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  Subjects -> CHEMISTRY (Total: 792 journals)
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CHEMISTRY (552 journals)            First | 1 2 3 4 5 6 | Last

Journal of Chromatography Library     Full-text available via subscription   (Followers: 5)
Journal of Colloid and Interface Science     Hybrid Journal   (Followers: 12)
Journal of Computational Chemistry     Hybrid Journal   (Followers: 13)
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: 3)
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: 2)
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: 20)
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: 4)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 189)
Journal of Membrane Science     Hybrid Journal   (Followers: 10)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 2)
Journal of Molecular Graphics and Modelling     Hybrid Journal   (Followers: 4)
Journal of Molecular Liquids     Hybrid Journal   (Followers: 3)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 3)
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: 5)
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: 2)
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: 4)
Journal of Polymer & Composites     Full-text available via subscription  
Journal of Polymer and Biopolymer Physics Chemistry     Open Access  
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 180)
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: 10)
Journal of Saudi Chemical Society     Open Access  
Journal of Solid State Chemistry     Hybrid Journal   (Followers: 14)
Journal of Solution Chemistry     Hybrid Journal  
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: 278)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 17)
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: 7)
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)
Kinetics and Catalysis     Hybrid Journal   (Followers: 3)
Korea-Australia Rheology Journal     Hybrid Journal  
Langmuir     Full-text available via subscription   (Followers: 36)
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: 4)
Macromolecular Rapid Communications     Hybrid Journal   (Followers: 4)
Macromolecular Research     Hybrid Journal  
Macromolecular Symposia     Hybrid Journal  
Macromolecular Theory and Simulations     Hybrid Journal  
Macromolecules     Full-text available via subscription   (Followers: 31)
Magnetic Resonance in Chemistry     Hybrid Journal   (Followers: 4)
Main Group Chemistry     Hybrid Journal  
Marine Chemistry     Hybrid Journal   (Followers: 4)
Marine Drugs     Open Access   (Followers: 4)
MATEC Web of Conferences     Open Access  
Materials Characterization     Hybrid Journal   (Followers: 23)
Materials Horizons     Full-text available via subscription  
Materials Research Bulletin     Hybrid Journal   (Followers: 17)
Materials Science Monographs     Full-text available via subscription   (Followers: 1)
Materials Science-Poland     Hybrid Journal  
Materials Sciences and Applications     Open Access   (Followers: 4)
MedChemComm     Full-text available via subscription   (Followers: 4)
Medicinal Chemistry Research     Hybrid Journal   (Followers: 10)

  First | 1 2 3 4 5 6 | Last

Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
   [10 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1386-1425
     Published by Elsevier Homepage  [2571 journals]   [SJR: 0.567]   [H-I: 58]
  • Green synthesis and applications of Au–Ag bimetallic nanoparticles
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): M. Meena Kumari , John Jacob , Daizy Philip
      This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core–shell nanostructures. The nanoparticles have been characterized using UV–vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k 4-nitrophenol < k 2-nitrophenol < k 3-nitrophenol. Thermal conductivity is measured as a function of volume fraction and it is observed that the incorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Novel porphyrin–daunomycin hybrids: Synthesis and preferential
           binding to G-quadruplexes over i-motif
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Ping Zhao , Shu-fang Jin , Jia-Zheng Lu , Jun-liang Lv , Gong-qing Wu , Pan-Pan Chen , Cai-Lian Tan , Dian-Wen Chen
      Encouraged by the enormous importance attributed to the structure and function of human telomeric DNA, herein we focused our attention on the interaction of a serious of newly prepared porphyrin–daunomycin (Por–DNR) hybrids with the guanine-rich single-strand oligomer (G4) and the complementary cytosine-rich strand (i-motif). Various spectral methods such as absorption and fluorescence titration, surface-enhanced Raman and circular dichroism spectrum were integrated in the experiment and it was found that these Por–DNR hybrids could serve as prominent molecules to recognize G4 and i-motif. What is more, interesting results were obtained that the hybrids with longer flexible links are more favorable in binding with both G4 and i-motif than the hybrid with shorter linkage. These Por–DNR hybrids may help to develop new ideas in the research of human telomeric DNA with small molecules.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Spectroscopic and molecular structure investigation of the
           phosphorus-containing G′2 dendrimer with terminal aldehyde groups
           using DFT method
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): V.L. Furer , A.E. Vandyukov , J.P. Majoral , A.M. Caminade , V.I. Kovalenko
      The FTIR and FT Raman spectra of the second generation dendrimer G′2 built from thiophosphoryl core with terminal aldehyde groups have been recorded. The structural optimization and normal mode analysis were performed for model compound C, consisting of thiophosphoryl core, one branch with three repeated units, and four 4-oxybenzaldehyde terminal groups on the basis of the density functional theory (DFT) at the PBE/TZ2P level. The vibrational frequencies, infrared and Raman intensities for the t,g,g- and t,-g,g-conformers of the terminal groups were calculated. The t,g,g-conformer is 2.0kcal/mol less stable compared to t,-g,g-conformer. A reliable assignment of the fundamental bands observed in the experimental IR and Raman spectra of dendrimer was achieved. For the low generations (G′1 to G′3) the disk form of studied dendrimer molecules is the most probable. For higher generations, the shape of dendrimer molecules will be that of a cauliflower.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Synthesis, characterization and in vitro antimicrobial studies of Co(II),
           
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): O.A. El-Gammal , M.M. Bekheit , S.A. El-Brashy
      New Co(II), Ni(II) and Cu(II) complexes derived from tetradentate macrocyclic nitrogen ligand, (1E,4E,8E,12E)-5,8,13,16-tetramethyl-1,4,9,12-tetrazacyclohexadeca-4,8,12,16-tetraene (EDHDH) have been synthesized. The complexes have been characterized by elemental analysis, spectral (IR, UV–Vis, 1H NMR and ESR (for Cu(II) complex)) mass, and magnetic as well as thermal analysis measurements. The complexes afforded the formulae: [Cu(EDHDH)Cl2]·2EtOH and [M(EDHDH)X2]·nH2O where M=Co(II) and Ni(II), X=Cl− or OH−, n =1,0, respectively. The data revealed an octahedral arrangement with N4 tetradentate donor sites in addition to two Cl atoms occupying the other two sites. ESR spectrum of Cu2+ complex confirmed the suggested geometry with values of a α2and β2 indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and are consistent with very strong σ-in-plane bonding in the complexes. The molecular modeling is drawn and showed the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all the title compounds using DFT method. Also, the thermal behavior and the kinetic parameters of degradation were determined using Coats–Redfern and Horowitz–Metzger methods. Moreover, the in vitro antibacterial studies of all compounds screened against pathogenic bacteria (two Gram +ve and two Gram −ve) to assess their inhibiting potential. The assay indicated that the inhibition potential is metal ion dependent. The ligand, EDHDH, Co(II) and Cu(II) complexes exhibited a remarkable antibacterial activity against Streptococcus Pyogenes as Gram +ve and Proteus vulgaris as Gram −ve bacterial strains. On the other hand, Ni(II) complex revealed a moderate antibacterial activity against both Gram +ve organisms and no activity against Gram −ve bacterial strain.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • The conformational analysis of 2-halocyclooctanones
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Thiago C. Rozada , Gisele F. Gauze , Fernanda A. Rosa , Denize C. Favaro , Roberto Rittner , Rodrigo M. Pontes , Ernani A. Basso
      The establishment of the most stable structures of eight membered rings is a challenging task to the field of conformational analysis. In this work, a series of 2-halocyclooctanones were synthesized (including fluorine, chlorine, bromine and iodine derivatives) and submitted to conformational studies using a combination of theoretical calculation and infrared spectroscopy. For each compound, four conformations were identified as the most important ones. These conformations are derived from the chair-boat conformation of cyclooctanone. The pseudo-equatorial (with respect to the halogen) conformer is preferred in vacuum and in low polarity solvents for chlorine, bromine and iodine derivatives. For 2-fluorocyclooctanone, the preferred conformation in vacuum is pseudo-axial. In acetonitrile, the pseudo-axial conformer becomes the most stable for the chlorine derivative. According to NBO calculations, the conformational preference is not dictated by electron delocalization, but by classical electrostatic repulsions.
      Graphical abstract image Highlights

