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Spectroscopic Techniques (spectroscopic + techniques)
Kinds of Spectroscopic Techniques Selected AbstractsDissolution and Doping of Polyaniline Emeraldine Base in Imidazolium Ionic Liquids Investigated by Spectroscopic TechniquesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2007Fabio Rodrigues Abstract Polyaniline is a model molecular system in the study of conductive polymers. Ionic liquids, on the other hand, are becoming more and more a very convenient alternative for conventional organic solvents. The dissolution of polyaniline-emeraldine base (PANI-EB) in imidazolium ILs leads to its doping, as indicated by optical and resonance Raman spectroscopies. In this study, it is proposed that the interaction of PANI-EB and imidazolium ILs involves the specific interaction of the quinoid moiety of the former with the imidazolium ring of the latter, an interpretation that is also based on N K -edge XANES measurements of neat PANI-EB, neat ILs, and of their solutions. [source] Optical absorption and EPR spectral studies of vauqueliniteCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2006K. Nagamuni Reddy Abstract Vauquelinite - a mineral - was investigated by EPR, NIR and optical spectroscopic techniques. EPR studies on powder sample confirm the presence of Cu(II) and Fe(III) impurity in the mineral. Optical absorption spectrum also indicates that Cu(II) impurity is present in rhombically distorted octahedral structure and Fe(III) in octahedral structure. NIR results are due to water fundamentals and phosphate combination tone. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Copper Oxide , Graphite Composite Electrodes: Application to Nitrite SensingELECTROANALYSIS, Issue 1 2007Biljana, ljuki Abstract A simple method for the modification of carbon powder with copper oxides is presented. Carbon powder is impregnated with copper(II) nitrate by stirring carbon powder in copper(II) nitrate solution for 1 hour and subsequently thermally treated at 823,K. The modified carbon powder was characterized using electrochemical and spectroscopic techniques. The existence of both copper(I) and copper(II) oxides have been established. The copper oxide modified carbon powder was used for preparation of composite electrodes, and the electrochemical and electrocatalytic behavior of the resulting composite electrodes was studied. The copper oxide modified carbon powder , epoxy composite electrodes showed a high electrocatalytic activity for the nitrite detection in aqueous media, with the detection limit comparable or lower than detection limits obtained with other electrochemical sensors. [source] Synthesis, X-ray Crystal Structures and Electrochemistry of (Indenyl)ruthenium Complexes Containing dppf and Heterocyclic Thiolato/Thione LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2008Sin Yee Ng Abstract A number of (indenyl)ruthenium complexes containing dppf [1,1,-bis(diphenylphosphanyl)ferrocene] and heterocyclic thiolato/thione ligands have been synthesized. All the complexes were fully characterized by microanalytical and spectroscopic techniques, together with X-ray diffraction analyses for those containing the benzothiazolato (thiolato) and the thiadiazole (thione) ligands. Cyclic voltammetry (CV) experiments indicated that these complexes can be oxidized in three one-electron processes at positive potentials. Differences in chemical reversibility observed during variable-temperature CV experiments indicated that it was likely that the oxidation processes occurred at two electronically noncommunicating sites within the molecules. One site could be assigned as the oxidation of the Ru ion (two one-electron processes), whilst the second site was assigned as the oxidation of the dppf (one one-electron process). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis, Structural Characterisation and Reactions of Some Vinylgold(I) Phosphane ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2006Fabian Mohr Abstract A series of vinylgold(I) complexes [Au(CR=CHR)L] (R = H, Me; L = PPh3, PPh2Me, PPhMe2) were prepared from the reaction of the Grignard reagents [MgBr(CR=CHR)] (R = H, Me) with the gold(I) phosphane complexes [AuCl(L)] (L = PPh3, PPh2Me, PPhMe2) at low temperature. The complexes were characterised by various spectroscopic techniques and, in the case of [Au(CMe=CHMe)(PPh3)], by a single-crystal X-ray structure determination. The gold,carbon bonds of these vinylgold(I) complexes are easily cleaved by acids and, in the presence of potassium permanganate, by species containing acidic protons. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthetic, Structural, and Electrochemical Studies of 2-Ferrocenyl- and2-Cymantrenyl-Functionalized 2,3-Dihydro-1H -1,3,2-diazaboroles and1,3,2-DiazaborolidenesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2005Lothar Weber Abstract Reaction of (dibromoboryl)ferrocene (1) with 1 equiv. of the diazabutadiene tBuN=CH,CH=NtBu, and subsequent reduction of the obtained borolium salt 2 with sodium amalgam, affords the first ferrocenyl-functionalized 1,3,2-diazaborole (3). Similarly, 1,1,-bis(dibromoboryl)ferrocene (4) can be transformed into compound 6, which contains two diazaborolyl substituents at the ferrocene core. Treatment of precursors 1 and 4 with 1,2-bis(tert -butylamino)ethane in the presence of Et3N gives rise to the formation of the diazaborolidine derivatives 13 and 14. 1-Dibromoboryl-3-methylcymantrene (7) was also treated with tBuN=CH,CH=NtBu to give the borolium salt 8, which was subsequently reduced to the 2-cymantrenyl-diazaborole 9. Treatment of 7 with tBuN(H)CH2CH2N(H)tBu in the presence of Et3N furnished the corresponding 2-cymantrenyl-diazaborolidine 15. The novel compounds were characterized by elemental analyses and various spectroscopic techniques (IR; 1H, 13C, and 11B NMR; MS). The molecular structures of 3, 6, and 15 were elucidated by X-ray diffraction analyses. Cyclovoltammetric studies of the ferrocene derivatives at high scan rates show features of a quasireversible oxidation at the iron center. The heterocyclic groups serve as electron donors, considerably lowering the oxidation potential of the central iron atoms when compared to the parent compound ferrocene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Metal-Controlled Stereoselectivity in Complex Formation: Assembly of Tetranuclear Copper(I) Complexes with Four Stereogenic Nitrogen Donor Functions in all-(R) and all-(S) ConfigurationsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2003Jörg Schneider Abstract The reaction of N,N, -dialkyl-3,7-diazanonane-1,9-dithiolate (NR2S2) ligands (R = Me, Et) with monovalent copper resulted in the formation of the chiral complexes [Cu4(NMe2S2)2] (1) and [Cu4(NEt2S2)2] (2) which were characterised by means of X-ray diffraction and spectroscopic techniques. They contain copper atoms in both linear {S,Cu,S} fragments, which act as linkers between mononuclear [Cu(NR2S2)], subsites, and in {CuS2N2} units within these building blocks, which can be described as incomplete coordination octahedra of unusual design. Due to favourable interplay between the spatial demands of the ligand system and the electronic requirements of the copper atom, the nitrogen donor atoms within the [Cu(NR2S2)], metallo ligands are restricted to identical absolute configurations. The combination of two [Cu(NR2S2)], metallo ligands with two further CuI ions to give the tetranuclear complexes 1 or 2 via S,Cu,S bridges underlies stereochemical control, resulting in optically active systems with (R,R,R,R) and (S,S,S,S) configurations. Consequently, metallo ligands in their enantiomeric forms cannot combine via S,Cu,S bridges to form optically inactive meso complexes with the (R,R,S,S) configuration. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Syntheses and Crystal Structures of Copper and Silver Complexes with New Imine Ligands , Air-Stable, Photoluminescent CuIN4 ChromophoresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2003Goutam Kumar Patra Abstract A series of new imine ligands [1 (C12H12N2S2), 2 (C12H12N2S2), 3 (C24H18N4S2), and 5 (C30H27N7)] have been synthesized (1 and 2 are structural isomers). CuI and AgI complexes of the nonconjugated dithiophene-diimine ligands 1, 2 and the tripodal imine-amine ligand 5 have also been prepared and thoroughly characterized by spectroscopic techniques as well as by X-ray diffraction. In cyclic voltammetry at a glassy carbon milli electrode in anhydrous dichloromethane under dry N2, the corresponding CuI complexes [6 (2C12H12N2S2·CuClO4), 7 (2C12H12N2S2·CuClO4), and 12 (C30H27N7·CuClO4)] show quasi-reversible CuII/I couples with high redox potentials (1.001 V for 6, 0.958 V for 7, and 0.692 V for 12, vs. Ag/AgCl). This indicates that the ,-acid ligands 1, 2, and 5 preferentially stabilize copper(I) over copper(II). The CuIN4 chromophores in the complexes 6, 7, and 12 display photoluminescence in dichloromethane at room temperature. The related silver complexes of the same three ligands 10 (2C12H12N2S2·AgClO4), 11 (2C12H12N2S2·AgClO4), and 13 [C30H27N7·Ag(CH3CN)ClO4] reveal similar structural features but lack specific photophysical properties. