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Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.628]   [H-I: 64]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [2970 journals]
  • Surface-enhanced Raman scattering studies of the reduction of
           p-nitroaniline catalyzed by a nanonized Ag porous-glass hybrid composite
    • Abstract: Publication date: 5 September 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 166
      Author(s): Genin Gary Huang, Nga-Lai Sou, Mei-Jou Hung
      Nanonized noble metal composites have been known for their excellent catalytic properties. However, the mechanism and intermediates formed on the surfaces of nanocatalysts during catalysis are speculated with mostly insufficient evidence. In this study, to obtain further understanding of the roles of noble metal nanocatalysts in a catalytic reaction, surface-enhanced Raman scattering (SERS) was used to monitor the surfaces of silver (Ag) nanocatalysts. Furthermore, UV–Vis spectrometry was used to trace the concentration variations of reactants and products in bulk solutions, thereby correlating the variations of the Ag nanocatalyst surfaces with those in the bulk solutions. Nanonized Ag porous-glass hybrid composites were prepared by reducing naked Ag nanoparticles on porous-glass filter plates and were used as catalysts for nitroanilines reduction. The complete process was monitored using SERS and UV–Vis spectrometry simultaneously. The results indicated that the reactant and product molecules adsorbed on the Ag nanocatalysts can reach equilibrium, and the equilibrium is affected by the reaction conditions, including reducing agent concentration, pH of the reaction system, and temperature. In addition, the reduction of reactants in the bulk solutions is also related to the behavior of Ag nanocatalyst surfaces. Furthermore, Ag nanocatalysts can act as electron relays even if their surfaces are occupied by reactants and products. Analyzing the collected SERS and UV–Vis spectra can provide a new insight into Ag nanoparticle catalysis, and the role of Ag nanocatalysts can be further comprehended.
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      PubDate: 2016-05-17T13:39:35Z
       
  • A novel ratiometric two-photon fluorescent probe for imaging of Pd2+ ions
           in living cells and tissues
    • Abstract: Publication date: 5 September 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 166
      Author(s): Liyi Zhou, Shunqin Hu, Haifei Wang, Hongyan Sun, Xiaobing Zhang
      Ratiometric two-photon fluorescent probes can not only eliminate interferences from environmental factors but also achieve deep-tissue imaging with improved spatial localization. To quantitatively track Pd2+ in biosystems, herein, we reported a ratiometric two-photon fluorescent probe, termed as Np-Pd, which based on a D-π-A-structure two-photon fluorophore of the naphthalimide derivative and deprotection of aryl propargyl ethers by palladium species. The probe Np-Pd displayed a more than 25-fold enhancement towards palladium species with high sensitivity and selectivity. Additionally, the probe Np-Pd was further used for fluorescence imaging of Pd2+ ions in living cells and tissues under two-photon excitation (820nm), which showed large tissue-imaging depth (19.6–184.6μm), and a high resolution for ratiometric imaging.
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      PubDate: 2016-05-17T13:39:35Z
       
  • Structure, IR and Raman spectra of phosphotrihydrazide studied by DFT
    • Abstract: Publication date: 5 September 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 166
      Author(s): V.L. Furer, A.E. Vandyukov, J.P. Majoral, A.M. Caminade, V.I. Kovalenko
      The FTIR and FT Raman measurements of the phosphotrihydrazide (S)P[N(Me)-NH2]3 have been performed. This compound is a zero generation dendrimer G 0 with terminal amine groups. Structural optimization and normal mode analysis were obtained for G 0 by the density functional theory (DFT). Optimized geometric bond length and angles obtained by DFT show good agreement with experiment. The amine terminal groups are characterized by the well-defined bands at 3321, 3238, 1614cm−1 in the experimental IR spectrum and by bands at 3327, 3241cm−1 in the Raman spectrum of G 0. The experimental frequencies of asymmetric and symmetric NH2 stretching vibrations of amine group are lower than theoretical values due to intramolecular NH⋯S hydrogen bond. This hydrogen bond is also responsible for higher experimental infrared intensity of these bands as compared with theoretical values. Relying on DFT calculations a complete vibrational assignment is proposed for the studied dendrimer.
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      PubDate: 2016-05-17T13:39:35Z
       
  • The oxidant and laser power-dependent plasmon-driven surface
           photocatalysis reaction of p-aminothiophenol dimerizing into
           p,p′-dimercaptoazobenzene on Au nanoparticles
    • Abstract: Publication date: 5 September 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 166
      Author(s): Enzhong Tan, Penggang Yin, Chunna Yu, Ge Yu, Chang Zhao
      Recently, plasmon-driven surface photocatalysis (PDSPC) reactions have attracted more and more attention by means of surface-enhanced Raman scattering (SERS) because we can in situ monitor the reaction process and determine the final products and their quantities by the real-time SERS spectrum. In this work, self-assembly AuNPs with both high catalytic activity and strong SERS effect were used as a bifunctional platform for in situ monitoring of PDSPC reactions. p-Aminothiophenol (PATP), a famous model molecule, was selected as a probe molecule and FeCl3 and NaClO were selected as oxidants. In this way, oxidation reaction of PATP dimerizing into p,p′-dimercaptoazobenzene (DMAB) has been investigated by SERS, and the results show that oxidant and laser power can alter the conversion rate of the reaction. This work provides a novel approach for controlling PDSPC reaction rate, which may be useful for understanding the mechanism of PDSPC reactions.
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      PubDate: 2016-05-17T13:39:35Z
       
  • Complexation of different transition metals with
           4,4′-dimethyl-2,2′-bipyridine: Crystal structure, UV spectra
           and Hirshfeld surfaces
    • Abstract: Publication date: 5 September 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 166
      Author(s): Li-Jing Yang, Qing-Ling Liu, Ming-Xin Wang, Lian-Shuai Gu, Yang-Hui Luo, Bai-Wang Sun
      Four new complexes, [Co(dmbpy)2(dca)2]·CH3OH (1), [Ni(dmbpy)2(dca)2]·CH3OH (2), [Zn(dmbpy)2(dca)2]·(3) and [Cu(dmbpy)2(OH)2]·5H2O (4) (dca=dicyanamide), derived from 4,4′-dimethyl-2,2′-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1–3 were mainly supported by OH⋯N, CH⋯N and π⋯π intermolecular interactions, and for complex 4, the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306nm. Moreover, after complexation, the absorption maximum bands about intraligand π→π* transitions similarly show slightly red shift compared to dmbpy ligand, consisting with the DFT calculations.
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      PubDate: 2016-05-11T00:34:28Z
       
