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Articles de revues sur le sujet « Spectroscopies Uv-Vis »

Auteur : Grafiati
Publié le 4 juin 2021
Mis à jour le 9 février 2022

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1

Görgülü, Güvenç. « Experimental and theoretical study of a novel naphthoquinone Schiff base ». Open Chemistry 16, no 1 (5 novembre 2018) : 1115–21. http://dx.doi.org/10.1515/chem-2018-0121.

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AbstractA novel Schiff base was synthesized and characterized by spectroscopic and theoretical methods. A potentially active agent 4-(2-hydroxy-5-methylphenylimino)naphthalen-1(4H)-one (PINQ) was designed and synthesized. The synthesis was carried out by a condensation reaction of 1-4-naphthoquinone and 2-amino-4-methyl phenol. The spectral and structural properties of the PINQ molecule were investigated by elemental analysis, 1H- and 13C-NMR, FT-IR and Uv-vis spectroscopies. The energetic, atomic, electronic, molecular, vibrational and magnetic data were theoretically obtained using density functional theory (DFT) at B3LYP level with 6-311++G(d,p) basis set. Chemical shifts were calculated using gauge-invariant atomic orbital (GIAO) method. UV-vis spectrum for the title compound was also obtained by time-dependent density functional theory (TD-DFT). The theoretical and experimental results were compared and interpreted. The theoretical data obtained from 1H- and 13C-NMR, FT-IR and Uv-vis spectroscopies were quite compatible with experimental ones.
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Birin, Kirill P., Anna I. Poddubnaya, Elena V. Isanbaeva, Yulia G. Gorbunova et Aslan Yu Tsivadze. « Crown-interlocked lanthanide diphthalocyaninates with switchable panchromatic absorption ». Journal of Porphyrins and Phthalocyanines 21, no 04-06 (avril 2017) : 406–15. http://dx.doi.org/10.1142/s1088424617500353.

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New class of clamshell-type lanthanide (Ce(IV), La(III) and Eu(III)) diphthalocyaninates bearing 24-crown-8 linking fragment are synthesized and characterized by means of NMR, UV-vis spectroscopies and MALDI-TOF mass spectrometry. A strong solvatochromism of the complexes, allowing switching the wide-range panchromatic absorption in polar solvents, is demonstrated by means of UV-vis and NMR spectroscopies and attributed to solvent-induced changing of sandwich conformations. The photodegradation of the obtained complexes was also investigated.
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Maheu, Clément, Luis Cardenas, Eric Puzenat, Pavel Afanasiev et Christophe Geantet. « UPS and UV spectroscopies combined to position the energy levels of TiO2 anatase and rutile nanopowders ». Physical Chemistry Chemical Physics 20, no 40 (2018) : 25629–37. http://dx.doi.org/10.1039/c8cp04614j.

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Loughrey, Jonathan J., Nathan J. Patmore, Amgalanbaatar Baldansuren, Alistair J. Fielding, Eric J. L. McInnes, Michaele J. Hardie, Stephen Sproules et Malcolm A. Halcrow. « Platinum(ii) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene ». Chemical Science 6, no 12 (2015) : 6935–48. http://dx.doi.org/10.1039/c5sc02776d.

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Monico, Letizia, Koen Janssens, Marine Cotte, Aldo Romani, Lorenzo Sorace, Chiara Grazia, Brunetto Giovanni Brunetti et Costanza Miliani. « Synchrotron-based X-ray spectromicroscopy and electron paramagnetic resonance spectroscopy to investigate the redox properties of lead chromate pigments under the effect of visible light ». Journal of Analytical Atomic Spectrometry 30, no 7 (2015) : 1500–1510. http://dx.doi.org/10.1039/c5ja00091b.

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Scintilla, Simone, Claudia Bonfio, Luca Belmonte, Michele Forlin, Daniele Rossetto, Jingwei Li, James A. Cowan et al. « Duplications of an iron–sulphur tripeptide leads to the formation of a protoferredoxin ». Chemical Communications 52, no 92 (2016) : 13456–59. http://dx.doi.org/10.1039/c6cc07912a.

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Flesch, Stefan, Luis I. Domenianni et Peter Vöhringer. « Probing the primary processes of a triazido–cobalt(iii) complex with femtosecond vibrational and electronic spectroscopies. Photochemical selectivity and multi-state reactivity ». Physical Chemistry Chemical Physics 22, no 44 (2020) : 25618–30. http://dx.doi.org/10.1039/d0cp04865h.

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Wang, Runju, Ying Yin, Kui Xu, Lamei Wu, Zhengxi Huang, Hsien-Yi Hsu, Jonathan L. Sessler et Zhan Zhang. « Doubly N-confused phlorin and phlorinone analogue ». Chemical Communications 57, no 22 (2021) : 2772–75. http://dx.doi.org/10.1039/d1cc00216c.

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A doubly N-confused phlorin and phlorinone analogue were synthesized from a β,β′-linked dipyrromethane precursor and characterized by means of NMR and UV-Vis spectroscopies, X-ray crystallography, and electrochemistry.
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Durigon, Daniele Cocco, Marcos Maragno Peterle, Adailton João Bortoluzzi, Ronny Rocha Ribeiro, Antonio Luiz Braga, Rosely Aparecida Peralta et Ademir Neves. « Cu(ii) complexes with tridentate sulfur and selenium ligands : catecholase and hydrolysis activity ». New Journal of Chemistry 44, no 36 (2020) : 15698–707. http://dx.doi.org/10.1039/d0nj02806a.

