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CHEMISTRY (527 journals)            First | 1 2 3 4 5 6 | Last

Journal of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (2 followers)
Journal of Inorganic Biochemistry     Hybrid Journal   (3 followers)
Journal of Labelled Compounds and Radiopharmaceuticals     Hybrid Journal  
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry     Hybrid Journal   (4 followers)
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Journal of Nanostructure in Chemistry     Open Access   (5 followers)
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Journal of Nepal Chemical Society     Open Access  
Journal of Nucleic Acids Investigation     Open Access   (2 followers)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (2 followers)
Journal of Organometallic Chemistry     Hybrid Journal   (12 followers)
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Journal of Taibah University for Science     Open Access  
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Langmuir     Full-text available via subscription   (35 followers)
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Nanoscale Research Letters     Open Access   (4 followers)

  First | 1 2 3 4 5 6 | Last

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy    [9 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1386-1425
     Published by Elsevier Homepage  [2556 journals]   [SJR: 0.567]   [H-I: 58]
  • A vibrational spectroscopic study of the phosphate mineral minyulite
           KAl2(OH,F)(PO4)2⋅4(H2O) and in comparison with wardite
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Ray L. Frost , Andrés López , Yunfei Xi , Luiz Henrique Cardoso , Ricardo Scholz
      Vibrational spectroscopy enables subtle details of the molecular structure of minyulite KAl2(OH,F)(PO4)2⋅4(H2O). Single crystals of a pure phase from a Brazilian pegmatite were used. Minyulite belongs to the orthorhombic crystal system. This indicates that it has three axes of unequal length, yet all are perpendicular to each other. The infrared and Raman spectroscopy were applied to compare the structure of minyulite with wardite. The reason for the comparison is that both are Al containing phosphate minerals. The Raman spectrum of minyulite shows an intense band at 1012cm−1 assigned to the ν1 PO 4 3 - symmetric stretching vibrations. A series of low intensity Raman bands at 1047, 1077, 1091 and 1105cm−1 are assigned to the ν3 PO 4 3 - antisymmetric stretching modes. The Raman bands at 1136, 1155, 1176 and 1190cm−1 are assigned to AlOH deformation modes. The infrared band at 1014cm−1 is ascribed to the PO 4 3 - ν1 symmetric stretching vibrational mode. The infrared bands at 1049, 1071, 1091 and 1123cm−1 are attributed to the PO 4 3 - ν3 antisymmetric stretching vibrations. The infrared bands at 1123, 1146 and 1157cm−1 are attributed to AlOH deformation modes. Raman bands at 575, 592, 606 and 628cm−1 are assigned to the ν4 out of plane bending modes of the PO 4 3 - unit. In the 2600–3800cm−1 spectral range, Raman bands for minyulite are found at 3661, 3669 and 3692cm−1 are assigned to AlOH/AlF stretching vibrations. Broad infrared bands are also found at 2904, 3105, 3307, 3453 and 3523cm−1. Raman bands at 3225, 3324cm−1 are assigned to water stretching vibrations. A comparison is made with the vibrational spectra of wardite. Raman spectroscopy complimented with infrared spectroscopy has enabled aspects of the structure of minyulite to be ascertained and compared with that of other phosphate minerals.
      Graphical abstract image Highlights

      PubDate: 2014-01-24T06:09:35Z
       
  • Spectral studies of 2-pyrazoline derivatives: Structural elucidation
           through single crystal XRD and DFT calculations
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): D. Chinnaraja , R. Rajalakshmi , T. Srinivasan , D. Velmurugan , J. Jayabharathi
      A series of biologically active N-thiocarbamoyl pyrazoline derivatives have been synthesized using anhydrous potassium carbonate as the catalyst. All the synthesized compounds were characterized by FT-IR, 1H NMR, 13C NMR spectral studies, LCMS, CHN Analysis and X-ray diffraction analysis (compound 7). In order to supplement the XRD parameters, molecular modelling was carried out by Gaussian 03W. From the optimized structure, the energy, dipolemoment and HOMO–LUMO energies of all the systems were calculated.
      Graphical abstract image Highlights Biologically active pyrazolines, synthesized and characterized by various spectroscopic techniques NMR, LCMS, CHN analysis, X-ray crystallographic and DFT calculations.

      PubDate: 2014-01-24T06:09:35Z
       
  • Dinuclear nickel(II) triple-stranded supramolecular cylinders: Syntheses,
           characterization and G-quadruplexes binding properties
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Xin-Xin Xu , Jing-Jing Na , Fei-Fei Bao , Wen Zhou , Chun-Yan Pang , Zaijun Li , Zhi-Guo Gu
      Three dinuclear nickel triple-stranded supramolecular cylinders [Ni2(L1)3][ClO4]4 (1), [Ni2(L2)3][ClO4]4 (2) and [Ni2(L3)3][ClO4]4 (3) with bis(pyridylimine) Schiff base containing triphenyl groups in the spacers as ligands were synthesized and characterized. The human telomeric G-quadruplexes binding properties of cylinders 1–3 were evaluated by means of UV–Vis spectroscopy, circular dichroism (CD) spectroscopy and fluorescence resonance energy transfer (FRET) melting assay. UV–Vis studies revealed that the supramolecular cylinders 1–3 could bind to G-quadruplex DNA with high binding constants (K b values ranging from 0.11–2.2×106 M−1). FRET melting studies indicated that the cylinders 1–3 had much stronger stabilizing effect on G-quadruplex DNA (ΔT m up to 24.5°C) than the traditional cylinder Ni 2 L 3 4 + just containing diphenylmethane spacers (ΔT m =10.6°C). Meanwhile, cylinders 1–3 were found to have a modest degree of selectivity for the quadruplex DNA versus duplex DNA in competition FRET assays. Moreover, CD spectroscopy revealed that complex 1 could induce G-quadruplex formation in the absence of metal ions solution and convert antiparallel G-quadruplex into hybrid structure in Na+ solution. These results provided a new insight into the development of supramolecular cylinders as potential anticancer drugs targeting G-quadruplex DNA.
      Graphical abstract image Highlights

      PubDate: 2014-01-24T06:09:35Z
       
  • A highly selective chemosensor for Al3+ based on
           2-oxo-quinoline-3-carbaldehyde Schiff-base
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Ke Zhang , Zheng-yin Yang , Bao-dui Wang , Shao-Bo Sun , Ying-Dong Li , Tian-rong Li , Zeng-chen Liu , Jun-mei An
      A new Schiff-base ligand (1) with good fluorescence response to Al3+, derived from 2-oxo-quinoline-3-carbaldehyde and nicotinic hydrazide, had been synthesized and investigated in this paper. Spectroscopic investigation revealed that the compound 1 exhibited a high selectivity and sensitivity toward Al(III) ions over other commonly coexisting metal ions in ethanol, and the detection limit of Al3+ ions is at the parts per billion level. The mass spectra and Job’s plot confirmed the 1:1 stoichiometry between 1 and Al3+. Potential utilization of 1 as intracellular sensors of Al3+ ions in human cancer (HeLa) cells was also examined by confocal fluorescence microscopy.
      Graphical abstract image

      PubDate: 2014-01-24T06:09:35Z
       
  • Li+-molecule interactions of lithium tetrafluoroborate in propylene
           carbonate + N,N-dimethylformamide mixtures: An FTIR spectroscopic study
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Binbin Zhang , Yuan Zhou , Xiang Li , Jingying Wang , Gang Li , Qiang Yun , Xiufang Wang
      FTIR (Fourier transformed infrared) spectra have been collected and analyzed for solutions of lithium tetrafluoroborate in propylene carbonate (PC), N,N-dimethylformamide (DMF), and PC+DMF mixtures. The band splitting and symmetric ring deformation for PC and OCN deformation for DMF suggest that there is a strong interaction between lithium cations and solvent molecules. The solvent molecules have been assigned to two types, the free and complexed molecules. By a comparison of the intensity for the corresponding bands, it has been concluded that Li+ cations are preferentially solvated by DMF molecules in the LiBF4/PC+DMF solutions. This has been explained by the difference in values of donor number (DN).
      Graphical abstract image Highlights

      PubDate: 2014-01-24T06:09:35Z
       
  • Binding of helicid to human serum albumin: A hybrid spectroscopic approach
           and conformational study
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Yuanyuan Yue , Jianming Liu , Ren Liu , Qiao Dong , Jing Fan
      The interaction between human serum albumin and helicid was studied by steady-state fluorescence, ultraviolet–visible, circular dichroism, Fourier transform infrared techniques and molecular modeling. The binding site numbers, association constants, and corresponding thermodynamic parameters were used to investigate the quenching mechanism. The alternations of protein secondary structure in the presence of helicid were demonstrated using synchronous fluorescence, Fourier transform infrared, circular dichroism and three-dimensional fluorescence spectra. The molecular modeling results revealed that helicid could bind to hydrophobic pocket of HSA with hydrophobic and hydrogen bond force. The binding site of helicid in HSA was ascertained. Moreover, an apparent distance of 3.33nm between the Trp214 and helicid was obtained via fluorescence resonance energy transfer method.
      Graphical abstract image Highlights The Scatchard plots for the fluorescence quenching of HSA in the presence of helicid and molecular docking analysis of HSA with helicid.