      PubDate: 2014-09-18T18:35:00Z
       
  • Spectroscopic (FT-IR, FT-Raman), first order hyperpolarizability, NBO
           analysis, HOMO and LUMO analysis of
           
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): J.B. Bhagyasree , Hema Tresa Varghese , C. Yohannan Panicker , Christian Van Alsenoy , Abdulaziz A. Al-Saadi , Martin Dolezal , Jadu Samuel
      The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-tert-Butyl-6-chloro-N-[(4-(trifluoromethyl)phenyl]pyrazine-2-carboxamide have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. From the NBO analysis it is evident that the increased electron density at the nitrogen, carbon atoms leads to the elongation of respective bond length and a lowering of the corresponding stretching wave number. The calculated geometrical parameters are in agreement with that of similar derivatives. The calculated first hyperpolarizability is high and the calculated data suggest an extended π-electron delocalization over the pyrazine ring and carboxamide moiety which is responsible for the nonlinearity of the molecule.
      Graphical abstract image Highlights

      PubDate: 2014-09-18T18:35:00Z
       
  • Conformational stability, vibrational (FT-IR and FT-Raman) spectra and
           computational analysis of m-trifluoromethyl benzoic acid
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): V. Balachandran , V. Karpagam , G. Santhi , B. Revathi , G. Ilango , M. Kavimani
      In this work, the vibrational characteristics of m-trifluoromethyl benzoic acid have been investigated and both the experimental and theoretical vibrational data indicate the presence of functional groups in the title molecule. The density functional theoretical (DFT) computations were performed at the B3LYP/6-31G (d, p), LSDA/6-31G (d, p), MP2/6-31G (d, p) levels to derive the optimized geometry, vibrational wavenumbers. Furthermore, the molecular orbital calculations such as natural bond orbitals (NBO), HOMO–LUMO energy gap and Mapped molecular electrostatic potential (MEP) surfaces, The Mulliken charges, the first-order hyperpolarizability were also performed with the same level of DFT. The thermal flexibility of molecule in associated with vibrational temperature was also illustrated on the basis of correlation graphs. The detailed interpretation of the vibrational spectra has been carried out with the aid of potential energy distribution (PED) results obtained from MOLVIB program. The delocalization of electron density of various constituents of the molecule has been discussed with the aid of NBO and HOMO–LUMO energy gap analysis.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Green synthesized conditions impacting on the reactivity of Fe NPs for the
           degradation of malachite green
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Lanlan Huang , Fang Luo , Zuliang Chen , Mallavarapu Megharaj , Ravendra Naidu
      This study investigates green tea extract synthesized conditions impacting on the reactivity of iron nanoparticles (Fe NPs) used for the degradation of malachite green (MG), including the volume ratio of Fe2+ and tea extract, the solution pH and temperature. Results indicated that the reactivity of Fe NPs increased with higher temperature, but fell with increasing pH and the volume ratio of Fe2+ and tea extract. Scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), Fourier transform infrared spectroscope (FTIR) and X-ray diffraction (XRD) indicated that Fe NPs were spherical in shape, their diameter was 70–80nm and they were mainly composed of iron oxide nanoparticles. UV–visible (UV–vis) indicated that reactivity of Fe NPs used in degradation of MG significantly depended on the synthesized conditions of Fe NPs. This was due to their impact on the reactivity and morphology of Fe NPs. Finally, degradation of MG showed that 90.56% of MG was removed using Fe NPs.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • The effect of operational parameters on the photocatalytic degradation of
           Congo red organic dye using ZnO–CdS core–shell nano-structure
           coated on glass by Doctor Blade method
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Mohammad Hossein Habibi , Mohammad Hossein Rahmati
      Photocatalytic degradation of Congo red was investigated using ZnO–CdS core–shell nano-structure coated on glass by Doctor Blade method in aqueous solution under irradiation. Field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques were used for the morphological and structural characterization of ZnO–CdS core–shell nanostructures. XRD results showed diffractions of wurtzite zinc oxide core and wurtzite cadmium sulfide shell. FESEM results showed that nanoparticles are nearly hexagonal with an average diameter of about 50nm. The effect of catalyst loading, UV-light irradiation time and solution pH on photocatalytic degradation of Congo red was studied and optimized values were obtained. Results showed that the employment of efficient photocatalyst and selection of optimal operational parameters may lead to complete decolorization of dye solutions. It was found that ZnO–CdS core–shell nano-structure is more favorable for the degradation of Congo red compare to pure ZnO or pure CdS due to lower electron hole recombination. The results showed that the photocatalytic degradation rate of Congo red is enhanced with increasing the content of ZnO up to ZnO(0.2M)/CdS(0.075M) which is reached 88.0% within 100min irradiation.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Photoinduced electron transfer between 2-methylanthraquinone and
           triethylamine in an ionic liquid: Time-resolved EPR and transient
           absorption spectroscopy study
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Guanglai Zhu , Yu Wang , Haiying Fu , Xinsheng Xu , Zhifeng Cui , Xuehan Ji , Guozhong Wu
      Photoinduced electron transfer between 2-methylanthraquinone (MeAQ) and triethylamine (TEA) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), was investigated by comparing the time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy and the transient absorption spectroscopy. The results of TR-EPR spectroscopy, in which MeAQ was 8mmolL−1 and TEA was 150mmolL−1, indicated that the transient radical would exist longer time in [bmim][PF6] than in acetonitrile. At the delay time of 8μs after laser excitation, the TR-EPR signal transformed from an emissive peak into an absorptive peak when the experiment was performed in [bmim][PF6]. The results of the transient absorption spectroscopy, in which MeAQ was 0.1mmolL−1 and TEA was 2.2mmolL−1, showed that the efficiency and the rate of the photoinduced electron transfer reaction in [bmim][PF6] were obviously lower than that in acetonitrile. It was concluded that various factors, such as concentration, viscosity and local structural transformation of the solution, have an influence on the process of photoinduced electron transfer in [bmim][PF6].
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Spectroscopic analyses on interaction of bovine serum albumin with novel
           spiro[cyclopropane-pyrrolizin]
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Xianyong Yu , Zhixi Liao , Bingfei Jiang , Xiaolian Hu , Xiaofang Li
      The interaction between novel spiro[cyclopropane-pyrrolizin] (NSCP) and bovine serum albumin (BSA) was analyzed by fluorescence and ultraviolet–visible (UV–Vis) spectroscopy at 298K, 304K and 310K under simulative physiological conditions. The results showed that NSCP can effectively quench the intrinsic fluorescence of BSA via static quenching. The binding constants, binding sites of NSCP with BSA were calculated. Hydrogen binds and van der Waals force played a major role in stabilizing the complex and the binding reaction were spontaneous. According to the Förster non-radiation energy transfer theory, the average binding distances between NSCP and BSA were obtained. What is more, the synchronous fluorescence spectra indicated that the conformation of BSA has been changed.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Synthesis, characterization and anti-bacterial activities of pure and
           Co-doped BaSO4 nanoparticles via chemical precipitation route
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): S. Sivakumar , P. Soundhirarajan , A. Venkatesan , Chandra Prasad Khatiwada
      In the present study, we reported that the synthesis and characterization of pure and diverse mole Co-doped BaSO4 nanoparticles have been synthesized by chemical precipitation technique. X-ray diffraction analysis (XRD) brought out the information about the synthesized products is orthorhombic structure and highly crystalline in nature. The average grain size of the samples was determined by using the Debye–Scherer’s equation. The existence of functional groups and band area of the samples were confirmed by Fourier transform infrared (FTIR) spectroscopy. The direct and indirect band gap energy of pure and doped samples was carried out using UV–VIS–DRS. The surface micrograph, morphological distribution and elemental compositions of the synthesized products were assessed by scanning electron microscopy (SEM) and Energy dispersive X-ray (EDS). Thermo gravimetric and differential thermal analysis (TG–DTA) techniques were analyzed thermal behaviour of pure and Co-doped samples. Finally, antibacterial activities found the Gram-positive and Gram-negative bacteria are more active in transporter, dehydrogenize and periplasmic enzymatic activities of pure and doped samples.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Synthesis, interaction with DNA and antiproliferative activities of two
