Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Terms modified by FTIR

  • ftir analysis
  • ftir measurement
  • ftir spectrometry
  • ftir spectroscopy
  • ftir spectrum
  • ftir studies

  • Selected Abstracts

    Synthesis and properties of ,-Fe2O3 nanorods

    R. Ramesh
    Abstract We report synthesis of ,-Fe2O3 (hematite) nanorods by reverse micelles method using cetyltrimethyl ammonium bromide (CTAB) as surfactant and calcined at 300 C. The calcined ,-Fe2O3 nanorods were characterized by X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The result showed that the ,-Fe2O3 nanorods were hexagonal structure. The nanorods have diameter of 30-50 nm and length of 120-150 nm. The weak ferromagnetic behavior was observed with saturation magnetization = 0.6 emu/g, coercive force = 25 Oe and remanant magnetization = 0.03 emu/g. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Optical properties of 2-aminopyridinium nitrato silver

    K. P. Bhuvana
    Abstract Crystals of 2-aminopyridinium nitrato silver have been synthesized by slow evaporation method. Grown crystals have been subjected to FTIR, Single crystal X-Ray diffraction and UV-Visible studies in order to investigate the structural and optical properties of the crystal. The FTIR spectrum reveals the presence of the functional group that corresponds to both 2-aminopyridine and silver nitrate, suggesting the formation of the compound, 2-aminopyridinium nitrato silver. From XRD it is observed that the crystal crystallizes in the structure of monoclinic with the space group of P21/c. The optical transmittance spectrum shows the maximum transparency of about 95% in the visible region is in consistent with the wide band gap, estimated as 4.738 eV. The optical constants n and k has also been determined from the transmittance data. The static dielectric constant is found to be 0.851. The wide band gap and the less dielectric constant suggest the suitability of this compound material for photoconductive applications. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Characterization of pure and doped potassium hydrogen tartrate single crystals grown in silica gel

    I. Quasim
    Abstract Growth of pure-, sodium- and lithium- doped potassium hydrogen tartrate single crystals by gel technique is reported. Growth conditions conducive for the growth of single crystals are worked out. The crystals are characterized by using powder XRD, SEM, FTIR, AES, EDAX, CH analysis and thermoanalytical techniques. The stoichiometric composition for the grown crystals are established as KHC4H4O6.H2O, (K)0.98(Na)0.02.H2O and (K)0.94(Li)0.06HC4H4O6.H2O. Doping of sodium and lithium in the pure potassium hydrogen tartrate single crystals is found to influence the size, perfection, morphology, crystal structure and the thermal stability of crystals. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Growth of YCOB single crystals by flux technique and their characterization

    R. Arun Kumar
    Abstract Nonlinear optical single crystals of YCOB with good optical quality were grown by the flux technique for the first time. Polycrystalline YCOB samples were synthesized by solid state reaction method. The thermal analysis of the sample was performed with lithium carbonate flux in different weight proportions and the growth temperature was optimised. Single crystals of YCOB with dimensions 3 3 5 mm3 were obtained by the method of ,slow-cooling'. The grown crystals were characterized by XRD, UV-VIS-NIR, EDAX, FTIR and etching studies. The powder XRD pattern revealed the formation of YCOB compound. The lattice parameters were identified through single crystal XRD studies. The UV-VIS-NIR results showed that the crystal has a sharp cutoff at 220 nm and is nearly 55% transparent over a wide wavelength range enabling applications in the UV region. The EDAX measurement revealed the ,flux-free' crystal formation. The presence of the functional groups belonging to the YCOB crystals was identified by the FTIR results. ,Hillock-like' patterns are observed in the etching studies. The primary emphasis in this study is laid to describe ,flux technique' as an alternative method to grow YCOB crystals. The results are presented and discussed. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Growth of tetrakis thiourea potassium iodide as new second order optical material

    J. Thomas Joseph Prakash
    Abstract A novel organometallic nonlinear optical (NLO) crystal, namely thiourea complex of tetrakis thiourea potassium iodide (TTPI), has been grown by slow evaporation solution growth technique. The harvested crystal is large in size. To our knowledge there is no report is available for the bulk size single crystal of TTPI. This material has a positive temperature coefficient and has been grown by slow evaporation solution growth technique. The grown crystal have been characterized by employing several techniques such as single crystal and powder X-ray diffraction, FTIR, UV-Vis-NIR spectra, thermo gravimetric analyses respectively. Etching studies have also been carried out in order to know the surface defects on the as grown specimen of TTPI. The relative second harmonic generation efficiency have been tested by using Nd:YAG laser as source. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and characterization of fine lithium niobate powders by sol- gel method

