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Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.717]   [H-I: 80]   [17 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [3044 journals]
  • Different spectrophotometric methods applied for the analysis of
           simeprevir in the presence of its oxidative degradation product:
           Acomparative study
    • Authors: Khalid A.M. Attia; Nasr M. El-Abasawi; Ahmed El-Olemy; Ahmed Serag
      Pages: 1 - 9
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Khalid A.M. Attia, Nasr M. El-Abasawi, Ahmed El-Olemy, Ahmed Serag
      Five simple spectrophotometric methods were developed for the determination of simeprevir in the presence of its oxidative degradation product namely, ratio difference, mean centering, derivative ratio using the Savitsky-Golay filters, second derivative and continuous wavelet transform. These methods are linear in the range of 2.5–40μg/mL and validated according to the ICH guidelines. The obtained results of accuracy, repeatability and precision were found to be within the acceptable limits. The specificity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. Furthermore, these methods were statistically comparable to RP-HPLC method and good results were obtained. So, they can be used for the routine analysis of simeprevir in quality-control laboratories.
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      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.08.066
      Issue No: Vol. 190 (2017)
       
  • A rapid Fourier transform infrared spectroscopic method for analysis of
           certain proton pump inhibitors in binary and ternary mixtures
    • Authors: Pakinaz Y. Khashaba; Hassan Refat H. Ali; Mohamed M. El-Wekil
      Pages: 10 - 14
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Pakinaz Y. Khashaba, Hassan Refat H. Ali, Mohamed M. El-Wekil
      A simple and non-destructive FTIR method was used to determine certain proton pump inhibitors (PPIs) in binary and ternary mixtures. Proton pump inhibitors (PPIs); omeprazole (OMZ), esomeprazole (EZM), lansoprazole (LAN), pantoprazole sodium (PAN sodium) and rabeprazole sodium (RAB sodium) in binary mixture with domperidone (DOM) and ternary mixture of OMZ, clarithromycin (CLM) and tinidazole (TNZ) were determined in the solid-state by FTIR spectroscopy for the first time. The method was validated according to ICH-guidelines where linearity was ranged from 20 to 850μg/g and 20–360μg/g for PPIs and DOM, respectively in binary mixtures and 10–400, 100–8000 and 150–14,000μg/g for OMZ, CLM and TNZ, respectively. Limits of detection were found to be 6–100 and 9–100μg/g for PPIs and DOM, respectively and 4, 40 and 50μg/g for OMZ, CLM and TNZ, respectively. The method was applied successfully for determination of the cited drugs in their respective pharmaceutical dosage forms.
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      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.09.003
      Issue No: Vol. 190 (2017)
       
  • Structure, isomerism, and vibrational assignment of
           aluminumtrifluoroacetylacetonate. An experimental and theoretical study
    • Authors: R. Afzali; M. Vakili; E. Boluri; S.F. Tayyari; A.-R. Nekoei; M. Hakimi-Tabar; V. Darugar
      Pages: 15 - 22
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): R. Afzali, M. Vakili, E. Boluri, S.F. Tayyari, A.-R. Nekoei, M. Hakimi-Tabar, V. Darugar
      An interpretation of the experimental IR and Raman spectra of Aluminum (III) trifluoroacetylacetonate (Al(TFAA)3) complex, which were synthesized by us, is first reported here. The charge distribution, isomerism, strength of metal‑oxygen binding and vibrational spectral properties for this complex structure were theoretically investigated through population analysis, geometry optimization and harmonic frequency calculations, performed at B3LYP/6-311G* level of theory. In the population analysis, two different approaches reffered to as “Atoms in molecules (AIM)”, and “Natural Bond Orbital (NBO)” were used. According to the calculation resuls, the energy difference between the cis and trans isomers of Al(TFAA)3 is very small and indicates that both isomers coexist in the sample in comparable proportions. Comparison of the calculated frequency and intensity data with the observed IR and Raman spectra of the complex has supported this conclusion. On the other hand, comparison of the structural and vibrational spectral data of Al(TFAA)3, which were experimentally measured and calculated at B3LYP/6-311G* level, with the corresponding data of Aluminum acetylacetonate (Al(AA)3) has revealed the effects of CF3 substitution on the structural and vibrational spectral data associated with the CH3 groups in the complex structure.
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      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.08.075
      Issue No: Vol. 190 (2017)
       
  • Insight into the effects of modifying chromophores on the performance of
           quinoline-based dye-sensitized solar cells
    • Authors: Mao Mao; Jian-Bo Wang; Xiu-Lin Liu; Guo-Hua Wu; Xia-Qin Fang; Qin-Hua Song
      Pages: 23 - 32
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Mao Mao, Jian-Bo Wang, Xiu-Lin Liu, Guo-Hua Wu, Xia-Qin Fang, Qin-Hua Song
      A series of organic dyes based on quinoline as an electron-deficient π-linker, were designed and synthesized for dye sensitized solar cells (DSSC) application. These push-pull conjugated dyes, sharing same anchoring group with distinctive electron-rich donating groups such as N,N-diethyl (DEA-Q), 3,6-dimethoxy carbazole (CBZ-Q), bis(4-butoxyphenyl)amine (BPA-Q), were synthesized by Riley oxidation of CH3 followed by Knoevenagel condensation of the corresponding aldehyde precursors 2a–c with cyanoacrylic acid. The optical, electrochemical, theoretical calculation and photovoltaic properties with these three dyes were systematically investigated. Compared to DEA-Q and CBZ-Q, BPA-Q possesses better light harvesting properties with regard to extended conjugate length, red-shifted intramolecular charge transfer band absorption and broaden light-responsive IPCE spectrum, resulting in a greater short circuit photocurrent density output. BPA-Q also has improved open-circuit voltage due to the apparent large charge recombination resistance. Consequently, assembled with iodine redox electrolytes, the device with BPA-Q achieved the best overall conversion efficiency value of 3.07% among three dyes under AM 1.5G standard conditions. This present investigation demonstrates the importance of various N-substituent chromophores in the prevalent D-π-A type organic sensitizers for tuning the photovoltaic performance of their DSSCs.
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      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.09.002
      Issue No: Vol. 190 (2017)
       
  • Spectroscopic and DFT investigation on the photo-chemical properties of a
           push-pull chromophore: 4-Dimethylamino-4′-nitrostilbene
    • Authors: Francesco Muniz-Miranda; Alfonso Pedone; Maurizio Muniz-Miranda
      Pages: 33 - 39
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Francesco Muniz-Miranda, Alfonso Pedone, Maurizio Muniz-Miranda
      4-Dimethylamino-4′-nitrostilbene (DANS), a π-conjugated push-pull molecule, has been investigated by means of a combined spectroscopic and computational approach. When the Raman excitation is close to the visible electronic transition of DANS, vibrational bands not belonging to DANS appear in the spectra, increasing with the laser power. These bands are observed at room temperature in the solid phase, but not at low temperature or in solution, and we interpret them as due to a thermally-activated photoreaction occurring under laser irradiation in the visible spectral region. Density-functional calculations correctly reproducing the electronic and vibrational spectra of DANS, describe the charge-transfer process, indicate that an azo-derivative is the product of the photoreaction of DANS and provide a reasonable interpretation of this process.
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      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.08.072
      Issue No: Vol. 190 (2017)
       
  • Raman analysis of cobalt blue pigment in blue and white porcelain: A
           reassessment
    • Authors: Xiaochenyang Jiang; Yanying Ma; Yue Chen; Yuanqiu Li; Qinglin Ma; Zhaoxia Zhang; Changsui Wang; Yimin Yang
      Pages: 61 - 67
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Xiaochenyang Jiang, Yanying Ma, Yue Chen, Yuanqiu Li, Qinglin Ma, Zhaoxia Zhang, Changsui Wang, Yimin Yang
      Cobalt blue is a famous pigment in human history. In the past decade it is widely reported that the cobalt aluminate has been detected in ancient ceramics as blue colorant in glaze, yet the acquired Raman spectra are incredibly different from that of synthesised references, necessitating a reassessment of such contradictory scenario with more accurate analytic strategies. In this study, micro-Raman spectroscopy (MRS) and scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) were performed on under-glaze cobalt pigments from one submerged blue and white porcelain shard dated from Wanli reign (1573–1620CE) of Ming dynasty (1365–1644CE) excavated at Nan'ao I shipwreck off the southern coast of China. The micro-structural inspection reveals that the pigment particles have characteristics of small account, tiny size, heterogeneously distribution, and more importantly, been completely enwrapped by well-developed anorthite crystals in the glaze, indicating that the signals recorded in previous publications are probably not from cobalt pigments themselves but from outside thickset anorthite shell. The further spectromicroscopic analyses confirm this presumption when the accurate spectra of cobalt aluminate pigment and surrounding anorthite were obtained separately with precise optical positioning. Accordingly, we reassess and clarify the previous Raman studies dedicated to cobalt blue pigment in ancient ceramics, e.g. cobalt blue in celadon glaze, and in turn demonstrate the superiority and necessity of coupling spectroscopic analysis with corresponding structure observation, especially in the characterization of pigments from complicated physico-chemical environment like antiquities. Thus, this study promotes a better understanding of Raman spectroscopy study of cobalt blue pigments in art and archaeology field.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.08.076
      Issue No: Vol. 190 (2017)
       