           novel Cu(II) complexes with norcantharidin and benzimidazole derivatives
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Wen-Ji Song , Qiu-Yue Lin , Wen-Jiao Jiang , Fang-Yuan Du , Qing-Yuan Qi , Qiong Wei
      Two novel complexes [Cu(L)2(Ac)2]·3H2O (1) (L =N-2-methyl benzimidazole demethylcantharate imide, C16H15N3O3, Ac=acetate, C2H3O2) and [Cu(bimz)2(DCA)] (2) (bimz=benzimidazole, C7H6N2; DCA=demethylcantharate, C8H8O5) were synthesized and characterized by elemental analysis, infrared spectra and X-ray diffraction techniques. Cu(II) ion was four-coordinated in complex 1, Cu(II) ion was five-coordinated in complex 2. A large amount of intermolecular hydrogen-bonding and π–π stacking interactions were observed in these complex structures. The DNA-binding properties of these complexes were investigated using electronic absorption spectra, fluorescence spectra, viscosity measurements and agarose gel electrophoresis. The interactions between the complexes and bovine serum albumin (BSA) were investigated by fluorescence spectra. The antiproliferative activities of the complexes against human hepatoma cells (SMMC7721) were tested in vitro. And the results showed that these complexes could bind to DNA in moderate intensity via partial intercalation, and complexes 1 and 2 could cleave plasmid DNA through hydroxyl radical mechanism. Title complexes could effectively quench the fluorescence of BSA through static quenching. Meanwhile, title complexes had stronger antiproliferative effect compared to L and Na2(DCA) within the tested concentration range. And complex 1 possessed more antiproliferative active than complex 2.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Highly selective and sensitive optical sensor for determination of Pb2+and
           Hg2+ ions based on the covalent immobilization of dithizone on agarose
           membrane
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Kiomars Zargoosh , Fatemeh Farhadian Babadi
      A highly sensitive and selective optical membrane for determination of Hg2+ and Pb2+ was prepared by covalent immobilization of dithizone on agarose membrane. In addition to its high stability, reproducibility and relatively long lifetime, the proposed optical sensor revealed good selectivity for target ions over a large number of alkali, alkaline earth, transition, and heavy metal ions. The proposed optical membrane displays linear responses from 1.1×10− 8 to 2.0×10−6 molL−1 and 1.2×10−8 to 2.4×10−6 molL−1 for Hg2+ and Pb2+, respectively. The limits of detection (LOD) were 2.0×10−9 molL−1 and 4.0×10−9 molL−1 for Hg2+ and Pb2, respectively. The prepared optical membrane was successfully applied to the determination of Hg2+ and Pb2+ in industrial wastes, spiked tap water and natural waters without any preconcentration step.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Application of hollow cylindrical wheat stem for electromembrane
           extraction of thorium in water samples
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Mostafa Khajeh , Stig Pedersen-Bjergaard , Afsaneh Barkhordar , Mousa Bohlooli
      In this study, wheat stem was used for electromembrane extraction (EME) for the first time. The EME technique involved the use of a wheat stem whose channel was filled with 3M HCl, immersed in 10mL of an aqueous sample solution. Thorium migrated from aqueous samples, through a thin layer of 1-octanol and 5%v/v Di-(2-ethylhexyl) phosphate (DEHP) immobilized in the pores of a porous stem, and into an acceptor phase solution present inside the lumen of the stem. The pH of donor and acceptor phases, extraction time, voltage, and stirring speed were optimized. At the optimum conditions, an enrichment factor of 50 and a limit of detection of 0.29ngmL−1 was obtained for thorium. The developed procedure was then applied to the extraction and determination of thorium in water samples and in reference material.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Dissection of the binding of hydrogen peroxide to trypsin using
           spectroscopic methods and molecular modeling
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Wei Song , Zehua Yu , Xinxin Hu , Rutao Liu
      Studies on the effects of environmental pollutants to protein in vitro has become a global attention. Hydrogen peroxide (H2O2) is used as an effective food preservative and bleacher in industrial production. The toxicity of H2O2 to trypsin was investigated by multiple spectroscopic techniques and the molecular docking method at the molecular level. The intrinsic fluorescence of trypsin was proved to be quenched in a static process based on the results of fluorescence lifetime experiment. Hydrogen bonds interaction and van der Waals forces were the main force to generate the trypsin-H2O2 complex on account of the negative ΔH0 and ΔS0. The binding of H2O2 changed the conformational structures and internal microenvironment of trypsin illustrated by UV–vis absorption, fluorescence, synchronous fluorescence, three-dimensional (3D) fluorescence and circular dichroism (CD) results. However, the binding site was far away from the active site of trypsin and the trypsin activity was only slightly affected by H2O2, which was further explained by molecular docking investigations.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Theoretical investigation on the non-linear optical properties,
           vibrational spectroscopy and frontier molecular orbital of
           (E)-2-cyano-3-(3-hydroxyphenyl)acrylamide molecule
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Li Xiao-Hong , Cui Hong-Ling , Zhang Rui-Zhou , Zhang Xian-Zhou
      The vibrational frequencies of (E)-2-cyano-3-(3-hydroxyphenyl)acrylamide (HB-CA) in the ground state have been calculated using density functional method (B3LYP) with B3LYP/6-311++G(d,p) basis set. The analysis of natural bond orbital was also performed. The IR spectra were obtained and interpreted by means of potential energies distributions (PEDs) using MOLVIB program. In addition, the results show that there exists CH⋯O hydrogen bond in the title compound, which is confirmed by the natural bond orbital analysis. The predicted NLO properties show that the title compound is a good candidate as nonlinear optical material. The analysis of frontier molecular orbitals shows that HB-CA has high excitation energies, good stability and high chemical hardness. The analysis of MEP map shows the negative and the positive potential sites.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Based on SERS conformational studies of ginsenoside Rb1 and its
           metabolites before and after combined with human serum albumin
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Wei Zhang , Yingping Wang , Xueyuan Bai , Bing Zhao
      Surface-enhanced Raman scattering (SERS) and fluorescence spectroscopy were employed to probe the interaction of the pharmaceutical and natural product molecules, ginsenoside Rb1, Rd, Rg3 and compound K (CK), with human serum albumin (HSA). Normal Raman spectra of these four ginsenosides were obtained from solid powder on glass slide. Based on the unsplit peak at 1445cm−1, the stacking modes of ginsenoside Rb1, Rd, Rg3 and CK were quite similar, when the deconvolution of alkyl chain was not occurred. SERS spectra of ginsenoside Rb1, Rd, Rg3 and CK were obtained from a colloidal silver surface on a self-assembled SERS substrate, the most enhanced modes were those with certain motions perpendicular to the metal surface, such as C24C25 stretch and CH out-of-plane bending from alkyl chain. The SERS spectra were used to predict similar perpendicular orientation of flexible alkyl chain and parallel orientation of carbocyclic rings on Ag colloid particles. Therefore, when combined with HSA, the transformations of four ginsenosides still exhibit similar, although in different binding cavities in subdomain IIA and IIIA by making the methyls at C26 and C27 perpendicular plugging into the hydrophobic site of HSA, while the aglycone and glucose nearby are perpendicularly exposed outside to fit other suitable active targeting sites.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Molybdenum modified phosphate glasses studied by 31P MAS NMR and Raman
           spectroscopy
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Magdalena Szumera
      Glasses have been synthesized in the system P2O5 SiO2 K2OMgOCaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and 31P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]OP and/or Mo[MoO4/MoO6]OSi bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations.
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      PubDate: 2014-09-18T18:35:00Z
       
