by least square support vector machine (LS-SVM), and then partial least square regression models were applied to each group and each property. The main difference between model 2 and model 3 was that the latter used the direct orthogonal signal correction (DOSC), which helped to get rid of the non-relevant variation in the spectra. Comparing these three models, two results could be concluded: (1) models for grouped samples had higher precision and smaller prediction error; (2) models with DOSC after LS-SVM classification yielded a considerable error reduction compared to models without DOSC.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Synthesis of uranyl(II), vanadyl(II) and zirconyl urate complexes,
           spectral, thermal and biological studies
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Samy M. El-Megharbel , Nashwa M. El-Metwaly , Moamen S. Refat
      Three urate chelations were obtained when uric acid was reacted with UO2(CH3COO)2H2O, VOSO4·XH2O and ZrOCl2·XH2O salts with neutralized with 0.1M NaOH aqueous media. The 1:2 metal-to-ligand complexes [(UO2)2(C5H2N4O3)2](H2O), [(ZrO)2(H2O)2(C5H2N4O3)2] and [VO((C5H3N4O3)2] were characterized by elemental analyses, molar conductivity, (infrared, Raman and UV–vis) spectra, effective magnetic moment in Bohr magnetons, and thermal analysis (TG/DTG). The urate ligand coordinates as mononegative bidentate donor towards the mononuclear central vanadium atom and coordinated as binegative tetradentate mode towards the binuclear dioxouranium and zirconyl centers. The antibacterial activity of the metal complexes were tested against some kind of bacteria and fungi strains and compared with uric acid. The ligand, ZrO(II) and UO2(II) complex showed a week potential degradation on calf thymus DNA, whereas VO(II) complex slightly degraded the DNA.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Conformational state of β-hydroxynaphthylamides: Barriers for the
           rotation of the amide group around CN bond and dynamics of the morpholine
           ring
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Tomasz Kozlecki , Peter M. Tolstoy , Agnieszka Kwocz , Mikhail A. Vovk , Andrzej Kochel , Izabela Polowczyk , Peter Yu. Tretyakov , Aleksander Filarowski
      Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analyzed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of 1H and 13C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair–chair ‘ring flip’ in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Experimental and theoretical investigation on the molecular structure,
           spectroscopic and electric properties of 2,4-dinitrodiphenylamine,
           2-nitro-4-(trifluoromethyl)aniline and 4-bromo-2-nitroaniline
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Javier Hernández-Paredes , Ofelia Hernández-Negrete , Roberto C. Carrillo-Torres , Raúl Sánchez-Zeferino , Alberto Duarte-Moller , Mario E. Alvarez-Ramos
      2,4-Dinitrodiphenylamine (I), 2-nitro-4-(trifluoromethyl)aniline (II) and 4-bromo-2-nitroaniline (III) have been investigated by DFT and experimental FTIR, Raman and UV–Vis spectroscopies. The gas-phase molecular geometries were consistent with similar compounds already reported in the literature. From the vibrational analysis, the main functional groups were identified and their absorption bands were assigned. Some differences were found between the calculated and the experimental UV–Vis spectra. These differences were analyzed and explained in terms of the TD-DFT/B3LYP limitations, which were mainly attributed to charge-transfer (CT) effects. These findings were in agreement with previous works, which reported that TD-DFT/B3LYP calculations diverge from experimental results when the electronic transitions involve CT. Despite this, TD-DFT/B3LYP calculations provided satisfactory results and a detailed description of the electronic transitions involved in the absorption bands of the UV–Vis spectra. In terms of the NLO properties, it was found that compound (I) is a good candidate for NLO applications and deserves further study due to its good β values. However, the β values for compounds (II) and (III) were negatively affected compared to those found on o-nitroaniline.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Photophysical properties of zinc phthalocyanine–uridine single
           walled carbon nanotube – conjugates