    L. H. Wang
    Abstract Lithium niobate (LN) nanocrystal powders were prepared by low-temperature sol-gel method. Dihydrate lithium acetate as lithium source, and niobium chloride as niobium source were used as starting materials. The gel and powders were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and Fourier transform infrared (FTIR) spectra. The results show that when the gel was heat-treated at 600C, the fine LN nanocrystals with the size of 40-60 nm were obtained, and the size of the powders become larger with the heat-treated temperature increasing. ( 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystals

    E. Ramachandran
    Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. ( 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Thermal, phase transition and spectral studies in erythromycin pseudopolymorphs: dihydrate and acetone solvate

    Zhanzhong Wang
    Abstract The thermal, phase transition and spectral studies of erythromycin A dihydrate and acetone solvate were performed by Differential Scanning calorimetry (DSC), Thermo Gravimetry (TG-DTA), X-Ray Powder Diffraction (XRPD) and Fourier Transform Infra-Red (FTIR) spectrum. The non-thermal kinetic analysis of erythromycin A dihydrate was carried out by DSC at different heating rates in dynamic nitrogen atmosphere. The result showed that heating rate has substantial influence on the thermal behavior of erythromycin dihydrate. The Arrhenius parameters were estimated according to the Kissinger method. Corresponding to dehydration of dihydrate, melting of dehydrated dihydrate, phase transition from dehydrated dihydrate to anhydrate, and melting of anhydrate, the calculated activation energy were 39.60, 269.85, 261.23, and 582.16 kJmol,1, the pre-exponential factors were 3.46 103, 8.06 1032, 9.23 1030, and 7.29 1063 s,1, respectively. Ozawa method was used to compare activation energy values calculated by Kissinger method. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Growth and properties of ferroelectric potassium ferrocyanide trihydrate single crystals

    R. Kanagadurai
    Abstract Single crystals of potassium ferrocyanide trihydrate, K4[Fe(CN)63H2O (KFCT), a ferroelectric material with Curie temperature 251K were grown in silica gel at room temperature for the first time by the solubility reduction method. Resorcinol and ethyl alcohol were used for the purpose of gel setting and supernatant liquid respectively. Optical and mechanical properties were studied for the grown crystal. The structure of the grown crystal was confirmed by X-ray diffraction analysis. Fourier Transform Infrared (FTIR) and FT Raman spectral analysis of the crystalline samples reveal that the crystalline sample consist consists of all functional groups. Thermal analysis of the crystalline sample was performed by TGA and DTA methods. The Vicker's micro hardness value was measured for KFCT crystals. The square etch pits with a hopper-like structure is an indicative of 2D nucleation mechanism. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and characterization of 4,4,-dihydroxy-,-methylstilbene crystal

    K. Rameshbabu
    Abstract 4,4,-dihydroxy-,-methylstilbene (DHAMS) was synthesized by condensation reaction with chloroacetone and phenol in the presence of concentrated sulfuric acid, and has been successfully grown by solution growth technique. This is the first report in the literature on the crystallization of DHAMS and exhibited the birefringent melt (liquid crystal property) of the optical properties. FTIR and FTNMR studies are in accordance with the structure. Good quality crystals were grown by slow evaporation technique by acetone as solvent. A transmission spectrum of the crystal was obtained in the region of 285 nm. The structural and optical properties were studied. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Spectroscopic and crystal structure analysis of diamminebis(2,4,6-triiodophenolato-O) copper(II)

    Glsn Gka
    Abstract The crystal structure of [Cu(C6H2I3O)2(NH3)2] (CCDC 238896) has been determined by x-ray diffraction. This monomeric centrosymmetric Cu(II) complex crystallizes in the monoclinic system. The CuO2N2 coordination sphere is trans -planar, [Cu,O: 1.943(5) and Cu-N: 1.972(7)] with the fifth and sixth coordination sites occupied by I atoms from the phenoxide ions [Cu,I1: 3.3552(8) ] to form a tetragonally elongated octahedral structure for CuO2N2I2 coordination. The complex molecules hold together in a one dimensional chain true [100] direction by intermolecular hydrogen bonds. Differantial scanning calorimeter, FTIR and magnetic susceptibility measurements were also performed in order to identify the title complex. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and characterization of potassium magnesium sulphate hexahydrate crystals