  • Chemiluminescence studies between aqueous phase synthesized
           mercaptosuccinic acid capped cadmium telluride quantum dots and
           luminol-H2O2
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Kulandaivelu Kaviyarasan, Sambandam Anandan, Ramalinga Viswanathan Mangalaraja, Abdullah M. Asiri, Jerry J. Wu
      Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes.
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      PubDate: 2016-04-30T07:15:14Z
       
  • Resolution of overlapped spectra for the determination of ternary mixture
           using different and modified spectrophotometric methods
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Bahia Abbas Moussa, Asmaa Ahmed El-Zaher, Marianne Alphonse Mahrouse, Maha Said Ahmed
      Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)–amlodipine besylate (AM)–hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor 1DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291nm, 380nm and 274.5nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form.
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      PubDate: 2016-04-30T07:15:14Z
       
  • Editorial Board
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164




      PubDate: 2016-04-30T07:15:14Z
       
  • A water-soluble and retrievable ruthenium-based probe for colorimetric
           recognition of Hg(II) and Cys
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Yali Cui, Yuanqiang Hao, Yintang Zhang, Baoxia Liu, Xu Zhu, Peng Qu, Deliang Li, Maotian Xu
      A new ruthenium-based complex 1 [(bis(4,4′-dimethylphosphonic-2,2′-bipyridine) dithiocyanato ruthenium (II))] was developed as a colorimetric probe for the detection of Hg(II) and Cys (Cysteine). The obtained compound 1 can give interconversional color changes upon the alternating addition of Hg(II) and Cys in 100% aqueous solution. The specific coordination between NCS groups with Hg(II) can lead to the formation of 1-Hg2+ complex, which can induce a remarkable spectral changes of probe 1. Afterwards the formed 1-Hg2+ complex can act as effective colorimetric sensor for Cys. Owing to the stronger binding affinity of sulfhydryl group to Hg2+, Cys can extract Hg2+ from 1-Hg2+ complex resulting in the release of 1 and the revival of absorption profile of the probe 1. By introducing the hydrophilic phosphonic acid groups, the proposed probe exhibited excellent water solubility. The limits of detection (LODs) of the assay for Hg2+ and Cys are calculated to be 15nM and 200nM, respectively.
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      PubDate: 2016-04-30T07:15:14Z
       
  • Fabrication and humidity sensing performance studies of a fluorescent film
           based on a cholesteryl derivative of perylene bisimide
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Shujuan Zhang, Feng Zhou, Haonan Peng, Taihong Liu, Liping Ding, Yu Fang
      A fluorescent film based on a cholesteryl derivative of perylene bisimide (PTCDI-co-CholDEA) was fabricated via utilization of an electrostatic spinning technique on a glass plate surface. SEM studies revealed that the film was characterized by fibrous network structure. It is the structure and the chemical composition that make the fluorescence emission of the film sensitive to the variation of local environmental humidity. The sensitivity of the sensing is 0.1497 (×104 a.u. of the intensity)/1% RH, of which RH is the abbreviation of relative humidity. The maximum quenching efficiency of the film is 55.4% when humidity reaches 97% RH. Furthermore, the sensing process is fully reversible, and presence of other commonly found liquids shows little effect to the monitoring process.
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      PubDate: 2016-04-30T07:15:14Z
       
  • Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence
           probes based on upconversion nanoparticles
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Cuicui Sun, Huanhuan Li, Anastasios Koidis, Quansheng Chen
      Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2ng·ml−1, and in the effective detection range 0.2 to 100ng·ml−1, good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil.
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      PubDate: 2016-04-30T07:15:14Z
       
  • Investigations on photoluminescence and cathodoluminescence properties of
           Ca3La6(SiO4)6:Tb3+, Mn2+
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Jia Zhang, Beibei Zhou, Xichen Wang
      Tb3+/Mn2+ activated Ca3La6(SiO4)6 (CLS) phosphors were prepared by solid-state reaction method, and their photoluminescence and cathodoluminescence (CL) properties were investigated. The CLS:Tb3+ sample shows a yellowish green emission under 377nm excitation, and the excitation spectrum reveals the excitation peaks between 340 and 390nm can match with the near-ultraviolet LED chip. Excellent thermal stability has been obtained in the CLS:Tb3+ phosphor by studying the temperature dependence of the Tb3+ emission intensity. By introducing Mn2+ into CLS:Tb3+, tunable emissions are generated due to the efficient energy transfer from Tb3+ to Mn2+. The CL spectrum of CLS:Tb3+ displays that the characteristic 5D4-7FJ (J=6−3) transitions of Tb3+ are found under electron beam excitation. The above investigation results imply that the CLS:Tb3+, Mn2+ phosphors could have potential applications on LEDs and FEDs.
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      PubDate: 2016-04-26T06:59:34Z
       
  • Accurate spectroscopic calculations of 21 electronic states of ClO radical
           including transition properties
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Xinxin Wang, Deheng Shi, Jinfeng Sun, Zunlue Zhu
      The potential energy curves were calculated for the 21 states (X2Π, A2Π, 32Π, 42Π, 52Π, 12Σ+, 22Σ+, 32Σ+, 12Σ−, 22Σ−, 32Σ−, 12Δ, 22Δ, 32Δ, 12Φ, 14Σ+, a4Σ−, 24Σ−, 14Π, 24Π and 14Δ), which originated from the two lowest dissociation channels of ClO radical. The calculations were done for internuclear separations approximately from 0.08 to 1.10nm using the CASSCF method, which was followed by the icMRCI approach with the aug-cc-pV5Z basis set. Of these 21 states, the 14Π, 24Π, 32Δ, 42Π, 52Π, 12Φ, 32Σ+, 14Δ and 24Σ− states are repulsive. The 12Δ, 12Σ−, 14Σ+, 22Σ−, 12Σ+, 22Σ+, 22Δ and 32Σ− states are very weakly bound. Only the A2Π state has one barrier. The avoided crossing exists between the A2Π and the 32Π state. However, the avoided crossing does not generate any double wells. Core- valence correlation correction was accounted for at the level of an aug-cc-pCVQZ basis set. Scalar relativistic correction was included by the third-order Douglas-Kroll Hamiltonian approximation at the level of an aug-cc-pVQZ basis set. All the potential energy curves were extrapolated to the complete basis set limit. The spectroscopic parameters were determined. The 12Σ−, 22Σ−, 32Σ− and 14Σ+ states may be very difficult to be detected in an experiment, since each of these Λ-S states has only one or two vibrational states. The Franck-Condon factors and radiative lifetimes were calculated for several low vibrational levels of the A2Π - X2Π, 32Π - a4Σ−, 22Δ - a4Σ− and 32Σ− - 12Σ− transitions. The spin-orbit coupling effect on the spectroscopic parameters of the X2Π, A2Π, 32Π, a4Σ− and 22Σ+ states were discussed. The spectroscopic properties reported here can be expected to be reliably predicted ones.
      Graphical abstract image