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Racheal O. Ogbodu , Edith K. Amuhaya , Philani Mashazi , Tebello Nyokong
      The photophysical properties of the conjugate of uridine and zinc mono carboxy phenoxy phthalocyanine (ZnMCPPc–uridine, 4) are reported in this work. The conjugate was also adsorbed onto single walled carbon nanotubes (ZnMCPPc–uridine–SWCNT, 5). The X-ray photoelectron spectroscopy of 4 showed three N 1s peaks while that of 5 showed four N 1s peak, a new peak at 399.4eV of 5 was assigned to pyrrolidonic nitrogen, due to the interaction of the pyrrolic nitrogen of 4 with the oxygen moiety of SWCNT–COOH in 5. The triplet lifetime, triplet and singlet oxygen quantum yields of the zinc mono carboxy phenoxy phthalocyanine increased by over 40% in the presence of uridine. SWCNTs resulted in only a small quenching of the triplet state parameters of 4.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation on
           1-phenyl-2-nitropropene by quantum computational calculations
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): S. Xavier , S. Periandy
      In this paper, the spectral analysis of 1-phenyl-2-nitropropene is carried out using the FTIR, FT Raman, FT NMR and UV–Vis spectra of the compound with the help of quantum mechanical computations using ab-initio and density functional theories. The FT-IR (4000–400cm−1) and FT-Raman (4000–100cm−1) spectra were recorded in solid phase, the 1H and 13C NMR spectra were recorded in CDCl3 solution phase and the UV–Vis (200–800nm) spectrum was recorded in ethanol solution phase. The different conformers of the compound and their minimum energies are studied using B3LYP functional with 6-311+G(d,p) basis set and two stable conformers with lowest energy were identified and the same was used for further computations. The computed wavenumbers from different methods are scaled so as to agree with the experimental values and the scaling factors are reported. All the modes of vibrations are assigned and the structure the molecule is analyzed in terms of parameters like bond length, bond angle and dihedral angle predicted by both B3LYP and B3PW91 methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets. The values of dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the molecule are reported, using which the non-linear property of the molecule is discussed. The HOMO–LUMO mappings are reported which reveals the different charge transfer possibilities within the molecule. The isotropic chemical shifts predicted for 1H and 13C atoms using gauge invariant atomic orbital (GIAO) theory show good agreement with experimental shifts. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. The local reactivity of the molecule has been studied using the Fukui function. The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated.
      Graphical abstract image Highlights 1-Phenyl-2-nitropropene is one of the important intermediate preparation of amphetamine, which is widely used as cognitive enhancer drug of the central nervous system. It exhibits the property of the dipole moment and hyperpolarizability three times higher than the NLO property of the urea. There are larger charge distribution and flow of charge from electrophile to nucleophile in the molecule.

      PubDate: 2015-05-20T14:33:13Z
       
  • A novel flavone-based fluorescent probe for relay recognition of
           HSO3− and Al3+
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Shuai Xu , Ruiren Tang , Zhen Wang , Yin Zhou , Rui Yan
      In this work, a new flavone-based fluorescent probe 3-hydroxy-3′-formylflavone (3HFF) was designed to achieve highly selective relay recognition of HSO3 − and Al3+ in DMSO–H2O (2:8, v/v) solution. 3HFF displayed a highly selective response to HSO3 − with a green fluorescence appearing at 524nm. Moreover, the in situ generated 3HFF+HSO3 − system demonstrated eminent relay recognition capability for Al3+ with a blue fluorescence appearing at 453nm by the formation of a 1:1 complex between 3HFF and Al3+ in DMSO–H2O (2:8, v/v) solution. However, only slight change was observed in emission intensity with addition of Al3+ to 3HFF, and indicated HSO3 − was essential for the sensing of Al3+. This work achieves the detection of HSO3 − and Al3+ by only one probe and provides another example for this rare combination (anion/metal).
