2018 |
Gomez-Jeria, J S; Clavijo, E; Gutierrez, S An Infrared, Sem and Xrf Study of the Paper of a 1588 Spanish Book Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (4), pp. 1581-1590, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: alum, analysis, archeology, cellulose, conservation, ft-ir gelatin, infrared margins paper postage potassium rags, sem, spain, spectra, spectroscopy, stamps, xrf @article{RN414, title = {An Infrared, Sem and Xrf Study of the Paper of a 1588 Spanish Book}, author = { J.S. Gomez-Jeria and E. Clavijo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000438848100213}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {4}, pages = {1581-1590}, abstract = {An infrared, scanning electron microscopy and X-ray fluorescence study was performed on the Spanish book entitled Treated of the True and False Prophecy printed in Segovia during 1588. Three small samples were taken from the margins of three pages. Two of them belong to the original book while the third one is from a page added later during the binding of the book. The first result is that the paper is contaminated with numerous metallic elements. The distribution of these contaminants in the three samples suggests that this process began after the binding of the book. The carbonate moiety of the calcium carbonate seems to have disappeared with the passing of time transformed in carbon dioxide. Al, K and S, components of potassium alum are detected by SEM and XRF analyses. Gelatin seems to be present because some IR bands of proline suggest that. There is an unsolved problem with some IR bands because of the fact that they can be ascribed to two different entities.}, keywords = {alum, analysis, archeology, cellulose, conservation, ft-ir gelatin, infrared margins paper postage potassium rags, sem, spain, spectra, spectroscopy, stamps, xrf}, pubstate = {published}, tppubtype = {article} } An infrared, scanning electron microscopy and X-ray fluorescence study was performed on the Spanish book entitled Treated of the True and False Prophecy printed in Segovia during 1588. Three small samples were taken from the margins of three pages. Two of them belong to the original book while the third one is from a page added later during the binding of the book. The first result is that the paper is contaminated with numerous metallic elements. The distribution of these contaminants in the three samples suggests that this process began after the binding of the book. The carbonate moiety of the calcium carbonate seems to have disappeared with the passing of time transformed in carbon dioxide. Al, K and S, components of potassium alum are detected by SEM and XRF analyses. Gelatin seems to be present because some IR bands of proline suggest that. There is an unsolved problem with some IR bands because of the fact that they can be ascribed to two different entities. |
Pinto, C; Galdámez, A; Barahona, P; Moris, S; Pena, O Crystal Structure, Raman Scattering and Magnetic Properties of Cucr2-Xzrxse4 and Cucr2-Xsnxse4 Selenospinels Artículo de revista Journal of Magnetism and Magnetic Materials, 456 , pp. 160-166, 2018, ISSN: 0304-8853. Resumen | Enlaces | BibTeX | Etiquetas: colossal crystal geometry magnetic magnetoresistance, properties, raman selenospinel, spectroscopy, structure @article{RN401, title = {Crystal Structure, Raman Scattering and Magnetic Properties of Cucr2-Xzrxse4 and Cucr2-Xsnxse4 Selenospinels}, author = { C. Pinto and A. Gald\'{a}mez and P. Barahona and S. Moris and O. Pena}, url = {/brokenurl#<Go to ISI>://WOS:000427580800023}, doi = {10.1016/j.jmmm.2018.02.023}, issn = {0304-8853}, year = {2018}, date = {2018-01-01}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {456}, pages = {160-166}, publisher = {2018 Elsevier B.V.}, abstract = {Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd3m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4.}, keywords = {colossal crystal geometry magnetic magnetoresistance, properties, raman selenospinel, spectroscopy, structure}, pubstate = {published}, tppubtype = {article} } Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd3m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4. |