  • Synthesis and characterization of bright green terbium coordination
           complex derived from 1,4-bis(carbonylmethyl)terephthalate: Structure and
           luminescence properties
    • Authors: Mengjiao Ma; Congcong Li; Dengkun Shu; Chaohua Wang; Peng Xi
      Pages: 68 - 75
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Mengjiao Ma, Congcong Li, Dengkun Shu, Chaohua Wang, Peng Xi
      A photoluminescent terbium (Tb) complex involving a novel benzoic-acid compound with a unique coordinated structure, namely 1,4-bis(carbonylmethyl)terephthalate (BCMT), has been designed and synthesized. The new coordinate structure and energy-transfer mechanism between the ligand and Tb(III) ions were investigated in detail. The results demonstrated that the BCMT–Tb(III) complex shows strong fluorescence intensity (4×106 a.u.) and long fluorescence lifetime (1.302ms), owing to the favorable degree of energy matching between the triplet excited level of the ligand and the resonant level of Tb(III) ions. Based on the analysis of three-dimensional luminescence spectra, the as-prepared Tb(III) complex can be effectively excited in the range of 250–310nm, and it shows high color purity, with a bright green appearance.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.09.009
      Issue No: Vol. 190 (2017)
       
  • The broad emission at 785nm in YAG:Ce3+,Cr3+ phosphor
    • Authors: Xianju Zhou; Xiaoxia Luo; Bing Wu; Sha Jiang; Li Li; Xiaobing Luo; Yu Pang
      Pages: 76 - 80
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Xianju Zhou, Xiaoxia Luo, Bing Wu, Sha Jiang, Li Li, Xiaobing Luo, Yu Pang
      Luminescence of defects and/or impurities is important for phosphors. One broad emission band centered at 785nm was observed in (Y0.97Ce0.03)3(Al1–xCrx)5O12 (x=0.005, 0.01, 0.03, 0.06, 0.09), (YAG:Ce,Cr) nano-particles synthesized by polymer-assisted sol-gel method in this work. In order to study the source of this wide emission band, the crystalline phase structure of the phosphors was examined by X-ray diffraction (XRD). No obvious diffraction peaks due to impurity phase were observed even though the calcining temperature of the samples arrived at 1400°C. The anti-site defects were excluded. No detectable signals of impurities were obtained by X-ray Photoelectron Spectroscopy (XPS) or inductively coupled plasma mass spectrometry (ICP-MS). Based on the photo-luminescence results of YAG:Ce,Cr, YAG:Ce and YAG:Fe phosphors, the wide emission band is attributed to the 4T1(4G)→ 6A1(6S) transition from the trace impurity of Fe3+. The excitation band at 280nm is assigned to Fe3+-O2– charge transfer band.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.09.011
      Issue No: Vol. 190 (2017)
       
  • Spectral and computational features of the binding between riparins and
           human serum albumin
    • Authors: Cintia Ramos Camargo; Ícaro Putinhon Caruso; Stanley Juan Chavez Gutierrez; Marcelo Andres Fossey; José Maria Barbosa Filho; Marinônio Lopes Cornélio
      Pages: 81 - 88
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Cintia Ramos Camargo, Ícaro Putinhon Caruso, Stanley Juan Chavez Gutierrez, Marcelo Andres Fossey, José Maria Barbosa Filho, Marinônio Lopes Cornélio
      The green Brazilian bay leaf, a spice much prized in local cuisine (Aniba riparia, Lauraceae), contains chemical compounds presenting benzoyl-derivatives named riparins, which have anti-inflammatory, antimicrobial and anxiolytic properties. However, it is unclear what kind of interaction riparins perform with any molecular target. As a profitable target, human serum albumin (HSA) is one of the principal extracellular proteins, with an exceptional capacity to interact with several molecules, and it also plays a crucial role in the transport, distribution, and metabolism of a wide variety of endogenous and exogenous ligands. To outline the HSA–riparin interaction mechanism, spectroscopy and computational methods were synergistically applied. An evaluation through fluorescence spectroscopy showed that the emission, attributed to Trp 214, at 346 nm decreased with titrations of riparins. A static quenching mechanism was observed in the binding of riparins to HSA. Fluorescence experiments performed at 298, 308 and 318 K made it possible to conduct thermodynamic analysis indicating a spontaneous reaction in the complex formation (ΔG<0). The enthalpy-entropy balance experiment with a molecular modeling calculation revealed that hydrophobic, hydrogen bond and non-specific interactions are present for riparin I–III with HSA. The set of results from fractional fluorescence changes obtained through Schatchard was inconclusive in establishing what kind of cooperativity is present in the interaction. To shed light upon the HSA-riparins complex, Hill's approach was utilized to distinguish the index of affinity and the binding constant. A correspondence between the molecular structures of riparins, due to the presence of the hydroxyl group in the B-ring, with thermodynamic parameters and index of affinity were observed. Riparin III performs an intramolecular hydrogen bond, which affects the Hill coefficient and the binding constant. Therefore, the presence of hydroxyl groups is capable of modulating the interaction between riparins and HSA. Site marker competitive experiments indicated Site I as being the most suitable, and the molecular modeling tools reinforced the experimental results detailing the participation of residues.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.08.068
      Issue No: Vol. 190 (2017)
       
  • Synthesis of water-soluble curcumin derivatives and their inhibition on
           lysozyme amyloid fibrillation
    • Authors: Sujuan Wang; Xixi Peng; Liangliang Cui; Tongtong Li; Bei Yu; Gang Ma; Xinwu Ba
      Pages: 89 - 95
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Sujuan Wang, Xixi Peng, Liangliang Cui, Tongtong Li, Bei Yu, Gang Ma, Xinwu Ba
      The potential application of curcumin was heavily limited in biomedicine because of its poor solubility in pure water. To circumvent the detracting feature, two novel water-soluble amino acid modified curcumin derivatives (MLC and DLC) have been synthesized through the condensation reaction between curcumin and Nα-Fmoc-Nε-Boc-l-lysine. Benefiting from the enhanced solubility of 3.32×10−2 g/mL for MLC and 4.66×10−2 g/mL for DLC, the inhibition effects of the as-prepared derivatives on the amyloid fibrillation of lysozyme (HEWL) were investigated detaily in water solution. The obtained results showed that the amyloid fibrillation of HEWL was inhibited to a great extent when the concentrations of MLC and DLC reach to 20.139mM and 49.622mM, respectively. The fluorescence quenching upon the addition of curcumin to HEWL provide a support for static and dynamic recombination quenching process. The binding driving force was assigned to classical hydrophobic interaction between curcumin derivatives and HEWL. In addition, UV–Vis absorption and circular dichroism (CD) spectra confirmed the change of the conformation of HEWL.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.09.010
      Issue No: Vol. 190 (2017)
       
  • A highly selective and sensitive turn-on probe for aluminum(III) based on
           quinoline Schiff's base and its cell imaging
    • Authors: Fenfen Zhou; Hongqing Wang; Pengying Liu; Qinghua Hu; Yuyuan Wang; Can Liu; Jiangke Hu
      Pages: 104 - 110
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Fenfen Zhou, Hongqing Wang, Pengying Liu, Qinghua Hu, Yuyuan Wang, Can Liu, Jiangke Hu
      A reversible Schiff's base fluorescence probe for Al3+, (3,5-dichloro-2- hydroxybenzylidene) quinoline-2-carbohydrazide (QC), based on quinoline derivative has been designed, synthesized and evaluated. The QC exhibited a high sensitivity and selectivity toward Al3+ in EtOH-H2O (v/v=1:9, pH=6) by forming a 1:1 complex with Al3+ and the detection limit of QC for Al3+ was as low as 0.012μM. Furthermore, these results displayed that the binding of QC Al3+ was broken by F−, so this system could be used to monitor F− in the future. The enhancement fluorescence of the QC could be attributed to the inhibition of PET and ESIPT and the emergency of CHEF process induced by Al3+. More importantly, QC was not only successfully used for the determination of trace Al3+ in the tap water and the human blood serum, but was valid for fluorescence imaging of Al3+ in the Hela cells.
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      PubDate: 2017-09-15T12:42:36Z
      DOI: 10.1016/j.saa.2017.09.007
      Issue No: Vol. 190 (2017)
       