  • NBO, conformational, NLO, HOMO–LUMO, NMR and electronic spectral
           study on 1-phenyl-1-propanol by quantum computational methods
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): S. Xavier , S. Periandy , S. Ramalingam
      In this study, FT-IR, FT-Raman, NMR and UV spectra of 1-phenyl-1-propanol, an intermediate of anti-depressant drug fluoxetine, has been investigated. The theoretical vibrational frequencies and optimized geometric parameters have been calculated by using HF and density functional theory with the hybrid methods B3LYP, B3PW91 and 6-311+G(d,p)/6-311++G(d,p) basis sets. The theoretical vibrational frequencies have been found in good agreement with the corresponding experimental data. 1H and 13C NMR spectra were recorded and chemical shifts of the molecule were compared to TMS by using the Gauge-Independent Atomic Orbital (GIAO) method. A study on the electronic and optical properties, absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies are performed using HF and DFT methods. The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated. 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. NLO properties related to polarizability and hyperpolarizability are also discussed.
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      PubDate: 2014-09-18T18:35:00Z
       
  • A comparative photophysicochemical study of phthalocyanines encapsulated
           in core–shell silica nanoparticles
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Adedayo Fashina , Edith Amuhaya , Tebello Nyokong
      This work presents the synthesis and characterization of a new zinc phthalocyanine complex tetrasubstituted with 3-carboxyphenoxy in the peripheral position. The photophysical properties of the new complex are compared with those of phthalocyanines tetra substituted with 3-carboxyphenoxy or 4-carboxyphenoxy at non-peripheral positions. Three phthalocyanine complexes were encapsulated within silica matrix to form a core shell and the hybrid nanoparticles particles obtained were spherical and mono dispersed. When encapsulated within the silica shell nanoparticles, phthalocyanines showed improved triplet quantum yields and singlet oxygen quantum yields than surface grafted derivatives. The improvements observed could be attributed to the protection provided for the phthalocyanine complexes by the silica matrix.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Synthesis, characterization and vibrational properties of
           p-fluorosulfinylaniline
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Ana L. Páez Jerez , Andrea Flores Antognini , Edgardo H. Cutin , Norma L. Robles
      The reaction of p-fluoroaniline and SOCl2 rendered p-fluorosulfinylaniline in good yield. The obtained dark yellowish liquid compound was characterized by NMR, UV–visible, FT-IR and Raman spectroscopies. The observed features were consistent with the existence of only one conformer, belonging to the CS symmetry group. A tentative assignment of the vibrational modes was performed on the basis of experimental spectra and quantum chemical calculations at different levels of theory (B3LYP and MP2 with 6-31+G(d), 6-311+G(d) and 6-311+G(df) basis sets). The conformational and vibrational properties of p-fluorosulfinylaniline were in good agreement with experimental data reported for other substituted sulfinylanilines and p-halogenanilines.
      Graphical abstract image

      PubDate: 2014-09-18T18:35:00Z
       
  • Structural characterization of titania by X-ray diffraction,
           photoacoustic, Raman spectroscopy and electron paramagnetic resonance
           spectroscopy
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): R.M. Kadam , B. Rajeswari , Arijit Sengupta , S.N. Achary , R.J. Kshirsagar , V. Natarajan
      A titania mineral (obtained from East coast, Orissa, India) was investigated by X-ray diffraction (XRD), photoacoustic spectroscopy (PAS), Raman and Electron Paramagnetic Resonance (EPR) studies. XRD studies indicated the presence of rutile (91%) and anatase (9%) phases in the mineral. Raman investigation supported this information. Both rutile and anatase phases have tetragonal structure (rutile: space group P42/mnm, a =4.5946(1) Å, c =2.9597(1) Å, V =62.48(1) (Å)3, Z =2; anatase: space group I41/amd, 3.7848(2) Å, 9.5098(11) Å, V =136.22(2) (Å)3, Z =4). The deconvoluted PAS spectrum showed nine peaks around 335, 370, 415,485, 555, 605, 659, 690,730 and 785nm and according to the ligand field theory, these peaks were attributed to the presence of V4+, Cr3+, Mn4+ and Fe3+ species. EPR studies revealed the presence of transition metal ions V4+(d1), Cr3+(d3), Mn4+(d3) and Fe3+(d5) at Ti4+ sites. The EPR spectra are characterized by very large crystal filed splitting (D term) and orthorhombic distortion term (E term) for multiple electron system (s >1) suggesting that the transition metal ions substitute the Ti4+ in the lattice which is situated in distorted octahedral coordination of oxygen. The possible reasons for observation of unusually large D and E term in the EPR spectra of transition metal ions (S =3/2 and 5/2) are discussed.
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      PubDate: 2014-09-18T18:35:00Z
       