    M. Dhandapani
    Abstract Potassium magnesium sulphate hexahydrate (picromerite) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at room temperature. The crystals were bright, colourless and transparent having well defined external faces. The grown crystals were characterized through Fourier Transform Infrared (FTIR) spectral studies and thermal analysis. The FTIR data were used to assign the characteristic vibrational frequencies of the various chemical bonds in the compound. The compound crystallizes in monoclinic lattice with the space group P21/c. The thermogravimetry (TG) indicates the removal of only two water molecules around 100 C. A suitable decomposition pattern was formulated based on the percentage weight losses observed in TG of the compound. The results of differential thermal analysis (DTA) conform to the results of TGA. Differential scanning calorimetry (DSC) analysis carried out at high temperature suggests that the occurrence of two phase transitions in the crystal between 140 and 180 C. When the crystal was cooled below the room temperature up to ,170 C, no thermal anomaly was observed. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Gel growth and characterization of , -DL-methionine

    E. Ramachandran
    Abstract DL-Methionine [C5H11NO2S] is one of the essential amino acids in humans. It has two crystalline forms, viz., ,- and ,- methionine. In the present study, , - form is crystallized in silica gel; under suitable pH conditions by single diffusion method. The grown crystals were characterized by density measurement and single crystal X-ray diffraction. Fourier transform infrared (FTIR) spectroscopic studies, thermal analysis and scanning electron microscopic (SEM) studies were also made as part of the structural studies. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Hydrothermal growth of boron nitride microcrystals

    Xiaopeng Hao
    Abstract Boron nitride (BN) crystals with size of several micrometers have been successfully synthesized by hydrothermal method. The reactants used in our experiments were boric acid (H3BO3), sodium azide (NaN3) and white phosphor (P). The samples were characterized by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), selective area electron diffraction (SAED). It is found that the existence of Cl - in the reaction mixture has much effect on the synthesis of BN. ( 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis, crystal structure and characterization of new transition metal compounds of bromophenols: Bis(2,4,6-tribromophenolato) di(N-methylimidazole)M(II) (M=Co, Cu)

    P. Camurlu
    Abstract Bis(2,4,6-tribromophenolato)di(N-methyl imidazole)M(II), where M stands for cobalt and copper metals, was synthesized via reaction of the corresponding metal sulphate and 2,4,6-tribromophenolate in aqueous media in the presence of N-methyl imidazole and sodium hydroxide. Although various crystallization procedures were applied only cobalt complex was obtained as single crystals. The Co(II) ion has a distorted octahedral enviroment involving two O atoms and two N atoms of the Bis(2,4,6-tribromophenolato)di(N-methyl imidazole) ligand. Powder x-ray diffraction pattern of copper compound was used for cooper complex. For characterizations of complexes carbon, hydrogen and nitrogen elemental analysis, FTIR and UV spectroscopy, DSC thermal analysis and magnetic susceptibility measurements at room temperature were performed. ( 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    A New Amperometric Hydrazine Sensor Based on Prussian Blue/Single-walled Carbon Nanotube Nanocomposites

    ELECTROANALYSIS, Issue 16 2010
    Cong Wang
    Abstract A slow reaction process has been successfully used to synthesize Prussian blue/single-walled carbon nanotubes (PB/SWNTs) nanocomposites. Electrochemical and surface characterization by cyclic voltammetry (CV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed the presence of PB nanocrystallites on SWNTs. PB/SWNTs modified glassy carbon electrode (GCE) exhibits efficient electron transfer ability and high electrochemical response towards hydrazine. The fabricated hydrazine sensor showed a wide linear range of 2.010,6,6.010,3,M with a response time less than 4,s and a detection limit of 0.5,,M. PB/SWNTs modified electrochemical sensors are promising candidates for cost-effective in the hydrazine assays. [source]

    Preparation and Characterization of a Tin Pentacyanonitrosylferrate-Modified Carbon Ceramic Electrode: Application to Electrocatalytic Oxidation and Amperometric Detection of L -Cysteine