  • Synthesis and characterization of 8-hydroxyquinolin-1-ium
           2,2,2-trifluoroacetate and 8-hydroxyquinolin-1-ium 2,2,2-trichloroacetate
           by z-scan technique
    • Authors: M.D. Zidan; A. Arfan; A. Allahham
      Pages: 135 - 139
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): M.D. Zidan, A. Arfan, A. Allahham
      The 8-hydroxyquinolin-1-ium 2,2,2-trifluoroacetate and 8-hydroxyquinolin-1-ium 2,2,2-trichloroacetate (8-HQ) salts have been synthesized and characterized by FTIR, NMR and UV–Vis absorption spectroscopic methods. The third order nonlinear optical properties (NLO) of the two 8-HQ salts have been investigated by z-scan technique. The recorded experimental data led to calculate the nonlinear optical absorption coefficient (β), the nonlinear refractive index (n2), the excited-state absorption cross section (σex) and the ground-state absorption cross section (σg) of the studied compounds. The two 8-HQ salts have been found to exhibit large optical nonlinearity. These types of materials may be considering new photonic applications.
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      PubDate: 2017-09-20T13:05:02Z
      DOI: 10.1016/j.saa.2017.09.022
      Issue No: Vol. 190 (2017)
       
  • Vacuum ultraviolet photoabsorption of prime ice analogues of Pluto and
           Charon
    • Authors: S. Pavithraa; J.-I. Lo; K. Rahul; B.N. Raja Sekhar; B.-M. Cheng; N.J. Mason; B. Sivaraman
      Pages: 172 - 176
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): S. Pavithraa, J.-I. Lo, K. Rahul, B.N. Raja Sekhar, B.-M. Cheng, N.J. Mason, B. Sivaraman
      Here we present the first Vacuum UltraViolet (VUV) photoabsorption spectra of ice analogues of Pluto and Charon ice mixtures. For Pluto the ice analogue is an icy mixture containing nitrogen (N2), carbon monoxide (CO), methane (CH4) and water (H2O) prepared with a 100:1:1:3 ratio, respectively. Photoabsorption of icy mixtures with and without H2O were recorded and no significant changes in the spectra due to presence of H2O were observed. For Charon a VUV photoabsorption spectra of an ice analogue containing ammonia (NH3) and H2O prepared with a 1:1 ratio was recorded, a spectrum of ammonium hydroxide (NH4OH) was also recorded. These spectra may help to interpret the P-Alice data from New Horizons.
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      PubDate: 2017-09-20T13:05:02Z
      DOI: 10.1016/j.saa.2017.08.060
      Issue No: Vol. 190 (2017)
       
  • A new low temperature solid modification in
           1-isothiocyanato-4-(trans‑4-propylcyclohexyl)benzene (3CHBT) probed by
           Raman spectroscopy and quantum chemical calculations
    • Authors: K. Vikram; Ranjan K. Singh; Satyendra Nath Gupta
      Pages: 188 - 196
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): K. Vikram, Ranjan K. Singh, Satyendra Nath Gupta
      Raman spectra of 1-isothiocyanato-4-(trans 4-propylcyclohexyl)benzene (3CHBT) were studied in the region, 1450–2300cm−1 at twenty two different temperatures in the range, 83–293K in cooling and heating cycles. All bands in this region were critically evaluated in term of linewidth, peak position and relative intensity. Raman bands at ~2085cm−1 and ~2120cm−1 shows clear evidence of a solid modification through anomaly in temperature dependence peak positions and linewidths variation in the temperature range 173–203K. A detailed analysis of the variation of the linewidth and peak position of the two component bands leads to the conclusion that the molecular/dimer arrangement in crystalline packing changed between 173K and 203K. This solid modification was also analyzed at the molecular level. The ~2085cm−1 and ~2120cm−1 bands were corresponded as parallel and anti-parallel dimers of 3CHBT, which are identified as dimer I (D1) and dimer II (D2), respectively. The structures of both the dimers have been optimized by quantum chemical calculations employing density functional theoretic (DFT) methods.
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      PubDate: 2017-09-20T13:05:02Z
      DOI: 10.1016/j.saa.2017.09.015
      Issue No: Vol. 190 (2017)
       
  • Ultrasound-assisted interaction between chlorin-e6 and human serum
           
    • Authors: Mihaela N. Mocanu; Fei Yan
      Pages: 208 - 214
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Mihaela N. Mocanu, Fei Yan
      The interaction between chlorin e6 (Ce6) and human serum albumin (HSA) in the presence and absence of ultrasound have been investigated by ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. Ce6 is found to bind strongly to HSA at or near physiological pH conditions, but the strength of the binding is significantly weakened at lower pHs. The intrinsic fluorescence of HSA is incrementally quenched with increasing concentration of Ce6, and the quenching is enhanced after exposure to high-frequency ultrasound. Our experimental results suggest that Ce6-induced sonodynamic oxidation of HSA is mainly mediated by singlet oxygen. The formulation of Ce6 by high molecular weight polyvinylpyrrolidone (PVP) increased its stability in aqueous solutions and its quantum yield of singlet oxygen under ultrasound irradiation.
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      PubDate: 2017-09-20T13:05:02Z
      DOI: 10.1016/j.saa.2017.09.017
      Issue No: Vol. 190 (2017)
       
  • Energy transfer and color tunable emission in Tb3+,Eu3+ co-doped
           Sr3LaNa(PO4)3F phosphors
    • Authors: Shuo Li; Ning Guo; Qimeng Liang; Yu Ding; Huitao Zhou; Ruizhuo Ouyang; Wei Lü
      Pages: 246 - 252
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Shuo Li, Ning Guo, Qimeng Liang, Yu Ding, Huitao Zhou, Ruizhuo Ouyang, Wei Lü
      A group of color tunable Sr3LaNa(PO4)3F:Tb3+,Eu3+ phosphors were prepared by conventional high temperature solid state method. The phase structures, luminescence properties, fluorescence lifetimes and energy transfer were investigated in detail. Under 369nm excitation, owing to efficient energy transfer of Tb3+ →Eu3+, the emission spectra both have green emission of Tb3+ and red emission of Eu3+. An efficient energy transfer occur in Tb3+, Eu3+ co-doped Sr3LaNa(PO4)3F phosphors. The most possible mechanism of energy transfer is dipole-dipole interaction by Dexter's theoretical model. The energy transfer of Tb3+ and Eu3+ was confirmed by the variations of emission and excitation spectra and Tb3+/Eu3+ decay lifetimes in Sr3LaNa(PO4)3F:Tb3+,Eu3+. The color tone can tuned from yellowish-green through yellow and eventually to reddish-orange with fixed Tb3+ content by changing Eu3+ concentrations. The results show that the prepared Tb3+, Eu3+ co-doped color tunable Sr3LaNa(PO4)3F phosphor can be used for white LED.
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      PubDate: 2017-09-20T13:05:02Z
      DOI: 10.1016/j.saa.2017.09.047
      Issue No: Vol. 190 (2017)
       
  • Dynamic surface-enhanced Raman spectroscopy and Chemometric methods for
           fast detection and intelligent identification of methamphetamine and 3,
           4-Methylenedioxy methamphetamine in human urine
    • Authors: Shizhuang Weng; Ronglu Dong; Zede Zhu; Dongyan Zhang; Jinling Zhao; Linsheng Huang; Dong Liang
      Pages: 1 - 7
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Shizhuang Weng, Ronglu Dong, Zede Zhu, Dongyan Zhang, Jinling Zhao, Linsheng Huang, Dong Liang
      Conventional Surface-Enhanced Raman Spectroscopy (SERS) for fast detection of drugs in urine on the portable Raman spectrometer remains challenges because of low sensitivity and unreliable Raman signal, and spectra process with manual intervention. Here, we develop a novel detection method of drugs in urine using chemometric methods and dynamic SERS (D-SERS) with mPEG-SH coated gold nanorods (GNRs). D-SERS combined with the uniform GNRs can obtain giant enhancement, and the signal is also of high reproducibility. On the basis of the above advantages, we obtained the spectra of urine, urine with methamphetamine (MAMP), urine with 3, 4-Methylenedioxy Methamphetamine (MDMA) using D-SERS. Simultaneously, some chemometric methods were introduced for the intelligent and automatic analysis of spectra. Firstly, the spectra at the critical state were selected through using K-means. Then, the spectra were proposed by random forest (RF) with feature selection and principal component analysis (PCA) to develop the recognition model. And the identification accuracy of model were 100%, 98.7% and 96.7%, respectively. To validate the effect in practical issue further, the drug abusers'urine samples with 0.4, 3, 30ppm MAMP were detected using D-SERS and identified by the classification model. The high recognition accuracy of >92.0% can meet the demand of practical application. Additionally, the parameter optimization of RF classification model was simple. Compared with the general laboratory method, the detection process of urine's spectra using D-SERS only need 2 mins and 2μL samples volume, and the identification of spectra based on chemometric methods can be finish in seconds. It is verified that the proposed approach can provide the accurate, convenient and rapid detection of drugs in urine.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.004
      Issue No: Vol. 189 (2017)
       
