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  Subjects -> CHEMISTRY (Total: 766 journals)
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    - CHEMISTRY (531 journals)
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CHEMISTRY (531 journals)            First | 1 2 3 4 5 6 | Last

Journal of Immunoassay and Immunochemistry     Hybrid Journal   (Followers: 3)
Journal of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (Followers: 2)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 2)
Journal of Labelled Compounds and Radiopharmaceuticals     Hybrid Journal   (Followers: 1)
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry     Hybrid Journal   (Followers: 4)
Journal of Mass Spectrometry     Hybrid Journal   (Followers: 20)
Journal of Materials Chemistry A : Materials for Energy and Sustainability     Full-text available via subscription   (Followers: 23)
Journal of Materials Chemistry B : Materials for Biology and Medicine     Full-text available via subscription   (Followers: 5)
Journal of Materials Chemistry C : Materials for Optical, Magnetic and Electronic Devices     Full-text available via subscription   (Followers: 6)
Journal of Materials Research     Full-text available via subscription   (Followers: 9)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 4)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 152)
Journal of Membrane Science     Hybrid Journal   (Followers: 9)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 2)
Journal of Molecular Graphics and Modelling     Hybrid Journal   (Followers: 3)
Journal of Molecular Liquids     Hybrid Journal   (Followers: 3)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 3)
Journal of Molecular Recognition     Hybrid Journal   (Followers: 1)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 6)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
Journal of Nanoparticles     Open Access  
Journal of Nanostructure in Chemistry     Open Access   (Followers: 5)
Journal of Natural Gas Chemistry     Full-text available via subscription   (Followers: 2)
Journal of Nepal Chemical Society     Open Access  
Journal of Nucleic Acids Investigation     Open Access   (Followers: 2)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 2)
Journal of Organometallic Chemistry     Hybrid Journal   (Followers: 12)
Journal of Photochemistry and Photobiology A: Chemistry     Hybrid Journal   (Followers: 4)
Journal of Photochemistry and Photobiology C: Photochemistry Reviews     Full-text available via subscription   (Followers: 4)
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 156)
Journal of Polymers     Open Access   (Followers: 1)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 2)
Journal of Pure and Applied Chemistry Research     Open Access  
Journal of Raman Spectroscopy     Hybrid Journal   (Followers: 9)
Journal of Saudi Chemical Society     Open Access  
Journal of Solid State Chemistry     Hybrid Journal   (Followers: 13)
Journal of Solution Chemistry     Hybrid Journal  
Journal of Structural Chemistry     Hybrid Journal  
Journal of Sulfur Chemistry     Hybrid Journal   (Followers: 2)
Journal of Superhard Materials     Hybrid Journal   (Followers: 1)
Journal of Surfactants and Detergents     Hybrid Journal   (Followers: 5)
Journal of Systems Chemistry     Open Access   (Followers: 1)
Journal of Taibah University for Science     Open Access  
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 236)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 15)
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 1)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Chilean Chemical Society     Open Access   (Followers: 2)
Journal of the Iranian Chemical Society     Hybrid Journal   (Followers: 1)
Journal of the Korean Society for Applied Biological Chemistry     Hybrid Journal   (Followers: 1)
Journal of the Mexican Chemical Society     Open Access   (Followers: 1)
Journal of Theoretical and Computational Chemistry     Hybrid Journal   (Followers: 7)
Journal of Theoretical Chemistry     Open Access  
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
JPC - Journal of Planar Chromatography - Modern TLC     Full-text available via subscription   (Followers: 6)
Jurnal Penelitian Sains (JPS)     Open Access  
Jurnal Teknologi Informasi     Open Access   (Followers: 3)
Kinetics and Catalysis     Hybrid Journal   (Followers: 3)
Korea-Australia Rheology Journal     Hybrid Journal  
Langmuir     Full-text available via subscription   (Followers: 35)
Latvian Journal of Chemistry     Open Access   (Followers: 1)
Lebensmittelchemie     Hybrid Journal   (Followers: 1)
Lipid Insights     Open Access   (Followers: 1)
Luminescence     Hybrid Journal   (Followers: 1)
Macromolecular Materials & Engineering     Hybrid Journal   (Followers: 4)
Macromolecular Rapid Communications     Hybrid Journal   (Followers: 4)
Macromolecular Research     Hybrid Journal  
Macromolecular Symposia     Hybrid Journal  
Macromolecular Theory and Simulations     Hybrid Journal  
Macromolecules     Full-text available via subscription   (Followers: 31)
Magnetic Resonance in Chemistry     Hybrid Journal   (Followers: 4)
Main Group Chemistry     Hybrid Journal  
Marine Chemistry     Hybrid Journal   (Followers: 4)
Marine Drugs     Open Access   (Followers: 4)
MATEC Web of Conferences     Open Access  
Materials Characterization     Hybrid Journal   (Followers: 21)
Materials Horizons     Full-text available via subscription  
Materials Research Bulletin     Hybrid Journal   (Followers: 16)
Materials Science Monographs     Full-text available via subscription   (Followers: 1)
Materials Science-Poland     Hybrid Journal  
Materials Sciences and Applications     Open Access   (Followers: 4)
MedChemComm     Full-text available via subscription   (Followers: 4)
Medicinal Chemistry Research     Hybrid Journal   (Followers: 10)
Metallography, Microstructure, and Analysis     Hybrid Journal   (Followers: 1)
Metallomics     Full-text available via subscription  
Micro and Nano Systems Letters     Open Access   (Followers: 1)
Microchimica Acta     Hybrid Journal   (Followers: 1)
Microporous and Mesoporous Materials     Hybrid Journal   (Followers: 3)
Modern Research in Catalysis     Open Access   (Followers: 2)
Molbank     Open Access  
Molecules     Open Access   (Followers: 3)
Molecules and Cells     Hybrid Journal   (Followers: 1)
Monatshefte für Chemie - Chemical Monthly     Hybrid Journal   (Followers: 3)
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 2)
MRS Bulletin     Full-text available via subscription   (Followers: 5)
MRS Online Proceedings     Full-text available via subscription   (Followers: 1)
Nachrichten aus der Chemie     Full-text available via subscription   (Followers: 1)
Nano Convergence     Open Access  
Nano Reviews     Open Access   (Followers: 15)

  First | 1 2 3 4 5 6 | Last

Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
   [9 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1386-1425
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.567]   [H-I: 58]
  • Synthesis, structure, spectroscopic and ferroelectric properties of an
           acentric polyoxotungstate containing 1:2-type
           [Sm(α-PW11O39)2]11− fragment and d-proline components
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Yingjie Liu , Hailou Li , Jingli Zhang , Junwei Zhao , Lijuan Chen
      An organic–inorganic hybrid mono-SmIII substituted phosphotungstate KNa3[HPro]7[Sm(α-PW11O39)2]·Pro·18H2O (1) (Pro= d-proline) has been synthesized in the conventional aqueous solution and structurally characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, IR spectra, UV spectra, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. The molecule of 1 consists of a classical 1:2-type [Sm(α-PW11O39)2]11− fragment and free d-proline components. It should be pointed out that the synergistic action between the in-situ formed chiral [Sm(α-PW11O39)2]11− fragment and chiral d-proline components results in the formation of the chiral 1. The luminescence emission of 1 reveals three characteristic bands that derive from the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2 and 4G5/2 → 6H9/2 transitions of the SmIII cation as well as the synergistic contribution of the O→W transitions of [α-PW11O39]7− moieties and a π*–n or π*–π transitions of Pro. Its ferroelectric behavior has been measured.
      Graphical abstract image Highlights An organic–inorganic hybrid mono-SmIII substituted phosphotungstate with amino acids has been synthesized and IR, UV spectra, the photoluminescence spectra and ferroelectric behavior have been studied.