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Synthesis of Carrier-Transporting Dendrimers with Perylenebis(dicarboximide)s as a Luminescent CoreEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2006Jianfeng Pan Abstract Well-defined, modular dendrimers enable processing techniques and electronic properties to be tuned independently. Moreover, the dendritic topology can isolate the core chromophore, thus reducing or eliminating strong intermolecular interactions. This paper presents the synthesis of three series of flexible, dendron-functionalized dendrimers as red-light-emitting materials by a convergent approach: (1) carbazole (CZ) or oxadiazole (OXZ) terminated imide-type dendrimers, (2) cascade energy-transferring imide-type dendrimers, and (3) CZ-terminated perylene bay-type dendrimers. They all consist of the luminescent core of perylenebis(dicarboximide)s with specific functional groups of CZ or OXZ at the periphery and are constructed from flexible Fréchet-type poly(aryl ether) dendrons. The chemical structures of the dendrons and dendrimers were determined by standard spectroscopic techniques including 1H and 13C NMR spectroscopy and low/high-resolution mass spectrometry (ESI or MALDI-TOF). The dendrimers are designed on the basis of the following considerations: (1) dendron functionalization to incorporate CZ or OXZ units to realize the carrier-injection adjustment, (2) tuning or improving solubility, functionality, glass-transition temperature (Tg) with well-defined dendrons, and (3) avoiding luminescence quenching with the help of high site-isolation of dendrons to enhance core luminescence. DSC results indicate that the incorporation of Fréchet-type poly(aryl ether) dendrons can improve the amorphous properties and increase Tg. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] 2-(Benzylsulfanyl)-6-chloro-9-isopropylpurine, a Valuable Intermediate in the Synthesis of Diaminopurine Cyclin Dependent Kinase InhibitorsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2005David Taddei Abstract The synthetic potential of a novel precursor of 2,6-diaminopurine CDK inhibitors, 2-(benzylsulfanyl)-6-chloro-9-isopropylpurine, is described. The Traube purine synthesis was chosen to prepare the required 2-(benzylsulfanyl)hypoxanthine intermediate. Attempts to prepare its purin-6-yl methanesulfonic ester analogue failed. Conversion to the 6-chloropurine derivative enabled the introduction of arylamines in the presence of catalytic amounts of acid. Further chemical variety was introduced on the purine through a regioselective Mitsunobu N -9 alkylation. Oxidative cleavage of the 2-(benzylsulfanyl) leaving group with an aliphatic amine was implemented as previously reported. Purvalanol A, a potent CDK inhibitor, was synthesised using this methodology. The template and intermediates were fully characterised by modern spectroscopic techniques and single-crystal X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Force Spectroscopic Investigations During the Local Oxidation of n -Octadecyltrichlorosilane Monolayers,ADVANCED FUNCTIONAL MATERIALS, Issue 1 2006S. Hoeppener Abstract Scanning force spectroscopy (SFS) is a powerful tool for investigating surface properties with high precision. Unlike most common spectroscopic techniques, information about local properties can also be obtained from surface areas with nanometer dimensions. This makes SFS a useful investigative tool for small lithographic structures. We apply the continuous recording of force curves to extract valuable information about the local oxidation of a monolayer of n -octadecyltrichlorosilane molecules self-assembled on silicon. The oxidation is carried out while simultaneously recording the force curves during the application of a bias voltage to the tip. The dynamics of the induced surface modifications and changes in the surface properties are followed by analyzing specific spots in the force curves. [source] Trichocarpinine, a Novel Hetidine,Hetisine Type Bisditerpenoid Alkaloid from Aconitum tanguticum var. trichocarpumHELVETICA CHIMICA ACTA, Issue 1 2010Ling Lin Abstract Trichocarpinine (1), the first hetidine,hetisine type bisditerpenoid alkaloid, was isolated from the whole herbs of Aconitum tanguticum