      PubDate: 2014-01-24T06:09:35Z
       
  • Temperature-dependent IR spectroscopic and structural study of 18-crown-6
           chelating ligand in the complexation with sodium surfactant salts and
           potassium picrate
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): Tea Mihelj , Vlasta Tomašić , Nikola Biliškov , Feng Liu
      18-crown-6 ether (18C6) complexes with the following anionic surfactants: sodium n-dodecylsulfate (18C6-NaDS), sodium 4-(1-pentylheptyl)benzenesulfonate (18C6-NaDBS); and potassium picrate (18C6-KP) were synthesized and studied in terms of their thermal and structural properties. Physico-chemical properties of new solid 1:1 coordination complexes were characterized by infrared (IR) spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray diffraction and microscopic observations. The strength of coordination between Na+ and oxygen atoms of 18C6 ligand does not depend on anionic part of the surfactant, as established by thermodynamical parameters obtained by temperature-dependent IR spectroscopy. Each of these complexes exhibit different kinds of endothermic transitions in heating scan. Diffraction maxima obtained by SAXS and WAXS, refer the behavior of the compounds 18C6-NaDS and 18C6-NaDBS as smectic liquid crystalline. Distortion of 18C6-NaDS and 18C6-KP complexes occurs in two steps. Temperature of the decomplexation of solid crystal complex 18C6-KP is considerably higher than of mesophase complexes, 18C6-NaDS, and 18C6-NaDBS. The structural and liquid crystalline properties of novel 18-crown-ether complexes are function of anionic molecule geometry, type of chosen cation (Na+, K+), as well as architecture of self-organized aggregates. A good combination of crown ether unit and amphiphile may provide a possibility for preparing new functionalized materials, opening the research field of ion complexation and of host–guest type behavior.
      Graphical abstract image Highlights

      PubDate: 2014-01-24T06:09:35Z
       
  • Quantum chemical determination of molecular geometries, interpretation of
           FT-IR, FT-Raman spectra and charge transfer properties for
           N-(2-cyanoethyl)-N-methylaniline
    • Abstract: Publication date: 24 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 124
      Author(s): B. Revathi , A. Nataraj , V. Balachandran
      FT-Raman and FT-IR spectra were recorded for N-(2-cyanoethyl)-N-methylaniline sample in solid state. The equilibrium geometries, harmonic vibrational frequencies, infrared and Raman scattering activities were computed using DFT method. Results obtained at this level of theory were used for a detailed interpretation of the infrared and Raman spectra, based on the potential energy distribution (PED) of the normal modes. Molecular parameters such as bond length, and bond angle were calculated with the same method. The intra-molecular charge transfer was calculated by means of natural bond orbital analysis (NBO). Hyperconjugative interaction energy was more during the π–π* transition. Energy gap of the molecule was found using HOMO and LUMO calculation, hence the less band gap, which seems to be more stable. Atomic charges of various atoms of title molecule and other thermo-dynamical parameters were calculated using same levels of calculation. The correlation equations between heat capacity, entropy, Gibb’s free energies changes with temperatures were fitted by quadratic formula. UV–VIS spectral analyses of title molecule have been researched by theoretical calculations. In order to understand electronic transitions of the compound, TD-DFT calculations on electronic absorption spectra in gas phase and solvent were performed. The calculated frontier orbital energies, absorption wavelengths (λ), oscillator strengths (f) and excitation energies (E) for gas phase in different solvent are also illustrated.
      Graphical abstract image Highlights

      PubDate: 2014-01-24T06:09:35Z
       
  • Growth, molecular structure, NBO analysis and vibrational spectral
           analysis of l-tartaric acid single crystal
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): V. Sasikala , D. Sajan , N. Vijayan , K. Chaitanya , M.S. Babu Raj , B.H. Selin Joy
      Single crystal of l-tartaric acid (LTA) has been grown by slow evaporation technique. The experimental and theoretical studies on molecular structure, vibrational spectra, electronic absorption spectra and non-linear optical property of the crystal are studied. The FT-IR, FT-Raman and UV–Vis–NIR experimental spectra of LTA crystal have been recorded in the range 400–4000cm−1, 100–3700cm−1 and 190–1100nm, respectively. Density functional theory calculations with B3LYP/6-311++G(d,p) basis sets was used to determine ground state molecular geometries, vibrational frequencies, ICT interactions, Mulliken population analysis on atomic charge, HOMO–LUMO analysis, non-linear optical response properties and thermodynamic properties for LTA and the results were discussed. Vibrational analysis confirms the formation of intramolecular OH⋯O hydrogen bonding. The stability of the molecule has been analyzed using NBO analysis. The results of electronic absorptions in gas phase and water phase LTA were calculated using TD-DFT method. The third-order nonlinear absorption behaviour of LTA was studied using open aperture Z-scan technique, with 5ns laser pulses at 532nm and the nonlinear absorption coefficient of the grown crystal was measured. The predicted NLO properties, UV absorption and Z-scan studies indicate that LTA is an attractive material for laser frequency doubling and optical limiting applications.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Crystal structure, thermal and spectral studies and growth of nonlinear
           optical L-lysinium fluoride crystal
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): R.P. Sukiasyan , H.A. Karapetyan , A.K. Atanesyan , R.A. Apreyan
      In current study properties of L-lysinium fluoride (L-Lys⋅HF) are determined by X-ray diffraction, infrared and Raman spectroscopy, SHG and by UV–vis transmittance spectrum measurement. L-Lys⋅HF (C6H15FN2O2), crystallizes in a monoclinic system with space group P21, a =5.464(1)Å, b =7.4717(15)Å, c =10.252(2)Å, α = γ =90°, β =99.17(3)°, Z =2, ρ c =1.336Mg/m3, ρ m =1.335(2)Mg/m3. By means of evaporation method high quality L-Lys⋅HF single crystals are grown from aqueous solutions. L-Lys⋅HF crystal is transparent in the wavelength region 240–1100nm and it exhibits powder SHG efficiency 0.65 times that of potassium dihydrogen phosphate (KDP).
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Fabrication of 2D nanosheet through self assembly behavior of
           sulfamethoxypyridazine inclusion complexes with α- and
           β-cyclodextrins
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): N. Rajendiran , G. Venkatesh , T. Mohandass
      A 2D nanosheet was fabricated through the supramolecular self assembly of sulfamethoxypyridazine (SMP) and β-cyclodextrin (β-CD) inclusion complexes. HRTEM image exhibited 2D nanosheet morphology with a length of 1200mm and the sheet thickness of 60mm. It is noted that the nanosheet did not form a single layer aggregation but a bulk aggregation of SMP/β-CD inclusion complex. The formation of this multilayer 2D nanosheet based on the self assembly of SMP/β-CD inclusion complexes is proposed by the topological transformation as well as molecular modeling calculations. But, nanorods are formed in SMP/α-CD inclusion complex indicated that the nature of the CD determined the shape of the self assembled supramolecular architecture. The formation of nanomaterial was characterized by using FT-IR, DSC, PXRD, 1H NMR, absorption, fluorescence and lifetime measurements.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Inter-hydrogen bond coupling in crystals of 3-phenylpyrazole polymorphs
           investigated by polarized IR spectroscopy
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Barbara Hachuła , Henryk T. Flakus , Aleksandra Garbacz , Agnieszka Stolarczyk
      The remarkably strong differences in the fine structure patterns of the νN–H and νN–D bands, temperature and H/D isotopic effects in crystals of two 3-phenylpyrazole (3PhPz) polymorphs, with tetrameric and hexameric hydrogen bond aggregates, were examined by polarized IR spectroscopy, aided by the calculations utilizing the “strong-coupling” model. Experimental and theoretical approaches have suggested that the anti-co-operativity of hydrogen bonds is the main factor responsible for the differences in the spectral properties of both polymorphs. This interaction affects hydrogen-bond geometry of the associates constituting the lattices and in consequence decides about the relative contribution of two different exciton coupling mechanism, “through-space” (SS) and “tail-to-head” (TH), in the spectra generation. The relative contribution of each individual exciton coupling mechanism in the spectra generation is temperature-dependent. In tetramers the TH coupling mechanism dominates at low temperatures, whereas the role of the SS mechanism increases at higher temperatures. For the hexamers the SS mechanism dominates in the wide temperature range. The two types of 3PhPz associates exhibit two different ways of occurring of the H/D isotopic recognition in the crystal hydrogen bonds. In the tetrameric polymorph identical hydrogen isotope atoms exist in entire hydrogen-bonded cycle of 3PhPz. In the case of 3PhPz hexamers, the H/D isotopic recognition mechanism involves pairs of the closely-spaced hydrogen bonds in a cycle.
      Graphical abstract image Highlights An experimental and theoretical study on inter-hydrogen bond interaction nature in crystals of two 3-phenylpyrazole polymorphs, with tetrameric and hexameric hydrogen bond aggregates, was reported.

