Synthesis and characterization of a new copper(II) complex with nadolol, an aminoalcoholic beta-blocker. Crystal structure of Na[Cu(nadololate)(CO(3))] center dot H(2)O

This work reports the synthesis and characterization of a new copper complex with nadolol, a beta-blocker aminoalcohol. The stoichiometry found was Na[Cu(nadololate)(CO(3))] center dot H(2)O. Electronic and vibrational spectroscopy analysis was performed, and the crystal structure of Na[Cu(nadololate)-(CO(3))] center dot H(2)O was determined by X-ray diffraction.

Preparation and characterization of new glassy system As2P2S8-Ga2S3

Glasses having the composition (100 - x)As2P2S8-xGa(2)S(3) with x ranging from 0 to 50% were investigated to determine the compositional effect on properties and local structure. The glass transition temperature (T-g) and the stability parameter against crystallization (T-x - T-g) increased with the addition of Ga2S3. The structure of these glasses was probed by Raman scattering, Fourier transform infrared (FT-IR) and P-31 nuclear magnetic resonance. On the basis of the observed vibrations and the strength of the P-31-P-31 homonuclear magnetic dipolar coupling, two scenarios can be proposed for the structural evolution induced by the addition of Ga2S3. For x <= 20% we may have the formation of GaS4E- groups (E = nonbonding electron), and for x >= 30% we have depolymerization of the As2P2S8 units and the formation of a network of GaPS4 units with each PS4/2 unit (Q(4)) species carrying a single positive formal charge.

Isolation, chemical composition and anti-inflammatory activity of Copaifera langsdorffii desf. fruit peels essential oil according to successive hydrodistillations

In this study, the isolation and characterization of chemical composition of C. langsdorffii (copaiba) fruit peel volatile oil from Alfenas - MG was carried out according to successive hydrodistillations, likewise the anti-inflammatory activity was evaluated by rat paw edema model. The chemical composition of the oil was determined by GC-MS analysis. The major components were (E)-caryophyllene, germacrene B, 1,5-epoxysalvial-4(14)-ene, caryophyllene oxide and isospathulenol. The inflammatory process was inhibited in 39 +/- 6 % (p<0.05, Tukey-Kramer) by one sample of essential oil. The C. langsdorffii fruit peel is a rich source of essential oil (3.8% w/w), and due to potential industrial interest of its components this ecotype presents feasible crop seeking productivity and it could constitutes in a good alternative to the sustainable use of this specie.

Digestive physiology and characterization of digestive cathepsin L-like proteinase from the sugarcane weevil Sphenophorus levis

Sugarcane is an important crop that has recently become subject to attacks from the weevil Sphenophorus levis, which is not efficiently controlled with chemical insecticides. This demands the development of new control devices for which digestive physiology data are needed. In the present study, ion-exchange chromatography of S. levis whole midgut homogenates, together with enzyme assays with natural and synthetic substrates and specific inhibitors, demonstrated that a cysteine proteinase is a major proteinase, trypsin is a minor one and chymotrypsin is probably negligible. Amylase, maltase and the cysteine proteinase occur in the gut contents and decrease throughout the midgut; trypsin is constant in the entire midgut, whereas a membrane-bound aminopeptidase predominates in the posterior midgut. The cysteine proteinase was purified to homogeneity through ion-exchange chromatography. The purified enzyme had a mass of 37 kDa and was able to hydrolyze Z-Phe-Arg-MCA and Z-Leu-Arg-MCA with k(cat)/K(m) values of 20.0 +/- 1.1 mu M(-1) s(-1) and 30.0 +/- 0.5 mu M(-1) s(-1), respectively, but not Z-Arg-Arg-MCA. The combined results suggest that protein digestion starts in the anterior midgut under the action of a cathepsin L-like proteinase and ends on the surface of posterior midgut cells. All starch digestion takes place in anterior midgut. These data will be instrumental to developing S. levis-resistant sugarcane. (C) 2011 Elsevier Ltd. All rights reserved.