  • “Turn-on” fluorescent probe for detection of H2S and its
           applications in bioimaging
    • Authors: Qi Zhao; Jin Kang; Ying Wen; Fangjun Huo; Yongbin Zhang; Caixia Yin
      Pages: 8 - 12
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Qi Zhao, Jin Kang, Ying Wen, Fangjun Huo, Yongbin Zhang, Caixia Yin
      A novel fluorescent probe (named YQ-1) containing disulfide-bond coumarin derivative was developed for H2S. In response to H2S, YQ-1 showed remarkable fluorescent emission enhancement at 462nm. Besides, YQ-1 exhibited higher selectivity, faster response rate, low cytotoxicity and low detection limit (0.052μM). Further, YQ-1 was used to detect the presence of H2S level in living A549 cells, indicating YQ-1 has good membrane permeability and fluorescence properties.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.002
      Issue No: Vol. 189 (2017)
       
  • Attaching naphthalene derivatives onto BODIPY for generating excited
           triplet state and singlet oxygen: Tuning PET-based photosensitizer by
           electron donors
    • Authors: Xian-Fu Zhang; Nan Feng
      Pages: 13 - 21
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Xian-Fu Zhang, Nan Feng
      meso-Naphthalene substituted BODIPY compounds were prepared in a facile one pot reaction. The naphthalene functionalization of BODIPY leads up to a 5-fold increase in the formation efficiency of excited triplet state and singlet oxygen in polar solvents. Steady state and time resolved fluorescence, laser flash photolysis, and quantum chemistry methods were used to reveal the mechanism. All measured data and quantum chemical results suggest that these systems can be viewed as electron donor-acceptor (D-A) pair (BODIPY acts as the acceptor), photoinduced charge transfer (PCT) or photoinduced electron transfer (PET) occurs upon photo excitation (D-A+hν→Dδ+-Aδ−, 0<δ≤1), and the charge recombination induced the formation of triplet state (Dδ+-Aδ− →D-A (T1). These novel PCT- or PET-based photosensitizers (PSs) show different features from traditional PSs, such as the strong tunability by facile structural modification and good selectivity upon medium polarity. The new character for this type of PSs can lead to important applications in organic oxygenation reactions and photodynamic therapy of tumors.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.005
      Issue No: Vol. 189 (2017)
       
  • A new fluorene-based Schiff-base as fluorescent chemosensor for selective
           detection of Cr3+ and Al3+
    • Authors: Mahmood Tajbakhsh; Gholam Babaei Chalmardi; Ahmadreza Bekhradnia; Rahman Hosseinzadeh; Nahid Hasani; Mohammadreza Azizi Amiri
      Pages: 22 - 31
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Mahmood Tajbakhsh, Gholam Babaei Chalmardi, Ahmadreza Bekhradnia, Rahman Hosseinzadeh, Nahid Hasani, Mohammadreza Azizi Amiri
      2-((9H-fluoren-2-ylimino) methyl)phenol (F3) was synthesized by condensation reaction of 9H-fluoren-2-amine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1H-,13C NMR and molecular mass. F3 exhibits a high selectivity for detection of Cr3+ and Al3+ ions as a fluorescent chemosensor and showed a single emission band at 536nm upon excitation at 333nm according to fluorescence emission studies. The addition of Cr3+ and Al3+ make a significant increase in fluorescent intensity at 536nm in CH3CN, while other metal ions have almost no influence on the fluorescence. The fluorescence enhancement was attributed to the inhibited CN isomerization and the obstructed excited state intra-molecular proton transfer (ESIPT) of compound F3. Job's plot and DFT calculations data showed that the binding stoichiometries of F3 with Cr3+ and Al3+ are 2:1. The association constants (Ka) for Cr3+ and Al3+ were calculated and found to be 8.33×104 M−1 and 5.44×104 M−1, respectively. The detection limits were also calculated for Cr3+ and Al3+ and found to be 2.5×10−7 mol/L and 3.1×10−7 mol/L, respectively.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.007
      Issue No: Vol. 189 (2017)
       
  • Fluorescence emission induced by the femtosecond filament transmitting
           through the butane/air flame
    • Authors: Suyu Li; Yanhua Li; Zhe Shi; Laizhi Sui; He Li; Qingyi Li; Anmin Chen; Yuanfei Jiang; Mingxing Jin
      Pages: 32 - 36
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Suyu Li, Yanhua Li, Zhe Shi, Laizhi Sui, He Li, Qingyi Li, Anmin Chen, Yuanfei Jiang, Mingxing Jin
      We measure the backward fluorescence spectra generated by the femtosecond filament transmitting through the butane/air flame, and study the fluorescence emission from combustion intermediates (CN, CH and C2 radicals), air (mainly N2 and N2 +). It is found that the fluorescence emission from combustion intermediates, N2 and N2 + shows difference when the femtosecond filament transmits through different parts of the butane/air flame, and we attempt to analyze it in this paper. This study demonstrates that the filament-induced fluorescence technique can be utilized to sense the combustion intermediates.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.006
      Issue No: Vol. 189 (2017)
       
  • Detection of olive oil adulteration with waste cooking oil via Raman
           spectroscopy combined with iPLS and SiPLS
    • Authors: Yuanpeng Li; Tao Fang; Siqi Zhu; Furong Huang; Zhenqiang Chen; Yong Wang
      Pages: 37 - 43
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Yuanpeng Li, Tao Fang, Siqi Zhu, Furong Huang, Zhenqiang Chen, Yong Wang
      Olive oil adulteration with waste cooking oil was detected and quantified by combining optical Raman scattering spectroscopy and chemometrics. Spectra of 96 olive oil samples with waste cooking oil (2.5%, 5%, 10%, 20%, 30% and 50%) were collected by the portable Raman spectroscopy system. iPLS and SiPLS quantitative analysis models were established. The results revealed that spectral data after SNV processing are the best for synergy interval partial least square (SiPLS) modeling and forecast. The root mean squared error of calibration (RMSEC) is 0.0503 and the root mean squared error of validation (RMSEV) is 0.0485. The lower limit of application (LLA) of the proposed method is c[WCO]=0.5%. According to linear regression calculation, the theoretical limit of detection (LOD) of the proposed method is about c[WCO]=0.475%. The established model could make effective quantitative analysis on adulteration of waste cooking oil. It provides a quick accurate method for adulteration detection of waste cooking oil in olive oil.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.06.049
      Issue No: Vol. 189 (2017)
       
  • A Cr(VI) selective probe based on a quinoline-amide calix[4]arene
    • Authors: Juliane F. Ferreira; Izilda A. Bagatin
      Pages: 44 - 50
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Juliane F. Ferreira, Izilda A. Bagatin
      A new quinoline-amide calix[4]arene 3-receptor for detection of hazardous anions and cations have been synthesized. The 3-receptor was examined for its sensing properties towards several different anions (Cr2O7 2, SCN−, F−, Cl−, NO3) and metal ions (Hg2+, Cd2+, Ag+) by UV–vis and fluorescence spectroscopies. It was detected that the 3-receptor has only sensing ability for Cr2O7 2 and Hg2+ ions, resulting in the association constants higher for Cr2O7 2 than to the Hg2+ ions. High selectivity towards Cr2O7 2 were also observed by fluorescence measurement among other ions (F−, Cl− , SCN−, Hg2+, Cd2+, Ag+) with a low limit of detection (7.36×10−6 moldm−3). Proton NMR anion-binding investigations revealed a strong interaction of Cr2O7 2 anion with NH and CH groups of the receptor, showing that the combination with hydrogen-bonds donor groups strengthened the anion receptor association. Furthermore, remarkable association constants for dichromate anion obtained by all techniques strongly suggest the 3-receptor as a selective Cr(VI) sensor.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.056
      Issue No: Vol. 189 (2017)
       
  • Carbon-dot-based dual-emission silica nanoparticles as a ratiometric
           fluorescent probe for vanadium(V) detection in mineral water samples
    • Authors: Lijun He; Heng Zhang; Huanhuan Fan; Xiuming Jiang; Wenjie Zhao; Guo Qiang Xiang
      Pages: 51 - 56
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Lijun He, Heng Zhang, Huanhuan Fan, Xiuming Jiang, Wenjie Zhao, Guo Qiang Xiang
      Herein, we propose a simple and effective strategy for designing a ratiometric fluorescent nanosensor. We designed and developed a carbon dots (CDs) based dual-emission nanosensor for vanadium(V) by coating the surface of dye-doped silica nanoparticles with CDs. The fluorescence of dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBrO3) oxidation. V(V) could catalyze KBrO3 oxidation reaction process, resulting in the ratiometric fluorescence quenching of dual-emission silica nanoparticles. We investigated several important parameters affecting the performance of the nanosensor. Under the optimized conditions, the detection limit of this nanosensor reached 1.1ngmL−1 and the linear range from 10 to 800ngmL−1. Furthermore, we found that the sensor was suitable for determination of V(V) in different mineral water samples with satisfactory results.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.010
      Issue No: Vol. 189 (2017)
       