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Two new copper(ii) mononuclear complexes (CSe and CS) were synthesized and characterized by the following techniques: X-ray crystallography, elemental analysis, IR, EPR and UV-vis spectroscopies, conductimetric analysis and mass spectrometry.
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Habeeb, Moustafa M. « Interaction Site and Proton Transfer Equilibrium in the 4-Aminoantipyrine-Pentachlorophenol Hydrogen–Bonded Adduct ». Journal of Chemical Research 2002, no 6 (juin 2002) : 255–56. http://dx.doi.org/10.3184/030823402103172095.

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The hydrogen-bonding interaction site between 4-aminoantipyrine (4AAP) and pentachlorophenol (PCP) was investigated in the crystalline form using FT-IR and in solution using FT-IR, UV-Vis and 1H,13C NMR spectroscopies.
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Katayama, Akira, Tomohiko Inomata, Tomohiro Ozawa et Hideki Masuda. « Ionic liquid promotes N2 coordination to titanocene(iii) monochloride ». Dalton Transactions 46, no 24 (2017) : 7668–71. http://dx.doi.org/10.1039/c7dt01063j.

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Parente, Juliana E., Luciana G. Naso, Khalil Jori, Carlos A. Franca, Ana Maria da Costa Ferreira, Patricia A. M. Williams et Evelina G. Ferrer. « In vitroexperiments and infrared spectroscopy analysis of acid and alkaline phosphatase inhibition by vanadium complexes ». New Journal of Chemistry 43, no 45 (2019) : 17603–19. http://dx.doi.org/10.1039/c9nj01638d.

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Two oxidovanadium complexes with 4-aminobenzoic acid and/or the peroxo anion as ligands were synthesized and characterized by elemental analysis, conductivity measurements, TGA/DTA,1H NMR, EPR, FTIR, and UV/vis spectroscopies.
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13

Hassan Omar, Omar, Marta Falcone, Alessandra Operamolla et Gianluigi Albano. « Impact of chirality on the aggregation modes of l-phenylalanine- and d-glucose-decorated phenylene–thiophene oligomers ». New Journal of Chemistry 45, no 27 (2021) : 12016–23. http://dx.doi.org/10.1039/d1nj02125g.

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Three l-phenylalanine- or d-glucose-decorated phenylene–thiophene oligomers have been studied using UV-Vis and ECD spectroscopies in different conditions of solution aggregation and thin films, investigating the impact of chirality on their aggregation modes.
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Xia, Guomin, Yang Liu, Benfei Ye, Jianqi Sun et Hongming Wang. « A squaraine-based colorimetric and F− dependent chemosensor for recyclable CO2 gas detection : highly sensitive off–on–off response ». Chemical Communications 51, no 72 (2015) : 13802–5. http://dx.doi.org/10.1039/c5cc04755b.

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An unsymmetrical squaraine-based chemosensor SH2 has been synthesized, and its sensing behavior towards CO2 gas was described in detail by UV-vis and 1H NMR spectroscopies in DMSO.
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15

Zhang, Ying, Dongdong Qi, Jianzhuang Jiang et Xuan Sun. « A novel photochromic and electrochromic europium tetraazaporphyrinato and phthalocyaninato heteroleptic double-decker for information storage ». Journal of Porphyrins and Phthalocyanines 13, no 12 (décembre 2009) : 1197–205. http://dx.doi.org/10.1142/s1088424609001558.

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A novel tetraazaporphyrinato and phthalocyaninato mixed heteroleptic double-decker sandwich rare-earth compound with photochromic and electrochromic features has been facilely synthesized by one-pot reaction using Eu(acac)3 ·n H2O , metal-free phthalocyanine H2Pc′ ( Pc′ = 2,3,9,10,16,17,23,24-octakis(decyloxy)phthalocyanine), and the photochromic precursor 1,2-dicyano-l,2-bis(2,3,5-trimethyl-3-thienyl)ethane as starting materials. The compound was well characterized by elemental analysis and various spectroscopic methods including UV-vis, IR, 1H NMR, and mass spectroscopies. The electrochemical behavior of this compound was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, which showed up to three one-electron oxidation and four one-electron reduction processes, demonstrating an electro-active compound for high-density information storage. The photochromic performance of the compound was detected by electronic absorption spectra, suggesting the compound to be a good candidate for non-destructive readout by means of UV-vis spectroscopy.
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Sahu, Sumit Ranjan, Mayanglambam Manolata Devi, Puspal Mukherjee, Pratik Sen et Krishanu Biswas. « Optical Property Characterization of Novel Graphene-X (X=Ag, Au and Cu) Nanoparticle Hybrids ». Journal of Nanomaterials 2013 (2013) : 1–9. http://dx.doi.org/10.1155/2013/232409.