      PubDate: 2014-01-08T11:20:05Z
       
  • Facile and low temperature route to synthesis of CuS nanostructure in
           mesoporous material by solvothermal method
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Sh. Sohrabnezhad , M.A. Zanjanchi , S. Hosseingholizadeh , R. Rahnama
      The synthesis of CuS nanomaterial in MCM-41 matrix has been realized by chemical synthesis between MCM-41, copper sulfate pentahydrate and thiourea via a solvothermal method in ethylene glycol and water, separately. X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FT-IR) were used to characterize the products. At synthesized CuS/MCM-41 sample in ethylene glycol, X-ray diffraction and diffuse reflectance spectroscopy showed pure covellite phase of copper sulfide with high crystality. But prepared CuS/MCM-41 sample in water shows the covellite, chalcocite and the djurleite phase of copper sulfide nanostructures. The formation of CuS nanostructures was confirmed by FT-IR. Photocatalytic activity of CuS/MCM-41 nanocomposites was studied for degradation of Methylene Blue (MB) under visible light. The CuS/MCM-41 nanocomposite is more effective nanocatalyst than synthesized CuS/MCM-41 sample in water for degradation of methylene blue. Several parameters were examined, catalyst amount (0.1–1gL−1), pH (1–13) and initial concentration of MB (0.96–10ppm). The extent of degradation was estimated from the residual concentration by spectrophotometrically. The support size was obtained in the range 60–145nm by TEM. In the same way, the average size of copper sulfide in CuSMCM-41E and CuS/MCM-41W nanostructures were obtained about 10nm and 16nm, respectively.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • Determination of ground and excited state dipole moments of dipolar laser
           dyes by solvatochromic shift method
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): S.K. Patil , M.N. Wari , C. Yohannan Panicker , S.R. Inamdar
      The absorption and fluorescence spectra of three medium sized dipolar laser dyes: coumarin 478 (C478), coumarin 519 (C519) and coumarin 523 (C523) have been recorded and studied comprehensively in various solvents at room temperature. The absorption and fluorescence spectra of C478, C519 and C523 show a bathochromic and hypsochromic shifts with increasing solvent polarity indicate that the transitions involved are π → π ∗ and n → π ∗. Onsager radii determined from ab initio calculations were used in the determination of dipole moments. The ground and excited state dipole moments were evaluated by using solvatochromic correlations. It is observed that the dipole moment values of excited states (μ e) are higher than corresponding ground state values (μ g) for the solvents studied. The ground and excited state dipole moments of these probes computed from ab initio calculations and those determined experimentally are compared and the results are discussed.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • Spectroscopic study on the reactions of bis-salophen with uranyl and then
           with fructose 1,6-bisphosphate and the analytical application
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Xing Shen , Lifu Liao , Lin Chen , Yunfei He , Canhui Xu , Xilin Xiao , Yingwu Lin , Changming Nie
      The chelating reaction of bis-salophen with uranyl to form binuclear complex uranyl-bis-salophen (UBS) was studied by fluorescence spectroscopy. The coordination reaction of UBS with fructose 1,6-bisphosphate (F-1,6-BP) to form supramolecular polymer was then studied by resonance light scattering (RLS) spectroscopy. The reaction of bis-salophen with uranyl results in a remarkable enhancement of fluorescence intensity. The maximum emission wavelength of the fluorescence is at 471nm. The reaction of UBS with F-1,6-BP results in a remarkable enhancement of RLS intensity. The maximum scattering wavelength of the RLS is at 460nm. The two reactions were used to establish fluorescence method for the determination of uranium (VI) and RLS method for the determination of F-1,6-BP, respectively. Under optimum conditions, the linear ranges for the detection of uranium (VI) and F-1,6-BP are 0.003–0.35nmol/mL and 0.05–5.0nmol/mL, respectively. The detection limits are 0.0017nmol/mL and 0.020nmol/mL, respectively. The proposed fluorescence method has been successfully applied for the determination of uranium (VI) in environmental water samples with the recoveries of 97.0–104.0%. The proposed RLS method has also been successfully applied for the determination of F-1,6-BP in medicine injection samples with the recoveries of 98.5–102.3%.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Comparison of rapidly synergistic cloud point extraction and
           ultrasound-assisted cloud point extraction for trace selenium coupled with
           spectrophotometric determination
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Xiaodong Wen , Yanyan Zhang , Chunyan Li , Xiang Fang , Xiaocan Zhang
      In this work, rapidly synergistic cloud point extraction (RS-CPE) and ultrasound-assisted cloud point extraction (UA-CPE) were firstly compared and coupled with spectrophotometer for selenium preconcentration and detection. The established RS-CPE pretreatment was simple, rapid and high effective. The extraction time was only 1min without heating process. Under the effect of ultrasound, UA-CPE accomplished extraction efficiently although the extraction procedure was relatively time-consuming. In this study, RS-CPE and UA-CPE were firstly applied for selenium preconcentration and coupled with conventional spectrophotometer. Their applications were expanded and the analytical performance of spectrophotometric determination for selenium was considerably improved. The influence factors relevant to RS-CPE and UA-CPE were studied in detail. Under the optimal conditions, the limits of detection (LODs) for selenium were respectively 0.2μgL−1 of RS-CPE and 0.3μgL−1 of UA-CPE with sensitivity enhancement factors (EFs) of 124 and 103. The developed methods were applied to the determination of trace selenium in real water samples with satisfactory analytical results.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Investigation of solvent polarity effect on molecular structure and
           vibrational spectrum of xanthine with the aid of quantum chemical
           computations
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Turgay Polat , Gurcan Yıldırım
      The main scope of this study is to determine the effects of 8 solvents on the geometric structure and vibrational spectra of the title compound, xanthine, by means of the DFT/B3LYP level of theory in the combination with the polarizable conductor continuum model (CPCM) for the first time. After determination of the most-steady state (favored structure) of the xanthine molecule, the role of the solvent polarity on the SCF energy (for the molecule stability), atomic charges (for charge distribution) and dipole moments (for molecular charge transfer) belonging to tautomer is discussed in detail. The results obtained indicate not only the presence of the hydrogen bonding and strong intra-molecular charge transfer (ICT) in the compound but the increment of the molecule stability with the solvent polarity, as well. Moreover, it is noted that the optimized geometric parameters and the theoretical vibrational frequencies are in good agreement with the available experimental results found in the literature. In fact, the correlations between the experimental and theoretical findings for the molecular structures improve with the enhancement of the solvent polarity. At the same time, the dimer forms of the xanthine compound are simulated to describe the effect of intermolecular hydrogen bonding on the molecular geometry and vibrational frequencies. It is found that the CO and NH stretching vibrations shift regularly to lower frequency value with higher IR intensity as the dielectric medium enhances systematically due to the intermolecular NH⋯O hydrogen bonds. Theoretical vibrational spectra are also assigned based on the potential energy distribution (PED) using the VEDA 4 program.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • FT-IR, FT-Raman spectra and other molecular properties of 2,4-
           dichlorobenzonitrile: A interpretation by a DFT study
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): D. Kattan , M. Alcolea Palafox , S. Kumar , D. Manimaran , Hubert Joe , V.K. Rastogi
      FT-IR and FT-Raman spectra of 2,4-dichlorobenzonitrile at room temperature have been recorded in the regions 200–3500cm− 1 and 0–3400cm− 1, respectively. The observed vibrational bands were analyzed and assigned to different normal modes of the molecule according to the Wilson’s notation. Density functional calculations were performed to support our frequency assignments. Specific scale equations deduced from the benzene molecule were employed to improve the calculated values. For the majority of the normal modes, the deviations between the corresponding experimental and scaled theoretical wavenumbers are located in the expected range. A correct characterization of each normal mode is of vital importance in the assignment of the observed bands, and the same has been successfully done by the aid of Potential Energy Distributions (PEDs) calculated separately for each normal mode of 2,4-dichlorobenzonitrile. The molecular structure was optimized and several thermodynamic parameters were determined. HOMO and LUMO orbital energy analysis were carried out.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction
           to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol
           complex from environmental and biological samples
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Sumaira Khan , Tasneem Gul Kazi , Mustafa Soylak
      A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid–liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40μgL−1 and 100, respectively. The relative standard deviation (RSD) of 50μgL−1 Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1–101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • DFT calculations and experimental FT-IR, dispersive-Raman and EPR spectral
           studies of Copper (II) chloride complex with 3-amino-1-methylbenzene
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Mustafa Kumru , Tayyibe Bardakçı , Sadik Güner
      In this study, we present the synthesis and the characterization of Copper (II) chloride complex with 3-amino-1-methylbenzene (3A1MB). This complex was characterized by vibrational and EPR spectroscopic techniques and elemental analysis. The molecular structure and spectrometry of this complex: Cu(3A1MB)2Cl2 and its ligand: 3A1MB have been investigated theoretically by performing DFT/B3LYP calculations. Cu(3A1MB)2Cl2 has been optimized as two conformers and the more stable conformer is determined. The optimized geometries and calculated vibrational frequencies have been evaluated via comparison with experimental values, and the normal modes were assigned on the basis of the percent potential energy distribution (PED). A good agreement between calculated and experimental data is observed.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • Investigation of the interaction between five alkaloids and human
           hemoglobin by fluorescence spectroscopy and molecular modeling
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Wu He , Huanjing Dou , Zhigang Li , Xiaogai Wang , Lvjing Wang , Ruiyong Wang , Junbiao Chang
      This work studied the interaction of human hemoglobin (HHb) with aminophylline, acefylline, caffeine, theophylline and diprophylline systematically by UV–vis absorption spectroscopy and fluorescence spectroscopy in combination with molecular modeling. Five alkaloids caused the fluorescence quenching of HHb by the formation of alkaloids-HHb complex. The binding constants and thermodynamic parameters were obtained. The hydrophobic and electrostatic interactions were the predominant intermolecular forces to stabilize these complexes. Results of thermodynamic analysis and molecular modeling showed that aminophylline was the strongest quencher and diprophylline was the weakest quencher.
      Graphical abstract image Highlights The synchronous fluorescence spectra of HHb in the absence and presence of Ami.