var. trichocarpum. Its structure was determined by a combination of spectroscopic techniques, including HR-ESI-MS and 1D- and 2D-NMR experiments. Its plausible biogenetic pathway was proposed as well (Scheme). [source] Spectroscopic Investigation of the Europium(3+) Ion in a New ZnY4W3O16 MatrixHELVETICA CHIMICA ACTA, Issue 11 2009bieta Tomaszewicz Abstract A new Zn and Eu tungstate was characterized by spectroscopic techniques. This tungstate, of the formula ZnEu4W3O16, crystallized in the orthorhombic system and was synthesized by a solid-state reaction. It melts incongruently at 1330°. The luminescent properties, including excitation and emission processes, luminescent dynamics, and local environments of the Eu3+ ions in ZnEu4W3O16 and ZnY4W3O16,:,Eu3+ diluted phases (1, 5, and 10,mol-% of Eu3+ ion) were studied basing on the f6 -intraconfigurational transitions in the 250,720,nm spectral range. The excitation spectra of this system (,em 615 and 470,nm) show broad bands with maxima at 265 and 315,nm related to the ligand-to-metal charge-transfer (LMCT) states. The emission spectra under excitation at the O,W (265,nm) and O,Eu3+ (315,nm) LMCT states present the blue-green emission bands. The emission of tungstate groups mainly originate from the charge-transfer state of excited 2p orbitals of O2, to the empty orbitals of the central W6+ ions. On the other hand, in the emission of the Eu3+ ions, both the charge transfer from O2, to Eu3+ and the energy transfer from W6+ ions to Eu3+ are involved. The emission spectra under excitation at the 7F0,5L6 transition of the Eu3+ ion (394,nm) of ZnY4W3O16,:,Eu3+ diluted samples show narrow emission lines from the 5D3, 5D2, and 5D1 emitting states. The effect of the active-ion (Eu3+) concentration on the colorimetric characteristic of the emissions of the compound under investigation are presented. [source] Novel Diterpenoids from Salvia dugesiiHELVETICA CHIMICA ACTA, Issue 4 2004Gang Xu Two novel rearranged clerodane diterpenoids, dugesin,A (1) and dugesin B (2), were isolated from the aerial parts of Salvia dugesii, together with five known clerodane diterpenoids: isosalvipuberulin (3), salvipuberulin (4), tilifodiolide (5), salvifolin (6), and salvifaricin (7). Their structures were elucidated on the basis of different spectroscopic techniques. The isolation and identification of these compounds are significant from both biosynthetisis and chemotaxonomy points of view. [source] Micranthin C, a Novel 13(12,11)abeo -Abietanoid from Isodon lophanthoids var. micranthusHELVETICA CHIMICA ACTA, Issue 10 2003Ai-Hua Zhao A novel 13(12,11)abeo -abietane skeletal diterpenoid, micranthin C (1), was isolated from Isodon lophanthoids var. micranthus. Its structure was determined by various spectroscopic techniques and finally confirmed by single-crystal X-ray diffraction. [source] Synthesis, characterization, and in vitro antimicrobial activities of organotin(IV) complexes of Schiff bases with ONO-type donor atomsHETEROATOM CHEMISTRY, Issue 6 2010Gülgün Yeni, ehirli A new series of diorganotin complexes of the type R2SnL (L1: N -(2-hydroxy-5-chlorophenyl)- 3-ethoxysalicylideneimine, R = Me, (Me2SnL1), R = n -Bu, (n -Bu2SnL1), R = Ph, (Ph2SnL1), L2: N -(2-hydroxy-4-nitro-5-chlorophenyl)-3-ethoxysalicylideneimine, R = Ph, Ph2SnL2, L3: N -(2-hydroxy-4-nitrophenyl)-3-methoxysalicylideneimine, R = Me, (Me2SnL3), R = n -Bu, (n -Bu2SnL3), L4: N -(2-hydroxy-4-nitrophenyl)-3-ethoxysalicylideneimine, R = Me, (Me2SnL4), R = n -Bu, (n -Bu2SnL4)) were synthesized and characterized by elemental analysis, infrared (IR), 1H, and 13C NMR mass spectroscopic techniques, and electrochemical measurements. Ph2SnL1 and Ph2SnL2 were also characterized by X-ray diffraction analysis and were found to show a fivefold C2NO2 coordination geometry nearly halfway between a trigonal bipyramidal and distorted square pyramidal arrangement. The CSnC angles in the complexes were calculated using Lockhart's equations with the 1J(117/119Sn- 13C) and 2J(117/119Sn- 1H) values from the 1H NMR and 13C NMR spectra. Biocidal activity tests against several micro-organisms and some fungi indicate that all the complexes are mildly active against Gram (+) bacteria and the fungi, A. niger and inactive against Gram (,) bacteria. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:373,385, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20628 [source] Synthesis of some novel bis(hetaryl)azo disperse dyes and investigation of their absorption spectraHETEROATOM CHEMISTRY, Issue 6 2007Zeynel Sefero 3-Amino-2-cyano-4,6-disubstituted-thieno{2,3-b}pyridines and 3-aminopyridine were diazotized and coupled with 2-phenylindole, 2-methylindole, and 1-methyl-2-phenylindole, respectively. These dyes were characterized by UV-Visible, FT-IR, 1H NMR, and mass spectroscopic techniques. Solvent effects on the visible absorption spectra of the dyes were evaluated. The color of the dyes is discussed with respect to the nature of the heterocyclic ring and substituent present therein. In addition, effects of temperature, concentration, as well as acid and base on the visible absorption maxima of the dyes are reported. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:622,630, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20361 [source] Single-Molecule Spectroscopy for Plastic Electronics: Materials Analysis from the Bottom-UpADVANCED MATERIALS, Issue 15 2010John M. Lupton Abstract , -conjugated polymers find a range of applications in electronic devices. These materials are generally highly disordered in terms of chain length and chain conformation, besides being influenced by a variety of chemical and physical defects. Although this characteristic can be of benefit in certain device applications, disorder severely complicates materials analysis. Accurate analytical techniques are, however, crucial to optimising synthetic procedures and assessing overall material purity. Fortunately, single-molecule spectroscopic techniques have emerged as an unlikely but uniquely powerful approach to unraveling intrinsic material properties from the bottom up. Building on the success of such techniques in the life sciences, single-molecule spectroscopy is finding increasing applicability in materials science, effectively enabling the dissection of the bulk down to the level of the individual molecular constituent. This article reviews recent progress in single molecule spectroscopy of conjugated polymers as used in organic electronics. [source] Mechanism of interaction of DNA bases with dichloro-[1-alkyl-2-(naphthylazo)imidazole]palladium(II) complexes: A cytosine caseINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2009Pradip Kumar Ghosh Interaction of cytosine (C) with dichloro-[1-alkyl-2-(,-naphthylazo)imidazole]-palladium(II) [Pd(,-NaiR)Cl2, 1] and dichloro-[1-alkyl-2-(,-naphthylazo)imidazole]-palladium(II) [Pd(,-NaiR)Cl2, 2] complexes {where alkyl R = Me (a), Et (b) or Bz (c)} in acetonitrile (MeCN)-water (50% v/v) medium to yield [{1-alkyl-2-(,-naphthylazo)-imidazole}bis(cytosine)]palladium(II)dichloride (3a, 3b, 3c) and [{1-alkyl-2-(,-naphthylazo)-imidazole}bis(cytosine)]palladium(II)dichloride (4a, 4b, 4c) was studied. The products were characterized by microanalytical data and spectroscopic techniques (FT-IR, UV,vis, and NMR). The reaction kinetics show first-order dependence of the rate on each of the concentration of Pd(II) complex and C. External addition of Cl, ion (LiCl) did not influence this nucleophilic substitution rate process and has proved the cleavage of first PdCl bond is the rate-determining step. Thermodynamic parameters standard enthalpy of activation (,,Ho) and standard entropy of activation (,,So) were determined from variable temperature kinetic studies. The negative values of ,,So indicate that the reaction proceeds through an associative inner sphere mechanism. The magnitude of the second-order rate constant k2 increases in the following order: Pd(NaiEt)Cl2 (b) < Pd(NaiMe)Cl2 (a) < Pd(NaiBz)Cl2 (c) as well as Pd(,-NaiR)Cl2 (1) < Pd(,-NaiR)Cl2 (2), which corroborates with the experimental ,,Ho values. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 463,472, 2009 [source] Studies on synthesis and characterization of a novel acrylic aromatic amide oligomer of aminolysed endproducts generated from pet waste with hydrazine monohydrate and its photocuring with acrylate monomersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010R. K. Soni Abstract A novel acrylic aromatic amide oligomer was synthesized by using depolymerized end product of PET waste with hydrazine monohydrate. The end product of aminolysed PET waste was synthesized under ambient conditions and was used in the preparation of novel acrylic oligomer with the reaction of acryloyl chloride prepared from acrylic acid. The acrylic oligomer was characterized by spectroscopic techniques, such as FTIR, 1H-NMR, UV, Mass spectrometry, and by other analytical techniques such as, Iodine value, TGA, and DSC. The proposed