Detection and Characterization of Cholesterol-Oxidized Products Using HPLC Coupled to Dopant Assisted Atmospheric Pressure Photoionization Tandem Mass Spectrometry

Oxidation of cholesterol (Ch) by a variety of reactive oxygen species gives rise mainly to hydroperoxides and aldehydes. Despite the growing interest in Ch-oxidized products, the detection and characterization of these products is still a matter of concern. In this work, the main Ch-oxidized products, namely, 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide (7 alpha-OOH), 3 beta-5 alpha-cholest-6-ene-5-hydroperoxide (5 alpha-OOH), 3 beta-hydroxycholest-4-ene-6 alpha-hydroperoxide (6 alpha-OOH), 3 beta-hydroxycholest-4-ene-6 beta-hydroperoxide (6 beta-OOH), and 3 beta-hydroxy-5 beta-hydroxy-B-norcholestane-6 beta-carboxaldehyde (ChAld), were detected in the same analysis using high-performance liquid chromatography (HPLC) coupled to dopant assisted atmospheric pressure photoionization tandem mass spectrometry. The use of selected reaction monitoring mode (SRM) allowed a sensitive detection of each oxidized product, while the enhanced product ion mode (EPI) helped to improve the confidence of the analyses. Isotopic labeling experiments enabled one to elucidate mechanistic features during fragmentation processes. The characteristic fragmentation pattern of Ch-oxidized products is the consecutive loss of 1120 molecules, yielding cationic fragments at m/z 401, 383, and 365. Homolytic scissions of the peroxide bond are also seen. With (18)O-labeling approach, it was possible to establish a fragmentation order for each isomer. The SRM transitions ratio along with EPI and (18)O-labeled experiments give detailed information about differences for water elimination, allowing a proper discrimination between the isomers:Phis is of special interest considering the emerging role of Ch-oxidized products in the development of diseases.

Characterization of the products of aniline peroxydisulfate oligo/polymerization in media with different pH by resonance Raman spectroscopy at 413.1 and 1064 nm excitation wavelengths

The pH-structure correlation of the products of aniline peroxydisulfate reaction was mainly investigated by resonance Raman spectroscopy. The reactions of aniline and ammonium peroxydisulfate were carried out in aqueous solutions of initial pH ranging from 4.9 to 13.2 and monomer/oxidant molar ratio of 4/1. For an initial pH of 4.9, the spectroscopic techniques showed that the emeraldine salt form of polyaniline (PANI-ES) is the main product, corroborating that the usual head-to-tail coupling mechanism is taking place. The resonance Raman spectra at 1064 nm exciting wavelength were useful to detect the emeraldine salt as a minor product for reactions at an initial pH of 5.3-11.5. The Raman spectra of the main product of the reaction at initial pH of 13.2 excited at 1064 and 413.1 nm showed new spectral features consistent with 1,4-Michael-type adducts of aniline monomers and 1,4-benzoquinone-monoimine unit. These compounds and their products of hydrolysis/oxidation are the predominant species for the reaction media of initial pH from 5.3 to 13.2. In order to get PANI with different nanoscale morphologies, a pH value of more than 0 or 1 was used in the aniline polymerization. The spectroscopic data obtained in this work reveal that head-to-tail coupling does not occur when aniline reacts at media pH higher than about 5. It is suggested that chemical structures of the products of aniline oxidation by an unusual mechanism are the driving force for the development of assorted morphologies. Copyright (C) 2011 John Wiley & Sons, Ltd.

Optical and electrical characterization of samaria-doped ceria

Ce(0.8)SM(0.2)O(1.9) and CeO(2) nanomaterials were prepared by a solution technique to produce an ultrafine particulate material with high sinterability. In this work, the structural characteristics, the photoluminescent behavior and the ionic conductivity of the synthesized materials are focused. The thermally decomposed material consists of less than 10 nm in diameter nanoparticles. The Raman spectrum of pure CeO(2) consists of a single triple degenerate F(2g) model characteristic of the fluorite-like structure. The full width at half maximum of this band decreases linearly with increasing calcination temperature. The photoluminescence spectra show a broadened emission band assigned to the ligand-to-metal charge-transfer states O -> Ce(4+). The emission spectra of the Ce(0.8)Sm(0.2)O(1.9) specimens present narrow bands arising from the 4G(5/2) -> (6)H(J) transitions (J = 5/2, 7/2, 9/2 and 11/2) of Sm(3+) ion due to the efficient energy transfer from the O -> Ce(4+) transitions to the emitter 4G(5/2) level. The ionic conductivity of sintered specimens shows a significant dependence on density. (C) 2009 Elsevier B.V. All rights reserved.