  • One-step, room temperature, colorimetric melamine sensing using an in-situ
           formation of silver nanoparticles through modified Tollens process
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Huiying Wang , Dinglong Chen , Longquan Yu , Ming Chang , Lijie Ci
      We have developed a rapid, sensitive, one-step, and selective colorimetric detection method for melamine (MEL) in milk powder based upon an in-situ formation of silver nanoparticles (AgNPs) through modified Tollens process at room temperature. The triazine ring N atoms of MEL molecule were strategically designed to complex the Ag+ through electron donor–acceptor interaction. During the AgNPs formation procedure, the MEL molecule, which has been covalently bonded with the Ag+ ions, was adsorbed to the surface of as-prepared AgNPs, resulting in the aggregation of the adjacent AgNPs with detectable decreases of absorption signal. The concentration of MEL can be determined with the naked eye or a UV–vis spectrometer at which the yellow-to-brown color change associated with aggregate enhancement takes place. This method enables rapid (less than 30min) and sensitive (limit of detection, LOD, 10nM) detection, and it was also able to discriminate MEL from sixteen other milk relevant coexisting compounds. This assay does not utilize organic cosolvents, enzymatic reactions, light-sensitive dye molecules, lengthy protocols, or sophisticated instrumentation thereby overcoming some of the limitations of conventional methods.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Structural characterizations and intense green upconversion emission in
           Yb3+, Pr3+ co-doped Y2O3 nano-phosphor
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): R.S. Yadav , R.K. Verma , A. Bahadur , S.B. Rai
      We report the structural and optical properties of Yb3+, Pr3+ co-doped Y2O3 nano-phosphor synthesized through solution combustion method. The structural studies reveal the nano-crystalline structure of the sample. The energy dispersive spectroscopy (EDS) measurements confirm the presence of Y, O, Pr and Yb elements in the sample. Fourier transform infrared studies show the vibrational features of the samples. The fluorescence spectra of the samples have been monitored on excitation with 976nm and the intense green upconversion emission observed at 552nm is due to 3P0 → 3H5 electronic transition. The concentration of Pr3+ ion in the sample is optimized and the fluorescence intensity is maximum at 0.08mol% of Pr3+. The power dependence studies reveal the involvement of two photons in the emission process. The possible mechanism of upconversion has been discussed on the basis of schematic energy level diagram. The sample annealed at higher temperature enhances the fluorescence intensity up to 8 times and this enhancement is discussed in terms of the removal of optical quenching centers. The nano-phosphor can be applicable in the field of display devices and green laser.
      Graphical abstract image Highlights

      PubDate: 2014-09-18T18:35:00Z
       
  • Two new heterodinuclear Schiff base complexes: Synthesis, crystal
           structure and thermal studies
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Alper Yardan , Cigdem Hopa , Yasemin Yahsi , Ahmet Karahan , Hulya Kara , Raif Kurtaran
      Two new heterodinuclear Schiff base complexes, [Hg(L)NiCl2(DMF)2] 1, and [Zn(L)NiCl2(DMF)2] 2, where H2L=N,N′-bis(salicylidene)-1,3-diaminopropane and DMF=dimethylformamide have been synthesized and characterized using elemental analysis, IR spectroscopy, thermal analysis and X-ray diffraction. Structural studies on 1 and 2 reveal the presence of a heterodinuclear [NiIIHgII] unit and [ZnIINiII] in which the central metal ions are connected to each other by two phenolate oxygen bridges. For complex 1 the Ni(II) ion adopts an elongated octahedral geometry (NiN2O4) while the Hg(II) ion assumes a distorted tetrahedral arrangement (HgO2Cl2) whereas for complex 2 the Zn(II) ion adopts an elongated octahedral geometry (ZnN2O4) while the Ni(II) ion assumes a distorted tetrahedral arrangement (NiO2Cl2). There are intermolecular CH···ClM interactions among the dinuclear complexes which are interconnected for 1 and 2. These intermolecular interactions result in the formation of a three dimensional structure for 1 and one dimensional zig-zag chains for 2.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Performance of Caesalpinia sappan heartwood extract as photo sensitizer
           for dye sensitized solar cells
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): S. Ananth , P. Vivek , G. Saravana Kumar , P. Murugakoothan
      A natural dye extracted from Caesalpinia sappan heartwood was used as photo sensitizer for the first time to fabricate titanium dioxide (TiO2) nanoparticles based dye sensitized solar cells. Brazilin and brazilein are the major pigments present in the natural dye and their optimized molecular structure were calculated using Density functional theory (DFT) at 6-31G (d) level. The HOMO–LUMO were performed to reveal the energy gap using optimized structure. Pure TiO2 nanoparticles in anatase phase were synthesized by sol–gel technique. The pure and natural dye sensitized TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Low cost and environment friendly dye sensitized solar cells were fabricated using natural dye sensitized TiO2 based photo anode. The solar light to electron conversion efficiency of Caesalpinia sappan heartwood extract sensitized dye sensitized solar cell is 1.1%.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Donor–acceptor binding interaction of
           1-(naphthalene-1-yl)-2,4,5-triphenyl-1H-imidazole with semiconductor
           nanomaterials
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): J. Jayabharathi , C. Karunakaran , V. Kalaiarasi , P. Ramanathan
      The dynamics of photoinduced electron injection from 1-(naphthalene-1-yl)-2,4,5-triphenyl-1H-imidazole (NTI) to pristine ZnO, Mn-doped TiO2 and BaTiO3 nanoparticles have been studied by absorption, fluorescence and lifetime spectroscopic methods. Both the absorption and fluorescence results suggest the association between the nanoparticles and NTI. The calculated free energy change (ΔGet ) confirms the electron injection from NTI to nano semiconductors. The critical energy transfer distance between NTI and the nanoparticles have been deduced. The emission of NTI is enhanced by pristine ZnO and quenched by Mn-doped TiO2 and BaTiO3 nanoparticles which are likely due to change of LUMO and HOMO levels of NTI on its association with nano semiconductors. The strong adsorption of the NTI on the surface of ZnO nanocrystals is likely due to the chemical affinity of the nitrogen atom of the NTI to the zinc ion on the surface of nanocrystals. Electron injection from photoexcited NTI to the CB(S∗ →S+ + e − CB) is likely to be the reason for the fluorescence enhancement.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Enhancement in photocatalytic activity of NiO by supporting onto an
           Iranian clinoptilolite nano-particles of aqueous solution of cefuroxime
           pharmaceutical capsule
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Asieh Pourtaheri , Alireza Nezamzadeh-Ejhieh
      NiO/nano-clinoptilolite (NiO–NCP) was prepared by ion exchanging process of the prepared ball-mill nano-clinoptilolite particles with nickel(II) chloride aqueous solution. The prepared composite was characterized by XRD, UV–Vis DRS, TEM and FT-IR and then used as a catalyst in the photodegradation of cefuroxime (CF) using Hg lamp. The best experimental parameters were obtained as: 0.025gL− 1 of the photocatalyst containing 13.3% NiO, 50 times diluted cefuroxime solution at pH 5. The degradation extent was monitored by UV–Vis spectroscopy and the results were confirmed by HPLC and COD. The kinetics of the photodegradation process obeyed the Langmuir–Hinshelwood model.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Theoretical spectroscopic studies and identification of metal-citrate (Cd
           and Pb) complexes by ESI-MS in aqueous solution
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Alexandre C. Bertoli , Ruy Carvalho , Matheus P. Freitas , Teodorico C. Ramalho , Daiana T. Mancini , Maria C. Oliveira , Amarílis de Varennes , Ana Dias
      The combined use of ESI-MS, FTIR-ATR and theoretical calculations for the determination of metal-citrate (metal=Cd and Pb) structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their molecular structures readjusted, since the deprotonation of citric acid differed from what was simulated. The calculations of thermodynamic stability (ΔH 0 (aq.)) for the complexes obtained by B3LYP/LANL2DZ were more exoenergetic than those found by PM6. However, for both methods, the stability of the complexes follows a trend, that is, the lowest-energy isomers in PM6 are also the most stable in B3LYP/LANL2DZ. The infrared analysis suggested that carboxyl groups are complexation sites and hydrogen bonds can help in the stability of the complexes. The vibrational frequencies in B3LYP/LANL2DZ had a good correlation with the experimental infrared results.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Effect of annealing temperature on optical properties of binary zinc tin
           oxide nano-composite prepared by sol–gel route using simple
           precursors: Structural and optical studies by DRS, FT-IR, XRD, FESEM
           investigations
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Mohammad Hossein Habibi , Maryam Mardani
      Binary zinc tin oxide nano-composite was synthesized by a facile sol–gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72eV to 3.11eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602cm−1 can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410cm−1 are due to the vibration of Zn–O or Sn–O groups in binary zinc tin oxide.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Dual emission behavior of phenyleneethynylene gold(I) complexes dictated
           by intersystem crossing: A theoretical perspective
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Li Wang , Yuanyuan Li , Yanxin Zhang , Hongqing He , Jinglai Zhang
      In commonly studied gold(I) complexes with oligo (o-, p-, or m-phenyleneethynylene) (PE) ligands, an intriguing photophysical behavior is dual emission composed of fluorescence from S1 and phosphorescence from T1 which is dictated by effective intersystem crossing (ISC) process. In order to explore the salient photodynamics of such oligo-PE gold(I) complexes effectively, we have deliberately chosen three model complexes, namely, PhCCAu(PMe3) (1a′) and PhCC(1,m)C6H4 CCAu(PMe3) (m =4, 2a′; m =3, 3a′) in place of the real system. Firstly, electronic structure methods based on DFT and TD-DFT are utilized to perform optimization calculations for the ground- and lowest-lying excited states, respectively. Next, basic photophysical properties including absorption and emission spectra are investigated by TD-DFT under the optimized geometries. Besides, on the basis of the electronic spectra herein, we succeed in searching for surface intersections as the minima on the seam of singlet–triplet surface crossings (SCs) at the CASSCF level of theory. By integration of the results available, the process of delayed fluorescence of triplet–triplet annihilation (TTA) and phosphorescence was displayed in detail with SCs playing the lead in monitoring the ISC.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide
           nanochains for biomedical applications
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): R. Yuvakkumar , J. Suresh , B. Saravanakumar , A. Joseph Nathanael , Sun Ig Hong , V. Rajendran
      A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ∼40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48h incubation with 7days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.
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      PubDate: 2014-09-18T18:35:00Z
       