structure of the oligomer is supported by its spectral analysis and the same is inferred from other techniques. The acrylic oligomer mixed with other acrylate monomers such as methylmethacrylate, ethylhexylacrylate, acrylic acid, and photoinitiator, can be cured by UV radiation and can thus be used as an adhesion promoter on metal/glass surface. This article presents the possibility of using a difunctional aromatic amide oligomer with excellent hydrogen bonding capacity as an alternative to urethane acrylates in radiation curable formulations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effects of pigments on the UV degradation of wood-flour/HDPE compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Hua Du Abstract The effects of different color pigments on the durability of wood-flour/high-density polyethylene composites (WF/HDPE) were evaluated by UV-accelerated weathering tests. WF/HDPE composites were dyed using three different color inorganic pigments, which were added at 2% based on the weight of the composite. Samples were weathered in Q-panel UV aging equipment for 1500 h. All samples showed significant fading and color changes in exposed areas. Changes in surface chemistry were studied using spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) was used to verify the occurrence of surface oxidation. Changes in carbonyl groups (CO), PE crystallinity, cellulose CO, and lignin aromatic CC were detected by Fourier transform infrared (FTIR) spectroscopy. The results indicate that surface oxidation occurred immediately within exposure 250 h for all samples; the surface of the control WF/HDPE composites was oxidized to a greater extent than that of the dyed WF/HDPE. This suggests that the addition of pigments to the WF/HDPE composites results in less weather-related damage. The surface configuration observed by scanning electron microscopy revealed that WF/HDPE composites degraded significantly on accelerated UV aging, with dense cracking apparent on the exposed surface. Carbon black had a more positive effect on color stability than the other pigments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Spectral characterization of lysozyme adsorption on dye-affinity beadsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Nilgün Basar Abstract Cibacron Blue F3GA-attached magnetic poly(2-hydroxyethyl methacrylate) [mPHEMA] beads were prepared by suspension polymerization of HEMA in the presence of magnetite (Fe3O4) nanopowder. Average diameter size of the mPHEMA beads was 150,200 ,m. The characteristic functional groups of Cibacron Blue F3GA-attached mPHEMA beads were analyzed by Fourier transform infrared spectrometer (FTIR) and Raman scattering spectrometer. The lysozyme adsorption and desorption characteristics of Cibacron Blue F3GA-attached mPHEMA beads were also investigated using FTIR and Raman spectroscopic techniques. When the Raman spectrum of lysozyme adsorbed mPHEMA is evaluated characteristic Amide-I band appears at 1657 cm,1. The intensity of this band decreases in the spectrum of lysozyme desorbed mPHEMA sample. When the characteristic bands of lysozyme adsorbed and desorbed mPHEMA samples are compared, the band intensities of desorbed sample are lower than those of lysozyme adsorbed sample except for the band appearing at 656 cm,1 (Tyr vCS). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Water-borne melamine,formaldehyde-cured epoxy,acrylate corrosion resistant coatingsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Sarvat Zafar Abstract Organic protective coatings are widely used in corrosion control. However, environmental standards establish that the volatile organic compounds either must be removed or controlled at the lowest possible levels. The carcinogenic environmental impact of volatile organic compounds has led to the substitution of solvent-borne coatings by water-borne coating systems. Among recently developed water-borne coatings, epoxy- and acrylic-based coatings have a special significance over other reported water-borne systems. Keeping in mind, the importance of water-borne coatings in the present work, we report the synthesis of water-borne epoxy,acrylate (EpAc) and melamine,formaldehyde (MF) as well as formulation of their anticorrosive coatings. The structural elucidation of MF-cured EpAc was carried out by FTIR, 1H NMR, and 13C NMR spectroscopic techniques. The coatings of EpAc-MF were applied on mild steel strips and were evaluated for physicochemical, physicomechanical