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Simultaneous determination of binary mixture of amlodipine besylate and
           atenolol based on dual wavelengths
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Nesrine T. Lamie
      Four, accurate, precise, and sensitive spectrophotometric methods are developed for simultaneous determination of a binary mixture of amlodipine besylate (AM) and atenolol (AT). AM is determined at its λ max 360nm (0D), while atenolol can be determined by four different methods. Method (A) is absorption factor (AF). Method (B) is the new ratio difference method (RD) which measures the difference in amplitudes between 210 and 226nm. Method (C) is novel constant center spectrophotometric method (CC). Method (D) is mean centering of the ratio spectra (MCR) at 284nm. The methods are tested by analyzing synthetic mixtures of the cited drugs and they are applied to their commercial pharmaceutical preparation. The validity of results is assessed by applying standard addition technique. The results obtained are found to agree statistically with those obtained by official methods, showing no significant difference with respect to accuracy and precision.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Surface enhanced Raman scattering of new acridine based fluorophore
           adsorbed on silver electrode
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Elena V. Solovyeva , Liubov A. Myund , Anna S. Denisova
      4,5-Bis(N,N-di(2-hydroxyethyl)iminomethyl)acridine (BHIA) is a new acridine based fluoroionophore and a highly-selective sensor for cadmium ion. The direct interaction of the aromatic nitrogen atom with a surface is impossible since there are bulky substituents in the 4,5-positions of the acridine fragment. Nevertheless BHIA molecule shows a reliable SERS spectrum while adsorbed on a silver electrode. The analysis of SERS spectra pH dependence reveals that BHIA species adsorbed on a surface can exist in both non-protonated and protonated forms. The adsorption of BHIA from alkaline solution is accompanied by carbonaceous species formation at the surface. The intensity of such “carbon bands” turned out to be related with the supporting electrolyte (KCl) concentration. Upon lowering the electrode potential the SERS spectra of BHIA do not undergo changes but the intensity of bands decreases. This indicates that the adsorption mechanism on the silver surface is realized via aromatic system of acridine fragment. In case of such an adsorption mechanism the chelate fragment of the BHIA molecule is capable of interaction with the solution components. Addition of Cd2+ ions to a system containing BHIA adsorbed on a silver electrode in equilibrium with the solution leads to the formation of BHIA/Cd2+ complex which desorption causes the loss of SERS signal.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Structural, thermal and optical properties of KTi0.92La0.08OPO4 and
           KTi0.94Nd0.06OPO4
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): S. Sadhasivam , Rajesh Narayana Perumal , P. Ramasamy
      KTi0.92La0.08OPO4 (KTP:La) and KTi0.94Nd0.06OPO4 (KTP:Nd) single crystals are grown using high temperature top seeded flux growth technique. The strain derived from doping is calculated from Williamson–Hall relation. The packing structure and lattice parameter of the grown crystals are analyzed using single crystal X-ray diffraction. The bonding, distortion and change in inter-atomic distances by strain effects of doping are assessed by Raman spectroscopy. Thermal stabilities of grown crystals are evaluated by specific heat capacity measurement. Pronounced high specific heat capacity is recorded as 1.16J/gK at 498K for KTP:Nd. Second harmonic generation intensities are measured for KTP:Nd and KTP:La single crystal.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Spectrophotometric determination of nitrite in soil and water using
           cefixime and central composite design
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Masoud Shariati-Rad , Mohsen Irandoust , Shabnam Mohammadi
      The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360nm which Beer’s Law is obeyed over the concentration range 0.02–15.00mgL−1 of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3×10−3 mgL−1 was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1×103 (Lmol−1 cm−1) and lower than 10%, respectively.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Raman and infrared spectroscopic study of turquoise minerals
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Jiří Čejka , Jiří Sejkora , Ivo Macek , Radana Malíková , Lina Wang , Ricardo Scholz , Yunfei Xi , Ray L. Frost
      Raman and infrared spectra of three well-defined turquoise samples, CuAl6(PO4)4(OH)8·4H2O, from Lavender Pit, Bisbee, Cochise county, Arizona; Kouroudaiko mine, Faleme river, Senegal and Lynch Station, Virginia were studied, interpreted and compared. Observed Raman and infrared bands were assigned to the stretching and bending vibrations of phosphate tetrahedra, water molecules and hydroxyl ions. Approximate O–H⋯O hydrogen bond lengths were inferred from the Raman and infrared spectra. No Raman and infrared bands attributable to the stretching and bending vibrations of (PO3OH)2− units were observed.