      PubDate: 2014-01-08T11:20:05Z
       
  • Photophysical behavior of some aromatic poly(1,3,4-oxadiazole-ether)s
           derivatives
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): A.M. Ipate , M. Homocianu , C. Hamciuc , A. Airinei , M. Bruma
      The change in electronic absorption and emission spectra of two fluorinated poly(1,3,4-oxadiazole-ether)s in neat and binary solvent mixtures has been studied. The optical properties, absorption and photoluminescence of these polymers were investigated in solution and in solid state. The results were discussed as a function of solvent nature, excitation wavelength and local solvent composition, X 2. The Catalan solvent scale was used for describing the solvatochromic shifts of the absorption and emission bands. The following binary solvent mixtures were used: chloroform-N,N′-dimethylformamide (CHCl3–DMF), chloroform–dimethyl sulfoxide (CHCl3–DMSO), and dimethylformamide–dimethyl sulfoxide (DMF–DMSO) and the influence of their composition on the absorption and emission maxima has been analyzed. The preferential solvation parameters such as local mole fraction ( X 2 L ), excess function (δ s2) and preferential solvation constant (K PS) were determined.
      Graphical abstract image Highlights Plot of ν ̃ 12 as a function of mole fraction of cosolvent for 6F–Ox in CHCl3–DMF binary mixtures (a) ground state (b) excited state. The straight lines represent ideal solvation. Experimental data were fitted to fourth order polynomials of the form ν ̃ 12 =A+Bx +Cx 2 +Dx 3 +Ex 4.

      PubDate: 2014-01-08T11:20:05Z
       
  • Molecular spectrum of lanthanide complexes with 2,3-dichlorobenzoic acid
           and 2,2-bipyridine
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Shu-Mei He , Shu-Jing Sun , Jun-Ru Zheng , Jian-Jun Zhang
      With 2,3-dichlorobenzoic acid as the first ligands and 2,2′-bipyridine as the second ligands, the lanthanide complexes [Ln(2,3-DClBA)3bipy]2 [Ln=Nd(a), Sm(b), Eu(c), Tb(d), Dy(e), Ho(f)] have been synthesized. By using Infrared (IR) and Raman (R) spectra, the characteristics of the groups can be identified. The bands of lanthanide complexes have been analyzed and attributed, and clearly demonstrated with the use of the complementarity of IR and R. The experiment reveals that the bands of complexes are affected by lanthanide elements (Ln). The frequency of stretching vibration and breathing vibration of ring, together with the stretching vibration of the carbonyl group (ν CO), tends to be rising as the atomic number of lanthanide increasing. Meanwhile, crystallography data demonstrate that the six carbonyl groups have different bond length and bond angle, which can lead to different vibration frequency. The second derivatives of IR show that there are multiple vibration frequencies existing in the symmetrical stretching vibration of the carbonyl group (ν sCO). Therefore the second derivative of IR spectrum is a characteristic band of different coordination modes of carbonyl group.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • A rhodamine derivative as selective fluorescent and colorimetric
           chemosensor for mercury (II) in buffer solution, test strips and living
           cells
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Meng Wang , Fan-Yong Yan , Yu Zou , Ning Yang , Li Chen , Li-Gong Chen
      In this paper, we reported a new rhodamine derivative bearing 2,4-dichloroquinazoline as a selective fluorescent chemosensor for Hg2+. The ring-opening process of spirolactam enabled the large fluorescent enhancement and colorimetric change by Hg2+ induced configuration transformation of the rhodamine. Moreover, the fluorescence changes of the chemosensor were dramatically specific for Hg2+ in the presence of other metal ions, which could meet the selective requirements for practical application. Under optimized experimental conditions, the linear response range covered the concentration range of Hg2+ from 0 to 1.0×10−6 M, and the limit of detection was calculated to be 2.7×10−8 M. In addition, the probe was also successfully applied to the determination of Hg2+ in water samples, test strips and living cells.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Improving surface-enhanced Raman scattering properties of TiO2
           nanoparticles by metal Co doping
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Libin Yang , Xiaoyu Qin , Mengdi Gong , Xin Jiang , Ming Yang , Xiuling Li , Guangzhi Li
      In this paper, pure and different amount Co ions doped TiO2 nanoparticles were synthesized by a sol–hydrothermal method and were served as SERS-active substrate. The effect of metal Co doping on SERS properties of TiO2 nanoparticles was mostly investigated. The results indicate that abundant metal doping energy levels can be formed in the energy gap of TiO2 by an appropriate amount Co ions doping, which can promote the charge transfer from TiO2 to molecule, and subsequently enhance SERS signal of adsorbed molecule on TiO2 substrate, and improve remarkably SERS properties of TiO2 nanoparticles.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • The spectroscopic (FT-IR, FT-Raman and NMR), NCA, Fukui function analysis
           first order hyperpolarizability, TGA of
           6-chloro-3,4dihydro-2H-1,2,4-benzothiazine-7-sulphonamide1,1-dioxide by ab
           initio HF and Density Functional method
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): E. Elamurugu Porchelvi , S. Muthu
      The Fourier-Transform Infrared and Fourier-Transform Raman spectra of 6-Chloro-3,4dihydro-2H-1,2,4-benzothiazine-7sulphonamide1,1-dioxide(6CDBSD) was recorded in the region 4000–450cm−1 and 4000–100cm−1respectively. Quantum chemical calculations of energies, geometrical structure and vibrational wave numbers of 6CDBSD were carried out by HF and DFT (B3LYP) method with 6-31G (d,p) basis set. The difference between the observed and scaled wavenumber value of most of the fundamentals is very small. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The linear polariazability (α) and the first order hyperpolarizability (β tot) values of the investigated molecule have been computed using HF and DFT with 6-31G (d,p) basis set. Stability of the molecule arising from hyper conjugative interaction and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The 1H and 13C Nuclear Magnetic Resonance (NMR) chemical shifts of the molecules were calculated using the Gauge-Invariant Atomic orbital (GIAO) method, confirms with the experimental values. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. Thermal stability of 6CDBSD was studied by thermo gravimetric analysis (TGA). Next Fukui functions was calculated to identify changes in the reactivity of molecule. Finally molecular electrostatic potential (MEP) and other molecular properties were performed.
      Graphical abstract image Highlights 6-Chloro-3,4dihydro-2H-1,2,4-benzothiazine-7-sulphonamide1,1-dioxide is diuretic which is commonly referred to as a water pill. The equilibrium geometry harmonic vibrational frequencies, infrared intensities and Raman scattering activities were calculated by HF and DFT method with 6-31G(d,p) basis set using Gaussian 03W program. The 1H and 13C Nuclear Magnetic Resonance (NMR) chemical shifts of the molecules were calculated using GIAO method.