      PubDate: 2014-07-25T23:11:54Z
       
  • Au@Phenyacetylene organogold clusters: Direct spectroscopic evidence of
           gold–carbon covalent band
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Hongyan Zhang , Penggang Yin , Tingting You , Tianyu Sun , Xiufeng Lang , Enzhong Tan , Xiu Liang , Lin Guo
      Surface-enhanced Raman Scattering (SERS) as a powerful vibrational spectroscope technique is used to investigate the existence of AuC band between gold nanoparticles (AuNPs) and phenylacetylene (PA) which is characterized by a new Raman-active peak at 405cm−1. The measurements with transmission electron microscopy (TEM) and extinction spectroscopy show an increasing in size and spectral redshift for AuNPs after the addition of the PA molecule demonstrating the production of gold–PA organogold cluster (Au:C2Ph). Furthermore, a strong band characteristic of AuC stretch mode is observed in the SERS spectra of Au:C2Ph and supported by the density functional theory (DFT) calculation. In addition, the optimal adsorption of PA on AuNPs’ surface is also investigated theoretically. These findings show a direct spectroscopic sight into AuC band, and offer promising alternative to thiol compounds for anchoring organic molecules to gold surface to form self-assembled monolayers.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • A combined experimental and theoretical study on vibrational spectra of
           2-acetylpyridine
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Cuiping Zhai , Fenghua Cui , Xuejun Liu
      The molecular geometries, FT-IR and Raman spectra of 2-acetylpyridine were studied using Density functional theory (DFT-B3LYP) with the large basis sets. Theoretical calculations indicate the cis conformer of 2-acetylpyridine is most stable though this conformation was seldom found in the crystal structures of coordinated compounds. Based on the stable conformer, comprehensive assignments of the experimental bands were made. The observed and calculated positions are found to be in good agreement with an average deviation of <4cm−1. The assignments provide valuable information for the fingerprint and identification of 2-acetylpyridine.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Experimental and theoretical studies on IR, Raman, and UV–Vis
           spectra of quinoline-7-carboxaldehyde
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): M. Kumru , V. Küçük , M. Kocademir , H.M. Alfanda , A. Altun , L. Sarı
      Spectroscopic properties of quinoline-7-carboxaldehyde (Q7C) have been studied in detail both experimentally and theoretically. The FT-IR (4000–50cm−1), FT-Raman (4000–50cm−1), dispersive-Raman (3500–50cm−1), and UV–Vis (200–400nm) spectra of Q7C were recorded at room temperature (25°C). Geometry parameters, potential energy surface about CCH(O) bond, harmonic vibrational frequencies, IR and Raman intensities, UV–Vis spectrum, and thermodynamic characteristics (at 298.15K) of Q7C were computed at Hartree–Fock (HF) and density functional B3LYP levels employing the 6-311++G(d,p) basis set. Frontier molecular orbitals, molecular electrostatic potential, and Mulliken charge analyses of Q7C have also been performed. Q7C has two stable conformers that are energetically very close to each other with slight preference to the conformer that has oxygen atom of the aldehyde away from the nitrogen atom of the quinoline.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis and characterization of palladium nanoparticles using
           Catharanthus roseus leaf extract and its application in the
           photo-catalytic degradation
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Aasaithambi Kalaiselvi , Selvaraj Mohana Roopan , Gunabalan Madhumitha , C. Ramalingam , Ganesh Elango
      The potential effect of Catharanthus roseus leaf extract for the formation of palladium nanoparticles and its application on dye degradation was discussed. The efficiency of C . roseus leaves are used as a bio-material for the first time as reducing agent. Synthesized palladium nanoparticles were supported by UV–vis spectrometry, XRD, FT-IR and TEM analysis. The secondary metabolites which are responsible for the formation of nanoparticles were identified by GC–MS. The results showed that effect of time was directly related to synthesized nanoparticles and functional groups has a critical role in reducing the metal ions and stabilizing the palladium nanoparticles in an eco-friendly process.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Spectroscopic studies on the interaction between novel
           polyvinylthiol-functionalized silver nanoparticles with lysozyme
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Mohd. Sajid Ali , Hamad A. Al-Lohedan , M.Z.A. Rafiquee , Ayman M. Atta , Abdurrahman O. Ezzat
      Silver nanoparticles were functionalized with polyvinylthiol (Ag-PVT) and their effect on the conformation of hen-egg white lysozyme was seen by means of spectroscopic techniques, viz., UV visible, fluorescence (intrinsic and synchronous), resonance Rayleigh scattering and circular dichroism. UV absorption spectra of lysozyme show a hyperchromic shift on the addition of Ag-PVT nanoparticles indicating the complex formation between the two. The interaction between lysozyme and Ag-PVT nanoparticles was takes place via static quenching with 1:1 binding ratio as revealed by the analysis of fluorescence measurements. Circular dichroism spectroscopic data show a decrease in α-helical content of lysozyme on interaction with Ag-PVT nanoparticles which was due to the partial unfolding of the protein. Synchronous fluorescence spectroscopy disclosed that the microenvironments of both tryptophan and tyrosine residues were perturbed in the presence of Ag-PVT nanoparticles and perturbation in the tryptophan environment was more prominent. Rayleigh scattering (RRS) intensity increases on increasing the Ag-PVT nanoparticles concentration till it reaches to the saturation. The RRS intensity increases four times as compared to the native protein indicating the possibility of protein aggregation at higher concentrations of nanoparticles.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Experimental and computational study on molecular structure and
           vibrational analysis of an antihyperglycemic biomolecule: Gliclazide
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Mustafa Karakaya , Mehmet Kürekçi , Buse Eskiyurt , Yusuf Sert , Çağrı Çırak
      In present study, the experimental and theoretical harmonic vibrational frequencies of gliclazide molecule have been investigated. The experimental FT-IR (400–4000cm−1) and Laser-Raman spectra (100–4000cm−1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths and bond angles) have been calculated using ab initio Hartree Fock (HF), density functional theory (B3LYP hybrid function) methods with 6-311++G(d,p) and 6-31G(d,p) basis sets by Gaussian 09W program. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. Theoretical optimized geometric parameters and vibrational frequencies have been compared with the corresponding experimental data, and they have been shown to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been found.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Optimization of reaction conditions to fabricate nano-silver using
           Couroupita guianensis Aubl. (leaf &amp; fruit) and its enhanced
           larvicidal effect
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): R.T.V. Vimala , Gnanasekar Sathishkumar , Sivaperumal Sivaramakrishnan
      Currently bioactive principles of plants and their nanoproducts have been extensively studied in agriculture and medicine. In this study Couroupita guianensis Aubl. leaf and fruit extracts were selected for rapid and cost-effective synthesis of silver nanoparticles (leaf-LAgNPs and fruit-FAgNPs). Various physiological conditions such as temperature, pH, concentration of metal ions, stoichiometric proportion of reaction mixture and reaction time showed influence on the size, dispersity and synthesis rate of AgNPs. Generation of AgNPs was initially confirmed with the surface plasmon vibrations at 420nm in UV–visible spectrophotometer. The results recorded from X-ray diffractometer (XRD) and Transmission electron microscope (TEM) supports the biosynthesis of cubic crystalline LAgNPs & FAgNPs with the size ranges between 10–45nm and 5–15nm respectively. Surface chemistry of synthesized AgNPs was studied with Fourier transform infrared spectroscopy (FTIR), it reveals that water soluble phenolic compounds present in the extracts act as reducing and stabilizing agent. Leaf, fruit extracts and synthesized AgNPs were evaluated against IV instar larvae of Aedes aegypti (Diptera; Culicidae). Furthermore, different extracts and synthesized AgNPs showed dose dependent larvicidal effect against A. aegypti after 24h of treatment. Compare to all extracts such as ethyl acetate (leaf; LC50 – 44.55ppm and LC90 – 318.39ppm & fruit; LC50 – 49.96ppm and LC90 – 568.84ppm respectively) and Methanol (leaf; LC50 – 85.75ppm and LC90 – 598.63ppm & fruit; LC50 – 67.78ppm and LC90 – 714.45ppm respectively) synthesized AgNPs showed extensive mortality rate (LAgNPs; LC50 – 2.1ppm and LC90 – 5.59ppm & FAgNPs; LC50 – 2.09ppm and LC90 – 5.7ppm). Hence, this study proves that C. guianensis is a potential bioresource for stable, reproducible nanoparticle synthesis (AgNPs) and also can be used as an efficient mosquito control agent.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Highly stable antibacterial silver nanoparticles as selective fluorescent
           sensor for Fe3+ ions
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Bharat A. Makwana , Disha J. Vyas , Keyur D. Bhatt , Vinod K. Jain , Yadvendra K. Agrawal
      Calix[4]resorcinarene polyhydrazide (CPH) protected water dispersible fluorescent silver nanaoparticles (AgNps) were prepared by one-pot method using water soluble CPH and AgNO3. (CPH) bearing hydrazide group on its periphery acts as a reducing agent and its web type of structure as a stabilizing agent for the formation of calix protected silver nanoparticles (CPH-AgNps). CPH-AgNps were found to be highly stable over 120 days at room temperature and at varied pH. CPH-AgNps were characterized by UV/Vis-spectroscopy, particle size analyzer (PSA), transmission electron microscopy (TEM) and Energy dispersive X-ray analysis (EDX). Duly characterized nanoparticles were explored for their application as sensitive and selective fluorescent chemosensors for various metal ions. It was found that nanoparticles were selective and sensitive only for Fe3+ ions with the linear range of detection from 0.1μM to 10μM. CPH-AgNps were also found to exhibit good antimicrobial activity when compared with standard Chloramphenicol. The selectivity and antimicrobial activity of CPH-AgNps suggests its potential use as a sensor for Fe(III) ions in ecosystems prone to industrial pollution and as an antimicrobial agent in biological applications.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • FT-IR, molecular structure, first order hyperpolarizability, MEP, HOMO and
           LUMO analysis and NBO analysis of
           4-[(3-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Rahul Raju , C. Yohannan Panicker , Prakash S. Nayak , B. Narayana , B.K. Sarojini , C. Van Alsenoy , Abdulaziz A. Al-Saadi
      4-[(3-Acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid is synthesized and the structure of the compound was confirmed by IR, 1H NMR and single crystal X-ray diffraction studies. FT-IR spectrum of 4-[(3-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods are assigned with the help of potential energy distribution analysis. The NH stretching frequency is red shifted in the IR spectrum with a strong intensity from the computed frequency, which indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The first hyperpolarizability and infrared intensities are also reported. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. Molecular electrostatic potential map was performed by the DFT method. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • A vibrational spectroscopic study of the silicate mineral pectolite
           – NaCa2Si3O8(OH)
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Ray L. Frost , Andrés López , Frederick L. Theiss , Antônio Wilson Romano , Ricardo Scholz
      The mineral pectolite NaCa2Si3O8(OH) is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and in other industrial applications. Raman bands at 974 and 1026cm−1 are assigned to the SiO stretching vibrations of linked units of Si3O8 units. Raman bands at 974 and 998cm−1 serve to identify Si3O8 units. The broad Raman band at around 936cm−1 is attributed to hydroxyl deformation modes. Intense Raman band at 653cm−1 is assigned to OSiO bending vibration. Intense Raman bands in the 2700–3000cm−1 spectral range are assigned to OH stretching vibrations of the OH units in pectolite. Infrared spectra are in harmony with the Raman spectra. Raman spectroscopy with complimentary infrared spectroscopy enables the characterisation of the silicate mineral pectolite.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • DNA-binding, topoisomerases I and II inhibition and in vitro cytotoxicity
           of ruthenium(II) polypyridyl complexes: [Ru(dppz)2L]2+ (L=dppz-11-CO2Me
           and dppz)
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Xiaojun He , Lianhe Jin , Lifeng Tan
      Two ruthenium(II) polypyridyl complexes, [Ru(dppz)2dppz-11-CO2Me](ClO4)2 (Ru1) and [Ru(dppz)3](ClO4)2 (Ru2), have been synthesized and characterized. The spectral characteristics of Ru1 and Ru2 were investigated by fluorescence spectroscopy and revealed that both complexes were sensitive to solvent polarity. The binding properties of the two complexes towards calf-thymus DNA (CT-DNA) have been investigated by different spectrophotometric methods and viscosity measurements, indicating that both complexes bind to CT-DNA by means of intercalation, but with different binding affinities. Topoisomerase inhibition and DNA strand passage assay demonstrates that the two complexes are dual inhibitors of topoisomerases I and IIa. On the other hand, the cytotoxicity of both complexes has been evaluated by MTT assays and Giemsa staining experiments. The main results reveal that the ester functional group has a significant effect on the DNA-binding affinities and topoisomerases inhibition effects of Ru1 and Ru2, and further advance our knowledge on the DNA-binding and topoisomerase inhibition by Ru(II) complexes.
      Graphical abstract image Highlights Ru1 and Ru2 can intercalate into DNA base pairs with different binding constants. The enzyme inhibition assay indicates that both complexes are dual inhibitors of topoisomerases I and IIa, but with different inhibitory effect. Cytotoxicity evaluation in vitro shows that both complexes displayed moderate antitumor activity against the selected tumor cell lines and can induce the apoptosis of HepG2 cells. The here reported results indicate that the ester functional group can modulate their DNA-binding affinities and topoisomerases inhibition effects of Ru1 and Ru2.