Theoretical Characterization of Hydrogen Polyoxides: HOOH, HOOOH, HOOOOH, and HOOO

We have investigated the polyoxides HOOH, HOOOH, HOOOOH, and HOOO employing the CCSD(T) methodology, and the correlation consistent basis sets. For all molecules, we have computed fundamental vibrational frequencies, structural parameters, rotational constants, and rotation-vibration corrections. For HOOOH, we have obtained a good agreement between our results and microwave and infrared spectra measurements, although for the symmetric OO stretch some important differences were found. Heats of formation were computed using atomization energies, and our recommendation is as follows: Delta H degrees(f,298)(HOOOH) = -21.50 kcal/mol and Delta H degrees(f,298)(HOOOOH) = -10.61 kcal/mol. In the case of HOOO, to estimate the heat of formation, we have constructed three isodesmic reactions to cancel high order correlation effects. The results obtained confirmed that the latter effects are very important for HOOO. The new Delta H degrees(f,298)(HOOO) obtained is 5.5 kcal/mol. We have also calculated the zero-point energies of DO and DOOO to correct the experimental lower limit determined for the Delta H degrees(f,298)(HOOO). The Delta(Delta ZPE) decreases the binding energy of HOOO by 0.56 kcal/mol. Employing the latter value, the new experimental lower limit for Delta H degrees(f,298)(HOOO) is 3.07 kcal/mol, just 2.4 kcal/mol lower than our determination. We expect that the fundamental vibrational frequencies and rotational constants determined for HOOOOH and DOOOOD contribute to its identification in the gas phase. The vibrational spectrum of HOOOOH shows some overlapping with that of HOOOH thus indicating that one may encounter some difficulties in its characterization. We discuss the consequences of the thermochemical properties determined in this work, and suggest that the amount of HOOO present in the atmosphere is smaller than that proposed recently in this journal (J. Phys. Chem A 2007, 111, 4727).

Characterization of anodic silicon oxide films grown in room temperature ionic liquids

The electroformation of silicon oxide was performed in two room temperature ionic liquids (RTIL), 1-butyl-3-methyl-imidazolium bis(trifluoromethane sulfonyl) imide (BMITFSI) and N-n-butyl-N-methylpiperidinium bis(trifluoromethane sulfonyl) imide (BMPTFSI). This phenomenon was studied by electrochemical techniques and it was observed that the oxide growth follows a high-field mechanism. X-ray Photoelectron Spectroscopy experiments have shown that a non-stoichiometric oxide film was formed, related to the low water content present in both RTILs (< 30 ppm). The roughness values obtained by using AFM technique of the silicon surface after etching with HF was 1.5 nm (RMS). The electrochemical impedance spectroscopy at low frequencies range was interpreted as a resistance in parallel with a CPE element, the capacitance obtained was associated with the dielectric nature of the oxide formed and the resistance was interpreted considering the chemical dissolution of the oxide by the presence of the TFSI anion. The CPE element was associated with the surface roughness and the very thin oxide film obtained. (C) 2007 Elsevier Ltd. All rights reserved.

Structural and vibrational characterization of polyaniline nanofibers prepared from interfacial polymerization

This work deals with the structural and vibrational characterization of PANI nanofibers prepared through interfacial polymerization using different concentrations of HCl aqueous solution. The results were compared to those obtained by PANI prepared through the conventional route. X-ray diffraction and small-angle X-ray scattering techniques showed that high concentrations of HCl solutions used in the preparation of the PANI nanofibers reduce their crystallinity. The increase of regions with granular morphology was also observed in the scanning electron microscopy images. The changes in the resonance Raman spectra from 200 to 500 cm(-1), FTIR spectra, and the EPR data of the PANI nanofibers reveal an increase in the torsion angles of C-ring-N-C-ring segments owing the formation of bipolarons in the PANI backbone higher than the PANI samples prepared by conventional route.

Preparation and characterization of the novels terpolymers of poly-{trans-[RuCl(2)(vpy)(4)]-styrene-divinylbenzene} and styrene-divinylbenzene-vinylpiridine impregnated with silver nanoparticles

This paper reports the preparation and characterization of poly-{trans-[RuCl(2)(vpy)(4)]-styrene-divinylbenzene} and styrene-divinylbenzene-vinylpiridine filled with nanosilver. Theses materials were synthesized by non aqueous polymerization through a chemical reaction using benzoyl peroxide as the initiator. The nanosilver was obtained from chemical reduction using NaBH(4) as reducing agent and sodium citrate as stabilizer. The nanometric dimension of nanosilver was monitored by UV-visible and confirmed through TEM. The morphology was characterized by SEM and the thermal properties were done by TGA and DSC. The antimicrobial action of the polymers impregnated with nanosilver was evaluated using both microorganisms, Staphylococcus aureus and Escherichia coli. The antimicrobial activity of the poly-{trans-[RuCl(2)(vpy)(4)]-styrene-divinylbenzene} filled with nanosilver was confirmed by the presence of an inhibition halo of the bacterial growth in seeded culture media, but was not confirmed to the styrene-divinylbenzene-vinylpiridine. The present work suggest that trans - [RuCl(2)(vpy)(4)] complex facilitate the release of silver ion from the media.