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The present investigation reports new results on optical properties of graphene-metal nanocomposites. These composites were prepared by a solution-based chemical approach. Graphene has been prepared by thermal reduction of graphene oxide (GO) at 90°C by hydrazine hydrate in an ammoniacal medium. This ammoniacal solution acts as a solvent as well as a basic medium where agglomeration of graphene can be prevented. This graphene solution has further been used for functionalization with Ag, Au, and Cu nanoparticles (NPs). The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Vis spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to reveal the nature and type of interaction of metal nanoparticles with graphene. The results indicate distinct shift of graphene bands both in Raman and UV-Vis spectroscopies due to the presence of the metal nanoparticles. Raman spectroscopic analysis indicates blue shift of D and G bands in Raman spectra of graphene due to the presence of metal nanoparticles except for the G band of Cu-G, which undergoes red shift, reflecting the charge transfer interaction between graphene sheets and metal nanoparticles. UV-Vis spectroscopic analysis also indicates blue shift of graphene absorption peak in the hybrids. The plasmon peak position undergoes blue shift in Ag-G, whereas red shift is observed in Au-G and Cu-G.
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Granados-Oliveros, Gilma, Fernando Martínez Ortega, Edgar Páez-Mozo, Corinne Ferronato et Jean-Marc Chovelon. « Photoactivity of Metal-Phenylporphyrins Adsorbed on TiO2 Under Visible Light Radiation : Influence of Central Metal ». Open Materials Science Journal 4, no 1 (27 février 2010) : 15–22. http://dx.doi.org/10.2174/1874088x01004010015.

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A set of Co, Cu, Zn and metal-free phenylporphyrins were studied by spectroscopic (UV-vis, FTIR) and quantum-chemical methods. The Q and Soret bands were identified in the UV-vis spectra of solid samples. In all the complexes the frontier molecular orbitals (OMs) predict that the electronic processes sites are localized on the ligand rather than in the metal atom. Metal ion has a largely influence on energy of OMs. The calculated values of electronic transitions between the OMs are in good agreement with the UV-vis data. Phenyl porphyrins were attached onto TiO2 to be evaluated as photocatalysts, under visible light irradiation. The interaction of porphyrins with TiO2 surface was investigated using UV-vis and FT-IR spectroscopies and it was found that the dyes were adsorbed to the semiconductor by carboxylate groups. Degradation of luminol and photooxidation of terephthalic acid to 2-hydroxyterephthalic acid (TAOH) were employed as probe reactions. Luminol was degraded from 20 – 60% in presence of O2. In the same way, the formation of TAOH values of comprises between 0.12 – 0.17 mM, in presence of H2O2 and O2 was obtained. It was found that superoxide anion radicals (O2•_) are primarily formed and they are the precursor for the hydroxyl radicals (•OH) production when H2O2 is added to suspension. Influence of metal on photoactivity was analyzed, specifically, in terms of: the nature of metal (number of d electrons), photophysical properties and energies of frontier molecular orbitals (OMs). Apparently, energy of OMs is an important factor which could affect photoactivity of sensitizers attached on TiO2
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Ju, Woo-Sung, Masaya Matsuoka et Masakazu Anpo. « Incorporation of silver (I) ions within zeolite cavities and their photocatalytic reactivity for the decomposition ofN2OintoN2andO2 ». International Journal of Photoenergy 5, no 1 (2003) : 17–19. http://dx.doi.org/10.1155/s1110662x03000060.

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Ag+/ZSM-5 catalysts were prepared by an ion-exchange method. UV-irradiation of theAg+/ZSM-5 catalysts in the presence ofN2Oled to the photocatalytic decomposition ofN2OintoN2andO2at 298 K. Investigations of the effective wavelength of the irradiated UV-light for the reaction as well as the in-situ characterization of the catalysts by means of UV-Vis, photoluminescence and FT-IR spectroscopies revealed that the photoexcitation of theAg+−N2Ocomplexes formed between gaseousN2Oand the isolatedAg+ions exchanged within the zeolite cavities plays a significant role in the reaction.
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Sionkowska, Alina, Marcin Wisniewski, Joanna Skopinska et Diego Mantovani. « Effects of solar radiation on collagen-based biomaterials ». International Journal of Photoenergy 2006 (2006) : 1–6. http://dx.doi.org/10.1155/ijp/2006/29196.

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The effect of solar radiation on collagen and collagen/synthetic polymer blends in the form of thin films and solutions has been studied by UV-VIS and FTIR spectroscopies. Films and solutions of collagen blended with poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) were irradiated by solar light. It was found that UV-VIS spectra, which characterize collagen, collagen/PVA, and collagen/PVP blended films, were significantly altered by solar radiation. FTIR spectra of collagen, collagen/PVA, and collagen/PVP films showed that after solar irradiation, the positions of Amide A bands were shifted to lower wavenumbers. There was not any significant alteration in the position of Amide I and Amide II bands of collagen and its blends after solar radiation. The effect of solar UV radiation in comparison with artificial UV radiation has been discussed.
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Stanculescu, Ioana, Cristina Mandravel, François Delattre, David Landy, Patrice Woisel et Gheorghe Surpateanu. « Cation binding characteristics of tetrandrine studied by UV-Vis absorption and fluorescence spectroscopies ». Journal of Photochemistry and Photobiology A : Chemistry 161, no 1 (novembre 2003) : 79–85. http://dx.doi.org/10.1016/s1010-6030(03)00268-5.

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Wang, T. T., X. Y. Zhang, M. L. Sun, X. Du, M. Guan, H. B. Peng et T. S. Wang. « γ-Irradiation effects in borosilicate glass studied by EPR and UV–Vis spectroscopies ». Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms 464 (février 2020) : 106–10. http://dx.doi.org/10.1016/j.nimb.2019.12.007.