  • Novel axially carborane-cage substituted silicon phthalocyanine
           photosensitizer; synthesis, characterization and photophysicochemical
           properties
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Göknur Yaşa Atmaca , Cemil Dizman , Tarık Eren , Ali Erdoğmuş
      The novel axially dicarborane substituted silicon (IV) (SiPc-DC) phthalocyanine was synthesized by treating silicon phthalocyanine dichloride SiPc(Cl)2 (SiPc) with o-Carborane monool. The compound was characterized by mass spectrometry, UV–Vis, FT-IR, 1H and 11B Nuclear Magnetic Resonance Spectroscopy (NMR). Spectral, photophysical (fluorescence quantum yield) and photochemical (singlet oxygen (Φ Δ) and photodegradation quantum yield (Φd )) properties of the complex were reported in different solutions (Dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) and Toluene). The results of spectral measurements showed that both SiPc and carborane cage can have potential to be used as sensitizers in photodynamic therapy (PDT) and boron neutron capture therapy (BNCT) by their singlet oxygen efficiencies (Φ Δ =0.41, 0.39).
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      PubDate: 2014-09-18T18:35:00Z
       
  • Phytosynthesis of stable Au, Ag and Au–Ag alloy nanoparticles using
           J. Sambac leaves extract, and their enhanced antimicrobial activity in
           presence of organic antimicrobials
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): S. Yallappa , J. Manjanna , B.L. Dhananjaya
      A green chemistry approach for the synthesis of Au, Ag and Au–Ag alloy nanoparticles (NPs) using the corresponding metal precursors and Jasminum sambac leaves extract as both reducing and capping media, under microwave irradiation, is reported. During the formation, as expected, the reaction mixture shows marginal decrease in pH and an increase in solution potential. The formation of NPs is evident from their surface plasmon resonance (SPR) peak observed at ∼555nm for Au, ∼435nm for Ag and ∼510nm for Au–Ag alloy. The XRD pattern shows fcc structure while the FTIR spectra indicate the presence of plant residues adsorbed on these NPs. Such a bio-capping of NPs is characterized by their weight loss, ∼35% due to thermal degradation of biomass, as observed in TG analysis. The colloidal dispersion of NPs is stable for about 6weeks. The near spherical shape of NPs (ϕ20–50nm) is observed by FE-SEM/TEM images and EDAX gives the expected elemental composition. Furthermore, these NPs showed enhanced antimicrobial activity (∼1–4-fold increase in zone of inhibition) in combination with antimicrobials against test strains. Thus, the phytosynthesized NPs could be used as effective growth inhibitors for various microorganisms.
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      PubDate: 2014-09-18T18:35:00Z
       
  • A TDDFT/EFP1 study on hydrogen bonding dynamics of coumarin 151 in water
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Mariyappa Ramegowda
      Change in energy of hydrogen bonds (HBs) upon excitation, plays an important role on the spectra of chemical and biological molecules. Effective fragment potential (EFP) method of explicit water molecules embedded in polarizable continuum medium (PCM) is used for the solvation of 7-Amino-4-(trifluoromethyl)coumarin (C151). Time dependent density functional theory (TDDFT) calculations combined with EFP/PCM had been carried out to study the electronic structure and the exited state properties of C151 with five water molecules (C151–(H2O)5 complex). S0 state and S1 state geometries were optimized using DFT/TDDFT with PBE0 functional combined with cc-pVDZ basis set, the transition energies are computed with same basis set and functional. Change in HB energy is calculated using the procedure proposed by T. Nagata et al. to calculate solute–solvent interaction energy in Nagata et al. (2011). Upon photoexcitation of C151–(H2O)5 complex, A type (N⋯HO) HB is weakened with decrease of energy by 4.37kJ/mol, whereas B and C type (CO⋯HO and NH⋯O) HBs are strengthened with increase of 5.62 and 10.21kJ/mol energy, respectively. This study again confirmed that the intermolecular hydrogen bonds between C151 chromophore and aqueous solvents are strengthened, not cleaved upon electronic excitation.
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      PubDate: 2014-09-08T16:16:08Z
       