The reaction of methyl radical with nitrogen atom on the triplet potential energy surface: A CCSD(T)/CBS characterization

CCSD(T)/cc-pVnZ (n = D, T, Q) calculations followed by extrapolations to the CBS limit are used to characterize stationary states of species participating in the N((4)S) + CH(3) (2A ``) reaction on the triplet PES. A mechanistic model is investigated and reaction rates are computed for every step and the overall reaction. Our best CBS estimate (1.93 x 10(10) cm(3) molecule(1) s(1)) for the overall rate constant leading to the formation of H(2)CN + H compares well with the experimental values (8.5 x 10 (11) and 1.3 x 10(10) cm(3) molecule(1) s(1)), thus reducing significantly the discrepancy of a previous theoretical result (9.1 x 10(12) cm(3) molecule(1) s(1)). (C) 2008 Elsevier B.V. All rights reserved.

Azo-hydrazone tautomerism in protonated aminoazobenzenes: Resonance Raman spectroscopy and quantum-chemical calculations

The protonation effect on the vibrational and electronic spectra of 4-aminoazobenzene and 4-(dimethylamino)azobenzene was investigated by resonance Raman spectroscopy, and the results were discussed on the basis of quantum-chemical calculations. Although this class of molecular systems has been investigated in the past concerning the azo-hydrazone tautomerism, the present work is the first to use CASSCF/CASPT2 calculations to unveil the structure of both tautomers as well the nature of the molecular orbitals involved in chromophoric moieties responsible for the resonance Raman enhancement patterns. More specifically both the resonance Raman and theoretical results show clearly that in the neutral species, the charge transfer transition involves mainly the azo moiety, whereas in the protonated forms there is a great difference, depending on the tautomer. In fact, for the azo tautomer the transition is similar to that observed in the corresponding neutral species, whereas in the hydrazone tautomer such a transition is much more delocalized due to the contribution of the quinoid structure. The characterization of protonated species and the understanding of the tautomerization mechanism are crucial for controlling molecular properties depending on the polarity and pH of the medium.

Electrostatic layer-by-layer deposition and electrochemical characterization of thin films composed of MnO(2) nanoparticles in a room-temperature ionic liquid

Thin films of MnO(2) nanoparticles were grown using the layer-by-layer method with poly (diallyldimetylammonium) as the intercalated layer. The film growth was followed by UV-vis, electrochemical quartz crystal microbalance (EQCM), and atomic force microscopy. Linear growth due to electrostatic immobilization of layers was observed up to 30 bilayers, but electrical connectivity was maintained only for 12 MnO(2)/PPDA bilayers. The electrochemical characterization of this film in 1-butyl-2,3-dimethyl-imidazolium (BMMI) bis(trifluoromethanesulfonyl)imide (TFSI) (BMMITFSI) with and without addition of a lithium salt indicated a higher electrochemical response of the nanostructured electrode in the lithium-containing electrolyte. On the basis of EQCM experiments, it was possible to confirm that the charge compensation process is achieved mainly by the TFSI anion at short times (<2 s) and by BMMI and lithium cations at longer times. The fact that large ions like TFSI and BMMI participate in the electroneutrality is attributed to the redox reaction that occurs at the superficial sites and to the high concentration of these species compared to that of lithium cations.

Spectroscopic Characterization of Oligoaniline Microspheres Obtained by an Aniline-Persulfate Approach

This paper investigates the structure of the pro; ducts obtained from the polymerization of aniline with ammonium persulfate in a citrate/phosphate buffer solution at pH 3 by resonance Raman, NMR, FTIR, and UV-vis-NIR spectroscopies. All the spectroscopic data showed that the major product presented segments that were formed by a 1,4-Michael reaction between aniline and p-benzoquinone monoimine, ruling out the formation of polyazane structure that has been recently proposed. The characterization of samples obtained at different stages of the reaction indicated that, as the reaction progressed, phenazine units were formed and 1,4-Michael-type adducts were hydrolyzed/oxidized to yield benzoquinone. Raman mapping data suggested that phenazine-like segments could be related to the formation of the microspheres morphology.