      PubDate: 2014-01-08T11:20:05Z
       
  • Competitive interactions of anti-carcinogens with serum albumin: A
           spectroscopic study of bendamustine and dexamethasone with the aid of
           chemometrics
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Yong Wang , Ruirui Zhu , Yongnian Ni , Serge Kokot
      Interactions between the anti-carcinogens, bendamustine (BDM) and dexamethasone (DXM), with bovine serum albumin (BSA) were investigated with the use of fluorescence and UV–vis spectroscopies under pseudo-physiological conditions (Tris–HCl buffer, pH 7.4). The static mechanism was responsible for the fluorescence quenching during the interactions; the binding formation constant of the BSA–BDM complex and the binding number were 5.14×105 Lmol−1 and 1.0, respectively. Spectroscopic studies for the formation of BDM–BSA complex were interpreted with the use of multivariate curve resolution – alternating least squares (MCR–ALS), which supported the complex formation. The BSA samples treated with site markers (warfarin – site I and ibuprofen – site II) were reacted separately with BDM and DXM; while both anti-carcinogens bound to site I, the binding constants suggested that DXM formed a more stable complex. Relative concentration profiles and the fluorescence spectra associated with BDM, DXM and BSA, were recovered simultaneously from the full fluorescence excitation–emission data with the use of the parallel factor analysis (PARAFAC) method. The results confirmed that on addition of DXM to the BDM–BSA complex, the BDM was replaced and the DXM–BSA complex formed; free BDM was released. This finding may have consequences for the transport of these drugs during any anti-cancer treatment.
      Graphical abstract image Highlights Interaction between anti-carcinogens, bendamustine (BDM) and dexamethasone (DXM), with BSA was investigated under pseudo-physiological conditions (pH 7.4; fluorescence and UV–vis spectroscopies). DMX replaced the bound BDM in the BDM–BSA complex.

      PubDate: 2014-01-08T11:20:05Z
       
  • In situ Bronsted–Lowry acid catalyzed syntheses, characterization,
           single crystal XRD, electronic spectral-, DPPH radical scavenging-, and
           DNA protection studies of aryl-3,3′-bis(indolyl)methanes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): G.S. Suresh Kumar , A. Antony Muthu Prabhu , P.G. Seethalaksmi , N. Bhuvanesh , S. Kumaresan
      A series of novel aryl-3,3′-bis(indolyl)methanes (BIMs) were synthesized using indole and formylphenoxyaliphatic acid(s) in water in the absence of any catalyst. The formylphenoxyaliphatic acid behaves as an in situ Bronsted–Lowry acid catalyst in water. UV–Visible and fluorescence spectra of the compounds were recorded in selected solvents. The gas phase geometry optimization of the compounds were achieved using DFT calculations at B3LYP/3-21G(*) level of theory. The electronic properties, such as HOMO–LUMO energies were calculated using the above method based on the optimized structure. Compounds have better DPPH radical scavenging activity and reduction of oxidative damage of DNA.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • Selective coordination ability of sulfamethazine Schiff-base ligand
           towards copper(II): Molecular structures, spectral and SAR study
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Ahmed M. Mansour
      In the present work, a combined experimental and theoretical study of the N-(4,6-Dimethyl-pyrimidin-2-yl)-4-[(2-hydroxy-benzylidene)amino]benzenesulfonamide ligand (H2L) and its mononuclear and magnetically diluted binuclear CuII complexes has been performed using IR, TG/DTA, magnetic, EPR, and conductivity measurements. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using the MPW1PW91 functional. Coordination of H2L to a CuII center, regardless of the binding site and Cu:L stoichiometry, leads to a significant decrease in the antibacterial activity compared to the free ligand as well as reference drugs in the case of Staphylococcus aureus. Structural-activity relationship suggests that E LUMO, ΔE, dipole moment, polarizability and electrophilicity index were the most significant descriptors for the correlation with the antibacterial activity.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Synthesis, crystal structure, photoluminescence property and
           photoelectronic behavior of two uranyl-organic frameworks constructed from
           1, 2, 4, 5-benzenetetracarboxylic acid as ligand
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Ya-Nan Hou , Yong-Heng Xing , Feng-Ying Bai , Qing-Lin Guan , Xuan Wang , Rui Zhang , Zhan Shi
      By using 1, 2, 4, 5-benzenetetracarboxylic acid as organic ligands, two uranyl coordination complexes, (UO2)2(bta)(DMA)2 (1) and [(UO2)2(bta)(μ3-OH2)]·2[HN(CH3)2]·H2O (2) (H4bta=1, 2, 4, 5-benzenetetracarboxylic acid, DMA=N,N-Dimethylacetamide) were synthesized. The X-ray single crystal analysis revealed that complex 1 exhibits a 3-demensional framework, while complex 2 exhibits a 2-demensional framework. In order to furthermore characterize the two complexes and extend their functional properties, spectroscopies of IR, UV–vis, photoluminescence and surface photovoltage were also studied primarily. In addition, thermogravimetric analyses and photocatalytic studies for complexes 1 and 2 were discussed in detail.
      Graphical abstract image Highlights Two coordination polymers, (UO2)2(bta)(DMA)2 (1) and [(UO2)2(bta)(μ3-OH2)]·2[HN(CH3)2]·H2O (2) (H4bta=1,2,4,5-benzenetetracarboxylic acid, DMA=N,N-Dimethylacetamide) have been firstly synthesized. Complexes 1 and 2 are both crystallizing in monoclinic, space group P21/c. The phtoelectronic property of the two complexes had been studied in detail.