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Zikeli, Florian, Vittorio Vinciguerra, Anna Rita Taddei, Alessandro D’Annibale, Manuela Romagnoli et Giuseppe Scarascia Mugnozza. « Isolation and characterization of lignin from beech wood and chestnut sawdust for the preparation of lignin nanoparticles (LNPs) from wood industry side-streams ». Holzforschung 72, no 11 (27 novembre 2018) : 961–72. http://dx.doi.org/10.1515/hf-2017-0208.

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AbstractLignin was isolated through mild acidolysis from local wood sources such as beech wood and chestnut wood sawdust, a high-volume side product of wood industries. The lignin fractions were characterized by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis) and two-dimensional heteronuclear single-quantum correlation nuclear magnetic resonance (2D HSQC NMR) spectroscopies and size exclusion chromatography (SEC). The Klason lignin (KL) content and polysaccharide composition were determined using traditional methods. Lignin nanoparticles (LNPs) were preparedviaa non-solvent method involving dialysis and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and FTIR and UV-VIS spectroscopies. Semi-porous as well as hollow nanoparticles endowed with a spherical shape were observed. The large majority of the LNPs exhibited an average particle diameter of 90–120 nm. Dynamic light scattering (DLS) analysis showed that both distribution and frequency of dimensional classes of LNPs are clearly affected by the lignin solvent system, i.e. solvent selection governs the size distribution of LNPs.
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VIJAYALAKSHMI, R., et V. RAJENDRAN. « IMPACT OF SURFACTANTS ON PHYSICAL PROPERTIES OF BaTiO3 NANOPARTICLES ». International Journal of Nanoscience 12, no 01 (février 2013) : 1350003. http://dx.doi.org/10.1142/s0219581x13500038.

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Nanocrystalline BaTiO3 particles of about 20–35 nm have been successfully synthesized by using cationic, anionic and nonionic surfactants such as cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly ethylene glycol (PEG) via hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The average particle size, measured by powder X-ray diffraction was determined to be 20–35 nm and was confirmed by transmission electron microscopy. Spherical-like morphologies were obtained by scanning electron microscopy (SEM) analysis. Optical properties of products were investigated by ultraviolet-visible (UV-Vis) absorption and PL spectroscopies.
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DEY, S. C., et S. S. NATH. « SIZE-DEPENDENT PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE OF COLLOIDAL CdSe QUANTUM DOTS ». International Journal of Nanoscience 12, no 02 (avril 2013) : 1350013. http://dx.doi.org/10.1142/s0219581x13500130.

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Here we adopt a convenient green chemical route for synthesis of CdSe quantum dots, their characterization by UV/Vis absorption spectroscopy, X-ray diffraction study and transmission electron microscopy. We carry out photoluminescence and electroluminescence spectroscopy to investigate the variation in electro-optical property with size. By UV/Vis spectroscopy, blue shift is revealed and bandgap is also calculated. X-ray diffraction spectrum reveals cubic structure and transmission electron micrographs show quantum dots of different size distributions (in the range 2–8 nm). Both the luminescence spectroscopies reveal green-orange luminescence depending upon the size distribution and indicate the possibility of using CdSe quantum dots as light emitting devices with better compatibility and faster response.
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Cheng, Shuying, Feng Gao, Karl I. Krummel et Marc Garland. « The application of BTEM to UV–vis and UV–vis CD spectroscopies : The reaction of Rh4(CO)12 with chiral and achiral ligands ». Talanta 74, no 5 (15 février 2008) : 1132–40. http://dx.doi.org/10.1016/j.talanta.2007.08.019.

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Stanila, Andreea, et Sorin Stanila. « Spectroscopic Studies of Aminoacids Complexes with Biometals ». Chemistry Journal of Moldova 7, no 1 (juin 2012) : 140–44. http://dx.doi.org/10.19261/cjm.2012.07(1).26.

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The [Cu(L)2]·H2O, [Co(L)2]·2H2O, [Zn(L)2]·H2O complexes with methionine (L) as ligand, were synthesized in water solution and analyzed by means of: elemental analysis, atomic absorption spectroscopy, thermogravimetry, FT-IR, UV-VIS and EPR spectroscopies. The atomic absorption spectroscopy and elemental measurements confi rm the ratio 1:2 metal ion: methionine composition for the synthesised compounds.The IR spectra show that amino acids act as bidentate ligands with coordination involving the carboxylic oxygen and the nitrogen atom of the amino group. Spectral UV-VIS data confi rmed the covalent metal-ligand bonds, the pseudotetrahedral symmetry around the copper and zinc ions and the octahedral environment for the cobalt ion. Powder ESR spectra at room temperature are typically for monomeric species.
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Al-Bataineh, Qais M., Ahmad A. Ahmad, Ahmad M. Alsaad et Ahmad Telfah. « New Insight on Photoisomerization Kinetics of Photo-Switchable Thin Films Based on Azobenzene/Graphene Hybrid Additives in Polyethylene Oxide ». Polymers 12, no 12 (10 décembre 2020) : 2954. http://dx.doi.org/10.3390/polym12122954.