      PubDate: 2016-04-26T06:59:34Z
       
  • Improved activity and thermo-stability of the horse radish peroxidase with
           graphene quantum dots and its application in fluorometric detection of
           hydrogen peroxide
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Zhou Xiaoyan, Jiang Yuanyuan, Li Zaijun, Gu Zhiguo, Wang Guangli
      Graphene quantum dots (GQDs) have received extensive concern in many fields such as optical probe, bioimaging and biosensor. However, few reports refer on the influence of GQDs on enzyme performance. The paper reports two kinds of graphene quantum dots (termed as GO-GQDs and N,S-GQDs) that were prepared by cutting of graphene oxide and pyrolysis of citric acid and l-cysteine, and their use for the horse radish peroxidase (HRP) modification. The study reveals that GO-GQDs and N,S-GQDs exhibit an opposite effect on the HRP performance. Only HRP modified with GO-GQDs offers an enhanced activity (more than 1.9 times of pristine enzyme) and thermo-stability. This is because GO-GQDs offer a larger conjugate rigid plane and fewer hydrophilic groups compared to N,S-GQDs. The characteristics can make GO-GQDs induce a proper conformational change in the HRP for the catalytic performance, improving the enzyme activity and thermo-stability. The HRP modified with green luminescent GO-GQDs was also employed as a biocatalyst for sensing of H2O2 by a fluorometric sensor. The colorless tetramethylbenzidine (TMB) is oxidized into blue oxidized TMB in the presence of H2O2 by the assistance of HRP/GO-GQDs, leading to an obvious fluorescence quenching. The fluorescence intensity linearly decreases with the increase of H2O2 concentration in the range from 2×10−9 to 2×10−4M with the detection limit of 6.8×10−10M. The analytical method provides the advantage of sensitivity, stability and accuracy compared with present H2O2 sensors based on the pristine HRP. It has been successfully applied in the determination of H2O2 in real water samples. The study also opens a new avenue for modification of enzyme activity and stability that offers great promise in applications such as biological catalysis, biosensing and enzyme engineering.
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      PubDate: 2016-04-26T06:59:34Z
       
  • A FRET-based fluorescent probe for mercury ions in water and living cells
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Bo Zhang, Pinyi Ma, Dejiang Gao, Xinghua Wang, Ying Sun, Daqian Song, Xuwen Li
      On the basis of fluorescence resonance energy transfer (FRET), a new rhodamine derivative (DRh) was synthesized as a ratiometric fluorescent probe for detecting Hg2+ in water and living cells samples. The recognition properties of the probe DRh with metal ions had been investigated in H2O/CH3CN (9:1, v/v; Tris-HCl 50mmolL−1; pH=7.0) solution by the UV–Vis spectrophotometry and the fluorescence spectrophotometry. The results showed that the probe DRh exhibited the selective recognition of Hg2+. Upon the addition of Hg2+, the spirolactam ring of probe DRh was opened. The 1:1 stoichiometric structure between DRh and Hg2+ were supported by Job's plot, MS and DFT theoretical calculations. The linearly fluorescence intensity ratio (I 582 /I 538 ) is proportional to the concentration of Hg2+ in the range 0–30μmolL−1. The limit of detection (LOD) of Hg2+ is 0.008μmolL−1 (base on S/N=3). The present probe was applied to the determination of Hg2+ in neutral water samples and gave recoveries ranging from 104.5 to 107.9%. Furthermore, the fluorescent probe also can be applied as a bioimaging reagent for Hg2+ detection in HeLa cells.
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      PubDate: 2016-04-26T06:59:34Z
       
  • Ultraviolet spectroscopy combined with ultra-fast liquid chromatography
           and multivariate statistical analysis for quality assessment of wild
           Wolfiporia extensa from different geographical origins
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Yan Li, Ji Zhang, Hang Jin, Honggao Liu, Yuanzhong Wang
      A quality assessment system comprised of a tandem technique of ultraviolet (UV) spectroscopy and ultra-fast liquid chromatography (UFLC) aided by multivariate analysis was presented for the determination of geographic origin of Wolfiporia extensa collected from five regions in Yunnan Province of China. Characteristic UV spectroscopic fingerprints of samples were determined based on its methanol extract. UFLC was applied for the determination of pachymic acid (a biomarker) presented in individual test samples. The spectrum data matrix and the content of pachymic acid were integrated and analyzed by partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). The results showed that chemical properties of samples were clearly dominated by the epidermis and inner part as well as geographical origins. The relationships among samples obtained from these five regions have been also presented. Moreover, an interesting finding implied that geographical origins had much greater influence on the chemical properties of epidermis compared with that of the inner part. This study demonstrated that a rapid tool for accurate discrimination of W. extensa by UV spectroscopy and UFLC could be available for quality control of complicated medicinal mushrooms.
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      PubDate: 2016-04-26T06:59:34Z
       
  • Conformational, electronic, and spectroscopic characterization of
           
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): F. Bardak, C. Karaca, S. Bilgili, A. Atac, T. Mavis, A.M. Asiri, M. Karabacak, E. Kose
      Isophthalic acid (C6H4(CO2H)2) is a noteworthy organic compound widely used in coating and synthesis of resins and the production of commercially important polymers such as drink plastic bottles. The effects of isophthalic acid (IPA) on human health, toxicology, and biodegradability are the main focus of many researchers. Because structural and spectroscopic investigation of molecules provides a deep understanding of interactional behaviors of compounds, this study stands for exploring those features. Therefore, the spectroscopic, structural, electronic, and thermodynamical properties of IPA were thoroughly studied in this work experimentally using UV–Vis, 1H and 13C NMR, FT-IR, FT-Raman and theoretically via DFT and TD-DFT calculations. The UV–Vis absorption spectrum in water was taken in the region 200–400nm. The NMR chemical shifts (1H and 13C) were recorded in DMSO solution. The infrared and Raman spectra of the solid IPA were recorded in the range of 4000–400cm−1 and 3500–50cm−1, respectively. DFT and TD-DFT calculations were performed at the level of B3LYP/6–311++G(d,p) in determination of geometrical structure, electronic structure analysis and normal mode. The 13C and 1H nuclear magnetic resonance (NMR) spectra were estimated by using the gauge-invariant atomic orbital (GIAO) method. The scaled quantum mechanics (SQM) method was used to determine the total energy distribution (TED) to assign the vibrational modes accurately. Weak interactions such as hydrogen bonding and Van der Walls were analyzed via reduced density gradient (RDG) analysis in monomeric and dimeric forms. Furthermore, the excitation energies, density of state (DOS) diagram, thermodynamical properties, molecular electro-static potential (MEP), and nonlinear optical (NLO) properties were obtained.
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      PubDate: 2016-04-26T06:59:34Z
       