    ELECTROANALYSIS, Issue 7 2009
    H. Razmi
    Abstract The sol-gel technique was used to construct tin pentacyanonitrosylferrate (SnPCNF) modified composite carbon ceramic electrode (CCE). This involves two steps: construction of CCE containing metallic Sn powder and then electrochemical creating of SnPCNF on the surface of CCE. The SnPCNF modified CCE (SnPCNFlCCE) was characterized by energy-dispersive X-ray (EDX), FTIR and cyclic voltammetry (CV) techniques. The SnPCNF film showed electrocatalytic activity toward the oxidation of L -cysteine. A linear calibration plot was obtained over the L -cysteine concentration range 1,51,,M using chronoamperometry. L -cysteine was determined amperometrically at the surface of this modified electrode. The detection limit (for a signal to noise of 3) and sensitivity were found to be 0.62,,M and 126,,A/mM, respectively. [source]

    Electrochemical Study of Anionic Ferrocene Derivatives Intercalated in Layered Double Hydroxides: Application to Glucose Amperometric Biosensors

    ELECTROANALYSIS, Issue 3-5 2009
    Christine Mousty
    Abstract Layered double hydroxides (Zn2Cr(OH)6X,nH2O LDH) containing (3-sulfopropyl)ferrocene-carboxylate (FcPSO3) and 1,1,-bis(3-sulfopropyl)ferrocene-carboxylate (Fc(PSO3)2) as interlayer anions (X) have been prepared by the co-precipitation method and characterized by PXRD, FTIR, SEM and XPS. The electrochemical behavior of these hybrid materials has been evaluated by cyclic voltammetry. A new amperometric biosensor based on the immobilization of glucose oxidase in ZnCr-FcPSO3 hybrid material was presented, the intercalated anions playing the role of mediators that shuttle electrons between the FAD centers in the enzyme and the electrode surface. The performance of the resulting biosensor for glucose determination under anaerobic conditions was evaluated by chronoamperometry at 0.5,V. The sensitivity (65,mA M,1 cm,2) determined in the concentration range 10,25,,M is higher than sensitivities reported for other glucose biosensors based on LDH host matrices. [source]

    Preparation, Electrochemistry, and Electrocatalytic Activity of Lead Pentacyanonitrosylferrate Film Immobilized on Carbon Ceramic Electrode

    ELECTROANALYSIS, Issue 21 2008
    H. Razmi
    Abstract Lead pentacyanonitrosylferrate (PbPCNF), a new Prussian blue analog, was immobilized on the surface of a carbon ceramic electrode (CCE) prepared by sol-gel method. The immobilization process consists of adding a certain amount of metallic lead to the electrode matrix before gelation, and chemical derivatization of Pb on the electrode surface to a PbPCNF solid film by immersing the electrode in a solution of sodium pentacyanonitrosylferrate (PCNF). The composition of the synthesized PbPCNF was characterized by FTIR, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) techniques. The resulting modified electrode showed electroactivity at two redox centers. The electrochemical behavior of the PbPCNF modified carbon ceramic electrode (PbPCNF|CCE) was studied by cyclic voltammetry. Under optimized conditions the peak-to-peak separation is only 39,mV, indicative of a surface reaction. Ion effects of the supporting electrolyte suggest that cations have a considerable effect on the electrochemical behavior of the modified electrode. The transfer coefficient (,) and the charge transfer rate constant at the modifying film|electrode interface (ks) were calculated. The electrocatalytic activity of the modified electrode toward the electro-reduction of peroxodisulfate was studied in details. [source]

    Trace metal distribution in soluble organic matter from municipal solid waste compost determined by size-exclusion chromatography

    Arno Kaschl
    Abstract Municipal solid waste (MSW) composts carry high amounts of trace metals and organic complexing agents that may influence metal bioavailability and mobility after application to soils. In order to assess the degree of organic complexation of trace metals in the solution phase of MSW compost and the relevance of organic ligand type, size exclusion chromatography (SEC) was applied to compost-extracted organic ligands. Adjustment of the elution conditions minimized the interaction with the gel matrix for compost humic substances and dissolved organic matter (DOM) fractions. The SEC was then used to separate the aqueous compost extract into samples with distinct differences in chemical constituents. The highest quantities of Cu, Zn, Ni, Mn, and Cd were found to coelute with the main peak of the SEC elution curve, which, as observed by Fourier-transformed infrared (FTIR) spectroscopy, also had the highest density of carboxyl groups. The ratio of aromatic to aliphatic structures was higher for eluates with low retention times, and cations such as Al, Cr, and Fe were preferably associated with these larger organic molecules. All trace metals in the compost solution phase were bound mostly to DOM rather than forming inorganic complexes. [source]