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis, characterization and catalytic activity of Ag-acidfuchsin
           nanohybrid system towards the ring opening polymerization of
           ε-caprolactone
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): B. Meenarathi , S. Palanikumar , L. Kannammal , R. Anbarasan
      The acidfuchsin (AF) decorated Ag nanoparticle (NP) was synthesized and its ability towards the ring opening polymerization (ROP) of ε-caprolactone (CL) was studied under N2 atmosphere at 160°C in the presence of stannous octoate (SO) as a catalyst. Both the nanohybrid and nanocomposites were characterized by various analytical tools like Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy, gel permeation chromatography (GPC), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The number of binding site from the fluorescence spectrum confirmed that all the functional groups present in AF might have been involved in the ROP of CL.
      Graphical abstract image Highlights Surface functionalization of Ag NP by acidfuchsin dye was carried out and its surface catalytic effect towards the ring opening polymerization (ROP) of ε-caprolactone (CL) was tested. Further, the polymerization of CL was confirmed by various analytical techniques.

      PubDate: 2014-07-25T23:11:54Z
       
  • Molecular structure, FT-IR, NBO, HOMO and LUMO, MEP and first order
           hyperpolarizability of
           (2E)-1-(2,4-Dichlorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one by
           HF and density functional methods
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Y. Sheena Mary , C. Yohannan Panicker , P.L. Anto , M. Sapnakumari , B. Narayana , B.K. Sarojini
      (2E)-1-(2,4-Dichlorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one is synthesized by using 2,4-dichloroacetophenone and 3,4,5-trimethoxybenzaldehyde in ethanol. The structure of the compound was confirmed by IR and single crystal X-ray diffraction studies. FT-IR spectrum of (2E)-1-(2,4-dichloro-phenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method. From the MEP map of the title molecule, negative region is mainly localized over the electronegative oxygen atoms, in the carbonyl group and the oxygen atom O4 of the methoxy group and the maximum positive region is localized on the phenyl rings.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • A view of microstructure with technological behavior of waste incorporated
           ceramic bricks
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): G. Nirmala , G. Viruthagiri
      Production of ceramic bricks from mixtures of ceramic industry wastes (up to 50wt%) from the area of Vriddhachalam, Cuddalore district, Tamilnadu, India and kaolinitic clay from Thiruvananthapuram district, Kerala were investigated. The firing behavior of the ceramic mixtures was studied by determining their changes in mineralogy and basic ceramic properties such as water absorption, porosity, compressive strength and firing shrinkage at temperatures ranging from 900 to 1200°C in short firing cycles. The effect of the rejects addition gradually up to 50wt% was analyzed with the variation of temperature on the mechanical properties and microstructure of the bricks. The highest compressive strength and lowest water absorption is observed for the sample with 40% rejects at 1100°C which is supported by the results of SEM analysis. The resulting ceramic bricks exhibit features that suggest possibilities of using the ceramic rejects in the conventional brick making methods.
      Graphical abstract image Highlights TG–DTA curve for raw clay (Kaolinite).