  • Thermodynamic study of β-cyclodextrin-dye inclusion complexes using
           gradient flow injection technique and molecular modeling
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Y. Izadmanesh, Jahan B. Ghasemi
      Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26±0.01), 1:1 (1.53±0.08), 1:1 (3.11±0.04), 1:1 (1.06±0.12), and 2:1 (5.27±0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.
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      PubDate: 2016-04-26T06:59:34Z
       
  • Calculating 14N16O2 spectral line parameters in an infrared range: A
           comparison of “global” and “local” effective
           operator methods
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): O.K. Voitsekhovskaya, O.V. Egorov, D.E. Kashirskii
      Nitrogen dioxide, 14N16O2, line positions and intensities calculated by us based on a “local” effective operator method are compared to the recent results of the “global” calculation. The comparison was made for theoretical absorption coefficients in the spectral range of 600–3700cm−1 using the measured data taken from the Pacific Northwest National Laboratory. In order to conduct the calculations, empirical parameters of the effective rotational Hamiltonian of the twenty-one vibrational states were applied from the most recent experimental works. The second order parameters of the dipole moment function of 14N16O2 were determined for the first time. The “local” line list in this research consists of one hundred and four bands and includes the line intensities of the v 1 + v 2 + v 3 band of 14N16O2 that have not yet been investigated in the literature. Among these bands, only eleven bands are included in HITRAN2012. The reasons behind the disagreements between the theoretical and measured absorption coefficients of 14N16O2 are discussed.
      Graphical abstract image

      PubDate: 2016-04-26T06:59:34Z
       
  • Diffractaic acid: Crystalline structure and physicochemical
           characterization
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Jéssica de Castro Fonseca, Yara Santiago de Oliveira, Beatriz P. Bezerra, Javier Ellena, Neli Kika Honda, Camilla V.N.S. Silva, Noemia Pereira da Silva Santos, Nereide Stela Santos-Magalhães, Alejandro Pedro Ayala

      Graphical abstract image

      PubDate: 2016-04-26T06:59:34Z
       
  • Unsupervised component analysis: PCA, POA and ICA data exploring -
           connecting the dots
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Jorge Costa Pereira, Julio Cesar R. Azevedo, Heloise G. Knapik, Hugh Douglas Burrows
      Under controlled conditions, each compound presents a specific spectral activity. Based on this assumption, this article discusses Principal Component Analysis (PCA), Principal Object Analysis (POA) and Independent Component Analysis (ICA) algorithms and some decision criteria in order to obtain unequivocal information on the number of active spectral components present in a certain aquatic system. The POA algorithm was shown to be a very robust unsupervised object-oriented exploratory data analysis, proven to be successful in correctly determining the number of independent components present in a given spectral dataset. In this work we found that POA combined with ICA is a robust and accurate unsupervised method to retrieve maximal spectral information (the number of components, respective signal sources and their contributions).
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      PubDate: 2016-04-26T06:59:34Z
       
  • IR and py/GC/MS examination of amber relics excavated from 6th century
           royal tomb in Korean Peninsula
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Jongseo Park, Eunyoung Yun, Hyungtae Kang, Jooyoung Ahn, Gyuho Kim
      Relics of amber were excavated from King Muryeong's tomb constructed in the 6th century on the Korean peninsula. To estimate the provenance, FTIR (Fourier transform infrared spectroscopy) and py/GC/MS (pyrolysis/gas chromatography/mass spectrometry) analysis were utilized. The reference Baltic amber sample was also analyzed with the same method for comparison. The relics were confirmed to be amber from the FTIR analysis where an absorption band near 1150cm−1, characteristic one in Baltic amber, was also observed. In py/GC/MS analysis, pyrolyzed products like butanedioic acid and dehydroabietic acid, known constituents of amber, were observed. In addition, d-fenchyl alcohol, camphor, borneol and butanedioic acid, typical constituents of Baltic amber, were observed in some samples. From this, it appears that some of relics were made from Baltic amber and that Baltic amber was transported to the Korean peninsula in the time of tomb construction.
      Graphical abstract image

      PubDate: 2016-04-26T06:59:34Z
       
  • Evaluation on the inhibition of pyrrol-2-yl ethanone derivatives to
           lactate dehydrogenase and anticancer activities
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Na-Na Lu, Zhao-Yue Weng, Qiu-Yun Chen, Daniel Boison, Xin-Xin Xiao, Jing Gao
      Lactate dehydrogenase A (LDH-A) is a potentially important metabolic target for the inhibition of the highly activated glycolysis pathway in cancer cells. In order to develop bifunctional compounds as inhibitor of LDH-A and anticancer agents, two pyrrol-2-yl methanone (or ethanone) derivatives (PM1 and PM2) were synthesized and evaluated as inhibitors of LDH-A based on the enzyme assay and cell assay by spectroscopy analysis. Fluorescence and CD spectra results demonstrated that both the change of second structure of LDH-A and the affinity interaction for compounds to LDH-A gave great effect on the activity of LDH-A. In particular, low concentration of compounds (1μμ–25μμ) could change the level of pyruvate in cancer cells. Moreover, the in vitro assay results demonstrated that pyrrol-2-yl ethanone derivatives can inhibit the proliferation of cancer cells. Therefore, pyrrol-2-yl ethanone derivatives (PM2) can be both LDH-A inhibitor and anticancer agents.
      Graphical abstract image

      PubDate: 2016-04-21T06:30:16Z
       
  • Morphology and molecular arrangement of perylene-3,4,9,10-(n-pentylester)
           in thin layers obtained by zone-casting
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Adrian Adamski, Ariadna B. Nowicka, Bolesław Barszcz, Mirosław Szybowicz, Emilia Piosik, Eryk Wolarz
      Liquid-crystalline perylene-3,4,9,10-tetra-(n-pentylester) zone-casted on hydrophilic glass substrates forms characteristic belt-like structures which are observed under optical microscope and atomic force microscope. Polarised Raman scattering spectra reveal the presence of anisotropic alignment of the molecules inside the obtained structures. Moreover, the absorption and fluorescence spectra confirm molecular aggregation in the belt-like structures. The research shows, that the belt-like structures are created by columns of molecules with the edge-on alignment on the glass substrate. Such organisation of the molecules is confirmed by spectroscopic methods. These structures can be interesting from the point of view of organic electronics.
      Graphical abstract image

      PubDate: 2016-04-21T06:30:16Z
       
  • A symmetrical subtraction combined with interpolated values for
           eliminating scattering from fluorescence EEM data
    • Abstract: Publication date: 5 August 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 165
      Author(s): Jing Xu, Xiaofei Liu, Yutian Wang
      Parallel factor analysis is a widely used method to extract qualitative and quantitative information of the analyte of interest from fluorescence emission-excitation matrix containing unknown components. Big amplitude of scattering will influence the results of parallel factor analysis. Many methods of eliminating scattering have been proposed. Each of these methods has its advantages and disadvantages. The combination of symmetrical subtraction and interpolated values has been discussed. The combination refers to both the combination of results and the combination of methods. Nine methods were used for comparison. The results show the combination of results can make a better concentration prediction for all the components.
      Graphical abstract image