  • Effects of essential oil treatments on the secondary protein structure of
           Vicia faba: A mid-infrared spectroscopic study supported by
           two-dimensional correlation analysis
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Mauro Mecozzi , Elena Sturchio
      In this study we investigated the effects of essential oil treatments on the secondary protein structure of the Vicia faba roots, a bioindicator plant, in order to obtain information for the potential allelopathic uses of these oils as alternative to the use of pesticides in agriculture. We tested two mixtures of essential oils consisting of Tween 20-emulsions of tea tree oil (TTO) and Tween 20-emulsion of Clove and Rosemary (GARROM) essential oils respectively at three different oil concentrations each. The molecular modifications caused in Vicia faba by exposure to oil emulsions were investigated by FTIR spectroscopy in diffuse reflectance (DRIFT) mode. We considered the specific Amide I, Amide II and Amide VI bands by ordinary and second derivative spectroscopy and the results showed that both Tween 20-emulsion of GARROM and Tween 20-emulsion of TTO oils cause transitions among the secondary (α-helix, β-sheet and β-turn) structures with in addition the appearance of random coil structures in exposed samples. The Amide VI bands, placed between 500 and 600cm−1, confirmed the structural transitions observed for the Amide I bands. In addition we observed the presence of a protein oxidation effect for TTO treated samples, oxidation which resulted negligible instead for the GARROM oil samples. At last, FTIR spectra were also submitted to two-dimensional correlation analysis (2DCORR) and double two-dimensional correlation analysis (D2DCORR); the results confirmed the different effects caused by the two typologies of essential oils on the secondary protein structures of Vicia faba roots.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • A simple-structured acridine derivative as a fluorescent enhancement
           chemosensor for the detection of Pd2+ in aqueous media
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Yanmei Zhou , Qi Huang , Qingyou Zhang , Yinghao Min , Enze Wang
      4,5-Bis(hydroxymethyl) acridine (sensor 1) has been discovered and synthesized as a simple-structured Pd2+ fluorescent probe. Sensor 1 showed highly selective recognition toward Pd2+ over other examined metal ions in aqueous solution. Under the optimized condition, fluorescence intensity was linearly proportional to the concentration of Pd2+ in the 0–1μM concentration range with detection limits of 0.021μM. The EDTA-adding and stoichiometry experiments indicated that sensor 1 was a reversible chemosensor for Pd2+ with a 2:1 ligand/metal complex at neutral pH. Moreover, the sensor 1 was also successfully applied to determination of Pd2+ in water samples and palladium-containing catalyst, which made it attractive for sensing applications.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • Thermal annealing effect on the optical properties of Ag10As30S60 thin
           film
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): M.I. Abd-Elrahman , A.Y. Abdel-Latief , Rasha M. Khafagy , Noha Younis , M.M. Hafiz
      Chalcogenide Ag10As30S60 thin films are prepared using the thermal evaporation technique from the bulk alloy. Deferential Scanning Calorimetry (DSC) curve reveals two crystallization stages for the bulk. The X-ray examination of the as-prepared and annealed films shows that the sample is crystallized in preferential orientations indicated with peaks corresponding the S8 and ternary AsAg3S3 phases. Transmission spectra show that the as-prepared and annealed films have highly transparent over the visible region. The presence of a sharp absorption edge for all films in the transmission spectra recommends Ag10As30S60 thin films as a good optical filter material. The improvement in transparency upon annealing is due to the enhancement in the crystallinity. The decrease in both optical band gap and refractive index of annealed films after crystallization temperatures is discussed in accordance with the structure changes upon annealing.
      Graphical abstract image Highlights

      PubDate: 2014-09-08T16:16:08Z
       
  • Growth, spectral, optical, thermal, surface analysis and third order
           nonlinear optical properties of an organic single crystal:
           1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): M. Nirosha , S. Kalainathan , S. Sarveswari , V. Vijayakumar , A. Srikanth
      Single crystal of 1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone was grown using slow evaporation solution growth technique. Single crystal X-ray diffraction study reveals the lattice parameters of the grown crystal. The modes of vibration of different molecular groups present in 2M6NQE were identified by FTIR spectral analysis. Its optical behavior was examined through UV–vis–NIR absorption and PL emission spectrum. They signify that the crystal has transparency in the region between 383 and 1100nm. The PL spectrum of the title compound shows green emission in the crystal. From the thermal analysis, 2M6NQE has found to be thermally stable up to 263°C, and the melting point of the material is 170°C. The estimations of third order non-linear optical properties like non-linear absorption coefficient (β), non-linear refractive index (n 2) and susceptibility [χ (3)] were calculated using Z-scan technique. It has observed that, crystal exhibits reverse saturation absorption and self-defocusing performance. Etching study was carried out for the grown crystal using different solvents.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • Synthesis, characterization and antibacterial activity of a tridentate
           Schiff base derived from cephalothin and sulfadiazine, and its transition
           metal complexes
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): J.R. Anacona , Natiana Noriega , Juan Camus
      Metal(II) coordination compounds of a cephalothin Schiff base (H2L) derived from the condensation of cephalothin antibiotic with sulfadiazine were synthesized. The Schiff base ligand, mononuclear [ML(H2O)3] (M(II)=Mn,Co,Ni,Zn) complexes and magnetically diluted dinuclear copper(II) complex [CuL(H2O)3]2 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 cephalothin Schiff base ligand H2L behaves as a dianionic tridentate NOO chelating agent. The biological applications of complexes have been studied on two bacteria strains (Escherichia coli and Staphylococcus aureus) by agar diffusion disc method.
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      PubDate: 2014-09-08T16:16:08Z
       
  • New metal complexes of N3 tridentate ligand: Synthesis, spectral studies
           and biological activity
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Abbas Ali Salih Al-Hamdani , Wail Al Zoubi
      New tridentate ligand 3-amino-4-{1,5-dimethyl-3-[2-(5-methyl-1H-indol-3-yl)-ethylimino]-2phenyl-2,3-dihydro-1H-pyrazol-4-ylazo}-phenol L was synthesized from the reaction of 1,5-dimethyl-3-[2-(5-methyl-1H-indol-3-yl)-ethylimino]-2-phenyl-2,3-dihydro-1H-pyrazol-4-ylamine and 3.4-amino phenol. A complexes of these ligand [Ni(II)(L)(H2O)2 Cl]Cl, [pt(IV)(L)Cl3]Cl and [M(II)(L)Cl]Cl (M=Pd (II), Zn (II), Cd (II) and Hg (II) were synthesized. The complexes were characterized by spectroscopic methods and magnetic moment measurements, elemental analysis, metal content, Chloride containing and conductance. These studies revealed octahedral geometries for the Ni (II), pt (IV) complexes, square planar for Pd (II) complex and tetrahedral for the Zn (II), Cd(II) and Hg (II) complexes. The study of complexes formation via molar ratio and job method in DMF solution has been investigated and results were consistent to those found in the solid complexes with a ratio of (M:L) as (1:1). The thermodynamic parameters, such as ΔE *, ΔH *, ΔS * ΔG * and K are calculated from the TGA curve using Coats–Redfern method. Hyper Chem-8 program has been used to predict structural geometries of compounds in gas phase. The synthesized ligand and its metal complexes were screened for their biological activity against bacterial species, two Gram positive bacteria (Bacillus subti lis and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa).
      Graphical abstract image Highlights