      PubDate: 2014-07-25T23:11:54Z
       
  • Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C
           NMR) investigations of (1,2-epoxyethyl)benzene and
           (1,2-epoxy-2-phenyl)propane
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): V. Arjunan , R. Anitha , L. Devi , S. Mohan , Haifeng Yang
      Aromatic epoxides are causative factors for mutagenic and carcinogenic activity of polycyclic arenes. The 1,2- or 2,3-epoxy compounds are widely used to a considerable extent in the textile, plastics, pharmaceutical, cosmetics, detergent and photochemical industries. The FTIR and FT-Raman spectra of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane are recorded in the regions 4000–400cm−1 and 4000–100cm−1, respectively. The observed fundamentals are assigned to different normal modes of vibration. The structure of the compound has been optimised with B3LYP method using 6-311++G** and cc-pVTZ basis sets. The IR and Raman intensities are determined. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron+nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of the compounds has been performed to indicate the presence of intramolecular charge transfer. The 1H and 13C NMR chemical shifts of the molecules have been analysed.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • A vibrational spectroscopic study of the silicate mineral lomonosovite
           Na5Ti2(Si2O7)(PO4)O2
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Ray L. Frost , Andrés López , Frederick L. Theiss , Leonardo M. Graça , Ricardo Scholz
      The mineral lomonosovite has been studied using a combination of scanning electron microscopy with energy dispersive X-ray analysis and vibrational spectroscopy. Qualitative chemical analysis gave Si, P, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and Al. The mineral lomonosovite has a formula Na5Ti2(Si2O7)(PO4)O2. Raman bands observed at 909, 925 and 939cm−1 are associated with phosphate units. Raman bands found at 975, 999, 1070, 1080 and 1084cm−1 are attributed to siloxane stretching vibrations. The observation of multiple bands in both the phosphate stretching and bending regions supports the concept that the symmetry of the phosphate anion in the structure of lomonosovite is significantly reduced. Infrared spectroscopy identifies bands in the water stretching and bending regions, thus suggesting that water is involved with the structure of lomonosovite either through adsorption on the surface or by bonding to the phosphate units.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Development of surface plasmon resonance sensor for determining zinc ion
           using novel active nanolayers as probe
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Yap Wing Fen , W. Mahmood Mat Yunus , Zainal Abidin Talib , Nor Azah Yusof
      In this study, novel active nanolayers in combination with surface plasmon resonance (SPR) system for zinc ion (Zn2+) detection has been developed. The gold surface used for the SPR system was modified with the novel developed active nanolayers, i.e. chitosan and chitosan–tetrabutyl thiuram disulfide (chitosan–TBTDS). Both chitosan and chitosan–TBTDS active layers were fabricated on the gold surface by spin coating technique. The system was used to monitor SPR signal for Zn2+ in aqueous media with and without sensitivity enhancement by TBTDS. For both active nanolayers, the shift of resonance angle is directly proportional to the concentration of Zn2+ in aqueous media. The higher shift of resonance angle was obtained for chitosan–TBTDS active nanolayer due to a specific binding of TBTDS with Zn2+. The chitosan–TBTDS active nanolayer enhanced the sensitivity of detection down to 0.1mg/l and also induced a selective detection towards Zn2+.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Silver nanoclusters emitting weak NIR fluorescence biomineralized by BSA
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Baoshun Li , Jianjun Li , Junwu Zhao
      Noble metal (e.g., gold and silver) nanomaterials possess unique physical and chemical properties. In present work, silver nanoclusters (also known as silver quantum clusters or silver quantum dots) were synthesized by bovine serum albumin (BSA) biomineralization. The synthesized silver nanoclusters were characterized by UV-VIS absorption spectroscopy, fluorescence spectroscopy, upconversion emission spectroscopy, TEM, HRTEM and FTIR spectroscopy. TEM results showed that the average size of the silver nanoclusters was 2.23nm. Fluorescence results showed that these silver nanoclusters could emit weak near-infrared (NIR) fluorescence (the central emission wavelength being about 765nm). And the central excitation wavelength was about 395nm, in the UV spectral region. These silver nanoclusters showed an extraordinarily large gap (about 370nm) between the central excitation wavelength and central emission wavelength. In addition, it was found that these silver nanoclusters possess upconversion emission property. Upconversion emission results showed that the upconversion emission spectrum of the silver nanoclusters agreed well with their normal fluorescence emission spectrum. The synthesized silver nanoclusters showed high stability in aqueous solution and it was considered that they might be confined in BSA molecules. It was found that silver nanoclusters might enhance and broaden the absorption of proteins, and the protein absorption peak showed an obvious red shift (being 7nm) after the formation of silver nanoclusters.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis of silver nanoparticles using A. indicum leaf extract and their
           antibacterial activity
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): S. Ashokkumar , S. Ravi , V. Kathiravan , S. Velmurugan
      Green synthesis of silver nanoparticles has been achieved using environmentally acceptable plant extract. It is observed that Abutilon indicum leaf extract can reduce silver ions into silver nanoparticles within 15min of reaction time. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV–Vis spectrophotometer analysis. The mean particle diameter of silver nanoparticles was calculated from the XRD pattern. FT-IR spectra of the leaf extract after the development of nanoparticles are determined to allow identification of possible functional groups responsible for the conversion of metal ions to metal nanoparticles. The AgNPs thus obtained showed highly potent antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus subtilis) and Gram-negative (Salmonella typhi and Escherichia coli) microorganisms.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Crystal structure, vibrational studies and optical properties of a new
           organic–inorganic hybrid compound (C10H28N4)CuCl5Cl⋅4H2O
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): A. Kessentini , M. Belhouchet , J.J. Suñol , Y. Abid , T. Mhiri
      A new organic–inorganic hybrid material, 1,4-bis(3-ammoniumpropyl) piperazinium pentachloridocuprate(II) chloride tetrahydrate [(C10H28N4)CuCl5Cl⋅4H2O], has been synthesized and characterized by X-ray diffraction, UV–visible absorption, Infrared and Raman spectroscopy. The compound crystallizes in the orthorhombic system and Pnma space group with a =8.18 (3)Å, b =10.96 (5)Å, c =21.26 (9)Å, V =2254.3 (15)Å3. In this structure, the Cu2+ ion, surrounded by five chlorides, adopts the square pyramidal coordination geometry. The structure of this compound consists of tetraprotonated 1,4-bis(3-ammoniumpropyl) piperazinium cations and the anionic sublattice is built up of isolated, square pyramid [CuCl5]3 − units, chloride ion Cl− and water molecules connected with each other by hydrogen bonds. Organic and inorganic entities are interconnected by means of hydrogen bonding contacts [NH⋯O(Cl), O(W)H⋯Cl and O(W)H⋯O]. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed on the basis of literature data. The optical study was also investigated by UV–Vis absorption. In fact, the organic–inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the (C10H28N4)CuCl5Cl⋅4H2O hybrid compound and it showed absorptions characteristics of CuCl based layered compounds centered at 275 and 374nm.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis, molecular structure and photoluminescence properties of
           1,2-diphenyl-4-(3-methoxyphenyl)-1,3-cyclopentadiene
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Junwei Ye , Dai Deng , Yuan Gao , Xiaoxiao Wang , Lijian Yang , Yuan Lin , Guiling Ning
      1,2-Diphenyl-4-(3-methoxyphenyl)-1,3-cyclopentadiene (DPMPCP) was synthesized via aldol condensation reaction followed by cyclization and dehydration reaction. Its structure was characterized by 1H NMR, 13C NMR spectra, high-resolution mass spectrometry and single-crystal X-ray diffraction. The UV–vis absorption and photoluminescence spectra of DPMPCP in solution and aggregation state were studied. It shows solvent-dependent fluorescence emission and aggregation-induced emission enhancement (AIEE) characteristic when DPMPCP aggregated in water/acetonitrile mixture or in crystals. The crystal structure analysis reveals combination effects of J-aggregation molecule stacking and restriction of intramolecular rotation by intermolecular interactions on AIEE. Additionally, the thermal stability, electrochemical property and DFT calculation of DPMPCP were investigated.
      Graphical abstract image Highlights 1,2-Diphenyl-4-(3-methoxyphenyl)-1,3-cyclopentadiene was facilely synthesized and exhibits weak emission in organic solvents but strong fluorescence in aggregated state, indicating that it is a typical aggregation-induced emission enhancement (AIEE) compound.