  • Chain length effects on the vibrational structure and molecular
           interactions in the liquid normal alkyl alcohols
    • Authors: Johannes Kiefer; Sabine Wagenfeld; Daniela Kerlé
      Pages: 57 - 65
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Johannes Kiefer, Sabine Wagenfeld, Daniela Kerlé
      Alkyl alcohols are widely used in academia, industry, and our everyday lives, e.g. as cleaning agents and solvents. Vibrational spectroscopy is commonly used to identify and quantify these compounds, but also to study their structure and behavior. However, a comprehensive investigation and comparison of all normal alkanols that are liquid at room temperature has not been performed, surprisingly. This study aims at bridging this gap with a combined experimental and computational effort. For this purpose, the alkyl alcohols from methanol to undecan-1-ol have been analyzed using infrared and Raman spectroscopy. A detailed assignment of the individual peaks is presented and the influence of the alkyl chain length on the hydrogen bonding network is discussed. A 2D vibrational mapping allows a straightforward visualization of the effects. The conclusions drawn from the experimental data are backed up with results from Monte Carlo simulations using the simulation package Cassandra.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.061
      Issue No: Vol. 189 (2017)
       
  • Anharmonic vibrational analysis of s-trans and s-cis conformers of
           acryloyl fluoride using numerical-analytic Van Vleck operator perturbation
           theory
    • Authors: Sergey V. Krasnoshchekov; Norman C. Craig; Lidiya A. Koroleva; Nikolay F. Stepanov
      Pages: 66 - 79
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Sergey V. Krasnoshchekov, Norman C. Craig, Lidiya A. Koroleva, Nikolay F. Stepanov
      A new gas-phase infrared (IR) spectrum of acryloyl fluoride (ACRF, CH2 CHCFO) with a resolution of 0.1cm−1 in the range 4000–450cm−1 was measured. Theoretical ab initio molecular structures, full quartic potential energy surfaces (PES), and cubic surfaces of dipole moments and polarizability tensor components (electro-optical properties, EOP) of the s-trans and s-cis conformers of the ACRF were calculated by the second-order Møller-Plesset electronic perturbation theory with a correlation consistent Dunning triple-ζ basis set. The numerical-analytic implementation of the second-order operator canonical Van Vleck perturbation theory was employed for predicting anharmonic IR and Raman scattering (RS) spectra of ACRF. To improve the anharmonic predictions, harmonic frequencies were replaced by their counterparts evaluated with the higher-level CCSD(T)/cc-pVTZ model, to form a “hybrid” PES. The original operator representation of the Hamiltonian is analytically reduced to a quasi-diagonal form, integrated in the harmonic oscillator basis and diagonalized to account for strong resonance couplings. Double canonical transformations of EOP expansions enabled prediction of integral intensities of both fundamental and multi-quanta transitions in IR/RS spectra. Enhanced band shape analysis reinforced the assignments. A thorough interpretation of the new IR experimental spectra and existing matrix-isolation literature data for the mixture of two conformers of ACRF was accomplished, and a number of assignments clarified.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.062
      Issue No: Vol. 189 (2017)
       
  • Effect of solvent on the electronic absorption spectral properties of some
           mixed β-octasubstituted Zn(II)-tetraphenylporphyrins
    • Authors: P. Bhyrappa; M. Sankar
      Pages: 80 - 85
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): P. Bhyrappa, M. Sankar
      A series of mixed β-octasubstituted Zn(II)-porphyrins, 2,3,12,13-tetra(chloro/cyano/methyl)-5,7,8,10,15,17,18,20-octaphenylporphinato zinc(II), ZnTPP(Ph)4X4 (X=CN, Cl and CH3) have been examined by electronic absorption spectroscopy in various solvents. These Zn(II)-porphyrins exhibited varying degree of red-shift of absorption bands as high as 20–30nm in ‘B’ band and 50–60nm in longest wavelength band, ‘Q(0,0)’ band in polar solvents relative to that found in nonpolar solvents. The red-shift of B and Q(0,0) bands showed an unusual trend, ZnTPP(Ph)4(CN)4 >ZnTPP(Ph)4(CH3)4 >ZnTPP(Ph)4Cl4 but fails to follow an anticipated anodic shift in first porphyrin ring oxidation (vs Ag/AgCl) potential: ZnTPP(Ph)4(CN)4 (1.02V)>ZnTPP(Ph)4Cl4 (0.74V)>ZnTPP(Ph)4(CH3)4 (0.38V). Such a trend suggests the combined effect of non-planarity of the macrocycle and electronic effect of the peripheral substituents. The equilibrium constants for the binding of nitrogenous bases with the Zn(II)-porphyrins showed as high as twenty fold increase for ZnTPP(Ph)4X4 (X=Br and CN) relative to ZnTPP(Ph)4(CH3)4 and follow the order: ZnTPP(Ph)4(CN)4 >ZnTPP(Ph)4Br4 >ZnTPP(Ph)4(CH3)4 ≤ZnTPP which is approximately in line with an increase in anodic shift of their first ring redox potentials (ZnTPP(Ph)4(CN)4 (1.02V)>ZnTPP(Ph)4Br4 (0.72V)>ZnTPP (0.84V)>ZnTPP(Ph)4(CH3)4) (0.38V).
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.059
      Issue No: Vol. 189 (2017)
       
  • Linear and circular dichroism characterization of thionine binding mode
           with DNA polynucleotides
    • Authors: Eimer Mary Tuite; Bengt Nordén
      Pages: 86 - 92
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Eimer Mary Tuite, Bengt Nordén
      The binding mode of thionine (3,7-diamino-5-phenothiazinium) with alternating and non-alternating DNA polynucleotides at low binding ratios was conclusively determined using linear and circular dichroism spectroscopies. The binding to [poly(dG-dC)]2 and poly(dG)·poly(dC) was purely intercalative and was insensitive to ionic strength. Intercalative binding to [poly(dA-dT)]2 is observed at low ionic strength, but a shift of some dye to an non-intercalative mode is observed as the background salt concentration increases. With poly(dA)·poly(dT), intercalative binding is unfavourable, although some dye molecules may intercalate at low ionic strength, and groove binding is strongly promoted with increasing concentration of background salt. However, stacking with bases is observed with single-stranded poly(dA) and with triplex poly(dT)⁎poly(dA)·poly(dT) which suggests that the unusual structure of poly(dA)·poly(dT) precludes intercalation. Thionine behaves similarly to the related dye methylene blue, and small differences may be attributed either to the ability of thionine to form H-bonds that stabilize intercalation or to its improved stacking interactions in the basepair pocket on steric grounds.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.064
      Issue No: Vol. 189 (2017)
       
  • Physicochemical analysis of Permian coprolites from Brazil
    • Authors: M.I.C. Rodrigues; J.H. da Silva; F. Eroni P. Santos; P. Dentzien-Dias; J.C. Cisneros; A.S. de Menezes; P.T.C. Freire; B.C. Viana
      Pages: 93 - 99
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): M.I.C. Rodrigues, J.H. da Silva, F. Eroni P. Santos, P. Dentzien-Dias, J.C. Cisneros, A.S. de Menezes, P.T.C. Freire, B.C. Viana
      In this paper we performed the study of two coprolites (fossilized feces) collected from the exposed levels of the Pedra de Fogo Formation, Parnaiba Sedimentary Basin, and Rio do Rasto Formation, Paraná Sedimentary Basin, both of the Palaeozoic era (Permian age). They were characterized using X-ray diffractometry, infrared, Raman and energy dispersive spectroscopy techniques in order to aid our understanding of the processes of fossilization and to discuss issues related to the feeding habits of the animals which generated those coprolites, probably cartilaginous fishes. The results obtained using a multitechnique approach showed that although these coprolites are from different geological formations, 3000km away from each other, they show the same major crystalline phases and elemental composition. The main phases found were hydroxyapatite, silica, calcite and hematite, which lead to infer that those coprolites were formed under similar conditions and produced by a similar group of carnivore or omnivore fishes.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.011
      Issue No: Vol. 189 (2017)
       
  • Different mathematical processing of absorption, ratio and derivative
           spectra for quantification of mixtures containing minor component: An
           application to the analysis of the recently co-formulated antidiabetic
           drugs; canagliflozin and metformin
    • Authors: Hayam M. Lotfy; Dalia Mohamed; Mona S. Elshahed
      Pages: 100 - 109
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Hayam M. Lotfy, Dalia Mohamed, Mona S. Elshahed
      In the presented work several spectrophotometric methods were performed for the quantification of canagliflozin (CGZ) and metformin hydrochloride (MTF) simultaneously in their binary mixture. Two of these methods; response correlation (RC) and advanced balance point-spectrum subtraction (ABP-SS) were developed and introduced for the first time in this work, where the latter method (ABP-SS) was performed on both the zero order and the first derivative spectra of the drugs. Besides, two recently established methods; advanced amplitude modulation (AAM) and advanced absorbance subtraction (AAS) were also accomplished. All the proposed methods were validated in accordance to the ICH guidelines, where all methods were proved to be accurate and precise. Additionally, the linearity range, limit of detection and limit of quantification were determined and the selectivity was examined through the analysis of laboratory prepared mixtures and the combined dosage form of the drugs. The proposed methods were capable of determining the two drugs in the ratio present in the pharmaceutical formulation CGZ:MTF (1:17) without the requirement of any preliminary separation, further dilution or standard spiking. The results obtained by the proposed methods were in compliance with the reported chromatographic method when compared statistically, proving the absence of any significant difference in accuracy and precision between the proposed and reported methods.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.015
      Issue No: Vol. 189 (2017)
       