      PubDate: 2016-04-21T06:30:16Z
       
  • Editorial Board
    • Abstract: Publication date: 15 June 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 163




      PubDate: 2016-04-17T01:11:35Z
       
  • Study on the fluorescent chemosensors based on a series of bis-Schiff
           bases for the detection of zinc(II)
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Wanguan Wang, Rong Li, Tianwen Song, Chunjiao Zhang, Yu Zhao
      In order to study the influence of different substituent groups on the fluorescence properties, a series of bis-Schiff bases (L) with electron-donating groups (salicylaldehyde, o-vanillin, 2,4-dihydroxybenzaldehyde) and electron-drawing group (4-formylbenzoic acid) have been synthesized, and characterized by IR spectrum, NMR, mass spectrum, and fluorescence spectroscopy. The investigation of the fluorescent properties reveals that the fluorescence can be enhanced when the bis-Schiff base ligands with electron-donating groups complex with Zn ion, while other kinds of metal complexes with these ligands do not show any enhancement, whereas no fluorescence enhancement can be observed when the ligand with electron-drawing group complexes with all different types of metal ions. In addition, as for the ligands with electron-donating groups detecting zinc ion, the fluorescence intensity is linear correlated with the concentration of zinc ion. Therefore, the study indicates that the ligands with electron-donating groups can be used as Zn ion fluorescent sensor.
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      PubDate: 2016-04-17T01:11:35Z
       
  • UV–Vis spectroscopy and solvatochromism of the tyrosine kinase
           inhibitor AG-1478
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Muhammad Khattab, Feng Wang, Andrew H.A. Clayton
      The effect of twenty-one solvents on the UV–Vis spectrum of the tyrosine kinase inhibitor AG-1478 was investigated. The absorption spectrum in the range 300–360nm consisted of two partially overlapping bands at approximately 340nm and 330nm. The higher energy absorption band was more sensitive to solvent and exhibited a peak position that varied from 327nm to 336nm, while the lower energy absorption band demonstrated a change in peak position from 340nm to 346nm in non-chlorinated solvents. The fluorescence spectrum of AG-1478 was particularly sensitive to solvent. The wavelength of peak intensity varied from 409nm to 495nm with the corresponding Stokes shift in the range of 64nm to 155nm (4536cm−1 to 9210cm−1). We used a number of methods to assess the relationship between spectroscopic properties and solvent properties. The detailed analysis revealed that for aprotic solvents, the peak position of the emission spectrum in wavenumber scale correlated with the polarity (dielectric constant or E T(30)) of the solvent. In protic solvents, a better correlation was observed between the hydrogen bonding power of the solvent and the position of the emission spectrum. Moreover, the fluorescence quantum yields were larger in aprotic solvents as compared to protic solvents. This analysis underscores the importance of polarity and hydrogen-bonding environment on the spectroscopic properties of AG-1478. These studies will assume relevance in understanding the interaction of AG-1478 in vitro and in vivo.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Revisiting the integrated infrared intensities and atomic polar tensors of
           the boron trihalides
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Wagner E. Richter, Roy E. Bruns
      Integrated infrared intensities obtained from spectra of the Pacific Northwest National Laboratory (PNNL) database are reported for BF3, BCl3 and BBr3. The BF3 and BCl3 intensities are compared with values reported much earlier whereas the asymmetric BBr3 stretching intensity is reported for the first time. Although agreement is good for the BF3 intensities, the result from the PNNL spectra for the asymmetric BCl3 stretching vibration is about three times larger than the one reported earlier. The intensities obtained from the PNNL spectra are in excellent agreement with results from QCISD/cc–pVTZ quantum chemical calculations having an rms error of only 32.9cm−1 or 5.9% of the average intensity. Revised experimental atomic polar tensors and GAPT charges are reported for all these molecules.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • Lorenzo Lotto's painting materials: an integrated diagnostic approach
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Maria Letizia Amadori, Gianluca Poldi, Sara Barcelli, Pietro Baraldi, Michela Berzioli, Antonella Casoli, Susanna Marras, Giulio Pojana, Giovanni C.F. Villa
      This paper presents the results of a comprehensive diagnostic investigation carried out on five paintings (three wood panels and two paintings on canvas) by Lorenzo Lotto, one of the most significant artists of the Italian Renaissance in the first half of 16th century. The paintings considered belong to 1508–1522 period, corresponding to the most significant years of Lotto's evolution. A wide array of non-invasive (reflectance spectrometry and X-ray fluorescence) and micro-invasive analytical techniques (optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, micro-FTIR spectroscopy, micro-Raman spectroscopy, gas chromatography coupled with mass spectrometry and high performance liquid chromatography coupled with photodiode array detection and mass spectrometry) were applied in order to provide a large set of significant data, limiting as much as possible the sampling. This study has proved that Lotto's painting palette was typical of Venetian practice of that period, but some significant peculiarities emerged: the use of two kinds of red lakes, the addition of calcium carbonate and colourless powdered glass, the latter frequently found in pictorial and ground layers. Moreover, the integrated investigation showed that Lotto's technique was sometimes characterized by the use of coloured priming and multi-layer sequences with complex mixtures. Chromatographic analyses allowed to identify in all specimens: azelaic, palmitic and stearic acids, generally referring to the presence of drying oils. The extension of additional non-invasive examination to about 50 paintings by the same author, spanning from 1505 to around 1556, helped to verify the evolution in the use of some pigments, such as the yellow ones, where Pb-Sb yellow was used alongside Pb-Sn yellow.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Binding of copper to lysozyme: Spectroscopic, isothermal titration
           calorimetry and molecular docking studies
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Mingyang Jing, Wei Song, Rutao Liu
      Although copper is essential to all living organisms, its potential toxicity to human health have aroused wide concerns. Previous studies have reported copper could alter physical properties of lysozyme. The direct binding of copper with lysozyme might induce the conformational and functional changes of lysozyme and then influence the body's resistance to bacterial attack. To better understand the potential toxicity and toxic mechanisms of copper, the interaction of copper with lysozyme was investigated by biophysical methods including multi-spectroscopic measurements, isothermal titration calorimetry (ITC), molecular docking study and enzyme activity assay. Multi-spectroscopic measurements proved that copper quenched the intrinsic fluorescence of lysozyme in a static process accompanied by complex formation and conformational changes. The ITC results indicated that the binding interaction was a spontaneous process with approximately three thermodynamical binding sites at 298K and the hydrophobic force is the predominant driven force. The enzyme activity was obviously inhibited by the addition of copper with catalytic residues Glu 35 and Asp 52 locating at the binding sites. This study helps to elucidate the molecular mechanism of the interaction between copper and lysozyme and provides reference for toxicological studies of copper.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Glutathione-capped Mn-doped ZnS quantum dots as a room-temperature
           phosphorescence sensor for the detection of Pb2+ ions
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Jialing Chen, Yaxian Zhu, Yong Zhang
      The room-temperature phosphorescence (RTP) of glutathione-capped Mn-doped ZnS quantum dots (GSH-Mn-ZnS QDs) was effectively quenched by the addition of Pb2+. A simple and sensitive RTP sensor for Pb2+ detection based on the quenching effect was developed. Under the optimal conditions, good linear correlations were obtained for Pb2+ over a concentration range from 1.0 to 100μg·L−1, and the detection limit was 0.45μg·L−1. The established method has been successfully applied for the determination of Pb2+ in real water samples without complicated sample pretreatment with the recoveries in the range of 95.4%–104.0%.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • Application of Micro-cloud point extraction for spectrophotometric
           determination of Malachite green, Crystal violet and Rhodamine B in
           aqueous samples
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Elham Ghasemi, Massoud Kaykhaii
      A novel, green, simple and fast method was developed for spectrophotometric determination of Malachite green, Crystal violet, and Rhodamine B in water samples based on Micro-cloud Point extraction (MCPE) at room temperature. This is the first report on the application of MCPE on dyes. In this method, to reach the cloud point at room temperature, the MCPE procedure was carried out in brine using Triton X-114 as a non-ionic surfactant. The factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, calibration curves were found to be linear in the concentration range of 0.06–0.60mg/L, 0.10–0.80mg/L, and 0.03–0.30mg/L with the enrichment factors of 29.26, 85.47 and 28.36, respectively for Malachite green, Crystal violet, and Rhodamine B. Limit of detections were between 2.2 and 5.1μg/L.
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      PubDate: 2016-04-17T01:11:35Z
       