      PubDate: 2014-07-25T23:11:54Z
       
  • Highly selective and sensitive nucleic acid detection based on
           polysaccharide-functionalized silver nanoparticles
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Jing-Kun Yan , Hai-Le Ma , Pan-Fu Cai , Jian-Yong Wu
      Polysaccharide-functionalized silver nanoparticles (Oc-AgNPs) with a mean diameter of 15nm were utilized as a novel and effective fluorescence-sensing platform for nucleic acid detection. Tests on the oligonucleotide sequences associated with the human immunodeficiency virus as a model system showed that the Oc-AgNPs effectively absorbed and quenched dye-labeled single-stranded DNA through strong hydrogen bonding interactions and slight electrostatic attractive interactions. The proposed system efficiently differentiated between complementary and mismatched nucleic acid sequences with high selectivity and good reproducibility at room temperature.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Mixed micelle cloud point-magnetic dispersive μ-solid phase
           extraction of doxazosin and alfuzosin
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Nannan Gao , Hao Wu , Yafen Chang , Xiaozhen Guo , Lizhen Zhang , Liming Du , Yunlong Fu
      Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive μ-solid phase extraction (MD-μ-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe3O4 magnetic nanoparticles were used as the adsorbent in MD-μ-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5–300ngmL−1, and the limits of detection were 0.21 and 0.16ngmL−1, respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Artificial neural network (ANN) method for modeling of sunset yellow dye
           adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic
           and isotherm study
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): M. Maghsoudi , M. Ghaedi , A. Zinali , A.M. Ghaedi , M.H. Habibi
      In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005–0.015g) and 5–40mg/L of sunset yellow dye over contact time of 0.5–30min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg–Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R 2) of 0.998 were found for prediction and modeling of SY removal. The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10min contact time; an adsorbent dose of 0.015g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85mg/g for 0.005g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • FT-IR, molecular structure, first order hyperpolarizability, NBO analysis,
           HOMO and LUMO and MEP analysis of 1-(10H-phenothiazin-2-yl)ethanone by HF
           and density functional methods
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): K.G. Vipin Das , C. Yohannan Panicker , B. Narayana , Prakash S. Nayak , B.K. Sarojini , Abdulaziz A. Al-Saadi
      FT-IR spectrum of 1-(10H-phenothiazin-2-yl)ethanone was recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational wavenumbers were investigated with the help of HF and DFT methods. The normal modes are assigned with the help of potential energy distribution analysis. The observed vibrational wavenumbers were compared with the calculated results. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The first hyperpolarizability value is also reported. Natural bond orbital analysis confirms the presence of intra-molecular charge transfer and hydrogen bonding interaction. The HOMO–LUMO gap explains the charge transfer interaction taking place within the molecule. The NH stretching frequency is red shifted in the IR spectrum with a strong intensity from the computed frequency, which indicates weakening of the NH bond resulting in proton transfer to the neighboring units. From the MEP analysis it is evident that the negative charge covers the carbonyl and benzene and the positive region is over the NH group.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Microwave-assisted of dispersive liquid–liquid microextraction and
           spectrophotometric determination of uranium after optimization based on
           Box–Behnken design and chemometrics methods
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Ali Niazi , Neda Khorshidi , Pegah Ghaemmaghami
      In this study an analytical procedure based on microwave-assisted dispersive liquid–liquid microextraction (MA-DLLME) and spectrophotometric coupled with chemometrics methods is proposed to determine uranium. In the proposed method, 4-(2-pyridylazo) resorcinol (PAR) is used as a chelating agent, and chloroform and ethanol are selected as extraction and dispersive solvent. The optimization strategy is carried out by using two level full factorial designs. Results of the two level full factorial design (24) based on an analysis of variance demonstrated that the pH, concentration of PAR, amount of dispersive and extraction solvents are statistically significant. Optimal condition for three variables: pH, concentration of PAR, amount of dispersive and extraction solvents are obtained by using Box–Behnken design. Under the optimum conditions, the calibration graphs are linear in the range of 20.0–350.0ngmL−1 with detection limit of 6.7ngmL−1 (3δ B/slope) and the enrichment factor of this method for uranium reached at 135. The relative standard deviation (R.S.D.) is 1.64% (n =7, c =50ngmL−1). The partial least squares (PLS) modeling was used for multivariate calibration of the spectrophotometric data. The orthogonal signal correction (OSC) was used for preprocessing of data matrices and the prediction results of model, with and without using OSC, were statistically compared. MA-DLLME-OSC-PLS method was presented for the first time in this study. The root mean squares error of prediction (RMSEP) for uranium determination using PLS and OSC-PLS models were 4.63 and 0.98, respectively. This procedure allows the determination of uranium synthesis and real samples such as waste water with good reliability of the determination.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Role of irradiation in the green synthesis of silver nanoparticles
           mediated by fig (Ficus carica) leaf extract
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Bulent Ulug , M. Haluk Turkdemir , Ahmet Cicek , Ahmet Mete
      Biosynthesis of silver nanoparticles in an aqueous mixture of fig (Ficus carica) leaf extract and AgNO3 solution exposed to a set of irradiances at different wavelengths are studied. Nanoparticle formation for irradiances between 6.5mW/cm2 and 13.3mW/cm2 in the 330–550nm wavelength range is investigated and the results are compared to those of the nanoparticles synthesized in the dark and under direct sunlight. Ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, along with particle size analysis and transmission electron microscopy are employed for the characterization of samples and extracts. Irradiance is found to have profound influence on the reduction rates. However, size and spherical shape of the nanoparticles are persistent, irrespective of irradiance and wavelength. Irradiance is discussed to influence the particle formation and aggregation rates through the formation of free radicals in the fig extract.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Asymmetric multibranched conjugated molecules: Synthesis, structure and
           photophysical properties
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Li Zhao , Wenji Wang , Mao-Sen Yuan
      The symmetric multibranched π-conjugated compounds with C 3 or C 6 configuration have been intensively studied. The reports on asymmetric multibranched compounds are very limited. In this work, we designed and synthesized two asymmetric multibranched π-conjugated molecules using truxene as the central core, diphenylamino and thiophenyl (or thiophenylethynyl) groups as the different branches respectively: 2,7-di(N,N-diphenylamino)-12-(2-thiophenyl)-5,5′,10,10′,15,15′-hexaethyltruxene and 2,7-di(N,N-diphenylamino)-12-(2-thiophenylethynyl)-5,5′,10,10′,15,15′-hexaethyltruxene. Their photophysical properties have been explored combining with their theoretical calculation and X-ray single-crystal structure of a key intermediate. Though their different π-conjugation length of branches, the two title compounds exhibit almost same absorption maxima. However, their emission peaks behave a gradual red-shift with the increase of the conjugation length. The theoretical calculation results indicate that the two asymmetric compounds behave a main transition from the HOMO−1 to the LUMO or from the HOMO to the LUMO+1 upon excited.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • The influence of the various central metals on photophysical and
           photochemical properties of benzothiazole-substituted phthalocyanines
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Asiye Nas , Gülsev Dilber , Mahmut Durmuş , Halit Kantekin
      The photophysical (fluorescence quantum yields and lifetimes, fluorescence quenching studies by 1,4-benzoquinone (BQ)) and photochemical (singlet oxygen quantum yields and photodegradation studies under light irradiation) properties of tetra-benzothiazole substituted metal-free (H2Pc, 1), lead (II) (PbPc, 2) and zinc(II) (ZnPc, 3) phthalocyanine compounds were investigated in tetrahydrofuran (THF) solution. All of these compounds did not show any aggregation and they produced good singlet oxygen (especially ZnPc). The influence of the various central metal ions (zinc, lead or without metal) on the photophysical and photochemical parameters was also investigated and compared.
      Graphical abstract image Highlights The fluorescence quantum yields and lifetimes, fluorescence quenching studies and singlet oxygen quantum yields and photodegradation studies of tetra-benzothiazole substituted metal-free (H2Pc, 1), lead(II) (PbPc, 2) and zinc(II) (ZnPc, 3) phthalocyanine compounds were investigated in tetrahydrofuran (THF) solution. The influence of the various central metal ions (zinc, lead or without metal) on the photophysical and photochemical parameters was also investigated and compared.