      PubDate: 2014-09-08T16:16:08Z
       
  • Spectroscopic study on the formation of DNA-Ag clusters and its
           application in temperature sensitive vehicles of DOX
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Ting-Ting Zhao , Qiu-Yun Chen , Huan Yang
      DNA silver nanoclusters (DNA-AgNCs) with a fluorescence emission at 610nm were synthesized using a special hairpin DNA sequence (5′-AGCACGTAG-C3AC3AC3GC3A-CTACGTGCT-3′). Spectroscopic data demonstrate that the DNA changed from an i-motif structure containing C-quadruplexes to anti-parallel four strands structure during the formation of DNA-AgNCs. Importantly, the loose and compact four strand structure caused by the melting and hybridization of stem duplex was confirmed by the reversible fluorescence change of DNA-AgNCs in the range of 25–66°C. Herein, DNA-AgNCs were used as temperature sensitive vehicles of drug loading. The drug loading capacity is 1 Doxorubicin (Dox) molecules per CG pairs on stem-duplexes. The loaded Dox can be released by raising temperature with the melt of stem duplex. Moreover, the special DNA sequence makes it sensitive to the HepG-2 cells.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • A vibrational spectroscopic study of the silicate mineral harmotome
           – (Ba,Na,K)1-2(Si,Al)8O16⋅6H2O – A natural zeolite
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Ray L. Frost , Andrés López , Lina Wang , Antônio Wilson Romano , Ricardo Scholz
      The mineral harmotome (Ba,Na,K)1-2(Si,Al)8O16⋅6H2O is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and other industrial applications. It is a natural zeolite with catalytic potential. Raman bands at 1020 and 1102cm−1 are assigned to the SiO stretching vibrations of three dimensional siloxane units. Raman bands at 428, 470 and 491cm−1 are assigned to OSiO bending modes. The broad Raman bands at around 699, 728, 768cm−1 are attributed to water librational modes. Intense Raman bands in the 3100 to 3800cm−1 spectral range are assigned to OH stretching vibrations of water in harmotome. Infrared spectra are in harmony with the Raman spectra. A sharp infrared band at 3731cm−1 is assigned to the OH stretching vibration of SiOH units. Raman spectroscopy with complimentary infrared spectroscopy enables the characterization of the silicate mineral harmotome.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • Development of electrochemical folic acid sensor based on hydroxyapatite
           nanoparticles
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): P. Kanchana , C. Sekar
      We report the synthesis of hydroxyapatite (HA) nanoparticles (NPs) by a simple microwave irradiation method and its application as sensing element for the precise determination of folic acid (FA) by electrochemical method. The structure and composition of the HA NPs characterized using XRD, FTIR, Raman and XPS. SEM and EDX studies confirmed the formation of elongated spherical shaped HA NPs with an average particle size of about 34nm. The HA NPs thin film on glassy carbon electrode (GCE) were deposited by drop casting method. Electrocatalytic behavior of FA in the physiological pH 7.0 was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. The fabricated HA/GCE exhibited a linear calibration plot over a wide FA concentration ranging from 1.0×10−7 to 3.5×10−4 M with the detection limit of 75nM. In addition, the HA NPs modified GCE showed good selectivity toward the determination of FA even in the presence of a 100-fold excess of ascorbic acid (AA) and 1000-fold excess of other common interferents. The fabricated biosensor exhibits good sensitivity and stability, and was successfully applied for the determination of FA in pharmaceutical samples.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • MM and QM: Conformational and vibrational spectra analysis of
           2-hydroxyethyl acrylate
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): O. Belaidi , M. Adjim , T. Bouchaour , U. Maschke
      2-Hydroxyethyl acrylate is generally used with other acrylic and methacrylic products in order to get the desired characteristics of the final product. In this work we are about to make an assignment of experimental infrared bands with the help of a theoretical quantum chemistry calculations. The exact knowledge of some bands which are not characteristics of acrylic materials will enable us to make a quick analysis with available techniques of low costs for mixtures of polymers based on acrylate and methacrylate molecules. In the experimental part, the infrared spectrum of 2-hydroxyethyl acrylate is obtained by using a FTIR Perkin Elmer model 2000. In the computational part and as first step, the theoretical calculations are performed by the semi-empirical AM1 method for excluding similar structures of 2-hydroxyethyl acrylate molecule by a meticulous conformational analysis. As a second step the obtained structures are optimized using DFT. The simulated frequencies are then scaled and a tentative assignment is made based on band intensities and PED percentages. The theoretical calculations predict the existence of thirteen conformations two of them represent the majority of experimental bands in the infrared spectrum. Two neighbor experimental bands located at 1301 and 1207cm−1 maybe used as characteristic bands to locate and distinguish the existence of one or both conformations.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • Impact of vanadium ions in barium borate glass
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): A.M. Abdelghany , Ahmed H. Hammad
      Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV–visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.
      Graphical abstract image

      PubDate: 2014-09-08T16:16:08Z
       
  • Raman spectroscopic study of “The Malatesta”: A Renaissance
           painting?
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Howell G.M. Edwards , Peter Vandenabeele , Timothy J. Benoy
      Raman spectroscopic analysis of the pigments on an Italian painting described as a “Full Length Portrait of a Gentleman”, known also as the “Malatesta”, and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research.
      Graphical abstract image Highlights

      PubDate: 2014-09-08T16:16:08Z
       
  • Vibrational spectroscopic investigation (FT-IR and FT-Raman) using ab
           initio (HF) and DFT (B3LYP) calculations of
           3-ethoxymethyl-1,4-dihydroquinolin-4-one
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Jamelah S. Al-Otaibi , Reem I. Al-Wabli
      The FT-IR and FT-Raman spectra of 3-ethoxymethyl-1,4-dihydroquinolin-4-one were recorded in the solid phase. The molecular geometry, harmonic vibrational frequencies, infrared intensities, Raman scattering activities, depolarization ratios and reduced masses were calculated by using the Hartree–Fock (HF) and density function theory (DFT/B3LYP) methods with the 6-311++G (d,p) basis set. The calculation results were applied to simulate infrared and Raman spectra of the title compound which showed good agreement with the observed spectra. A detailed interpretation of the infrared and Raman spectra of 3-ethoxymethyl-1,4-dihydroquinolin-4-one is reported. The theoretical spectrograms for FT-IR and FT-Raman spectra of the title compound have been constructed.
      Graphical abstract image

      PubDate: 2014-09-02T15:43:06Z
       
  • Preparation and investigation of CaZr4(PO4)6:Dy3+ single-phase full-color
           phosphor
    • Abstract: Publication date: 25 February 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 137
      Author(s): Zhi-wei Zhang , Lu Liu , Xian-fu Zhang , Jian-ping Zhang , Wei-guo Zhang , Dong-jun Wang
      A novel single-phase full-color phosphor CaZr4(PO4)6:Dy3+ has been synthesized by a high-temperature solid-state reaction. X-ray powder diffraction (XRD) analysis and FT-IR spectra confirmed the phase formation of CaZr4(PO4)6:Dy3+ materials. The photoluminescence excitation and emission spectra, the concentration dependence of the emission intensity, decay curves, ultraviolet–visible absorption spectroscopy and Commission International de I’Eclairage (CIE) of the phosphor were investigated. The results showed that the phosphor could be efficiently excited by the near ultraviolet (NUV) light region from 340 to 440nm, and it exhibited blue (487nm) and yellow (577nm) emission corresponding to 4F9/2 → 6H15/2 transitions and 4F9/2 → 6H13/2 transitions, respectively. The luminescence intensity of Ca1− x Zr4(PO4)6:xDy3+ phosphor firstly increased and then decreased with increasing Dy3+ concentration, and reached the maximum at x =0.04. The band gap energy of CaZr4(PO4)6 and Ca0.96Zr4(PO4)6:0.04Dy3+ are about 4.184eV from the diffuse reflection spectrum. The decay time was also determined for various concentrations of Dy3+ in CaZr4(PO4)6. The calculated color coordinates lies in the blue white region. Therefore, these obtained results suggest that the prepared phosphors exhibit great potential for use as single-phase full-color phosphor for near ultraviolet white light emitting diodes (NUV WLEDs).
      Graphical abstract image

      PubDate: 2014-09-02T15:43:06Z
       
 
 
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