  • The spectroscopic constants and anharmonic force field of AgSH: An ab
           initio study
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Yanliang Zhao, Meishan Wang, Chuanlu Yang, Xiaoguang Ma, Ziliang Zhu
      The equilibrium structure, spectroscopy constants, and anharmonic force field of silver hydrosulfide (AgSH) have been calculated at B3P86, B3PW91 and MP2 methods employing two basis sets, TZP and QZP, respectively. The calculated geometries, ground state rotational constants, harmonic vibrational wave numbers, and quartic and sextic centrifugal distortion constants are compared with the available experimental and theoretical data. The equilibrium rotational constants, fundamental frequencies, anharmonic constants, and vibration-rotation interaction constants, Coriolis coupling constants, cubic and quartic force constants are predicted. The calculated results show that the MP2/TZP results are in good agreement with experiment observation and are also an advisable choice to study the anharmonic force field of AgSH.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • A new aromatic probe — The ring stretching vibration Raman
           spectroscopy frequency
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Yan-bo Guo, Zi-zhong Liu, Hong-xia Liu, Feng-ying Zhang, Jun-qing Yin
      A new aromatic criterion is presented to determine the aromatic degree of the high symmetric molecules. Group theory is used to explain the correlation between the aromatic degree and the value of Ring Stretching Vibration Raman Spectroscopic Frequency (RSVRSF). The calculations of the geometrical optimization, nucleus-independent chemical shifts (NICS) and values of the Raman Spectroscopy for the aromatic molecules—LnHn (L=C, Si, Ge, n=3, 5–8) were performed using the Density Functional Theory (DFT) Method, as well as the correlations between the values of their RSVRSF and NICS values by Statistic Package for Social Science (SPSS17.0). There are high positive correlations between the theoretical calculated the NICS values and the value of the RSVRSF (A1g/A1′) of the LnHn (L=C, Si, Ge, n=3, 5–8). The bigger the aromatic degree, the bigger the RSVRSF is. The value of the RSVRSF is a new probe of aromaticity. Expectedly, it is predicted that the experimental determination of the aromatic degree can be achieved by the determination of the ring stretching vibration (A1g/A1′) Raman spectrum frequencies for the aromatic target molecules.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • Metal complexes of a pentadentate N2O3 bis(semicarbazone) Schiff-base. A
           case study of structure-spectroscopy correlation
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Mayara Hissami Inoue, Ronny Rocha Ribeiro, José Ricardo Sabino, Fábio Souza Nunes
      Schiff condensation of 2,6-diformyl 4-methylphenol with semicarbazide hydrochloride in 1:2 molar ratio produces the bis(semicarbazone) ligand, herein called H3L. A comprehensive spectroscopic analysis of the compound was performed by 1H and 13C NMR, FTIR and electronic spectroscopies. Assignments to the UV–vis spectrum of H3L were supported by semi-empirical quantum mechanics ZINDO/S calculations. The ligand H3L forms monoclinic crystals in the space group P2 1 /c and its structure is stabilized by classic hydrogen bonds with propanone molecules. It promptly reacts with first row metal ions to produce the following coordination compounds: [Co2(L)(μ-NO3)]·DMF, [Ni2(H2L)(μ-CH3COO)(CH3COO)2]·2H2O, [Cu2(L)(μ-NO3)(H2O)2]·H2O, [Cu2(L)(μ-CH3COO)(H2O)2]·H2O and [Cu2(H2L)(μ-Cl)Cl2]·3H2O, that have different compositions, depending on the degree of deprotonation of the ligand upon coordination. Electronic and EPR spectroscopies as well as effective magnetic moment measurements of the complexes were used in an attempt to better understand their mode of coordination, the microsymmetry around the metal ions and magnetic properties.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • Synergic application of spectroscopic and theoretical methods to the
           chlorogenic acid structure elucidation
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Svetlana Marković, Jelena Tošović, Jasmina M. Dimitrić Marković
      Although chlorogenic acid (5-O-caffeoylquinic acid, 5CQA) is a dietary polyphenol known for its pharmacological and nutritional properties, its structural features have not been completely elucidated. This is the first study whose aim is to contribute to clarification of the 5CQA structure by comparing the experimental and simulated IR, Raman, 1H NMR, 13C NMR, and UV spectra. For this purpose, a comprehensive conformational analysis of 5CQA was performed to reveal its most stable conformations in the gas-state and solution (DMSO and methanol). The lowest-energy conformers were used to predict the spectra at two levels of theory: B3LYP-D3/and M06-2X/6–311+G(d,p) in combination with the CPCM solvation model. Both methods provide very good agreement between all experimental and simulated spectra, thus indicating correct arrangement of the atoms in the 5CQA molecule. The quinic moiety is characterized with directed hydrogen bonds, where the carboxylic hydrogen is not oriented towards the carbonyl oxygen of the carboxylic group, but towards the oxygen of the proximate hydroxyl group. In the gas-state the lowest-energy conformers are characterized with the O4H4⋯O9′ hydrogen bond, whereas in the solvated state the structures with the O4H4⋯O10′ hydrogen bond prevail. Knowing the fine structural details, i.e. the proper conformation of 5CQA, provides a solid base for all further investigations related to this compound.
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      PubDate: 2016-04-17T01:11:35Z
       