      Graphical abstract image Highlights

      PubDate: 2015-05-20T14:33:13Z
       
  • Effective intercalation of sodium dodecylsulfate (SDS) into hydrocalumite:
           Mechanism discussion via near-infrared and mid-infrared investigations
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Ping Zhang , Tianqi Wang , Guangren Qian , Daishe Wu , Ray L. Frost
      The intercalation of an anionic surfactant, sodium dodecylsulfate (SDS), into hydrocalumite (CaAl-LDH-Cl) was investigated in this study. To understand the intercalation behavior, X-ray diffraction (XRD), mid-infrared spectroscopy (MIR), near-infrared spectroscopy (NIR) and scanning electron microscopy (SEM) were undertaken. The near-infrared spectra indicated a special spectral range from 6000 to 5600cm−1and prominent bands of CaAl-LDH-Cl intercalated with SDS around 8388cm−1. This band was assigned to the second overtone of the first fundamental of CH stretching vibrations of SDS, and it could be used to determinate the result of CaAl-LDH-Cl modified by SDS. Moreover, the results revealed that different adsorption behaviors were observed at different (high and low) concentrations of SDS. When the SDS concentration was around 0.2molL−1, anion exchange intercalation occurred and the interlayer distance expanded to about 3.25nm. When SDS concentration was 0.005molL−1, the surface adsorption of DS− was the major anion exchange event.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Impact of the different electron-releasing subunits on the dye-sensitized
           solar cell performance of new triphenylamine–benzimidazole based
           molecules
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Haluk Dinçalp , Gözde Murat Saltan , Deniz Aykut , Ceylan Zafer
      New triphenylamine–benzimidazole type small molecules with different electron-releasing groups were designed and synthesized to investigate their photovoltaic performances in dye sensitized solar cells (DSSCs). Their good visible absorptions covering the 400–535nm in addition to suitable lowest unoccupied molecular orbital (LUMO) energy levels between −3.03 and −3.11eV make good candidates them for DSSC devices. Fluorescence quenching studies of the dyes with pristine titania support the good electron injection to conduction band of TiO2. Time resolved measurements of the dyes in solutions indicate the occurence of charge generation during the excited state. One of the used dyes in DSSC devices, TPA5a, carrying a methoxy group in triphenylamine part of the structure, gave much higher power conversion efficiency (PCE) value of 4.31% as compared to the other derivatives. Device fabricated from TPA5a dye gives good external quantum efficiency (EQE) value above 70% at 460nm. Also, electron impedance spectroscopy (EIS) analysis of the devices gives a good explanation of the understanding of the cell performances.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Study on DNA binding behavior and light switch effect of new
           coumarin-derived Ru(II) complexes
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Xue-Wen Liu , You-Ming Shen , Zhi-Xin Li , Xiao Zhong , Yuan-Dao Chen , Song-Bai Zhang
      A new ligand mhcip (mhcip=2-(4-methyl-7-hydroxyl-8-coumarinyl)imidazo[4,5-f]-[1,10]phenanthroline) and its ruthenium complexes, [Ru(L)2mhcip]2+ (L=bpy (2,2′-bipyridine), phen (1,10-phenanthroline)), have been synthesized and characterized. The introduction of coumarin ring may play an important role in the strong fluorescence of the complexes. Intercalative binding mode between both complexes and CT-DNA was determined by UV–visible spectroscopy, fluorescence spectroscopy and viscosity measurements. The two complexes show efficient DNA photocleavage under irradiation at 365nm. The cycling of light switch off and on has been achieved for both complexes through the introduction of Cu2+ and EDTA in the absence or presence of DNA.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Molecular structure, spectroscopic characterization of
           (S)-2-Oxopyrrolidin-1-yl Butanamide and ab initio, DFT based quantum
           chemical calculations
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): T. Ramya , S. Gunasekaran , G.R. Ramkumaar
      The experimental and theoretical spectra of (S)-2-Oxopyrrolidin-1-yl Butanamide (S2OPB) were studied. FT-IR and FT-Raman spectra of S2OPB in the solid phase were recorded and analyzed in the range 4000–450 and 5000–50cm−1 respectively. The structural and spectroscopic analyses of S2OPB were calculated using ab initio Hartree Fock (HF) and density functional theory calculations (B3PW91, B3LYP) with 6-31G(d,p) basis set. A complete vibrational interpretation has been made on the basis of the calculated Potential Energy Distribution (PED). The HF, B3LYP and B3PW91 methods based NMR calculation has been used to assign the 1H NMR and 13C NMR chemical shift of S2OPB. Comparative study on UV–Vis spectral analysis between the experimental and theoretical (B3PW91, B3LYP) methods and the global chemical parameters and local descriptor of reactivity through the Fukui function were performed. Finally the thermodynamic properties of S2OPB were calculated at different temperatures and the corresponding relations between the properties and temperature were also studied.