      PubDate: 2014-01-08T11:20:05Z
       
  • Analysis of variation matrix array by bilinear least
           squares–residual bilinearization (BLLS–RBL) for resolving and
           quantifying of foodstuff dyes in a candy sample
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Karim Asadpour-Zeynali , S. Maryam Sajjadi , Fatemeh Taherzadeh , Reza Rahmanian
      Bilinear least square (BLLS) method is one of the most suitable algorithms for second-order calibration. Original BLLS method is not applicable to the second order pH-spectral data when an analyte has more than one spectroscopically active species. Bilinear least square-residual bilinearization (BLLS–RBL) was developed to achieve the second order advantage for analysis of complex mixtures. Although the modified method is useful, the pure profiles cannot be obtained and only the linear combination will be obtained. Moreover, for prediction of analyte in an unknown sample, the original algorithm of RBL may diverge; instead of converging to the desired analyte concentrations. Therefore, Gauss Newton-RLB algorithm should be used, which is not as simple as original protocol. Also, the analyte concentration can be predicted on the basis of each of the equilibrating species of the component of interest that are not exactly the same. The aim of the present work is to tackle the non-uniqueness problem in the second order calibration of monoprotic acid mixtures and divergence of RBL. Each pH-absorbance matrix was pretreated by subtraction of the first spectrum from other spectra in the data set to produce full rank array that is called variation matrix. Then variation matrices were analyzed uniquely by original BLLS–RBL that is more parsimonious than its modified counterpart. The proposed method was performed on the simulated as well as the analysis of real data. Sunset yellow and Carmosine as monoprotic acids were determined in candy sample in the presence of unknown interference by this method.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Theoretical investigation of phenothiazine–triphenylamine-based
           
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Ximing Chen , Chunyang Jia , Zhongquan Wan , Jiaqiang Zhang , Xiaojun Yao
      Three phenothiazine–triphenylamine-based organic dyes (CD-1, CD-2 and CD-3) are designed based on the dye WD-8. The geometries, electronic structures, and electronic absorption spectra of these dyes before and after binding to TiO2 are studied by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The calculated geometries indicate that these dyes show good steric hindrance effect which is advantage to inhibit the close intermolecular π–π aggregation effectively. The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels of these dyes could ensure positive effect on the process of electron injection and dye regeneration. The simulated spectra of CD-1∼3 show better absorption than that of WD-8 in the low energy zone. All the calculated results demonstrate that these dyes could be used as potential sensitizers for DSSCs and show better performances than WD-8.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • DFT calculations of structure and vibrational properties of
           2,2,2-trichloroethylacetate, CH3CO2CH2CCl3
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Diego M. Gil , María E. Tuttolomondo , Aída Ben Altabef
      The molecular structure and conformational properties of 2,2,2-trichloroethylacetate, CH3CO2CH2CCl3, were determined by ab initio (MP2) and DFT quantum chemical calculations at different levels of theory. The theoretical study was complemented with experimental measurements such as IR and Raman spectroscopy. The experimental and calculations confirm the presence of two conformers, one with anti, gauche conformation (C1 symmetry) and another with anti, anti form (Cs symmetry). The conformational preference was studied using the total energy scheme, NBO and AIM analysis. The infrared spectra of CH3CO2CH2CCl3 are reported in the liquid and solid phases and the Raman spectrum in liquid phase. Using calculated frequencies as a guide, evidence for both C1 and Cs conformers is obtained in the IR and Raman spectra.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • A novel method for aqueous synthesis of CdTe duantum dots
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Lei Feng , Huiyan Kuang , Xiaoyun Yuan , Haowen Huang , Shoujun Yi , Tianlun Wang , Keqin Deng , Chunran Tang , Yunlong Zeng
      We have developed a simple and an economical one-pot method to synthesize water-soluble CdTe quantum dots (QDs) using hydroxylamine hydrochloride (HAH) as reduction and l-cysteine (CYS) as the ligand. The size of the CdTe QDs could easily be controlled by the duration of reflux and monitored by absorption and photoluminescence spectra. The factors influencing the photoluminescence quantum yields (PL QYs) on the QYs of CdTe NCs were investigated and the optimum conditions were determined. Under the optimum conditions (pH=11.0, the concentration of Cd2+ was 1.0mmolL−1 and the molar ratio of Cd2+:Te2 −:CYS:HAH was 1:0.05:2.4:5), photoluminescence quantum yields of the CdTe QDs have been improved significantly and the maximum QYs of the QDs can achieve to 47%. The QDs were characterized by Fourier transform infrared spectrometry (FTIR), transmission-electron microscopy (TEM) and X-ray powder diffraction (XRD). The XRD patterns indicated that CdS was formed in the preparation process of CdTe QDs. This CdS shell could effectively passivate the surface trap states, and enhance the PL QY and stability of the CdTe QDs.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Effect of pH on the fluorescence characteristics of some flavones probes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Mariana Voicescu , Sorana Ionescu , Florentina Gatea
      The photophysical properties such as electronic absorption, molar extinction coefficient, emission spectra, fluorescence quantum yield and lifetime of three different hydroxyflavones (a typical model of flavonols) such as: 3-HF, 3,6-diHF and 3,7-diHF, have been studied in the pH range from 2.5 to 9.2. Both electronic absorption and fluorescence spectra are sensitive to pH. The fluorescence quantum yield at pH 7.4 of the mentioned flavones probes have been determined. The fluorescence lifetime of different emissive species (Normal, Tautomer and Anion forms) as pH dependence have been also estimated. The effect of pH on the intramolecular excited state proton transfer process (ESIPT) has been discussed. The normal and tautomeric forms change as a function of pH, the normal one being more sensitive. The position of the –OH group on the second aromatic ring in the flavonol’s structure has been also discussed. The results have relevance to compounds which have photoreactions accompanied by dual fluorescence.
      Graphical abstract image Highlights

      PubDate: 2014-01-08T11:20:05Z
       
  • Molecular structure, vibrational investigation of
           2-chloro-α-α-α-trifluoro-3,5-dinitrotoluene using DFT
           (LSDA, B3LYP, B3PW91 and MPW1PW91) and UV–Vis absorption spectra in
           organic solvents: A IEF-PCM/TD-DFT study
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): R. Gayathri , M. Arivazhagan
      Theoretical Spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra. The effect of solvent polarity on the optimized structure is studied by the density functional theory calculation (LSDA, B3LYP, B3PW91 and MPW1PW91 with 6-311++G(d,p)) in gas phase and selected solvents benzene (non-polar solvent), tetrahydrofuran THF (polar aprotic solvent), DMSO, Methanol (polar solvent) and water (protic solvent). In addition variation of dipole moment and charges on atoms in the solvents are studied. With the help of TD-DFT study, the electrostatic effects of different solvents and the energy difference between the excited electronic states noticeably depends on the size of the solute cavity used in the PCM calculations. On the basis of the thermodynamic properties of the title compound at different temperatures have been calculated in gas phase, reverling the correlations between standard heat capacities (C), standard entropies (S), standard enthalpy (H) and vibrational and rotational temperatures. The solvation influence on the geometrical parameters, atomic charges and HOMO–LUMO energies was estimated with the use of PCM method. The presence of solvent did not alter these parameters, but affected the orbital energies. The aggregation phenomena were studied with dimer and trimer structure of the title compound.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • Specific binding and inhibition of 6-benzylaminopurine to catalase:
           Multiple spectroscopic methods combined with molecular docking study
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Qin Xu , Yanni Lu , Longyun Jing , Lijuan Cai , Xinfeng Zhu , Ju Xie , Xiaoya Hu
      6-Benzylaminopurine (6-BA) is a kind of cytokinin which could regulate the activities of the antioxidant defense system of plants. In this work, its interaction with and inhibition of beef liver catalase have been systematically investigated using spectroscopic, isothermal titration calorimetric and molecular docking methods under physiological conditions. The fluorescence quenching of beef liver catalase (BLC) by 6-BA is due to the formation of 6-BA–BLC complex. Hydrogen bonds and van der Waals interactions play major roles in stabilizing the complex. The Stern–Volmer quenching constant, binding constant, the corresponding thermodynamic parameters and binding numbers were measured. The results of UV–vis absorption, three-dimensional fluorescence, synchronous fluorescence and circular dichroism spectroscopic results demonstrate that the binding of 6-BA results in the micro-environment change around tyrosine (Tyr) and tryptophan (Trp) residues of BLC. The BLC-mediated conversion of H2O2 to H2O and O2, in the presence and absence of 6-BA, was also studied. Lineweaver–Burk plot indicates a noncompetitive type of inhibition. Molecular docking study was used to find the binding sites.
      Graphical abstract image