  • In-situ micro-FTIR spectroscopic observation on the hydration process of
           Poria cocos
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Yi Zhao, Na Wang, Shu-Feng Pang, Yun-Hong Zhang
      In Poria cocos, triterpene compound and polysaccharides are the main compositions. The heteropolysaccharide was identified as a linear chain of β-(1→3)-d-glucan, which has the strong water absorbing capacity. In order to investigate the effect of water on the structure of Poria cocos, which belongs to a kind of Polyporaceae, the Micro-Fourier transform infrared spectroscopy (micro-FTIR) technique has been employed with the ambient relative humidity (RH) increasing. The gained IR spectra are measured and analyzed in detail. Because of strong overlaps between some bands, the differential spectra and band decompositions have been applied to analyze the structural change. IR spectra show the transformation of hydrogen bonds with the RH. The blue shift of the CH2 bending vibration from 1417 to 1424cm−1 with the increase in RH means that the hydrogen bonds are formed between CH2 groups and water molecules at lower RH and some transferred to weak hydrogen bonds. The further study suggests that the C1OH, C2OH, and C3OH groups from polysaccharide bond formed C1OH⋯H2O, C2OH⋯H2O, and C3OH⋯H2O steady modes, respectively, with water molecules.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Development and validation of different methods manipulating zero order
           and first order spectra for determination of the partially overlapped
           mixture benazepril and amlodipine: A comparative study
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): A. Hemdan
      Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238nm or from their first order spectra at 253nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240nm and 238nm, respectively, or from their first order spectra at 214nm and 253nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5–60μg/mL for Benazepril and 5–30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Monitoring dehydration of the organic–inorganic
           [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and
           Raman studies
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): S. Hajlaoui, I. Chaabane, K. Guidara, A. Bulou
      In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356–376 (T1) K and at 393K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800cm−1 covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(SnO)+νs(SnCl)), based on an order–disorder model allowed us to obtain information relative to the activation energy and correlation length.
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      PubDate: 2016-04-17T01:11:35Z
       
  • Phase transition, thermal dissociation and dynamics of NH3 ligands in
           [Cd(NH3)4](ReO4)2
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Łukasz Hetmańczyk, Joanna Hetmańczyk
      High temperature phase transition in [Cd(NH3)4](ReO4)2 at T c =368.5K (on heating) was reported for the first time. Thermal stability was investigated by thermal analysis methods. The titled compound decomposes in three main stages. The first two are connected with deamination process whereas in the last step Re2O7 evaporates. The activation energy for NH3 lost processes was estimated from TG measurements. The dynamics of NH3 ligands in the low temperature phase was probed by various complementary techniques. Temperature dependent band shape analysis of properly chosen infrared and Raman scattering vibrational bands was performed. It was found that activation energy for NH3 reorientational motion (below 300K) is rather small and is equal to ca. 4kJmol−1. The quasielastic neutron scattering measurements revealed that NH3 groups perform fast stochastic reorientational motion even in the low temperatures. The neutron and X-ray powder diffraction data do not revealed any drastic changes in the crystal structure in the wide temperature range.
      Graphical abstract image

      PubDate: 2016-04-17T01:11:35Z
       
  • Comment on “Structural and vibrational studies on 1-(5-Methyl-
           [1,3,4] thiadiazol-2-yl)-pyrolidin-2-ol” [Spectrochimica Acta Part
           A, 152 (2016) 252–261]. The importance of intramolecular OH⋯N
           hydrogen bonding in the conformational properties of
           thiadiazol-pyrrolidin-2-ol bearing species
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Sergio L. Laurella, Mauricio F. Erben
      The title paper [1] reports a study on the spectroscopic and physicochemical properties of 1-(5-methyl- [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (MTPN) based on experimental and theoretical data. The latter ones are based on the computed molecular structure for a rather unusual conformer. Here, after a careful analysis of the conformational space of MTPN, the most stable conformation was determined for the molecule isolated in a vacuum, which results to be 21.9kJ/mol more stable than the conformer reported previously. Our study also includes the closely related species 1-(5-trifluoromethyl- [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (FMTPN). An intramolecular OH⋯N hydrogen bond determines the conformational behavior of the [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol group as demonstrated by Natural Bond Orbital population analysis.
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      PubDate: 2016-04-09T13:33:32Z
       
  • Branched truxene and triindole compounds and their solid-state luminescent
           enhancement
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Xianchao Du, Mao-Sen Yuan, Fan Xu, Hui Wang, Qin Wang, Wenji Wang, Dong-En Wang, Jinyi Wang
      C 3-symmetric truxene and triindole have been widely used to design the branched optoelectronic molecules. However, most of them exhibit high luminous efficiency in the solution and quenched luminescence in the solid state. Here, we respectively chose alkylated truxene and triindole as the central core, 2-methylphenyl as the peripheral functional groups to synthesize three branched compounds. Their photophysical properties have been explored combining with the theoretical calculation. The three compounds exhibit good solubility and high solid-state fluorescence quantum yields. The absorption and emission peaks of triindole compound exhibit apparent red-shift in comparison with those of truxene compounds, which indicates triindole more highly electron delocalization than truxene. The single-crystal structure shows that alkylation of the central core and branched steric bulkiness of these molecules effectively reduce the intermolecular π⋯π stacking and avoid the non-radiative transition of these molecules from excited state to ground state in the solid state.
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      PubDate: 2016-04-09T13:33:32Z
       
  • Evaluation of the efficiency of continuous wavelet transform as processing
           and preprocessing algorithm for resolution of overlapped signals in
           univariate and multivariate regression analyses; an application to ternary
           and quaternary mixtures
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Maha A. Hegazy, Hayam M. Lotfy, Shereen Mowaka, Ekram Hany Mohamed
      Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations.
      Graphical abstract image