characterization, and the anticorrosive performance under different environmental conditions. The present coating system EpAc coatings exhibited superior performance as compared to the reported water-borne epoxy,acrylatecoatings. The presence of melamine,formaldehyde in the resin increases the scratch hardness, impact resistance, alkali resistance, and thermal stability of these coatings. EpAc-MF-1 was found to cure at ambient temperature and exhibit good physicomechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Label-free biochemical characterization of stem cells using vibrational spectroscopyJOURNAL OF BIOPHOTONICS, Issue 11 2009James W. Chan Abstract Raman and infrared (IR) spectroscopy are two complementary vibrational spectroscopic techniques that have experienced a tremendous growth in their use in biological and biomedical research. This is, in large part, due to their unique capability of providing label-free intrinsic chemical information of living biological samples at tissue, cellular, or sub-cellular resolutions. This article reviews recent developments in applying these techniques for the characterization of stem cells. A discussion of the potential for these methods to address some of the major challenges in stem cell research is presented, as well as the technological and scientific advancements that are needed to progress the knowledge in the field. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis of benzo[b][1,4]thiazepines by the reaction of 3-aryl-1-(3-coumarinyl)propen-1-ones with 2-aminothiophenol,JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2007Albert Lévai 3-(2-Aryl-2,3-dihydro-benzo[b][1,4]thiazepin-4-yl)chromen-2-ones (2a, e, f) and (Z)-3-(2,3-dihydro-2-arylbenzo[b][1,4]thiazepin-4(5H)-ylidene)chroman-2-ones (3a-f) have been synthesized by the reaction of 3-aryl-1-(3-coumarinyl)propen-1-ones (1a-f) with 2-aminothiophenol in a hot mixture of toluene and acetic acid. Structures of all new compounds and their complete 1H and 13C assignments were achieved applying different one- and two-dimensional nmr experiments in combination with various spectroscopic techniques. [source] Structure and composition of CO2/H2 and CO2/H2/C3H8 hydrate in relation to simultaneous CO2 capture and H2 productionAICHE JOURNAL, Issue 6 2009Rajnish Kumar Gas hydrates from a (40/60 mol %) CO2/H2 mixture, and from a (38.2/59.2/2.6 mol %) CO2/H2/C3H8 mixture, were synthesized using ice powder. The gas uptake curves were determined from pressure drop measurements and samples were analyzed using spectroscopic techniques to identify the structure and determine the cage occupancies. Powder X-ray diffraction (PXRD) analysis at ,110°C was used to determine the crystal structure. From the PXRD measurement it was found that the CO2/H2 hydrate is structure I and shows a self-preservation behavior similar to that of CO2 hydrate. The ternary gas mixture was found to form pure structure II hydrate at 3.8 MPa. We have applied attenuated total reflection infrared spectroscopic analysis to measure the CO2 distribution over the large and small cavities. 1H MAS NMR and Raman were used to follow H2 enclathration in the small cages of structure I, as well as structure II hydrate. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] The molecular mechanism of human group IIA phospholipase A2 inactivation by bolinaquinoneJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2009Maria Chiara Monti Abstract The molecular basis of the human group IIA secretory phospholipase A2 inactivation by bolinaquinone (BLQ), a hydroxyquinone marine terpenoid, has been investigated for the comprehension of its relevant antiinflammatory properties, through the combination of spectroscopic techniques, biosensors analysis, mass spectrometry (MS) and molecular docking. Indeed, sPLA2s are well known to be implicated in the pathogenesis of inflammation such as rheumatoid arthritis, septic shock, psoriasis and asthma. Our results suggest a mechanism of competitive inhibition guided by a non-covalent molecular recognition event, disclosing the key role of the BLQ hydroxyl-quinone moiety in the chelation of the catalytic Ca2+ ion inside the enzyme active site. The understanding of the sPLA2 -IIA inactivation mechanism by BLQ could be useful for the development of a new chemical class of PLA2 inhibitors, able to specifically target the enzyme active site. Copyright © 2009 John Wiley & Sons, Ltd. [source] Establishing quantitative in-line analysis of multiple