      Graphical abstract image Highlights

      PubDate: 2015-05-20T14:33:13Z
       
  • Investigation of Fluorescence Resonance Energy Transfer between
           Fluorescein and Rhodamine 6G
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Jaba Saha , Arpan Datta Roy , Dibyendu Dey , Santanu Chakraborty , D. Bhattacharjee , P.K. Paul , Syed Arshad Hussain
      Fluorescence Resonance Energy Transfer between two organic dyes Fluorescein and Rhodamine 6G was investigated in aqueous solution in presence and absence of synthetic clay laponite. Spectroscopic studies suggest that both the dyes were present mainly as monomer in solution. Fluorescence Resonance Energy Transfer occurred from Fluorescein to Rhodamine 6G in solutions. Energy transfer efficiency increases in presence of laponite and the maximum efficiency was 72.00% in aqueous laponite dispersion. Energy transfer efficiency was found to be pH sensitive. It has been demonstrated that with proper calibration it is possible to use the present system under investigation to sense pH over a wide range from 1.5 to 8.0.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Influence of homo buffer layer thickness on the quality of ZnO epilayers
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): E.A. Eid , A.N. Fouda
      ZnO buffer layers with different thicknesses were deposited on a-plane sapphire substrates at 300°C. ZnO epilayers were grown on ZnO buffers at 600°C by radio-frequency magnetron sputtering and vacuum annealed at 900°C for an hour. Influence of nucleation layer thickness on the structural and quality of ZnO thin films was investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and Raman spectroscopy. The best ZnO film quality was obtained with the ZnO buffer layer of 45nm thick which provided the smoothest surface with RMS value of 0.3nm. X-ray diffraction measurements reveal that the films have a single phase wurtzite structure with (0001) preferred crystal orientation. As evident from narrow FWHM of ZnO (0002) rocking curve, ZnO buffer can serve as a good template for the growth of high-quality ZnO films with little tilt. In addition, the micro-Raman scattering measurements at room temperature revealed the existence of Raman active phonon modes of ZnO; A1(TO), A1(LO) and E2(high). The latter two modes were not observed in thin buffer layer beside the dis-appearance of E2(low) mode in all films.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Virgin silver nanoparticles as colorimetric nanoprobe for simultaneous
           detection of iodide and bromide ion in aqueous medium
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Shilpa Bothra , Rajender Kumar , Ranjan K. Pati , Anil Kuwar , Heung-Jin Choi , Suban K. Sahoo
      A simple colorimetric nanoprobe based on virgin silver nanoparticles (AgNPs) was developed for the selective detection of iodide and bromide ions via aggregation and anti-aggregation mechanism. With addition of I− ions, virgin AgNPs, in presence of Fe3+, showed perceptible color change from yellow to colorless along with disappearance of surface plasmon resonance (SPR) band of AgNPs at 400nm. But in presence of Cr3+, AgNPs turned yellow upon addition of I−and Br− anions. The developed virgin AgNPs probe showed high specificity and selectivity with the detection limits down to 0.32μM and 1.32μM for I− ions via two different mechanistic routes. Also, the designed probe detects Br− with a detection limit down to 1.67μM.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Study on the interaction between Besifloxacin and bovine serum albumin by
           spectroscopic techniques
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Xianyong Yu , Bingfei Jiang , Zhixi Liao , Yue Jiao , Pinggui Yi
      The interaction between Besifloxacin (BFLX) and bovine serum albumin (BSA) was investigated by spectroscopic (fluorescence, UV–Vis absorption and circular dichroism) techniques under imitated physiological conditions. The experiments were conducted at different temperatures (298, 304 and 310K) and the results showed that the BFLX caused the fluorescence quenching of BSA through a static quenching procedure. The binding constant (K a), binding sites (n) were obtained. The corresponding thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated at different temperatures. The results revealed that the binding process was spontaneous and the acting force between BFLX and BSA were mainly electrostatic forces. According to Förster non-radiation energy transfer theory, the binding distance between BFLX and BSA was calculated to be 4.96nm. What is more, both synchronous fluorescence and circular dichroism spectra confirmed conformational changes of BSA.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Tuning zinc(II) coordination architectures by rigid long bis(triazole) and
           