  • Spectrophotometric methods for the determination of urea in real samples
           using silver nanoparticles by standard addition and 2nd order derivative
           methods
    • Authors: Nauman Ali; Muhammad Ismail; Adnan Khan; Hamayun Khan; Sajjad Haider; Tahseen Kamal
      Pages: 110 - 115
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Nauman Ali, Muhammad Ismail, Adnan Khan, Hamayun Khan, Sajjad Haider, Tahseen Kamal
      In this work, we have developed simple, sensitive and inexpensive methods for the spectrophotometric determination of urea in urine samples using silver nanoparticles (AgNPs). The standard addition and 2nd order derivative methods were adopted for this purpose. AgNPs were prepared by chemical reduction of AgNO3 with hydrazine using 1,3-di-(1H-imidazol-1-yl)-2-propanol (DIPO) as a stabilizing agent in aqueous medium. The proposed methods were based on the complexation of AgNPs with urea. Using this concept, urea in the urine samples was successfully determined spectrophotometric methods. The results showed high percent recovery with ±RSD. The recoveries of urea in the three urine samples by spectrophotometric standard addition were 99.2%±5.37, 96.3%±4.49, 104.88%±4.99 and that of spectrophotometric 2nd order derivative method were 115.3%±5.2, 103.4%±2.6, 105.93%±0.76. The results show that these methods can open doors for a potential role of AgNPs in the clinical determination of urea in urine, blood, biological, non-biological fluids.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.063
      Issue No: Vol. 189 (2017)
       
  • Photoelectron spectra and biological activity of cinnamic acid derivatives
           revisited
    • Authors: Igor Novak; Leo Klasinc; Sean P. McGlynn
      Pages: 129 - 132
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Igor Novak, Leo Klasinc, Sean P. McGlynn
      The electronic structures of several derivatives of cinnamic acid have been studied by UV photoelectron spectroscopy (UPS) and Green's function quantum chemical calculations. The spectra reveal the presence of dimers in the gas phase for p-coumaric and ferulic acids. The electronic structure analysis has been related to the biological properties of these compounds through the analysis of some structure-activity relationships (SAR).
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.030
      Issue No: Vol. 189 (2017)
       
  • Fluorescence and electron paramagnetic resonance studies of norfloxacin
           and N-donor mixed-ligand ternary copper(II) complexes: Stability and
           interaction with SDS micelles
    • Authors: Gabriel S. Vignoli Muniz; Jimmy Llontop Incio; Odivaldo C. Alves; Klaus Krambrock; Letícia R. Teixeira; Sonia R.W. Louro
      Pages: 133 - 138
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Gabriel S. Vignoli Muniz, Jimmy Llontop Incio, Odivaldo C. Alves, Klaus Krambrock, Letícia R. Teixeira, Sonia R.W. Louro
      The stability of ternary copper(II) complexes of a heterocyclic ligand, L (L being 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen)) and the fluorescent antibacterial agent norfloxacin (NFX) as the second ligand was studied at pH7.4 and different ionic strengths. Fluorescence quenching upon titration of NFX with the binary complexes allowed to obtain stability constants for NFX binding, Kb, as a function of ionic strength. The Kb values vary by more than two orders of magnitude when buffer concentration varies from 0.5 to 100mM. It was observed that previously synthesized ternary complexes dissociate in buffer according with the obtained stability constants. This shows that equimolar solutions of NFX and binary complexes are equivalent to solutions of synthesized ternary complexes. The interaction of the ternary copper complexes with anionic SDS (sodium dodecyl sulfate) micelles was studied by fluorescence and electron paramagnetic resonance (EPR). Titration of NFX-loaded SDS micelles with the complexes Cu:L allowed to determine the stability constants inside the micelles. Fluorescence quenching demonstrated that SDS micelles increase the stability constants by factors around 50. EPR spectra gave details of the copper(II) local environment, and demonstrated that the structure of the ternary complexes inside SDS micelles is different from that in buffer. Mononuclear ternary complexes formed inside the micelles, while in buffer most ternary complexes are binuclear. The results show that anionic membrane interfaces increase formation of copper fluoroquinolone complexes, which can influence bioavailability, membrane diffusion, and mechanism of action of the antibiotics.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.013
      Issue No: Vol. 189 (2017)
       
  • A portable synthesis of water-soluble carbon dots for highly sensitive and
           selective detection of chlorogenic acid based on inner filter effect
    • Authors: Huan Yang; Liu Yang; Yusheng Yuan; Shuang Pan; Jidong Yang; Jingjing Yan; Hui Zhang; Qianqian Sun; Xiaoli Hu
      Pages: 139 - 146
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Huan Yang, Liu Yang, Yusheng Yuan, Shuang Pan, Jidong Yang, Jingjing Yan, Hui Zhang, Qianqian Sun, Xiaoli Hu
      In this work, a simple and facile hydrothermal method for synthesis of water-soluble carbon dots (CDs) with malic acid and urea, and were then employed as a high-performance fluorescent probe for selective and sensitive determination of chlorogenic acid (CGA) based on inner filter effect. The as-synthesized CDs was systematically characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Energy disperse spectroscopy (EDS), UV-vis absorption spectroscopy, spectrofluorophotometry, and the results indicated that the sizes of CDs were mainly distributed in the range of 1.0nm–3.0nm with an average diameter of 2.1nm. More significantly, the as-prepared CDs possessed remarkable selectivity and sensitivity towards CGA with the linear range of 0.15μmolL−1–60μmolL−1 and the detection limit for CGA was 45nmolL−1 (3σ/k). The practical applications of CDs for detection of CGA have already been successfully demonstrated in Honeysuckle. This sensitive, selective method has a great application prospect in the pharmaceutical and biological analysis field owing to its simplicity and rapidity for the detection of CGA.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.065
      Issue No: Vol. 189 (2017)
       
  • Distance dependent fluorescence quenching and enhancement of gold
           nanoclusters by gold nanoparticles
    • Authors: Haiyan Qin; Diao Ma; Jianxiu Du
      Pages: 161 - 166
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Haiyan Qin, Diao Ma, Jianxiu Du
      The interaction between fluorescent gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) has been investigated. It was observed that the fluorescence of AuNCs was remarkably quenched when direct contact with AuNPs. The fluorescence quenching of AuNCs by AuNPs was dynamic quenching and exhibited size-dependent property. A larger size of AuNPs displayed a stronger quenching effect and gave a larger quenching constant. When a silica spacer shell was introduced between AuNPs and AuNCs, a fluorescence enhancement of AuNCs by Au@SiO2 NPs was observed. The fluorescence enhancement was strongly dependent on the separation distance between the AuNPs and the AuNCs. A maximal enhancement of 3.72 times was observed when Au@SiO2 NPs have a silica shell thickness of 12nm. This nanocomposite consisting of relatively nontoxic AuNPs and AuNCs may have a potential application in developing novel fluorescent sensor.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.025
      Issue No: Vol. 189 (2017)
       
  • Correlation of cholinergic drug induced quenching of acetylcholinesterase
           bound thioflavin-T fluorescence with their inhibition activity
    • Authors: Mullah Muhaiminul Islam; Mostofa Ataur Rohman; Arun Bahadur Gurung; Atanu Bhattacharjee; Kripamoy Aguan; Sivaprasad Mitra
      Pages: 250 - 257
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Mullah Muhaiminul Islam, Mostofa Ataur Rohman, Arun Bahadur Gurung, Atanu Bhattacharjee, Kripamoy Aguan, Sivaprasad Mitra
      The development of new acetylcholinesterase inhibitors (AChEIs) and subsequent assay of their inhibition efficiency is considered to be a key step for AD treatment. The fluorescence intensity of thioflavin-T (ThT) bound in the active site of acetylcholinesterase (AChE) quenches substantially in presence of standard AChEI drugs due to the dynamic replacement of the fluorophore from the AChE active site as confirmed from steady state emission as well as time-resolved fluorescence anisotropy measurement and molecular dynamics simulation in conjunction with docking calculation. The parametrized % quenching data for individual system shows excellent correlation with enzyme inhibition activity measured independently by standard Ellman AChE assay method in a high throughput plate reader system. The results are encouraging towards design of a fluorescence intensity based AChE inhibition assay method and may provide a better toolset to rapidly evaluate as well as develop newer AChE-inhibitors for AD treatment.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.009
      Issue No: Vol. 189 (2017)
       