    Synthesis and Characterisation of a New Cu(O2CNAllyl2)2 Carbamato Complex and an Unusual Polymeric CuI Complex [CuI4Cl4(NHAllyl2)4]n: New Insights into Metal Carbamato Chemistry

    Alberto Albinati
    Abstract Transition-metal N,N -dialkylcarbamato complexes represent an interesting class of compounds that can be conveniently used as precursors for the controlled formation of inorganic compounds, typically oxides. They can also be used as convenient precursors for chemical grafting of metal oxides on oxide surfaces as well as for the synthesis of inorganic,organic hybrid materials. In this last case, the presence of double bonds on the complex would enable its covalent embedding into a polymer matrix through reaction with suitable monomers. To this aim, we addressed the synthesis of an allyl-functionalised copper carbamato complex. During the synthesis of the N,N -diallylcarbamato complex Cu(O2CNAllyl2)2 (Cu1), the formation of the crystalline and unusual polymeric CuI complex [CuI4Cl4(NHAllyl2)4]n (Cu2) was observed. The new compound was characterised by X-ray single crystal diffraction and FTIR, 1H and 13C NMR spectroscopic analysis. In an attempt to investigate the redox mechanism and the equilibria leading to the formation of the observed unusual CuI polymeric complex, gas chromatography coupled with mass spectrometry (GC,MS) experiments were carried out, which allowed us to identify 3,4-dimethylpyrrole as the oxidation product of the reaction, leading to the reduction of CuII to CuI.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

    Cyanoimide-Bridged, Bi- and Trinuclear, Heterometallic Complexes with an NCN,Mo,NCN Phosphinic Core

    Snia M. P. R. M. Cunha
    Abstract The heterometallic dinuclear complexes of the types trans -[Mo(NCN)(dppe)2(,-NCN)M] [M = WCl4(PPh3), ReOCl3(PPh3) or mer -ReCl(N2)(PMePh2)3; dppe = Ph2PCH2CH2PPh2] and [Mo(NCN)(dppe)2(,-NCN)M][BF4]Br [M = trans -Fe(NCC6H4NO2 -4)(depe)2; depe = Et2PCH2CH2PEt2] and the trinuclear ones [Mo(dppe)2{(,-NCN)M}2] [M = VCl3(thf) or PtCl2(PEt3)] were prepared by reaction of the bis(cyanoimido)molybdenum complex trans -[Mo(NCN)2(dppe)2] with the corresponding transition-metal Lewis acid (M) precursors, particularly [VCl3(thf)3], [WCl4(PPh3)2], [ReOCl3(PPh3)2], trans -[ReCl(N2)(PMePh2)4], trans -[FeBr(NCC6H4NO2 -4)(depe)2][BF4] and [Pt2Cl4(PEt3)2]. These adducts were characterized by FTIR, 1H, 13C and 31P{1H} NMR spectroscopy, mass spectrometry and cyclic voltammetry. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

    Mechanistic Insights into Acetophenone Transfer Hydrogenation Catalyzed by Half-Sandwich Ruthenium(II) Complexes Containing 2-(Diphenylphosphanyl)aniline , A Combined Experimental and Theoretical Study

    Alessia Bacchi
    Abstract Several new half-sandwich ruthenium(II) complexes containing 2-(diphenyphosphanyl)aniline (PNH2) of formula {Ru[(,2P,N)PNH2](p -cymene)Cl}Y [Y = Cl (1a), PF6 (1b), BF4 (1c), BPh4 (1d), TfO (1e)] were synthesized and fully characterized both in solution (1H NMR and 31P{1H} NMR spectroscopy) and in the solid state (FTIR, X-ray analysis on single crystal). Complexes 1a and 1b are active precatalysts in the hydrogen transfer reaction of acetophenone, leading to tof values up to 4440 h,1. In comparison, the {Ru[(,2P,N)PNMe2](p -cymene)Cl}Cl complex leads to a tof value of 100 h,1 under the same catalytic conditions. The mechanism through which the precatalysts operate was deeply explored by high-resolution MS (ESI) and DFT/PCM studies. The results reveal that the complexes containing PNH2 operate through a bifunctional mechanism analogous to that proposed for diamines and amino alcohol ligands. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