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Xiao-xiao Wang , Zuo-xi Li , Baoyi Yu , Kristof Van Hecke , Guang-hua Cui
      Three metal–organic coordination polymers containing rigid bis(triazole) ligand, namely, [Zn1.5(btb)(nbta)(H2O)] n (1), {[Zn(btb)(3-nph)]·(H2O)} n (2) and [Zn(btb)(4-nph)] n (3) (btb=4,4′-bis(1,2,4-triazolyl-1-yl)-biphenyl, 3-H2nph=3-nitrophthalic acid, H3nbta=5-nitro-1,2,3-benzenetricarboxylic acid, and 4-H2nph=4-nitrophthalic acid) were synthesized under hydrothermal conditions and structurally characterized by X-ray single-crystal diffraction. Complex 1 possesses an interesting 3D coordination framework with a rarely binodal (4,4)-connected frl topological structure. Complexes 2 and 3 exhibit similiar 2D (4,4) grid layers with different point symbol (44 ·64) in 2 and (44 ·62) in 3. Furthermore, thermal stability of these compounds has been discussed. Complexes 1–3 exhibit strong solid-state fluorescence at room temperature in solid state.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Visual detection of trace copper ions based on copper-catalyzed reaction
           of ascorbic acid with oxygen
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Xin Yan Hou , Shu Chen , Lian Ju Shun , Yi Ni Zhao , Zhi Wu Zhang , Yun Fei Long , Li Zhu
      A visual detection method for trace Cu2+ in aqueous solutions using triangular silver nanoplates (abbreviated as TAgNPs) as the probe was developed. The method is based on that TAgNPs could be corroded in sodium thiosulfate (Na2S2O3) solutions. The absorption spectrum of TAgNPs solution changed when it is corroded by Na2S2O3. The reaction of oxygen with ascorbic acid (Vc) in the presence of a low concentration of Cu2+ generates hydrogen peroxide that reacts with Na2S2O3, which leads the concentration of Na2S2O3 in the solution to be decreased. Therefore, the reaction between TAgNPs and the reacted mixture of Na2S2O3/Vc/Cu2+ was prevented efficiently. When the Na2S2O3 concentration and reaction time are constant, the decrease in the concentration of Na2S2O3 is directly proportional to the Cu2+ concentration. Thus, morphology, color, and maximum absorption wavelength of TAgNPs changed with the change of Cu2+ concentration. The changed maximum absorption wavelength of TAgNPs (Δλ) is proportional to Cu2+ concentration in the range from 7.5×10−9 to 5.0×10−7 M with a correlation coefficient of r =0.9956. Moreover, color change of TAgNP solution was observed clearly over a Cu2+ concentration range from 7.5×10−8 to 5.0×10−7 M. This method has been used to detect the Cu2+ content of a human hair sample, and the result is in agreement with that obtained by the atomic absorption spectroscopy (AAS) method.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • A new chalcone structure of
           (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one: Synthesis,
           structural characterizations, quantum chemical investigations and
           biological evaluations
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Kaliyaperumal Thanigaimani , Suhana Arshad , Nuridayanti Che Khalib , Ibrahim Abdul Razak , C. Arunagiri , A. Subashini , Shaida Fariza Sulaiman , Nurul Shafiqah Hashim , Kheng Leong Ooi
      The structure of (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one (C19H13BrO) crystallized in the triclinic system of P-1 space group. The unit cell dimensions are: a =5.8944 (9)Å, b =7.8190 (12)Å, c =16.320 (2)Å, α =102.4364 (19)°, β =95.943 (2)°, γ =96.274 (2)° and Z =2. The physical properties of this compound was determined by the spectroscopic methods (FTIR and 1H and 13C NMR). Quantum chemical investigations have been employed to investigate the structural and spectral properties. The molecular structure, vibrational assignments, 1H and 13C NMR chemical shift values, non-linear optical (NLO) effect, HOMO–LUMO analysis and natural bonding orbital (NBO) analysis were calculated using HF and DFT/B3LYP methods with 6-311++G(d,p) basis set in the ground state. The results show that the theoretical calculation of the geometrical parameters, vibrational frequencies and chemical shifts are comparable with the experimental data. The crystal structure is influenced and stabilized by weak C–H⋯π interactions connecting the molecules into infinite supramolecular one dimensional ladder-like arrangement. Additionally, this compound is evaluated for their antibacterial activities against gram positive and gram negative strains using a micro dilution procedure and shows activities against a panel of microorganisms.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Solvent-dependent “turn-on” fluorescence chemosensor for Mg2+