      PubDate: 2014-01-08T11:20:05Z
       
  • A long persistent phosphor based on recombination centers originating from
           Zn imperfections
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Yang Li , Xi Du , Kaniyarakkal Sharafudeen , Chenxing Liao , Jianrong Qiu
      The recombination luminescence from Zn imperfections has been extensively investigated; however, there have been few reports on the long persistent luminescence of Zn imperfections as emitting centers. Here, we observed a long persistent luminescence in blue-white visible region from 6 ZnO:3 GeO2:Al2O3 phosphor with Zn imperfections as emitting centers. Persistent luminescence could be observed beyond 2h with naked eyes. The properties of traps were also elaborated by the measurements of thermo-luminescence spectra and photo-stimulated luminescence decay curves. Furthermore, a long persistent phosphor with warm white color was developed by doping Cr3+ into 6 ZnO:3 GeO2:Al2O3 phosphor.
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Fluorescence spectra and crystal field analysis of BaMoO4: Eu3+ phosphors
           for white light-emitting diodes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Bo Wu , Weiqing Yang , Honggang Liu , Li Huang , Bowen Zhao , Ce Wang , Guoliang Xu , Yuan Lin
      The red phosphors play a vital role in controlling luminous efficiency, color rendering index and adjustability in color temperature of white light emitting diodes (w-LEDs). Here, we demonstrate a type of red-emitting phosphors Eu3+-doped barium molybdate phosphors effectively excited by the blue light (464nm). These phosphors present the strong emission spectra around 613nm and their color coordinate values are close to the NTSC standard values. More importantly, by constructing a complete 3003×3003 energy matrix by an effective operator Hamiltonian including the free ion and crystal field interactions, for the first time, the fluorescent mechanism for Eu3+ ions at the tetragonal (S 4) Ba2+ site of BaMoO4 crystal were investigated by a complete diagonalization (of energy matrix) method (CMD). The fitting values are close to the experimental results, demonstrating the feasibility of using the complete diagonalization method to study the phosphors for w-LEDs.
      Graphical abstract image Highlights A type of as-grown red Eu3+-doped barium molybdate phosphors shows the strong emission spectra around 613nm. By constructing a complete 3003×3003 energy matrix, for the first time, the spectra positions for Eu3+ ions at the tetragonal (S 4) Ba2+ site of BaMoO4 crystal were accurately identified from a complete diagonalization (of energy matrix) method. The fitting values are close to the experimental results, demonstrating the feasibility of using the complete diagonalization method to study the phosphors for w-LEDs.

      PubDate: 2014-01-04T05:28:09Z
       
  • Hg2+ mediated quinazoline ensemble for highly selective recognition of
           Cysteine
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Thangaraj Anand , Gandhi Sivaraman , Duraisamy Chellappa
      A fluorimetric sensor for Hg2+ ion and Cysteine based on quinazoline platform was designed and synthesized by one step reaction and characterized by using common spectroscopic methods. Time Dependent Density Functional Theory calculations shows that probe behaves as “ON–OFF” fluorescent quenching sensor via electron transfer/heavy atom effect. Receptor was found to exhibit selective fluorescence quenching behavior over the other competitive metal ions, and also the receptor-Hg2+ ensemble act as an efficient “OFF–ON” sensor for Cysteine. Moreover this sensor has also been successfully applied to detection of Hg2+ in natural water samples with good recovery.
      Graphical abstract image Highlights

      PubDate: 2014-01-04T05:28:09Z
       
  • Synthesis and spectroscopic characterization of magnesium oxalate
           nano-crystals
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): S. Lakshmi Reddy , T. Ravindra Reddy , G. Siva Reddy , Tamio Endo , Ray L. Frost
      Synthesis of MgC2O4⋅2H2O nano particles was carried out by thermal double decomposition of solutions of oxalic acid dihydrate (C2H2O4⋅2H2O) and Mg(OAc)2⋅4H2O employing CATA-2R microwave reactor. Structural elucidation was carried out by employing X-ray diffraction (XRD), particle size and shape were studied by transmission electron microscopy (TEM) and nature of bonding was investigated by optical absorption and near-infrared (NIR) spectral studies. The powder resulting from this method is pure and possesses distorted rhombic octahedral structure. The synthesized nano rod is 80nm in diameter and 549nm in length.
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Synthesis, crystal structures and spectral properties of
           6′-phenyl-2,2′-bipyridine derivatives and their CdLI2
           complexes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Xuesong Zhao , Yanxin Chen , Junshan Luo , Hui Wang , Shengli Li , Hongping Zhou , Jieying Wu , Yupeng Tian
      Two novel 6′-phenyl-2,2′-bipyridine ligands (L1, L2) and their CdL1,2 I2 complexes (1, 2) were synthesized and characterized by elemental analysis, 1H NMR, IR, MALDI-TOF spectroscopy, and single crystal X-ray diffraction analysis. The results reveal that the central cadmium(II) atom in the complexes was coordinated by two iodide ions and two nitrogen atoms from L1, L2, forming a distorted coordination geometry. The electronic absorption properties of them were investigated on the basis of theoretical calculations (TD-DFT).
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Spectroscopic and quantum chemical investigations of substituent effects
           on the azo-hydrazone tautomerism and acid–base properties of arylazo
           pyridone dyes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): J. Dostanić , D. Mijin , G. Ušćumlić , D.M. Jovanović , M. Zlatar , D. Lončarević
      A series of 5-(4-substituted arylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone dyes was synthesized and the structure of the dyes was confirmed by UV–Vis, FT-IR, 1H NMR and 13C NMR spectroscopic techniques. The azo-hydrazone tautomeric equilibrium was found to depend on the substituents as well as on the acidity and basicity of the media. Ionization constant, pK a, of the dyes was determined by UV–Vis spectroscopy and correlated with the Hammett substituent constants, σ p and σ I. The interpretation of the effect of different substituent in phenyl ring of arylazo pyridone dyes on their spectroscopic and structural properties was based on quantum chemical calculations performed by the density functional theory (DFT/M06-2X) method. The DFT calculations confirmed the existence of two forms in water solution: hydrazone form in acidic and neutral media and anionic form in basic media. The different contribution of azo and hydrazone canonical forms of anionic form is observed for dyes with electron-donating and dyes with electron-withdrawing groups. The dependence of absorption spectra and determined pK a values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form.
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Synthesis and nonlinear optical properties in the near-IR range of
           stilbazolium dyes
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Fuying Hao , Dongpo Zhu , Jilong Ma , Lanlan Chai
      A series of stilbazolium salts based on donor-π-acceptor (D-π-A) structure have been synthesized and fully characterized. Photophysical properties including linear absorption, one-photon excited fluorescence (OPEF), two-photon absorption (2PA) properties were systematically investigated. The results suggest that increasing electron-releasing character of the terminal group leads to a more pronounced donor-to-acceptor intramolecular charge transfer (ICT). In addition, the dyes possess the largest 2PA cross sections in the near infrared region (NIR) and display maximum two-photon absorption cross sections within the narrow wavelength range from 950 to 970nm and BL3 exhibits a large nonlinear refractive index coefficient and possesses very large values of the real part of the cubic hyperpolarizability χ (3) at 960nm. Furthermore, the initial density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations provide reasonable explanations for their absorption spectra, meanwhile we used the Lippert–Mataga equation to evaluate the dipole moment changes of the dyes with photoexcitation, the results are corresponding with linear and nonlinear optical properties of the dyes.
      Graphical abstract image Highlights A series of D-π-A type two-photon absorption organic salts based on pyridinium were and synthesized. Experimental results revealed the dyes possess the largest 2PA cross sections in the near infrared region (NIR) and display maximum two-photon absorption cross sections within the narrow wavelength range from 950 to 970nm. Furthermore, the 2PA cross section values present enhanced trend in turn with the lengthen of the alkyl chain. In addition, we used the Lippert–Mataga equation to evaluate the dipole moment changes of the dyes with photoexcitation, the results are corresponding with linear and nonlinear optical properties of the dyes.