  • High pressure studies on bis(l-histidinate)nickel(II) monohydrate
    • Authors: J.R. Maia; J.A. Lima; P.T.C. Freire; F.E.A. Melo; A.S. de Menezes; C.M.R. Remédios; L.P. Cardoso
      Pages: 258 - 264
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): J.R. Maia, J.A. Lima, P.T.C. Freire, F.E.A. Melo, A.S. de Menezes, C.M.R. Remédios, L.P. Cardoso
      Raman spectra of bis(l-histidinate)nickel(II) monohydrate crystal were obtained for pressures up to 9.5GPa. Our results show the disappearance of some of the Raman modes and the appearance of other modes. These modifications evidence that the sample undergoes phase transitions at around 0.8 and 3.2GPa. The role played by the Ni ions and hydrogen bonds in the dynamics of the phase transitions is discussed. Under decompression, down to atmospheric pressure, the original Raman spectra are recovered, showing that both phase transitions are fully reversible.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.040
      Issue No: Vol. 189 (2017)
       
  • Rapid classification of heavy metal-exposed freshwater bacteria by
           infrared spectroscopy coupled with chemometrics using supervised method
    • Authors: Rafig Gurbanov; Ayse Gul Gozen; Feride Severcan
      Pages: 282 - 290
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Rafig Gurbanov, Ayse Gul Gozen, Feride Severcan
      Rapid, cost-effective, sensitive and accurate methodologies to classify bacteria are still in the process of development. The major drawbacks of standard microbiological, molecular and immunological techniques call for the possible usage of infrared (IR) spectroscopy based supervised chemometric techniques. Previous applications of IR based chemometric methods have demonstrated outstanding findings in the classification of bacteria. Therefore, we have exploited an IR spectroscopy based chemometrics using supervised method namely Soft Independent Modeling of Class Analogy (SIMCA) technique for the first time to classify heavy metal-exposed bacteria to be used in the selection of suitable bacteria to evaluate their potential for environmental cleanup applications. Herein, we present the powerful differentiation and classification of laboratory strains (Escherichia coli and Staphylococcus aureus) and environmental isolates (Gordonia sp. and Microbacterium oxydans) of bacteria exposed to growth inhibitory concentrations of silver (Ag), cadmium (Cd) and lead (Pb). Our results demonstrated that SIMCA was able to differentiate all heavy metal-exposed and control groups from each other with 95% confidence level. Correct identification of randomly chosen test samples in their corresponding groups and high model distances between the classes were also achieved. We report, for the first time, the success of IR spectroscopy coupled with supervised chemometric technique SIMCA in classification of different bacteria under a given treatment.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.038
      Issue No: Vol. 189 (2017)
       
  • Triphenylamine based reactive coloro/fluorimetric chemosensors: Structural
           isomerism and solvent dependent sensitivity and selectivity
    • Authors: Anu Kundu; Savarimuthu Philip Anthony
      Pages: 342 - 348
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Anu Kundu, Savarimuthu Philip Anthony
      Triphenyl amine based chemosensors, (2-(((2-(9H-carbazol-9-yl)phenyl)imino)methyl)-5-(diphenylamino)phenol ( ortho-CPDP) and 2-(((4-(9H–carbazol-9-yl)phenyl)imino)methyl)-5-(diphenylamino)phenol ( para-CPDP), showed solvent and isomerism dependent selective coloro/fluorometric sensing of multiple metal ions (Fe3+, Al3+ and Zn2+) with distinguishable responses. In CH3CN, ortho and para - CPDP selectively produced yellow color upon addition of Al3+ and Fe3+ that was slowly disappeared. The yellow color of ortho and para-CPDP in DMF was decolourised selectively by adding Al3+ and Fe3+. Both ortho and para-CPDP in CH3CN showed nearly similar rate of decolourization for Fe3+ and Al3+. However, the rate of decolourization of ortho and para-CPDP in DMF was different for Fe3+ (10μM, 8min) and Al3+ (5×10−4 M, 40min) ions. The limit of detection of para-CPDP for Fe3+ is 10μM and Al3+ 500μM. The mechanistic studies revealed the imine hydrolysis of ortho and para-CPDP in presence of Lewis acidic Fe3+ and Al3+. The reactivity based sensing lead to high selectivity for Al3+ and Fe3+ ions. Further, para-CPDP exhibited selective fluorescence turn-on for Zn2+ in DMF (λmax =513nm) and detection limit of 6.0μM. Thus, reactive chemosensors, ortho and para-CPDP, exhibited selective and distinguishable colorimetric sensing of Fe3+ and Al3+ ions and isomerism and solvent dependent fluorescence sensing of Zn2+.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.037
      Issue No: Vol. 189 (2017)
       
  • Photoluminescence, thermoluminescence glow curve and emission
           characteristics of Y2O3:Er3+ nanophosphor
    • Authors: Shivaramu N.J.; Lakshminarasappa B.N.; Nagabhushana K.R.; Swart H.C.; Singh Fouran
      Pages: 349 - 356
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Shivaramu N.J., Lakshminarasappa B.N., Nagabhushana K.R., Swart H.C., Singh Fouran
      Nanocrystalline Er3+ doped Y2O3crystals were prepared by a sol gel technique. X-ray diffraction (XRD) patterns showed the cubic structure of Y2O3 and the crystallite size was found to be ~25nm. Optical absorption showed absorption peaks at 454, 495 and 521nm. These peaks are attributed to the 4F3/2 + 4F5/2, 4F7/2 and 2H11/2 + 4S3/2 transitions of Er3+. Under excitation at 378nm, the appearance of strong green (520–565nm) down conversion emission assigned to the (2H11/2, 4S3/2)→ 4I15/2 transition and the feeble red (650–665nm) emission is assigned to the 4F9/2 → 4I15/2 transition. The color chromaticity coordinates showed emission in the green region. The strong green emission of Y2O3:Er3+ nanophosphor may be useful for applications in solid compact laser devices. Thermoluminescence (TL) studies of γ-irradiated Y2O3:Er3+ showed a prominent TL glow peak maximum at 383K along with a less intense shoulder peak at ~425K and a weak glow at 598K. TL emission peaks with maxima at 545, 490, 588 and 622nm for the doped sample were observed at a temperature of 383K and these emissions were due to defect related to the host material. TL kinetic parameters were calculated by a glow curve deconvolution (GCD) method and the obtained results are discussed in detail for their possible usage in high dose dosimetry.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.07.070
      Issue No: Vol. 189 (2017)
       
  • Two emissive-magnetic composite platforms for Hg(II) sensing and removal:
           The combination of magnetic core, silica molecular sieve and rhodamine
           chemosensors
    • Authors: Hanping Mao; Zhongshou Liu
      Pages: 366 - 373
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Hanping Mao, Zhongshou Liu
      In this paper, a composite sensing platform for Hg(II) optical sensing and removal was designed and reported. A core-shell structure was adopted, using magnetic Fe3O4 nanoparticles as the core, silica molecular sieve MCM-41 as the shell, respectively. Two rhodamine derivatives were synthesized as chemosensor and covalently immobilized into MCM-41 tunnels. Corresponding composite samples were characterized with SEM/TEM images, XRD analysis, IR spectra, thermogravimetry and N2 adsorption/desorption analysis, which confirmed their core-shell structure. Their emission was increased by Hg(II), showing emission turn on effect. High selectivity, linear working curves and recyclability were obtained from these composite samples.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.036
      Issue No: Vol. 189 (2017)
       
  • Influence of chlorine atoms in bay positions of perylene-tetracarboxylic
           acids on their spectral properties in Langmuir-Blodgett films
    • Authors: Emilia Piosik; Anna Synak; Tomasz Martyński
      Pages: 374 - 380
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Emilia Piosik, Anna Synak, Tomasz Martyński
      The influence of chlorine atoms in the bay positions of the perylene-3,4,9,10-tetracarboxylic acids with the different alkyl chains length on their spectral properties in monomolecular films has been studied. The chlorinated (PCln) and for comparison non-chlorinated (Pn) perylene derivatives were deposited onto quartz plates using a Langmuir-Blodgett (LB) technique. The absorption spectra showed that the PCln and Pn dyes form in monolayers the I- and J-type aggregates, respectively. In turn, their steady-state and time-resolved emission spectra revealed presence of two emitter types, which we assigned to monomers and excimers. The luminescence lifetimes of the PCln monomers and excimers determined with a time-correlated single photon counting method (TCSPC) are significantly shorter than these obtained for the same emitter types in the Pn monolayers. In the case of the chlorinated dyes, the contribution of the monomer emission dominates over the excimer emission and is almost independent from the alkyl chain length. By contrast, the share of the Pn monomer emission increases strongly with a number of carbon atoms in their hydrocarbon chains. The luminescence quantum yields (LQY) of the Pn and PCln monolayers measured in an integrating sphere are in the range of 0.06–0.11. The presented results reveal that the PCln dyes exhibit lower tendency for aggregation than the non-chlorinated derivatives. It can be explained by limited intermolecular interaction between neighbouring PCln molecules caused by deformation of the perylene core as a result of strongly electronegative chlorine atoms in the bay positions of these dyes. Moreover, the strong influence of the alkyl chain length on the Pn aggregation contrary to the case of the PCln derivatives was observed.
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      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.043
      Issue No: Vol. 189 (2017)
       