           based on combination of CN isomerization and inhibition of ESIPT
           mechanisms
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Zhaodi Liu , Huajie Xu , Shuisheng Chen , Liangquan Sheng , Hong Zhang , Fuying Hao , Pengfei Su , Wenlong Wang
      A fluorescent chemosensor (L) for Mg2+ has been synthesized and characterized, which exhibits turn-on fluorescence response for Mg2+ only in alcohol solvent (methanol or ethanol) with high sensitivity and selectivity. But in both nonpolar and polar solvents (cyclohexane, DCM, DMSO or MeCN), L showed negligible fluorescent response for Mg2+. In order to discover the unique phenomenon, optical measurements, liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) and a high performance liquid chromatography with a fluorescence detector (HPLC–FLD) of L and L with Mg2+ ions in solvents were studied. In alcohol solvent, [L+alcohol molecule] was formed and the mechanism aspect of L concerning the remarkable fluorescence response for Mg2+ has been discussed.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Charge-transfer complexes of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone
           with amino molecules in polar solvents
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Silvia Berto , Enrico Chiavazza , Valentina Ribotta , Pier Giuseppe Daniele , Claudia Barolo , Agnese Giacomino , Davide Vione , Mery Malandrino
      The charge-transfer complexes have scientific relevance because this type of molecular interaction is at the basis of the activity of pharmacological compounds and because the absorption bands of the complexes can be used for the quantification of electron donor molecules. This work aims to assess the stability of the charge-transfer complexes between the electron acceptor 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and two drugs, procaine and atenolol, in acetonitrile and ethanol. The stability of DDQ in solution and the time required to obtain the maximum complex formation were evaluated. The stoichiometry and the stability of the complexes were determined, respectively, by Job’s plot method and by the elaboration of UV–vis titrations data. The latter task was carried out by using the non-linear global analysis approach to determine the equilibrium constants. This approach to data elaboration allowed us to overcome the disadvantages of the classical linear-regression method, to obtain reliable values of the association constants and to calculate the entire spectra of the complexes. NMR spectra were recorded to identify the portion of the donor molecule that was involved in the interaction. The data support the participation of the aliphatic amino groups in complex formation and exclude the involvement of the aromatic amine present in the procaine molecule.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • A direct method of quantification of maximal chemisorption of
           3-aminopropylsilyl groups on silica gel using DRIFT spectroscopy
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Miha Bukleski , Vladimir Ivanovski , Evamarie Hey-Hawkins
      3-Aminopropylsilyl (APS) modified silica gel plays an important role as a precursor for further modifications, where APS acts as a spacer or bridging molecule. A monolayer of APS which is most suitable for this purpose was obtained in anhydrous conditions. The properties of the APS-modified silica gel depend on the amount of molecules chemisorbed on the surface. A direct quantitative method using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy was proposed. The obtained results were further supported by elemental analysis. The conclusion was that the proposed methodology can be used for the quantification of APS groups chemisorbed on silica gel when the grafting chemical reaction was mainly irreversible.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Ultrafast imaging of electronic relaxation in n-propylbenzene: Direct
           observation of intermediate state
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Yuzhu Liu , Thomas Gerber , Peter Radi , Gregor Knopp
      The ultrafast dynamics of the second singlet electronically excited state (S 2) in n-propylbenzene has been investigated by femtosecond time-resolved photoelectron imaging coupled with photofragmentation spectroscopy. The intermediate state for the deactivation of the S 2 state is observed by transient photoelectron kinetic energy distributions and photoelectron angular distributions. An ultrafast electronic relaxation process on timescale of the fitted ∼50fs was observed in the S 2 state by time-resolved photoelectron imaging and it is attributed to the S 1 ← S 2 internal conversion (IC). The time constant of 1.23 (±0.2)ps is determined for the further deactivation of the intermediate S 1 state.