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis, crystal growth, characterization and theoretical studies of
           4-aminobenzophenonium picrate
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): A. Aditya Prasad , K. Muthu , M. Rajasekar , V. Meenatchi , S.P. Meenakshisundaram
      Single crystals of 4-aminobenzophenonium picrate (4ABPP) were grown by slow evaporation of a mixed solvent system methanol–acetone (1:1,v/v) containing equimolar quantities of picric acid and 4-aminobenzophenone. The proton and carbon signals are confirmed by nuclear magnetic resonance spectroscopy. The various functional groups present in the molecule are identified by FT-IR analysis. Optimized geometry, first-order molecular hyperpolarizability (β), polarizability (α), bond length, bond angles and excited state energy from theoretical UV were derived by Hartree–Fock calculations. The complete assignment of the vibrational modes for 4-aminobenzophenonium picrate was performed by the scaled quantum mechanics force field (SQMFF) methodology using potential energy distribution. Natural bond orbital (NBO) calculations were employed to study the stabilities arising from charge delocalization and intermolecular interactions of 4ABPP. The atomic charge distributions of the various atoms present in 4ABPP are obtained by Mulliken charge population analysis. The as-grown crystal is further characterized by thermal and optical absorbance studies.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Studies on the growth, structural, spectral and third-order nonlinear
           optical properties of Ammonium 3-carboxy-4-hydroxy benzenesulfonate
           monohydrate single crystal
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): A. Silambarasan , M. Krishna Kumar , A. Thirunavukkarasu , R. Mohan Kumar , P.R. Umarani
      An organic nonlinear optical bulk single crystal, Ammonium 3-carboxy-4-hydroxy benzenesulfonate monohydrate (ACHBS) was successfully grown by solution growth technique. Single crystal X-ray diffraction study confirms that, the grown crystal belongs to P21/c space group. Powder X-ray diffraction and high resolution X-ray diffraction analyses revealed the crystallinity of the grown crystal. Infrared spectral analysis showed the vibrational behavior of chemical bonds and its functional groups. The thermal stability and decomposition stages of the grown crystal were studied by TG-DTA analysis. UV–Visible transmittance studies showed the transparency region and cut-off wavelength of the grown crystal. The third-order nonlinear optical susceptibility of the grown crystal was estimated by Z-scan technique using HeNe laser source. The mechanical property of the grown crystal was studied by using Vicker’s microhardness test.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Vibrational dephasing and frequency shifts of hydrogen-bonded
           pyridine–water complexes
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): A.G. Kalampounias , G. Tsilomelekis , S. Boghosian
      In this paper we present the picosecond vibrational dynamics and Raman shifts of hydrogen-bonded pyridine–water complexes present in aqueous solutions in a wide concentration range from dense to extreme dilute solutions. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The concentration induced variations in bandwidths, band frequencies and characteristic dephasing times have been estimated and interpreted as effects due to solute–solvent interactions. The time-correlation functions of vibrational dephasing were obtained for the ring breathing mode of both “free” and hydrogen-bonded pyridine molecules and it was found that sufficiently deviate from the Kubo model. There is a general agreement in the whole concentration range with the modeling proposed by the Rothschild approach, which applies to complex liquids. The results have shown that the reorientation of pyridine aqueous solutions is very slow and hence in both scattering geometries only vibrational dephasing is probed. It is proposed that the spectral changes depend on the perturbations induced by the dynamics of the water molecules in the first hydration cell and water in bulk, while at extreme dilution conditions, the number of bulk water molecules increases and the interchange between molecules belonging to the first hydration cell may not be the predominant modulation mechanism. The evolution of several parameters, such as the characteristic times, the percentage of Gaussian character in the peak shape and the a parameter are indicative of drastic variations at extreme dilution revealing changes in the vibrational relaxation of the pyridine complexes in the aqueous environment. The higher dilution is correlated to diffusion of water molecules into the reference pyridine system in agreement with the jump diffusion model, while at extreme dilutions, almost all pyridine molecules are elaborated in hydrogen bonding. The results are discussed in the framework of the current phenomenological status of the field.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Growth and characterization of Cadmium Thiosemicarbazide Bromide crystals
           for antibacterial and nonlinear optical applications
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): J. Thomas Joseph Prakash , J. Martin Sam Gnanaraj
      Semiorganic nonlinear optical crystals of Cadmium Thiosemicarbazide Bromide was grown by slow evaporation solution growth technique. The unit cell parameters were estimated by subjecting the crystals to single crystal X-ray diffraction. The grown crystals were subjected to Powder X-ray diffraction for analyzing the crystalline nature of the sample. FTIR studies reveal the functional groups and the optical characters were analyzed by UV–Vis spectral studies. Mechanical stability of the sample was assessed by Vicker’s micro hardness test. The presence of surface dislocations was identified by chemical etching technique. Antibacterial study was carried out against ACDP declared harmful pathogens. SHG efficiency of CTSB crystal was tested using Nd: YAG laser and it was found to be ∼1.8times that of potassium dihydrogen phosphate.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Synthesis of some metallophthalocyanines with dimethyl
           5-(phenoxy)-isophthalate substituents and evaluation of their
           antioxidant-antibacterial activities
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): M. Salih Ağırtaş , Ceyhun Karataş , Sadin Özdemir
      The synthesis, characterization, spectral, antioxidant and antibacterial properties of dimethyl 5-(phenoxy)-isophthalate substituted Zinc, Cobalt, Copper, and Nickel phthalocyanines are reported. The novel compounds have been characterized by using electronic absorption, nuclear magnetic resonance spectroscopy, infrared, elemental analysis and mass spectrometry. The antioxidant and antibacterial activities of newly synthesized phthalocyanines and its starting material are tested. The DPPH free radical scavenging ability of phthalocyanine Co(II) and Zn(II) complexes on DPPH are 44.8% and 40.1% at 100mg/L concentration, respectively. The phthalocyanine Co(II) and Cu(II) complexes show very strong ferrous ion chelating activity of 91.2% and 89.3% at concentration of 100mg/L, respectively. Compound 3 displays strong reducing power like α-tocopherol. Antibacterial activities of phthalocyanine Co(II) and Amikacin (30μg/disk) against Micrococcus luteus (ATCC 9341) are 16mm in diameter.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Tebipenem pivoxyl. Derivative spectroscopy study of stability of the first
           oral carbapenem
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Judyta Cielecka-Piontek , Magdalena Paczkowska , Przemysław Zalewski , Alicja Talaczyńska , Mikołaj Mizera
      A simple and selective derivative spectrophotometric method was developed for the quantitative determination of tebipenem and its pivoxyl ester in the presence of degradation products formed during degradation in aqueous solutions (hydrolysis, oxidation, phosphate buffer pH ∼6.0) and in the solid state (photolysis, thermolysis in dry air and at an increased relative air humidity). The method was based on zero-crossing first-derivative spectrophotometry (λ =341nm for tebipenem pivoxyl and λ =320nm for tebipenem), which eliminated the overlapping caused by various degradation products. The selectivity of the method for determination of tebipenem pivoxyl and tepipenem during stability studies was an effect of lack of substituents containing π-bond system chromophores in degradation products. It was also confirmed by comparison of the experimental spectra sample with the theoretical UV spectra and their first derivatives which were obtained by using the density functional theory with the B3LYP hybrid functional and 6-31G(d,p) basis set. The method were linear in the concentration range 16.70–220.0μgmL−1 for tebipenem (λ =320nm; r =0.9989) and 10.70–160.0μgmL−1 for tebipenem pivoxyl (λ =341nm, r =0.9990). The limits of detection and quantitation were 4.72 and 15.60μgmL−1 for tebipenem and 2.54 and 8.40μgmL−1 for tebipenem pivoxyl, respectively. The method had a good intra-day precision (RSD from 0.12% to 0.62%) and inter-day precision (RSD from 0.22% to 2.13%). The recovery of tebipenem and tebipenem pivoxyl ranged from 99.61% to 99.86% and from 99.38% to 99.87%, respectively. First-derivative spectrophotometry was used for a routine analysis of tebipenem and its ester as well as to monitor the conversion of tebipenem pivoxyl to tebipenem and to predict their degradation pathways.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • The synthesis, characterization and optical properties of novel 2-acyl
           6-arylindolizines
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Yan Qing Ge , Xue Yong Gong , Guang Jie Song , Xiao Qun Cao , Jian Wu Wang
      A series of novel 2-acyl-6-aryl substituted indolizine derivatives was synthesized by a novel tandem reaction between 4-acyl-pyrrole-2-carbaldehyde derivatives and ethyl 4-bromo-3-arylbut-2-enoate under mild conditions. The compounds were characterized using IR, 1H NMR 13C NMR and HRMS. The crystal structure of 7a was determined using single crystal X-ray crystallography. The absorption results showed that compounds 7a–e presented their absorption maxima at ca. 270nm, while compounds 7f and 7g with a larger conjugation system exhibited red-shifted absorption character (ca. 280nm). Fluorescence spectra revealed that these compounds exhibited blue fluorescence (434–456nm) in dilute solutions and showed quantum yields of fluorescence between 0.02 and 0.39 in dichloromethane.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Vibrational spectroscopy and density functional theory study of
           3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide
    • Abstract: Publication date: 25 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 135
      Author(s): Ran Li , Zhu Mao , Lei Chen , Haiming Lv , Jianbo Cheng , Bing Zhao
      In this work, the structural parameters of the title molecule (MTT) have been obtained at the B3LYP/6-311++G** level of theory. The two phenyl rings and the two heterocyclic rings are found in four different planes. The tetrazolium ring was connected with other three rings and their distances are also different in decrease order of 1.461Å (from tetrazolium ring to carbon connected phenyl)>1.445Å (from tetrazolium ring to nitrogen connected phenyl)>1.425Å (from tetrazolium ring to thiazolyl ring). Fourier transform infrared (FTIR) and Raman spectra of the compound were obtained experimentally. All FTIR and Raman bands of the compound obtained experimentally were assigned based on the modeling results obtained at the B3LYP/6-311++G** level. The calculated vibrational frequencies were in good agreement with the experimental values. In addition, the UV–Vis spectra were obtained experimentally and theoretically. Considering the effect of the PCM modelling error, the calculated absorbance peaks obtained at the B3LYP/6-311++G** level were also in good agreement with the experimental values. The HOMO–LUMO gap was predicted to be 1.83eV at the B3LYP/6-311++G** level.
      Graphical abstract image Highlights 3-[4,5-Dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide (MTT) was designed as a model molecule for theoretical and experimental studies of the molecule structure. Fourier transform infrared (FTIR) and Raman spectra of the compound have been obtained experimentally. Most of the fundamentals vibrations agree well with the predicted frequencies.