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In this work, we reported a new insight on the kinetics of photoisomerization and time evolution of hybrid thin films considering the azo-dye methyl red (MR) incorporated with graphene accommodated in polyethylene oxide (PEO). The kinetics of photoisomerization and time-evolution of hybrid thin films were investigated using UV-Vis s and FTIR spectroscopies, as well as appropriate models developed with new analytical methods. The existence of azo-dye MR in the complex is crucial for the resource action of the trans↔cis cycles through UV-illumination ↔ Visible-illumination relaxations. The results of the UV–Vis and the FTIR investigations prove the cyclical trans ↔ cis-states. Consequently, PEO-(MR-Graphene) hybrid composite thin films can be introduced as possible applicants for photochromic molecular switches, light-gated transistors, and molecular solar thermal energy storage media.
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Balcar, Hynek, Jiří Čejka, Jiří Kubišta, Lidmila Petrusová, Pavel Kubát et Vratislav Blechta. « Preparation and Properties of Isomeric N-(4-Substituted Benzylidene)-4-ethynylanilines and 4-Substituted N-(4-Ethynylbenzylidene)anilines ». Collection of Czechoslovak Chemical Communications 65, no 2 (2000) : 203–15. http://dx.doi.org/10.1135/cccc20000203.

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4-Substituted N-(4-ethynylbenzylidene)anilines (4-HC≡C-C6H4-CH=N-C6H4-4-R; R = Me, t-Bu, OMe, F, Cl, Br, I, CF3 and NO2) have been prepared by condensation of 4-ethynylbenzaldehyde with appropriate anilines under mild conditions in good yields. The products obtained were fully characterized by GC-MS, IR, NMR and UV-VIS spectroscopies and their properties were compared with a series of 4-ethynyl-N-(4-substituted benzylidene)anilines (4-HC≡C-C6H4-N=CH-C6H4-4-R; R = H, Me, t-Bu, F, Br, NO2, CN, NMe2). The influence of substituent R on spectroscopic characteristics is discussed.
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Lewis, James E. M., et James D. Crowley. « Copper(II) Complexes of a Tripyridyl Ligand : Anion-Dependent Metallosupramolecular Structures ». Australian Journal of Chemistry 66, no 11 (2013) : 1447. http://dx.doi.org/10.1071/ch13379.

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A series of copper(ii) complexes of the ligand 2,6-bis(pyridin-3-ylethynyl)pyridine have been synthesised and characterised by 1H and DOSY NMR, IR and UV-Vis spectroscopies, mass spectrometry, elemental analysis and single crystal X-ray diffraction. In solution these systems display almost identical spectroscopic properties, however the solid state structures are shown to vary widely, depending upon the choice of anion. The tetrafluoroborate salt was revealed to be a discrete Cu2L4 cage-like helicate. The tosylate salt, whilst of the same Cu2L4 stoichiometry, was shown to be a coordination polymer. Finally the nitrate salt structure was observed to be a discrete Cu2L2 metallocycle.
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Moreira, Leonardo Marmo, Alessandra Lima Poli, Juliana Pereira Lyon, Flávio Aimbire, José Carlos Toledo, Antonio José Costa-Filho et Hidetake Imasato. « Ligand changes in ferric species of the giant extracellular hemoglobin of Glossoscolex paulistus as function of pH : correlations between redox, spectroscopic and oligomeric properties and general implications with different hemoproteins ». Journal of Porphyrins and Phthalocyanines 14, no 03 (mars 2010) : 199–218. http://dx.doi.org/10.1142/s108842461000201x.

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The present review is focused on the relationship between oligomeric and heme properties of HbGp, emphasizing the characteristics that can be generalized to other hemoproteins. This study represents the state-of-the-art with respect to the approaches for investigating giant extracellular hemoglobins as well as the correlation between oligomeric assembly alterations and their consequent changes in the first coordination sphere. A wide introduction focused on the properties of this hemoglobin is developed. Indeed, this hemoprotein is considered an interesting prototype of blood substitute and biosensor due to its peculiar properties, such as resistance to autoxidation and oligomeric stability. Previous studies by our group employing UV-vis, EPR and CD spectroscopies have been revised in a complete approach, in agreement with recent and relevant data from the literature. In fact, a consistent and inter-related spectroscopic study is described propitiating a wide assignment of "fingerprint" peaks found in the techniques evaluated in this paper. This review furnishes physicochemical information regarding the identification of ferric heme species of hemoproteins and metallic complexes through their spectroscopic bands. This effort at the attribution of UV-vis, EPR and CD peaks is not restricted to HbGp, and includes a comparative analysis of several hemoproteins involving relevant implications regarding several types of iron-porphyrin systems.
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Hu, Tao, Li Ping Wang, Xiao Long Lei et Xiao Xia Sun. « Synthesis of a New Monomer : 4,7-bis(5-phenylthiophen-2-yl)benzo[c][1,2,5]selenadiazole ». Applied Mechanics and Materials 707 (décembre 2014) : 28–31. http://dx.doi.org/10.4028/www.scientific.net/amm.707.28.

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A donor/acceptor/donor-type benzoselenadiazole-incorporated monomer was synthesized. The procedure described herein offer several advantages, including high product yields, easy purification and large scale production. Optical properties of the resulting compounds were examined by means of UV-vis and fluorescence spectroscopies. The fluorescence spectra exhibit that the emission maxima of material at 419 nm belongs to blue light region.
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Dirtu, Daniela, Lucia Odochian, Aurel Pui et Ionel Humelnicu. « Thermal decomposition of ammonia. N2H4-an intermediate reaction product ». Open Chemistry 4, no 4 (1 décembre 2006) : 666–73. http://dx.doi.org/10.2478/s11532-006-0030-4.