    IR Laser-Induced Carbothermal Reduction of Silica

    Markta Urbanov
    Abstract Pulsed IR-laser irradiation of silica in the presence of gaseous hydrocarbons (benzene or ethyne) results in carbothermal reduction of silica by hydrocarbon decomposition products and allows deposition of amorphous solids which were analyzed by FTIR, Raman, X-ray photoelectron and Auger spectra and by electron microscopy and revealed as nanosized carbon,silicon oxycarbide composites containing crystalline silica domains. The reported IR laser-induced process is the first approach to deposition of nanosized carbon,silicon oxycarbide composites. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

    Synthesis of para -Amino Benzoic Acid,TiO2 Hybrid Nanostructures of Controlled Functionality by an Aqueous One-Step Process

    Raed Rahal
    Abstract In situ amino acid surface-modified TiO2 nanoparticle syntheses were performed by a simple one-pot hydrolysis of heteroleptic titanium alkoxide [Ti(OiPr)3(O2CC6H4NH2)]m in water with NnBu4Br. This process allowed precise control of the surface grafting rate by varying the amount of precursors and provided highly functionalized nanomaterials. Their compositions and microstructures were determined by C, H and N elemental analyses, TGA-MS, 13C CP-MAS NMR, XRD, TEM, BET, Raleigh diffusion, FTIR, Raman, XPS and UV/Vis experiments. The results indicated that (i) the aggregation rate increased with an increase in the loading of the organic substrate and (ii) the amino acid is chemisorbed as a carboxylate group onto the TiO2 nanoparticles, which leads to a strong interaction between the amino acid and the TiO2 nanoparticle and good stability of these hybrids. Applications of low-aggregated nanomaterials were demonstrated as efficient protection additive against UVA + UVB radiations.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

    Pyridine Carboxylate Complexes of MoII as Active Catalysts in Homogeneous and Heterogeneous Polymerization

    Maria Vasconcellos-Dias
    Abstract New lamellar materials intercalated with molybdenum(II) complexes with potential catalytic properties were prepared by a stepwise procedure. The lamellar material was first calcined at 823 K for four hours to eliminate all the carbonate ions; the layered structure was reconstructed after treatment with a solution of either pycH (pyridine-2-carboxylic acid) or pydcH2 (pyridine-2,6-dicarboxylic acid) in a KOH solution of dmf at 343 K. Impregnation with a solution of the organometallic precursor [Mo(CO)3I2(NCCH3)2] led to substitution of the nitrile groups by two pyridine ligands. All the materials were characterized by powder X-ray diffraction, FTIR, and 13C CP MAS and 27Al MAS solid-state NMR spectroscopy. Similar MoII complexes were also prepared by using pycH or pydcH2 and characterized by elemental analysis as well as FTIR and 1H and 13C solution NMR spectroscopy. These new materials and the complexes of pyc or pydc ligands containing 4.54 wt.-% and 6.33 wt.-% of Mo respectively, catalyze the ring-opening-metathesis polymerization of norbornene and the polymerization of styrene at 333 K, their performance increasing upon the addition of methylalumoxane (MAO) as cocatalyst.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    A Trinuclear Aqua Cyano-Bridged Ruthenium Complex [{(,5 -C5H5)(PPh3)2Ru(,-CN)}2RuCl2(PPh3)(H2O)]PF6: Synthesis, Characterization and Crystal Structure

    Viatcheslav Vertlib
    Abstract The organometallic trinuclear aqua cyano-bridged complex [{(,5 -C5H5)(PPh3)2Ru(,-CN)}2RuCl2(PPh3)(H2O)]PF6 (1), in which the fragment [RuCl2(PPh3)(H2O)] acts as a bridge and an acceptor group between the two terminal cyclopentadienyl ruthenium cyano moieties, was isolated in moderate yield from the reaction of [(,5 -C5H5)(PPh3)2RuCN] with [RuCl2(PPh3)3] in THF. To the best of our knowledge, compound 1 is one of the few examples of a trinuclear array of ruthenium fragments bridged by the nitrogen atom of the,C,N, group (Ru,C,N,Ru,,N,C,Ru) with a Ru-coordinated water molecule. The new aqua complex was structurally characterized by FTIR, 1H, 13C, and 31P NMR spectroscopy, mass spectrometry, elemental analysis, single-crystal X-ray diffraction, and cyclic voltammetry. The title complex crystallizes in a triclinic unit cell a = 17.3477(6) , b = 17.8551(5) , c = 18.2460(7) , , = 95.693(2), , = 111.648(2), and , = 97.839(2) in the space group P with Z = 2.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    Highly Organosoluble Metal-Free Phthalocyanines and Metallophthalocyanines: Synthesis and Characterization