solid-state transformations during dehydrationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2008Karin Kogermann Abstract The aim of the study was to conduct quantitative solid phase analysis of piroxicam (PRX) and carbamazepine (CBZ) during isothermal dehydration in situ, and additionally exploit the constructed quantitative models to analyze the solid-state forms in-line during fluidized bed drying. Vibrational spectroscopy (near-infrared (NIR), Raman) was employed for monitoring the dehydration and the quantitative model was based on partial least squares (PLS) regression. PLS quantification was confirmed experimentally using isothermal thermogravimetric analysis (TGA) and X-ray powder diffractometry (XRPD). To appraise the quality of quantitative models several model parameters were evaluated. The hot-stage spectroscopy quantification results were found to be in reasonable agreement with TGA and XRPD results. Quantification of PRX forms showed complementary results with both spectroscopic techniques. The solid-state forms observed during CBZ dihydrate dehydration were quantified with Raman spectroscopy, but NIR spectroscopy failed to differentiate between the anhydrous solid-state forms of CBZ. In addition to in situ dehydration quantification, Raman spectroscopy in combination with PLS regression enabled in-line analysis of the solid-state transformations of CBZ during dehydration in a fluidized bed dryer. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4983,4999, 2008 [source] Qualitative in situ analysis of multiple solid-state forms using spectroscopy and partial least squares discriminant modelingJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2007Karin Kogermann Abstract This study used in situ spectroscopy to reveal the multiple solid-state forms that appear during isothermal dehydration. Hydrate forms of piroxicam and carbamazepine (CBZ) were investigated on hot-stage at different temperatures using near-infrared (NIR) and Raman spectroscopy combined with multivariate modeling. Variable temperature X-ray powder diffraction, differential scanning calorimetry, thermogravimetric analysis, and Karl Fisher titrimetry were used as reference methods. Partial least squares discriminant analysis (PLS-DA) was performed to qualitatively evaluate the phase transition. It was shown that the constructed PLS-DA models, where spectral differences were directly correlated to solid-state modifications, enabled differentiation between the multiple forms. Qualitative analysis revealed that during dehydration, hydrates, such as CBZ dihydrate, may go through several solid-state forms, which must be considered in quantitative model construction. This study demonstrates that in situ analysis can be used to monitor the dehydration and reveal associated solid-state forms prior to quantification. The utility of the complementary spectroscopic techniques, NIR and Raman, have been shown. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 1802,1820, 2007 [source] A study of sulfamerazine single crystals using atomic force microscopy, transmission light microscopy, and Raman spectroscopyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2005Xiaoping Cao Abstract Sulfamerazine (SMZ) Form I and II single crystals were prepared from aqueous dispersions of SMZ bulk samples and studied using several microscopic and spectroscopic techniques. Transmission light microscopy and Raman spectroscopy were used to observe and identify single crystals. The results indicated that Form I single crystals tended to be rectangular laths while Form II ones tended to be hexagonal laths. Surface morphology of individual single crystals was further investigated by atomic force microscopy (AFM). AFM images revealed a smooth top surface, a uniform height, and sharp edges for both forms of single crystals. Both height and phase images showed crystalline terraces with different step heights for the top surface of Form I. Surface properties of single crystals were evaluated using AFM force measurements. Experimental results indicated that the top surface of Form I single crystals was more hydrophilic than that of Form II. Theoretical calculations predicted a dominant crystal face of (020) for the Form I single crystals and (002) for the Form II ones. The correlations between calculation predictions and experimental results were discussed. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:1881,1892, 2005 [source] | |||||||||||||||||||||||||||||||||||||||||||