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AbstractThe paper reports the thermal decomposition of ammonia under dynamic conditions at 800°C in a quartz reactor. Its purpose is to confirm the homogeneous-heterogeneous degenerated branched chain mechanism established in previous studies, which assume the formation of N2H4 as a molecular intermediate; this paper identifies hydrazine as a product of thermal decomposition using FT-IR and UV-VIS spectroscopies.
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Nelson, Gilbert L., Amanda M. Lines, Job M. Bello et Samuel A. Bryan. « Online Monitoring of Solutions Within Microfluidic Chips : Simultaneous Raman and UV–Vis Absorption Spectroscopies ». ACS Sensors 4, no 9 (22 août 2019) : 2288–95. http://dx.doi.org/10.1021/acssensors.9b00736.

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Alkrad, Jamal Alyoussef, Yahya Mrestani, Dieter Stroehl, Siegfried Wartewig et Reinhard Neubert. « Characterization of enzymatically digested hyaluronic acid using NMR, Raman, IR, and UV–Vis spectroscopies ». Journal of Pharmaceutical and Biomedical Analysis 31, no 3 (mars 2003) : 545–50. http://dx.doi.org/10.1016/s0731-7085(02)00682-9.

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Pessôa, Mônica M. B., Gustavo F. S. Andrade, Márcia R. dos Santos et Marcia L. A. Temperini. « The electrochemical reduction of 2-formylpyridine thiosemicarbazone monitored by SERS and UV–vis spectroscopies ». Journal of Electroanalytical Chemistry 545 (mars 2003) : 117–22. http://dx.doi.org/10.1016/s0022-0728(03)00120-7.

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Panzarasa, Guido, Giovanni Consolati, Marco Scavini, Mariangela Longhi et Fiorenza Quasso. « Convenient Preparation of Graphene Oxide from Expandable Graphite and Its Characterization by Positron Annihilation Lifetime Spectroscopy ». C 5, no 1 (11 janvier 2019) : 6. http://dx.doi.org/10.3390/c5010006.

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Graphene oxide (GO) is conveniently prepared from expandable graphite using a simplified Hummers’ method. The product is thoroughly characterized by usual techniques (UV-vis, Fourier-transform infrared (FTIR) and Raman spectroscopies, zeta potential, electron microscopy, X-ray diffraction, nitrogen adsorption) to confirm the success of synthesis. Positron annihilation lifetime spectroscopy (PALS) is then used to extract information on the microenvironment in between the layers of graphene oxide.
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Burns, Duncan Thorburn, Michael John Walker et Christopher Mussell. « Chondroitin Sulfate : A Critical Review of Generic and Specific Problems in Its Characterization and Determination—An Exemplar of a Material with an Unknown or Variable Composition (UVCB) ». Journal of AOAC INTERNATIONAL 101, no 1 (1 janvier 2018) : 196–202. http://dx.doi.org/10.5740/jaoacint.17-0115.

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Abstract This review discusses the criteria for the selection of appropriate reference samples of chondroitin sulfate (CS) and the properties and specific problems of analytical methods for CS, namely titration with cetylpyridinium chloride; various separations; and UV-Vis, NMR, MS, and IR spectroscopies. Suggestions are put forward with regard to acceptable protocols for manufactures’ and for official/referee analysts for the analysis of CS in products.
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Černý, Jiří, Lenka Dokládalová, Antonín Lyčka, Tomáš Mikysek et Filip Bureš. « Preparation, characterization and investigation of photo-physical properties of thiophene-substituted rare-earth bisphthalocyanines ». Journal of Porphyrins and Phthalocyanines 21, no 01 (janvier 2017) : 31–36. http://dx.doi.org/10.1142/s1088424617500018.

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Three bis[octakis-(2-thienyl)phthalocyaninato] rare-earth metal(III) phthalocyanine complexes (Pc[Formula: see text]Pr, Pc[Formula: see text]Sm, Pc[Formula: see text]Gd) were synthesized for the first time. The new compounds were characterized by UV-vis, NMR, FT-IR, mass spectroscopies as well as elemental analysis and electrochemistry. Production of singlet oxygen was also estimated by 9,10-dimethylanthracene method.
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Aseman, Marzieh Dadkhah, S. Masoud Nabavizadeh, Hamid R. Shahsavari et Mehdi Rashidi. « C–H reductive elimination during the reaction of cycloplatinated(ii) complexes with pyridine-2-thione : kinetic follow up ». RSC Advances 5, no 29 (2015) : 22692–702. http://dx.doi.org/10.1039/c5ra01341k.

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Reactions of the cycloplatinated(ii) complexes [PtR(ppy)(SMe2)], 1, where ppy = deprotonated 2-phenylpyridine and R = Me or p-MeC6H4, with pyridine-2-thione, C5H5SN, were studied by UV-vis and 1H NMR spectroscopies and on the basis of the data a mechanism is proposed.
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Politi, Jane, Jolanda Spadavecchia, Gabriella Fiorentino, Immacolata Antonucci et Luca De Stefano. « Arsenate reductase from Thermus thermophilus conjugated to polyethylene glycol-stabilized gold nanospheres allow trace sensing and speciation of arsenic ions ». Journal of The Royal Society Interface 13, no 123 (octobre 2016) : 20160629. http://dx.doi.org/10.1098/rsif.2016.0629.