      PubDate: 2014-07-25T23:11:54Z
       
  • Spectrofluorimetric determination of 3-methylflavone-8-carboxylic acid,
           the main active metabolite of flavoxate hydrochloride in human urine
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Hala E. Zaazaa , Afaf O. Mohamed , Maha A. Hawwam , Mohamed Abdelkawy
      A simple, sensitive and selective spectrofluorimetric method has been developed for the determination of 3-methylflavone-8-carboxylic acid as the main active metabolite of flavoxate hydrochloride in human urine. The proposed method was based on the measurement of the native fluorescence of the metabolite in methanol at an emission wavelength 390nm, upon excitation at 338nm. Moreover, the urinary excretion pattern has been calculated using the proposed method. Taking the advantage that 3-methylflavone-8-carboxylic acid is also the alkaline degradate, the proposed method was applied to in vitro determination of flavoxate hydrochloride in tablets dosage form via the measurement of its corresponding degradate. The method was validated in accordance with the ICH requirements and statistically compared to the official method with no significant difference in performance.
      Graphical abstract image Highlights Excretion studies of flavoxate by monitoring the fluorescence character of its active metabolite (MFA) in urine.

      PubDate: 2014-07-25T23:11:54Z
       
  • Determination of N-acetylation degree in chitosan using Raman spectroscopy
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): A. Zając , J. Hanuza , M. Wandas , L. Dymińska
      Application of Raman spectroscopy in determination of the acetylation degree (DA) of chitosan has been developed. The spectra of several chitosan samples characterized by different DD (degree of deacetylation) in the range 50–100% have been measured. The integral intensities of the bands assigned to the vibrations of amine group and glucosidic ring were used to calculate the DA from the intensity ratio. The assignment of the bands to the respective normal modes of chitosan was based on the DFT quantum chemical calculations. This method has a number of advantages over other techniques. It is fast and does not require purification of the sample nor require dissolution of the chitosan in any solvent.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Complexation of solvents and conformational equilibria in solutions of the
           simplest calix[4]arenes
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Oleg V. Surov , Mikhail A. Krestianinov , Marina I. Voronova
      Structure optimization and calculation of electronic adsorption spectra of 25,26,27,28-tetrahydroxycalix[4]arene and 25,27-dimethoxy-26,28-dihydroxycalix[4]arene conformers have been performed by density-functional theory using hybrid B3LYP functional in cc-p VTZ and cc-p VDZ basis sets in Gaussian 09 package. Analysis of experimental UV–Vis spectra of solutions of 25,26,27,28-tetrahydroxycalix[4]arene, 4-tert-butylcalix[4]arene and 25,27-dimethoxy-26,28-dihydroxycalix[4]arene in various solvents has been carried out. It was shown that the ratio of absorption maxima at characteristic wavelengths at ca. 274 and 283nm may be used to assess the extent of calix[4]arene/solvent interactions. The conclusion is drawn that spectral characteristics of calix[4]arenes are strongly affected by acid–base interactions.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Vibrational spectroscopic studies, normal co-ordinate analysis, first
           order hyperpolarizability, HOMO–LUMO of midodrine by using density
           functional methods
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): R. Shahidha , Abdulaziz A. Al-Saadi , S. Muthu
      The FTIR (4000–400cm−1), FT-Raman (4000–100cm−1) and UV–Visible (400–200nm) spectra of midodrine were recorded in the condensed state. The complete vibrational frequencies, optimized geometry, intensity of vibrational bands and atomic charges were obtained by using Density Functional Theory (DFT) with the help of 6-311++G(d,p) basis set. The first order hyperpolarizability (β) and related properties (μ, α and Δα) of this molecular system were calculated by using DFT/6-311++G(d,p) method based on the finite-field approach. The assignments of the vibrational spectra have been carried out with the help of Normal Co-ordinate Analysis (NCA) following the scaled quantum mechanical force methodology. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using NBO analysis. From the recorded UV–Visible spectrum, the electronic properties such as excitation energies, oscillator strength and wavelength are calculated by DFT in water and gas methods using 6-311++G(d,p) basis set. The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. Besides MEP, NLO and thermodynamic properties were also calculated and interpreted. The electron density-based local reactivity descriptor such as Fukui functions was calculated to explain the chemical selectivity or reactivity site in midodrine.
      Graphical abstract image Highlights Midodrine is a prodrug acting as α-adrenergic agonist useful in the treatment of neurogenic orthostatic hypotension. An extensive work has been carried out on the title compound and its derivatives in recent year. At present, vibrational spectroscopy is used not only for functional group identification of organic compounds, but also to investigate the molecular conformation, reaction kinetics.

      PubDate: 2014-07-25T23:11:54Z
       
  • A comparative study of phytohaemagglutinin and extract of Phaseolus
           vulgaris seeds by characterization and cytogenetics
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): A.R.S. Badari Nath , A. Sivaramakrishna , K.M. Marimuthu , Radha Saraswathy
      Phytohaemagglutinin (PHA) is a lectin obtained from Phaseolus vulgaris (red kidney beans), that acts as a mitogen in human leucocyte culture and is commercially available from Gibco®. This PHA (Gibco®) was found to be very expensive, hence other inexpensive sources that can be used in all kinds of cytogenetics labs (rich and poor), were attempted. One such successful attempt was PHA extract from seeds of P . vulgaris. This paper details the methodology of extraction and application of PHA from seeds of P . vulgaris. Attempts has been made to identify the chemical and physical properties of the products in the extract, analyzed by various spectroscopic and analytical techniques. The analysis clearly indicates that the product from Phaseolus seeds extract was found to be similar to the commercially available PHA (Gibco®) in the cytogenetic study of human leucocyte cultures. The present study enforces the possible utility of the plant extract directly for human leucocyte cultures.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • A study of vibrational spectra and investigations of charge transfer and
           chemical bonding features of 2-chloro benzimidazole based on DFT
           computations
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): S. Muthunatesan , V. Ragavendran
      Benzimidazoles are bicyclic heteroatomic molecules. Polycyclic heteroatomic molecules have extensive coupling of different modes leading to strong coupling of force constants associated with the various chemical bonds of the molecules. To carry out a detailed vibrational spectroscopic analysis of such a bicyclic heteroatomic molecule, FT-IR and FT-Raman spectra of 2-chloro benzimidazole (CBZ) have been recorded in the condensed phase. Density Functional Theory calculations in the B3LYP/6-31G* level have been carried out to determine the optimized geometry and vibrational frequencies. In order to obtain a close agreement between theoretical and observed frequencies and hence to perform a reliable assignment, the theoretical DFT force field was transformed from Cartesian to local symmetry co-ordinates and then scaled empirically using SQM methodology. The SQM treatment resulted in a RMS deviation of 9.4cm−1. For visual comparison, the observed and calculated spectra are presented on a common wavenumber scale. From the NBO analysis, the electron density (ED) charge transfers in the σ* and π* antibonding orbitals and second order delocalization energies E (2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The calculated Homo and Lumo energies show that charge transfer occurs within the molecule. The results obtained from the vibrational, NBO and HOMO–LUMO analyses have been properly tabulated.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Preparation and structure investigation of novel Schiff bases using
           spectroscopic, thermal analyses and molecular orbital calculations and
           studying their biological activities
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Ehab M. Zayed , M.A. Zayed , M. El-Desawy
      Two novel Schiff’s bases (EB1 and L1) as new macrocyclic compounds were prepared via condensation reactions between bisaldehyde (2,2′-(ethane-1,2-diylbis(oxy))dibenzaldehyde): firstly with hydrazine carbothioamide to give (EB1), secondly with 4,6-diaminopyrimidine-2-thiol to give (L1). EB1 has a general formula C18H20N6O2S2 of mole mass=416.520, and IUPAC name ((N,N′Z,N,N′E)-N,N′-(((ethane1,2diylbis(oxy))bis(2,1phenylene))bis(methanylylidene))bis(1hydrazinylmethanethioamide). L1 has a general formula C20H16N4O2S of mole mass=376.10; and IUPAC name 1,2-bis(2-vinylphenoxy)ethane4,6-diaminopyrimidine-2-thiol). The structures of the compounds obtained were characterized based on elemental analysis, FT-IR and 1H NMR spectra, mass, and thermogravimetric analysis (TG, DTG). The activation thermodynamic parameters, such as, ΔE *, ΔH *, ΔS * and ΔG * were calculated from the TG curves using Coats–Redfern method. It is important to investigate their structures to know the active groups and weak bond responsible for their biological activities. The obtained thermal (TA) and mass (MS) practical results are confirmed by semi-empirical MO-calculation using PM3 procedure, on the neutral and positively charged forms of these novel Schiff bases. Therefore, comparison between MS and TA helps in selection of the proper pathway representing the decomposition of these compounds to give indication about their structures and consequently their biological activities. Their biological activities have been tested in vitro against Escherichia coli, Proteus vulgaris, Bacillissubtilies and Staphylococcus aurous bacteria in order to assess their antimicrobial potential.
      Graphical abstract image