    Ahmet Bilgin
    Abstract The syntheses and characterization of metal-free and metal-containing (Zn and Ni) derivatives of a symmetrically octa-substituted phthalocyanine derived from 4,5:12,13-bis(4,- tert -butylbenzo)-8,9-(4,,5,-dicyanobenzo)-6,11-ditosyl-6,11-diaza-2,15-dithiacyclohexadeca-4,8,12-triene and CuPc from 4,5:12,13-bis(4,- tert -butylbenzo)-8,9-(4,,5,-dibromobenzo)-6,11-ditosyl-6,11-diaza-2,15-dithiacyclohexadeca-4,8,12-triene were carried out. Pentanuclear silver(I) and palladium(II) complexes have also been prepared from nickel(II) phthalocyaninate derivatives. The prepared phthalocyanines were semiconducting materials in the range of 10,5 to10,10 S,cm,1 in vacuo and under atmospheric pressure. The extraction abilities of NiPc and detosylated phthalocyanines were evaluated in chloroform/water by using several heavy-metal picrates such as Ag+, Cd2+, Cu2+, Hg2+, Pb2+, Pd2+, and Zn2+. The extraction affinities of NiPc and detosylated phthalocyanines for Ag+ were found to be the highest in solvent extraction experiments. The new compounds were characterized by using elemental analysis, UV/Vis, FTIR, NMR, MS spectroscopic data and DTA/TG. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    Thermal Behavior of Tetrahydropyran-Intercalated VOPO4: Structural and Dynamics Study

    Klra Melnov
    Abstract The thermal behavior of tetrahydropyran-(THP-)intercalated VOPO4 was probed by an extensive combination of experimental methods (XRD, DSC, FTIR, solid-state NMR) and quantum chemical calculations. Two temperature-induced transitions were detected and all polymorphs exhibit a high degree of molecular order and tight packing of THP in VOPO4. The first reversible thermal transition at around 100 C was attributed to boat/chair conformation changes of the THP molecules. Most probably, a low-temperature boat conformation of the guest molecules present in the interlayer space of VOPO4 changes to a high-temperature chair conformation. This rearrangement of the THP molecules was confirmed by variable-temperature 13C CP/MAS NMR spectroscopy. Quantum chemical calculations using a B3LYP functional and 6-31G(d) basis set also support this idea. The second change at around 140 C is probably caused by a weakening of the donor,acceptor bond between the oxygen molecule of THP and the vanadium atom of the host and the formation of a disorder in packing of the THP molecules. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    Crystal Structure, Solid-State NMR Spectroscopic and Photoluminescence Studies of Organic-Inorganic Hybrid Materials (HL)6[Ge6(OH)6(hedp)6]2(L)nH2O, L = hqn or phen,

    Lus Mafra
    Abstract Two germanium,hedp4, solids with heteroaromatic amines 8-hydroxyquinoline (hqn) and 1,10-phenanthroline (phen), (HL)6[Ge6(OH)6(hedp)6]2(L)nH2O (L = hqn or phen), in I and II respectively, have been prepared and characterised by single-crystal XRD, thermogravimetry, FTIR and UV/Vis spectroscopy. The complex hydrogen-bond networks, particularly in compound I, have been studied by advanced high-resolution solid-state NMR spectroscopy that combines homonuclear recoupling techniques (two-dimensional 1H- 1H DQF and 1H- 1H RFDR MAS NMR) and combined rotation and multiple-pulse spectroscopy (two-dimensional 1H- 1H FS-LG, 1H- 31P FS-LG). The fine details of the crystal structure of I have been elucidated, mainly those involving the ,,, stacking of 8-hydroxyquinoline and the relative orientation of adjacent such molecules. Compound II exhibits an emission from the lowest triplet-state energy (,,,* 0-phonon transition) of the aromatic rings at 320 nm (31250 cm,1) from 14 K to room temperature. In contrast, the triplet emission of I at 530 nm (18868 cm,1) is only detected at low temperature, because of thermally activated non-radiative mechanisms. The emission spectra of I and II display a lower-energy component with a larger life time, which results from the formation of an excimer state that originated from the ,,, phenanthroline and hydroxyquinoline interactions, respectively. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]