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Water sources pollution by arsenic ions is a serious environmental problem all around the world. Arsenate reductase enzyme ( TtArsC ) from Thermus thermophilus extremophile bacterium, naturally binds arsenic ions, As(V) and As (III), in aqueous solutions. In this research, TtArsC enzyme adsorption onto hybrid polyethylene glycol-stabilized gold nanoparticles (AuNPs) was studied at different pH values as an innovative nanobiosystem for metal concentration monitoring. Characterizations were performed by UV/Vis and circular dichroism spectroscopies, TEM images and in terms of surface charge changes. The molecular interaction between arsenic ions and the TtArsC -AuNPs nanobiosystem was also monitored at all pH values considered by UV/Vis spectroscopy. Tests performed revealed high sensitivities and limits of detection equal to 10 ± 3 M −12 and 7.7 ± 0.3 M −12 for As(III) and As(V), respectively.
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Pramitha, Citra Putri, Nanik Siti Aminah et Alfinda Novi Kristanti. « Skopoletin Senyawa Fenilpropanoid dari Kulit Umbi Ubi Jalar (Ipomoea batatas L.) varietas IR-melati ». Jurnal Kimia Riset 1, no 2 (21 décembre 2016) : 81. http://dx.doi.org/10.20473/jkr.v1i2.3087.

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AbstrakTelah berhasil diisolasi senyawa golongan fenilpropanoid dengan nama “skopoletin” dari kulit umbi ubi jalar (Ipomoea batatas L.). Ekstraksi senyawa dilakukan dengan metode maserasi menggunakan pelarut metanol, dilanjutkan dengan partisi menggunakan n-heksana dan etil asetat. Pemisahan dan pemurnian senyawa dilakukan menggunakan teknik kromatografi kolom gravitasi. Struktur senyawa dianalisis berdasarkan data spektroskopi UV/Vis, 1D, dan 2D-NMR. Kata kunci : fenilpropanoid, skopoletin, Ipomoea batatas L. AbstractIt has been isolated phenylpropanoid group compound named scopoletin from the tuber peel of Ipomoea batatas L. Extraction of this compound was done by maceration method using methanol solvent, followed by partition with n-hexane and ethyl acetate. Separation and purofication of compound was done by gravity column chromatography techniques. Structure of compound was analyzed by UV/Vis, 1D and 2D NMR spectroscopies. Keywords : phenylpropanoid, scopoletin, Ipomoea batatas L.
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SIMON, V., I. ARDELEAN, I. MILEA, M. PETEANU et S. SIMON. « SPECTROSCOPIC PROPERTIES OF B2O3–PbO–Nd2O3 GLASSES ». Modern Physics Letters B 13, no 24 (20 octobre 1999) : 879–84. http://dx.doi.org/10.1142/s021798499900107x.

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Samples belonging to x Nd 2 O 3(100-x) [ 2B 2 O 3· PbO ] glass system, with 0≤ x≤ 40 mol%, are investigated by IR and UV–VIS spectroscopies in order to obtain evidence for the influence of Nd 2 O 3 on the local order from 2B 2 O 3· PbO glass matrix. Besides the IR absorption bands characteristic to lead and boron arrangements, typical absorption lines of Nd 3+ ions around 4000 cm -1 and 6000 cm -1 are recorded. The 6000 cm -1 band appears only for the samples with x≥25 mol% Nd 2 O 3. The split of some UV–VIS absorption bands arising from transitions of neodymium ions in doublet lines as well as the shift of the absorption bands as the Nd 2 O 3 content increases denote the influence of the lead–borate matrix on the radiative transitions of the lanthanide ion.
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Picca, Rosaria Anna, Anna Di Maria, Lenka Riháková, Annalisa Volpe, Maria Chiara Sportelli, Pietro Mario Lugarà, Antonio Ancona et Nicola Cioffi. « Laser Ablation Synthesis of Hybrid Copper/Silver Nanocolloids for Prospective Application as Nanoantimicrobial Agents for Food Packaging ». MRS Advances 1, no 56 (2016) : 3735–40. http://dx.doi.org/10.1557/adv.2016.336.

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ABSTRACTThis work is focused on the laser ablation synthesis of Cu/Ag nanocolloids in chitosan-based aqueous solution using a flow cell. A two-step process using femtosecond laser pulses was applied to consecutively ablate each metal. As-prepared nanomaterials were morphologically and spectroscopically characterized by Transmission Electron Microscopy, UV-Vis and X-ray Photoelectron spectroscopies. Application of Cu/Ag nanomaterials is envisaged as antibacterial materials for food packaging.
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POPOVICI, S., W. LEYFFER et R. HOLZE. « The Mechanism of Dioxygen Reduction at Iron meso-Tetrakis (Pyridyl) Porphyrin : a Spectroelectrochemical Study ». Journal of Porphyrins and Phthalocyanines 02, no 03 (mai 1998) : 249–60. http://dx.doi.org/10.1002/(sici)1099-1409(199805/06)2:3<249 ::aid-jpp77>3.0.co;2-3.