      PubDate: 2014-07-25T23:11:54Z
       
  • Spectroscopic, potentiometric and theoretical studies of novel
           imino-phenolate chelators for Fe(III)
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Rati Kanta Bera , Minati Baral , Suban K. Sahoo , B.K. Kanungo
      The present study was targeted to explore the binding properties of two strong chelators for Fe(III) based on tripodal-iminophenolate moiety. Complexation behavior of the tripodal systems cis–cis cyclohexane-1,3,5-tricarboxylic acid tris-({2-[(2-hydroxy-benzylidene)-amino]-ethyl}-amide (CYCOENSAL, L1) and cis–cis cyclohexane-1,3,5-tricarboxylic acid tris-({3-[(2-hydroxy-benzylidene)-amino]-propyl}-amide (CYCOPNSAL, L2) is described. Three protonation constants obtained are assigned for three hydroxyl groups of aromatic ring were employed for the evaluation of the formation constants of the metal complexes. Both ligands liberate three protons each forming monomeric complexes of type FeLH3, FeLH2, FeLH and FeL (L=L1 and L2). The first species FeLH3 depicted at low pH, where the ligands were coordinated through three imine nitrogen and other species form subsequently from FeLH3 in steps upon deprotonation and coordination of the phenolic oxygen giving encapsulated tris(phenolate) complexes. The probable structures of the metal complexes formed in solution were proposed through molecular modeling calculations. L2 was observed to be highly selective towards Fe(III) as compared to L1.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Investigation of trypsin–CdSe quantum dot interactions via
           spectroscopic methods and effects on enzymatic activity
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Gurvir Kaur , S.K. Tripathi
      The paper presents the interactions between trypsin and water soluble cadmium selenide (CdSe) quantum dots investigated by spectrophotometric methods. CdSe quantum dots have strong ability to quench the intrinsic fluorescence of trypsin by a static quenching mechanism. The quenching has been studied at three different temperatures where the results revealed that electrostatic interactions exist between CdSe quantum dots and trypsin and are responsible to stabilize the complex. The Scatchard plot from quenching revealed 1 binding site for quantum dots by trypsin, the same has been confirmed by making isothermal titrations of quantum dots against trypsin. The distance between donor and acceptor for trypsin–CdSe quantum dot complexes is calculated to be 2.8nm by energy transfer mechanisms. The intrinsic fluorescence of CdSe quantum dots has also been enhanced by the trypsin, and is linear for concentration of trypsin ranging 1–80μl. All the observations evidence the formation of trypsin–CdSe quantum dot conjugates, where trypsin retains the enzymatic activity which in turn is temperature and pH dependent.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Structural and photophysical properties of HPPCO
           (4-hydroxy-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-6-one) derivatives
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Yong-Kwang Jeong , Min-Ah Kim , Hyo-Sung Lee , Jong-Moon Kim , Sung Woo Lee , Jun-Gill Kang
      Proton-substitution effects of 4-hydroxy-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-6-one (HPPCO) on structural and photophysical properties were presented. HPPCO crystallized in the orthorhombic space group Pbca with an intermolecular hydrogen bonding between OH and oxygen atom of the carbonyl. The proton-substituted derivatives, 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl acetate (OPPCA) and 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl benzoate (OPPCB), crystallized in the monoclinic P21/c space group. For OPPCA and OPPCB, a weak interaction between carbonyl oxygen atom in the substituted group and carbon atom in the fused ring was responsible for three-dimensional arrangements. In addition, 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl furan-2-carboxylate (OPPCF), and 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl naphthoate (OPPCN) were also synthesized. HPPCO and the four derivatives excited by ultraviolet (UV) light produced blue emission. Proton substitution of the OH group significantly increased the radiative transitions and moderately decreased the non-radiative transitions. Consequently the luminescence quantum yields of the derivatives enhanced more than 4.6-fold, no matter what the groups were substituted. Structural and optical properties were further determined using density functional theory (DFT) and ZINDO calculations. The planar structure of the pyridocarbazole-fused ring resulted in π→π* electronic transitions within the main frame, with an additional transition from the n(O) of carbonyl to the π* of the main frame. The three excited states that arose from these transitions were responsible for the blue luminescence.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Characterization of 1,5-dimethoxynaphthalene by vibrational spectroscopy
           (FT-IR and FT-Raman) and density functional theory calculations
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): M. Kandasamy , G. Velraj , S. Kalaichelvan , G. Mariappan
      In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and natural bond orbital (NBO) analysis of 1,5-dimethoxynaphthalene. The optimized molecular structure, atomic charges, vibrational frequencies and natural bond orbital analysis of 1,5-dimethoxynaphthalene have been studied by performing DFT/B3LYP/6-31G(d,p) level of theory. The FTIR, FT-Raman spectra were recorded in the region of 4000–400cm− 1 and 3500–50cm− 1 respectively. The scaled wavenumbers are compared with the experimental values. The difference between the observed and scaled wavenumber values of the most fundamentals is very small. The formation of hydrogen bond was investigated in terms of the charge density by the NBO analysis. Natural Population Analysis (NPA) was used for charge determination in the title molecule. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis were investigated using theoretical calculations.
      Graphical abstract image Highlights

      PubDate: 2014-07-25T23:11:54Z
       
  • Ni(II) and Zn(II) complexes of 2-((thiophen-2-ylmethylene)amino)benzamide:
           Synthesis, spectroscopic characterization, thermal, DFT and anticancer
           activities
    • Abstract: Publication date: 5 January 2015
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 134
      Author(s): Prateek Tyagi , Sulekh Chandra , B.S. Saraswat
      The paper presents the synthesis of Ni(II) and Zn(II) complexes of general composition M(L)X2 and M(L)2X2 (M=Ni(II), Zn(II), X=Cl−1, OAc−1) with Schiff base obtained through the condensation of 2-aminobenzamide with thiophene-2-carbaldehyde. The characterization of newly formed complexes was done by 1H NMR, UV–VIS, TGA, IR, mass spectrophotometry and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff’s base and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies a distorted octahedral geometry has been assigned for Ni(II) complexes and tetrahedral geometry for Zn(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (HepG2) were studied and compared with those of free ligand.
      Graphical abstract image Highlights TGA curves of (red) ligand (L), (voilet) [Ni(L1)(OAc)2(H2O)](H2O), (green) [Zn(L1)(OAc)2] complexes in nitrogen atmosphere.

      PubDate: 2014-07-25T23:11:54Z
       
 
 
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