      PubDate: 2016-04-09T13:33:32Z
       
  • Electronic, structural and vibrational induced effects upon ionization of
           2-quinolinone
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): A. Bellili, Y. Pan, M.M. Al Mogren, K.C. Lau, M. Hochlaf
      Using first principle methodologies, we characterize the lowest electronic states of 2-quinolinone+ cation. The ground state of this ion is of X ˜ 2 A ″ nature. We deduce the adiabatic ionization energy of 2-quinolinone to be equal 8.249eV using the explicitly correlated coupled cluster level and where zero point vibrational energy, core-valence and scalar relativistic effects are taken into account. We examine also the ionization induced structural changes and vibrational shifts and analyze the electron density differences between the neutral and ionic species. These data show that the formation of 2-quinolinone+ X ˜ 2 A ″ from 2-quinolinone affects strongly the HNCO group, whereas the carbon skeletal is perturbed when the upper electronic cationic states are populated. The comparison to 2-pyridone allows the elucidation of the effect of benzene ring fused with this heterocyclic ring. Since quinolones and pyridones are both model systems of DNA bases, these findings might help in understanding the charge redistribution in these biological entities upon ionization.
      Graphical abstract image

      PubDate: 2016-04-07T13:32:19Z
       
  • Deep-red to near-infrared fluorescent dyes: Synthesis, photophysical
           properties, and application in cell imaging
    • Abstract: Publication date: 5 July 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 164
      Author(s): Qi Li, Weimin Liu, Jiasheng Wu, Bingjiang Zhou, Guangle Niu, Hongyan Zhang, Jiechao Ge, Pengfei Wang
      More and more attention has been paid to the design of new fluorescent imaging agents with good photostability and water solubility, especially those with emissions in the deep-red and near-infrared regions. In this work, we designed and synthesized four novel fluorescent dyes with deep-red or NIR fluorescence by hybridizing coumarin and pyronin moieties based on our previous work. Introduction of carboxylic acid in the dyes not only imparted the dyes with water solubility but also provided a versatile sensing platform for designing the fluorescent probes and sensors of biomolecules. The photophysical properties of these new dyes were investigated through absorption and fluorescence spectroscopy. Cell imaging experiments showed that esterification products could selectively stain lysosomes with good photostability, thereby indicating that they could be useful in the development of fluorescent probes for bioimaging.
      Graphical abstract image

      PubDate: 2016-04-07T13:32:19Z
       
  • MDL and RMSEP assessment of spectral pretreatments by adding different
           noises in calibration/validation datasets
    • Abstract: Publication date: 15 June 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 163
      Author(s): Na Zhao, Zhisheng Wu, Yaqian Cheng, Xinyuan Shi, Yanjiang Qiao
      In multivariate calibration, the optimization of pretreatment methods is usually according to the prediction error and there is a lack of robustness evaluation. This study investigated the robustness of pretreatment methods by adding different simulate noises to validation dataset, calibration and validation datasets, respectively. The root mean squared error of prediction (RMSEP) and multivariate detection limits (MDL) were simultaneously calculated to assess the robustness of different pretreatment methods. The result with two different near-infrared (NIR) datasets illustrated that Multiplicative Scatter Correction (MSC) and Standard normal variate (SNV) were substantially more robust to additive noise with smaller REMSP and MDL value.
      Graphical abstract image

      PubDate: 2016-04-02T13:07:53Z
       
  • Surfactant assisted control on optical, fluorescence and phonon lifetime
           in α-Bi2O3 microrods
    • Abstract: Publication date: 15 June 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 163
      Author(s): Hariharan S., Udayabhaskar R., Ravindran T.R., Karthikeyan B.
      We report preparation of pure and surfactant added α-Bi2O3 microrods through simple chemical method at moderate temperature. Cetyltrimethyl ammonium bromide (CTAB) is used as a surfactant. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, UV–Vis absorption and photoluminescence (PL) measurements were carried out to understand the effect of surfactant (CTAB) on structural, phonon and optical properties of the prepared material. It is observed that the crystallite size, optical band gap and the structural defects (oxygen vacancies) decreases due to the effect of surfactant. Raman spectral studies exhibit various phonon modes of Bi2O3 and also decrease in the FWHM of the phonon modes is observed after the addition of CTAB.
      Graphical abstract image

      PubDate: 2016-04-02T13:07:53Z
       
  • An ultrasensitive and selective method for the determination of
           Ceftriaxone using cysteine capped cadmium sulfide fluorescence quenched
           quantum dots as fluorescence probes
    • Abstract: Publication date: 15 June 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 163
      Author(s): Naser Samadi, Saeedeh Narimani
      In this paper, l-cysteine (Cys) coated CdS quantum dots (QDs) have been prepared, which have excellent water-solubility and are highly stable in aqueous solution. These QDs is proposed as sensitizers for the determination of Ceftriaxone. The quantum dot nanoparticles were structurally and optically characterized by Ultra Violet–Visible absorption Spectroscopy (UV–vis absorption spectroscopy), Fourier transform infrared spectroscopy (FT-IR spectra) and photoluminescence (PL) emission spectroscopy. High resolution transmission electron microscopy (HRTEM) confirms that the Cys-CdS QDs have a spherical structure with good crystallinity. Therefore, a new simple and selective PL analysis system was developed for the determination of Ceftriaxone (CFX). Under the optimum conditions, The response of l-Cys capped CdS QDs as the probe was linearly proportional to the concentration of Ceftriaxone ions in the range of 1.6×10−9–1.1×10−3 M with a correlation coefficient (R2) of 0.9902. The limit of detection of this system was found to be 1.3nM. This method is simple, sensitive and low cost.
      Graphical abstract image

      PubDate: 2016-03-28T12:49:42Z
       
  • Synthesis, characterization of α-amino acid Schiff base derived Ru/Pt
           complexes: Induces cytotoxicity in HepG2 cell via protein binding and ROS
           generation
    • Abstract: Publication date: 15 June 2016
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 163
      Author(s): Ali Alsalme, Sameen Laeeq, Sourabh Dwivedi, Mohd. Shahnawaz Khan, Khalid Al Farhan, Javed Musarrat, Rais Ahmad Khan
      We have synthesized two new complexes of platinum (1) and ruthenium (2) with α-amino acid, l-alanine, and 2,3-dihydroxybenzaldehyde derived Schiff base (L). The ligand and both complexes were characterized by using elemental analysis and several other spectroscopic techniques viz; IR, 1H, 13C NMR, EPR, and ESI-MS. Furthermore, the protein-binding ability of synthesized complexes was monitored by UV–visible, fluorescence and circular dichroism techniques with a model protein, human serum albumin (HSA). Both the PtL2 and RuL2 complexes displayed significant binding towards HSA. Also, in vitro cytotoxicity assay for both complexes was carried out on human hepatocellular carcinoma cancer (HepG2) cell line. The results showed concentration-dependent inhibition of cell viability. Moreover, the generation of reactive oxygen species was also evaluated, and results exhibited substantial role in cytotoxicity.
      Graphical abstract image

      PubDate: 2016-03-23T14:10:18Z
       
 
 
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