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The mechanism of the dioxygen interaction with and reduction reaction at iron α,β,γ,δ-tetra(4-pyridyl) porphyrin ( FeTPyP ) deposited on carbon and silver supporting electrodes was investigated with cyclic voltammetry and FTIR, UV-vis and resonance Raman spectroscopies. Results indicate a strong influence of the ligand upon the reduction electrocatalysis. Spectroelectrochemical results support a two-electron pathway resulting most probably in hydrogen peroxide as the primary reduction product.
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Yazıcı, Senem Çolak, Sibel Kahraman, Salih Z. Yıldız et Mahmut D. Yılmaz. « Peripherally substituted soluble nickel phthalocyanines : Synthesis, characterization, aggregation behavior and antioxidant properties ». Journal of Porphyrins and Phthalocyanines 23, no 11n12 (décembre 2019) : 1478–85. http://dx.doi.org/10.1142/s1088424619501645.

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Tetra-zwitterionic-substituted nickel(II) phthalocyanine derivatives were newly synthesized starting from nonionic 2(3),9(10),16(17),23(24)-tetrakis-[2-([Formula: see text]-((3-dimethylamino)propyl)carbamate)oxyethyl)phthalocyaninato nickel (II). The novel compounds have been characterized by a combination of UV-vis, FT-IR and mass spectroscopies and elemental analysis. The critical micelle concentrations of the prepared compounds were measured, and the antioxidant activities were analyzed with radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). The zwitterionic molecules showed aggregated spectra in the UV-vis region, and they might be good surfactant candidates for the detergent industry with their appropriate critical micelle concentration (CMC) properties in water. The compounds exhibited ABTS radical scavenging activity and thus they have antioxidant activity.
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Assimiadis, Manolis K., Petros A. Tarantilis et Moschos G. Polissiou. « UV-Vis, FT-Raman, and 1H NMR Spectroscopies of cis-trans Carotenoids from Saffron (Crocus sativus L.) ». Applied Spectroscopy 52, no 4 (avril 1998) : 519–22. http://dx.doi.org/10.1366/0003702981944058.

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Stigmata of Crocus sativus L. were extracted in water, and the extract was analyzed by using a high-pressure liquid chromatography (HPLC) method. The carotenoids of saffron [ cis and trans glycosyl esters of crocetin or crocins (CRCs)] were isolated, and the two major isomer compounds (all- trans-digentiobiosyl crocetin and 13- cis-digentiobiosyl crocetin) were characterized spectroscopically with ultraviolet-visible (UV-vis), Fourier transform (FT)-Raman, and 1H NMR spectroscopies. The 13 -cis compound showed in a UV-vis spectrum an additional peak at 330 nm, in an FT-Raman spectrum the presence of a peak at 1138 cm−1, and in the 1H NMR downfield shifts of protons 12 and 15 and an uptield shift of proton 14, with respect to the all-trans isomer, according to differences in their skeletal structures. These features are shown also by the profile of their two-dimensional spectra.
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B. B. Ferrari, Priscila, Alessandro K. Jordão, Anna C. Cunha, Vitor F. Ferreira, Juliana Schultz, Carlos I. Yamamoto et Antônio S. Mangrich. « Evaluation of Antioxidant Additives for Biodiesel by EPR and UV-Vis Spectroscopies, and the Rancimat Method (EN 14112) ». Revista Virtual de Química 13, no 4 (2021) : 900–909. http://dx.doi.org/10.21577/1984-6835.20210016.

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Brousseau, J. L., N. Vibet, R. M. Leblanc, K. S. Rein et D. G. Baden. « UV-Visible and Inelastic Electron Tunneling Spectroscopies of Brevetoxins ». Applied Spectroscopy 52, no 4 (avril 1998) : 523–27. http://dx.doi.org/10.1366/0003702981944067.

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We have studied the UV-vis and vibrational spectra of the brevetoxins PbTx-2, PbTx-3, PbTx-9, and 2, 3, 27, 28, 41, 43-hexahydro-(reduced) PbTx-3. The absorption at 194 nm (ε ≈ 18 000 L mol−1 cm−1) of PbTx-2 and PbTx-3 is assigned to the Π–Π* transition of the lactone conjugated double bonds. The n-Π* transition of the lactone is seen at 239 nm (∈ ≈ 2 800 L mol−1 cm−1). The absorption band at 208 nm for PbTx-2 is assigned to the conjugated double bonds of the aldehyde function located on the K-ring side chain. The inelastic electron tunneling spectra of PbTx-2, PbTx-3, PbTx-9, and fully reduced PbTx-3 are presented and the vibrational bands are assigned. We show that inelastic electron tunneling spectroscopy can be used to monitor and measure the vibrational fingerprint of the brevetoxins at a level as low as 1 ng.
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Cannavà, C., V. Crupi, P. Ficarra, M. Guardo, D. Majolino, R. Stancanelli et V. Venuti. « Physicochemical characterization of coumestrol/β-cyclodextrins inclusion complexes by UV–vis and FTIR-ATR spectroscopies ». Vibrational Spectroscopy 48, no 2 (novembre 2008) : 172–78. http://dx.doi.org/10.1016/j.vibspec.2007.12.013.

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Marchese, Leonardo, Thomas Maschmeyer, Enrica Gianotti, Salvatore Coluccia et John M. Thomas. « Probing the Titanium Sites in Ti−MCM41 by Diffuse Reflectance and Photoluminescence UV−Vis Spectroscopies ». Journal of Physical Chemistry B 101, no 44 (octobre 1997) : 8836–38. http://dx.doi.org/10.1021/jp971963w.

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