      Graphical abstract image Highlights

      PubDate: 2015-05-20T14:33:13Z
       
  • Spectroscopic and statistical approach of archaeological artifacts
           recently excavated from Tamilnadu, South India
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): D. Seetha , G. Velraj
      The ancient materials characterization will bring back the more evidence of the ancient people life styles. In this study, the archaeological pottery shards recently excavated from Kodumanal, Erode District in Tamilnadu, South India were investigated. The experimental results enlighten us to the elemental and the mineral composition of the pottery shards. The FT-IR technique tells that the mineralogy and the firing temperature of the samples are less than 800°C, in the oxidizing/reducing atmosphere and the XRD was used as a complementary technique for the mineralogy. A thorough scientific study of SEM–EDS with the help of statistical approach done to find the provenance of the selected pot shards has not yet been performed. EDS and XRF results revealed that the investigated samples have the elements O, Si, Al, Fe, Mn, Mg, Ca, Ti, K and Na are in different compositions. For establishing the provenance (same or different origin) of pottery samples, Al and Si concentration ratio as well as hierarchical cluster analysis (HCA) was used and the results are correlated.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Pure white OLED based on an organic small molecule:
           2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Jian Liu
      2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine (DBIP) was synthesized. The single-crystal structure of DBIP was resolved. DBIP-based OLED was fabricated. The electroluminescence for the device corresponds to a pure white emission. In addition, thermal stability, UV–vis, photoluminescence and electrochemical behaviors of DBIP were investigated as well.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Surface-enhanced Raman scattering (SERS) study of anthocyanidins
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Chiara Zaffino , Bianca Russo , Silvia Bruni
      Anthocyanins are an important class of natural compounds responsible for the red, purple and blue colors in a large number of flowers, fruits and cereal grains. They are polyhydroxy- and polymethoxy-derivatives of 2-phenylbenzopyrylium (flavylium) salts, which are present in nature as glycosylated molecules. The aim of the present study is to assess the identification of anthocyanidins, i.e. anthocyanins without the glycosidic moiety, by means of surface-enhanced Raman spectroscopy (SERS), a very chemically-specific technique which is moreover sensitive to subtle changes in molecular structures. These features can lead to elect SERS, among the spectroscopic tools currently at disposal of scientists, as a technique of choice for the identification of anthocyanidins, since: (1) anthocyanidins structurally present the same benzopyrylium moiety and differentiate only for the substitution pattern on their phenyl ring, (2) different species are present in aqueous solution depending on the pH. It will be demonstrated that, while resonance Raman spectra of anthocyanidins are very similar to one another, SER spectra show greater differences, leading to a further step in the identification of such important compounds in diluted solutions by means of vibrational spectroscopy. Moreover, the dependence on the pH of the six most common anthocyanidins, i.e. cyanidin, delphinidin, pelargonidin, peonidin, malvidin and petunidin, is studied. To the best of the authors’ knowledge, a complete SERS study of such important molecules is reported in the present work for the first time.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
  • Validation of four different spectrophotometric methods for simultaneous
           determination of Domperidone and Ranitidine in bulk and pharmaceutical
           formulation
    • Abstract: Publication date: 5 October 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 149
      Author(s): Maha F. Abdel-Ghany , Omar Abdel-Aziz , Yomna Y. Mohammed
      Four simple, specific, accurate and precise spectrophotometric methods were developed and validated for simultaneous determination of Domperidone (DP) and Ranitidine Hydrochloride (RT) in bulk powder and pharmaceutical formulation. The first method was simultaneous ratio subtraction (SRS), the second was ratio subtraction (RS) coupled with zero order spectrophotometry (D0), the third was first derivative of the ratio spectra (1DD) and the fourth method was mean centering of ratio spectra (MCR). The calibration curve is linear over the concentration range of 0.5–5 and 1–45μgmL−1 for DP and RT, respectively. The proposed spectrophotometric methods can analyze both drugs without any prior separation steps. The selectivity of the adopted methods was tested by analyzing synthetic mixtures of the investigated drugs, also in their pharmaceutical formulation. The suggested methods were validated according to International Conference of Harmonization (ICH) guidelines and the results revealed that; they were precise and reproducible. All the obtained results were statistically compared with those of the reported method, where there was no significant difference.
      Graphical abstract image

      PubDate: 2015-05-20T14:33:13Z
       
 
 
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