  • Ultrasensitive and highly selective detection of Cu2+ ions based on a new
           carbazole-Schiff
    • Authors: Jun Yin; Qijing Bing; Lin Wang; Guang Wang
      Pages: 495 - 501
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Jun Yin, Qijing Bing, Lin Wang, Guang Wang
      A new chemosensor for Cu2+ based on Schiff base with high sensitivity and selectivity was designed and synthesized. The fluorescence intensity of the chemosensor in CH3CN solution was enhanced 160-fold after the addition of 10 equiv. Cu2+ over other metal ions. In addition, it also facilitates colorimetric detection for Cu2+ in CH3CN solution. The chemosensor displayed low detection limit and fast response time to Cu2+.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.057
      Issue No: Vol. 189 (2017)
       
  • Spectroscopic investigations on the interaction of thioacetamide with ZnO
           quantum dots and application for its fluorescence sensing
    • Authors: Dipika Saha; Devendra P.S. Negi
      Pages: 516 - 521
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Dipika Saha, Devendra P.S. Negi
      The purpose of the present work was to develop a method for the sensing of thioacetamide by using spectroscopic techniques. Thioacetamide is a carcinogen and it is important to detect its presence in food-stuffs. Semiconductor quantum dots are frequently employed as sensing probes since their absorption and fluorescence properties are highly sensitive to the interaction with substrates present in the solution. In the present work, the interaction between thioacetamide and ZnO quantum dots has been investigated by using UV–visible, fluorescence and infrared spectroscopy. Besides, dynamic light scattering (DLS) has also been utilized for the interaction studies. UV–visible absorption studies indicated the bonding of the lone pair of sulphur atom of thioacetamide with the surface of the semiconductor. The fluorescence band of the ZnO quantum dots was found to be quenched in the presence of micromolar concentrations of thioacetamide. The quenching was found to follow the Stern-Volmer relationship. The Stern-Volmer constant was evaluated to be 1.20×105 M−1. Infrared spectroscopic measurements indicated the participation of the NH2 group and the sulphur atom of thioacetamide in bonding with the surface of the ZnO quantum dots. DLS measurements indicated that the surface charge of the semiconductor was shielded by the thioacetamide molecules.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.053
      Issue No: Vol. 189 (2017)
       
  • Additive-induced aggregate changes of two structurally similar dyes in
           aqueous solutions: A comparative photophysical study
    • Authors: A. Ghanadzadeh Gilani; Z. Poormohammadi-Ahandani; R. Kian
      Pages: 543 - 555
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): A. Ghanadzadeh Gilani, Z. Poormohammadi-Ahandani, R. Kian
      Absorption and emission spectral characteristics of the two structurally similar phenothiazine dyes, azure B and toluidine blue, in aqueous solutions of the two sets of molecular additives (ureas and monosaccharides) were studied as a function of the dye and additive concentrations. The absorption spectra of the dyes were also studied in pure tetramethylurea with an aprotic nature. The spectral data were analyzed using DECOM Program. The dimer structure of the interacting molecules in these dyes was discussed using the exciton model. The urea class of additives was found to act as water structure-breakers over the range of studied concentration. The carbohydrate additives were found to act as water structure-breakers at low concentrations. However, the water structure breaking process may be disfavored by the additive-additive interactions at higher concentrations. It can be concluded that at low additive concentrations, the main driving force for breaking the dye association is water-additive interaction, which disrupts the water hydrogen bonds induced by the additives. However, at the high additive concentrations, the different phenomena including additive-additive and additive-dye interactions can change the structure, strength, and aggregative properties of the dyes. Finally, the urea in water induces noticeably fluorescence quenching in emission spectra of both the dyes.
      Graphical abstract image

      PubDate: 2017-09-02T11:34:24Z
      DOI: 10.1016/j.saa.2017.08.048
      Issue No: Vol. 189 (2017)
       
  • Dual fluorescence of
           (E)-N-(4-(dimethylamino)benzylidene)-2H-1,2,4-triazol-3-amine
           (DMABA-Amtr): A ground state perspective
    • Authors: Ephriem T. Mengesha; Taye B. Demissie; Mesfin Redi-Abshiro; Ahmed M. Mohammed
      Pages: 601 - 607
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Ephriem T. Mengesha, Taye B. Demissie, Mesfin Redi-Abshiro, Ahmed M. Mohammed
      We present the absorption and fluorescence spectra of (E)-N-(4-(dimethylamino)benzylidene)-2H-1,2,4-triazol-3-amine (DMABA-Amtr), an electron donor-π-acceptor system. The molecule shows a single fluorescence emission band in non-polar solvents while dual emissions were observed in polar aprotic solvents. Although several researchers over the years provide different explanations for the mechanism of the phenomena, based on solvent assisted excited state geometry changes of such systems, it is still a matter of controversy since such systems are unique as they contradict Kasha's rule. The emission spectrum of the molecule shows strong dependence on solvent polarity and excitation wavelength. This observation together with a single iso-emissive point found in the area normalize emission spectra indicates the presence of two ground state equilibrium structures of the compound which are both fluorescent. Density functional theory (DFT) and time-dependent (TD-DFT) calculations also support the experimental findings.
      Graphical abstract image

      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.08.070
      Issue No: Vol. 189 (2017)
       
  • Study of hydrogen bonding in ethanol-water binary solutions by Raman
           spectroscopy
    • Authors: Fabing Li; Zhiwei Men; Shuo Li; Shenghan Wang; Zhanlong Li; Chenglin Sun
      Pages: 621 - 624
      Abstract: Publication date: 15 January 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 189
      Author(s): Fabing Li, Zhiwei Men, Shuo Li, Shenghan Wang, Zhanlong Li, Chenglin Sun
      Raman spectra of ethanol-water binary solutions have been observed at room temperature and atmospheric pressure. We find that with increasing ethanol concentration, the symmetric and asymmetric OH stretching vibrational mode (3286 and 3434cm−1) of water are shifted to lower frequency and the weak shoulder peak at 3615cm−1 (free OH) disappears. These results indicate that ethanol strengthens hydrogen bonds in water. Simultaneously, our experiment shows that Raman shifts of ethanol reverses when the volume ratio of ethanol and the overall solution is 0.2, which demonstrates that ethanol-water structure undergoes a phase transition.
      Graphical abstract image

      PubDate: 2017-09-09T12:06:07Z
      DOI: 10.1016/j.saa.2017.08.077
      Issue No: Vol. 189 (2017)
       
  • A highly selective fluorescent chemosensor for CN− based on a novel
           bis(salamo)-type tetraoxime ligand
    • Authors: Fei Wang; Lei Gao Qing Zhao Yang Zhang Wen-Kui Dong
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Fei Wang, Lei Gao, Qing Zhao, Yang Zhang, Wen-Kui Dong, Yu-Jie Ding
      The optical properties of a novel chemosensor for cyanide anions based on a symmetric bis(salamo)-type ligand (H3L) were investigated by UV–Vis and fluorescence spectroscopy in MeOH/H2O (1:1 v/v) solution. Sensor H3L can selectively sense CN− based on prominent color changes among other anions. The chemosensor exhibits an apparent fluorescence enhancement at 482nm to CN− which because cyanide ions interact with CN bonds. Combining the corrected Benesi-Hildebrand formula, the binding constant of the formed host-guest complex was calculated as 2.42×105 M−1. Meanwhile, the detection limit of the sensor toward CN− was 8.91×10−7 M. It is worth noting that the designed sensor can be used for rapid detection of cyanide anions in basic pH range, and has great practical value.
      Graphical abstract image

      PubDate: 2017-09-15T12:42:36Z
       
  • Synthesis and application of a highly selective copper ions fluorescent
           probe based on the coumarin group
    • Authors: Guangjie Xiangli; Liu Jinhe Liguo Linlin Yang Aiying Fan Songjun
      Abstract: Publication date: 5 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 190
      Author(s): Guangjie He, Xiangli Liu, Jinhe Xu, Liguo Ji, Linlin Yang, Aiying Fan, Songjun Wang, Qingzhi Wang
      A highly selective copper ions fluorescent probe based on the coumarin-type Schiff base derivative 1 (probe) was produced by condensation reaction between coumarin carbohydrazide and 1H-indazole-3-carbaldehyde. The UV–vis spectroscopy showed that the maximum absorption peak of compound 1 appeared at 439nm. In the presence of Cu2+ ions, the maximum peak decreased remarkably compared with other physiological important metal ions and a new absorption peak at 500nm appeared. The job's plot experiments showed that complexes of 1:2 binding mode were formed in CH3CN:HEPES (3:2, v/v) solution. Compound 1 exhibited a strong blue fluorescence. Upon addition of copper ions, the fluorescence gradually decreased and reached a plateau with the fluorescence quenching rate up to 98.73%. The detection limit for Cu2+ ions was estimated to 0.384ppm. Fluorescent microscopy experiments demonstrated that probe 1 had potential to be used to investigate biological processes involving Cu2+ ions within living cells.
      Graphical abstract image

      PubDate: 2017-09-15T12:42:36Z
       
 
 
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