      PubDate: 2014-01-04T05:28:09Z
       
  • Vibrational spectroscopy of the multianion mineral gartrellite from the
           Anticline Deposit, Ashburton Downs, Western Australia
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Andrés López , Ray L. Frost , Yunfei Xi
      The multianion mineral gartrellite PbCu(Fe3+,Cu)(AsO4)2(OH,H2O)2 has been studied by a combination of Raman and infrared spectroscopy. The molecular structure of gartrellite is assessed. Gartrellite is one of the tsumcorite mineral group based upon arsenate and/or sulphate anions. Crystal symmetry is either triclinic in the case of an ordered occupation of two cationic sites, triclinic due to ordering of the H bonds in the case of species with two water molecules per formula unit, or monoclinic in the other cases. Characteristic Raman spectra of the mineral gartrellite enable the assignment of the bands to specific vibrational modes. These spectra are related to the structure of gartrellite. The position of the hydroxyl and water stretching vibrations are related to the strength of the hydrogen bond formed between the OH unit and the AsO 4 3 - anion.
      Graphical abstract image Highlights

      PubDate: 2014-01-04T05:28:09Z
       
  • Structural, spectral, pH-metric and biological studies on mercury (II),
           cadmium (II) and binuclear zinc (II) complexes of NS donor
           thiosemicarbazide ligand
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Ola A. El-Gammal , Gaber M. Abu El-Reash , Mohammed M. El-Gamil
      Hg(II), Cd(II) and binuclear Zn(II) complexes derived from the tetradentate N1-ethyl-N2-(pyridine-2-yl) hydrazine-1, 2-bis (carbothioamide) ligand (H2PET) have been prepared and characterized by conventional techniques. The isolated complexes acquired the formulas, [Hg(HPET)(H2O)2Cl]⋅H2O, [Cd(HPET)Cl] and [Zn2(HPET)(PET)(OAc)]⋅H2O, respectively. IR data revealed that the ligand behaves as monobasic tridentate through (CN)py, (C–S) and new ( NC ) azomethine ∗ groups in both Hg(II) and Cd(II) complexes. In the binuclear Zn(II) complex, the behavior of ligand contains two types, where H2PET acts as dibasic tetradentate via (CN)py, both deprotonated (C–SH) and the new ( NC ) azomethine ∗ towards two Zn atoms and also it acts as monobasic tridentate via (CS), deprotonated (C–SH) and (CN)py towards the same Zn atoms. An octahedral geometry for Hg(II) complex and tetrahedral geometry for both Cd(II) and Zn(II) complexes were proposed. The bond lengths, bond angles, HOMO, LUMO and dipole moment have been calculated by DFT using materials studio program to confirm the geometry of ligand and its metal complexes. The association constant of the ligand and the stability constants of its complexes as well as the thermodynamic parameters were calculated by pH metric measurements at 298, 308 and 318K in 50% dioxane–water mixture, respectively. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz–Metzger methods. Moreover, the anti-oxidant (using ABTS and DPPH methods), anti-hemolytic, and cytotoxic activities of the compounds have been tested.
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Theoretical and experimental study of a novel psolaren derivate:
           (E)-9-(3,4-dimethylpent-2-enyloxy)-7H-furo[3,2-g]chromen-7-one
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): S. Turbay , O.E. Piro , G.A. Echeverría , A. Navarro , M.P. Fernández-Liencres , M. Fortuna , M.E. Tuttolomondo
      A new psolaren derivate, (E)-9-(3,4-dimethylpent-2-enyloxy)-7H-furo[3,2-g]chromen-7-one, has been isolated and characterized by experimental and theoretical methodologies. The solid state molecular structure has been determined by X-ray diffraction methods. The substance crystallizes in the monoclinic P21/c space group with a =4.2389(5), b =26.090(3), c =12.482(1)Å, β =96.990(9)°, and Z =4 molecules per unit cell. The crystal structure shows the molecule fused phenyl and hetero-cycle rings to be coplanar with each other. Ab initio(MP2) and DFT methods have been used to predict the molecular structure in the isolated molecule approximation and the results compared with the experimental data. The MP2/6-311G(d,p) calculations are in good agreement with the X-ray results. The calculated HOMO–LUMO energy gap shows that the intra-molecular charge transfer could easily occur, a prediction closely related to the observed bioactivity of this new compound. In addition, the infrared absorption and Raman dispersion spectra were recorded and an assignment of the observed spectral features to molecular vibrations was made. The vibrational study was assisted by quantum chemistry calculations at the MP2 and DFT level, which provided theoretical mode frequencies. The study was completed by natural bond orbital (NBO) analysis.
      Graphical abstract image Highlights A novel psolaren derivate (E)-9-(3,4-dimethylpent-2-enyloxy)-7H-furo[3,2-g]chromen-7-one, named 8-IOP, which has been recently isolated and chemically characterized. The molecular structure has been studied experimentally by X-ray diffraction methods and theoretically calculations. In addition, the UV/VIS, Raman and infrared spectra were measured for the substance and the vibrational wavenumbers calculated by quantum chemistry procedures.

      PubDate: 2014-01-04T05:28:09Z
       
  • Growth, optical, luminescence, thermal and mechanical behavior of an
           
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): M. Nirosha , S. Kalainathan , S. Sarveswari , V. Vijayakumar
      A single crystal of 3-acetyl-2-methyl-4-phenylquinolin-1-ium chloride has grown by slow evaporation solution growth technique using ethanol as solvent. The structural, thermal, optical and mechanical property has studied for the grown crystal. Single crystal XRD revealed that the crystal belongs to monoclinic system with space group P21/c. The presences of Functional groups in the crystallized material have confirmed using the FTIR vibrational spectrum. The optical absorbance spectrum recorded from 190 to 1100nm shows the cut-off wavelength occurs at 371nm. The material shows its transparency in the entire region of the visible spectrum. The photoluminescence spectrum shows the ultraviolet and blue emission in the crystal. Thermogravimetric and differential thermal analysis reveal the thermal stability of the grown crystal. Etching study shows the grown mechanism and surface features of the crystal. Vickers microhardness studies have carried out on the (01-1) plane to understand the mechanical properties of the grown crystal. The hardness of the title compound increases on increasing the load. The Meyer’s index number (n), and the stiffness constants for different loads has calculated and reported.
      Graphical abstract image Highlights

      PubDate: 2014-01-04T05:28:09Z
       
  • Preconcentration of Sn (II) using the methylene blue on the activated
           carbon and its determination by spectrophotometry method
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Saeid Khodadoust , Narges Cham kouri
      A simple and accurate spectrophotometric method for determination of trace amounts of Sn (II) ion in soil sample was developed by using the methylene blue (MB) in the presence of activated carbon (AC) as the adsorbent Solid Phase Extraction (SPE) of Sn (II) and then determined by UV–Vis. The Beer’s law is obeyed over the concentration range of 1–80ngmL−1 of Sn (II) with the detection limits of 0.34ngmL−1. The influence of type and volume of eluent, concentration of MB, pH, and amount of AC on sensitivity of spectrophotometric method were optimized. The method has been successfully applied for Sn (II) ion determination in soil sample.
      Graphical abstract image

      PubDate: 2014-01-04T05:28:09Z
       
  • Pd(II) complexes based on quinoline derivative: Structural
           characterization and their role as a catalyst for hydrogenation of
           (E)-1-methyl-4-(2-nitrovinyl)benzene
    • Abstract: Publication date: 5 April 2014
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 123
      Author(s): Mohammad Azam , Mohammad Shahidul Islam , Saud I. Al-Resayes , M. Rafiq Siddiqui , Agata Trzesowska-Kruszynska , Rafal Kruszynski
      A series of two new Pd(II) complexes with ligand, HL, (z)-2-((quinolin-3-ylimino)methyl)phenol, derived from 3-aminoquinoline and 2-hydroxybenzaldehyde was reported. The structure of ligand, HL was determined by single crystal X-ray diffraction. The ligand, HL crystallizes in the space group P21/n of the monoclinic system with unit cell dimensions a =8.8733(8), b =6.3318(5), c =11.5145(9). The reaction of ligand, HL with PdX2 [X=Cl−, OAc] in 2:1molar ratio yielded complexes of the type [Pd(HL)2X2] [X=Cl−, OAc]. The ligand, HL and its Pd(II) complexes were characterized by various physico-chemical techniques; elemental analyses, ionization mass spectrometry (ESI-MS), UV/Vis, FT-IR, 1H and 13C NMR spectroscopy. UV/Vis absorption studies showed a square planar geometry around Pd (II) ion. The selective hydrogenation of (E)-1-methyl-4-(2-nitrovinyl)benzene in ethanol using synthesized Pd(II) complexes as catalysts was investigated at room temperature. The Pd(II) complexes catalyzed the hydrogenation of (E)-1-methyl-4-(2-nitrovinyl)benzene to (E)-1-methyl-4-(2-aminovinyl) benzene. Furthermore, the catalytic activity increased with increasing the quantity of Pd(II) complexes as catalysts.
      Graphical abstract image

      PubDate: 2013-12-30T19:52:40Z
       
 
 
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