Gomez-Jeria, J S; Clavijo, E; Gutierrez, S A Qualitative Infrared and Scanning Electron Microscopy Study of the Margins of Fourteen World Postage Stamps Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (6), pp. 1719-+, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: archeology, cellulose, electron ft-ir infrared kaolinite, microscopy, paper philately, pigments, postage raman scanning sem, spectra, spectroscopy, stamps, xrf @article{RN415, title = {A Qualitative Infrared and Scanning Electron Microscopy Study of the Margins of Fourteen World Postage Stamps}, author = { J.S. Gomez-Jeria and E. Clavijo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000449630700274}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {6}, pages = {1719-+}, abstract = {Fourteen heavily damaged postage stamps were chosen for an infrared and scanning electron microscopy (SEM) characterization of their non-printed margins. The results show the presence of kaolinite used as filler in all but two samples. These last two contain aluminum (with an Al-OH moiety). One stamp seems to contain barium in the form of sulfate. One stamp contains lead in an unknown chemical compound. All these results were incorporated into a database for future analysis. Quantum chemical calculations of diverse large models of cellulose seem absolutely necessary for the IR band assignments.}, keywords = {archeology, cellulose, electron ft-ir infrared kaolinite, microscopy, paper philately, pigments, postage raman scanning sem, spectra, spectroscopy, stamps, xrf}, pubstate = {published}, tppubtype = {article} } Fourteen heavily damaged postage stamps were chosen for an infrared and scanning electron microscopy (SEM) characterization of their non-printed margins. The results show the presence of kaolinite used as filler in all but two samples. These last two contain aluminum (with an Al-OH moiety). One stamp seems to contain barium in the form of sulfate. One stamp contains lead in an unknown chemical compound. All these results were incorporated into a database for future analysis. Quantum chemical calculations of diverse large models of cellulose seem absolutely necessary for the IR band assignments. |
Arriaza, B; Ogalde, J P; Campos-Vallette, M; Paipa, C; Leyton, P; Lara, N Toxic Pigment in a Capacocha Burial: Instrumental Identification of Cinnabar in Inca Human Remains from Iquique, Chile Artículo de revista Archaeometry, 60 (6), pp. 1324-1333, 2018, ISSN: 0003-813x. Resumen | Enlaces | BibTeX | Etiquetas: ancient cerro coast esmeralda, exposure, hematite, insight, mercury mercury, mortuary nasca, pigments, poisoning, pottery, raman red rituals, sem, soils, spectroscopy @article{RN408, title = {Toxic Pigment in a Capacocha Burial: Instrumental Identification of Cinnabar in Inca Human Remains from Iquique, Chile}, author = { B. Arriaza and J.P. Ogalde and M. Campos-Vallette and C. Paipa and P. Leyton and N. Lara}, url = {/brokenurl#<Go to ISI>://WOS:000449888500012}, doi = {10.1111/arcm.12392}, issn = {0003-813x}, year = {2018}, date = {2018-01-01}, journal = {Archaeometry}, volume = {60}, number = {6}, pages = {1324-1333}, abstract = {We report on the analysis of a red pigment found in a lavish Inca burial from Cerro Esmeralda, Chile, associated with the human sacrifice of two young girls. The outcome shows that the red pigment is mainly cinnabar, with 95% of HgS content. Cinnabar is rarely found in the archaeological record of Chile. Thus, we propose that our results are another line of evidence supporting Iquique's Cerro Esmeralda inhumation as a unique Inca ritual. It was a special lower-elevation capacocha burial, most probably undertaken to politically and symbolically incorporate the coastal people into the Tawantinsuyo Empire.}, keywords = {ancient cerro coast esmeralda, exposure, hematite, insight, mercury mercury, mortuary nasca, pigments, poisoning, pottery, raman red rituals, sem, soils, spectroscopy}, pubstate = {published}, tppubtype = {article} } We report on the analysis of a red pigment found in a lavish Inca burial from Cerro Esmeralda, Chile, associated with the human sacrifice of two young girls. The outcome shows that the red pigment is mainly cinnabar, with 95% of HgS content. Cinnabar is rarely found in the archaeological record of Chile. Thus, we propose that our results are another line of evidence supporting Iquique's Cerro Esmeralda inhumation as a unique Inca ritual. It was a special lower-elevation capacocha burial, most probably undertaken to politically and symbolically incorporate the coastal people into the Tawantinsuyo Empire. |
2017 |
Marcaida, I; Maguregui, M; Morillas, H; Garcia-Florentino, C; Pintus, V; Aguayo, T; Campos-Vallette, M; Madariaga, J Optimization of Sample Treatment for the Identification of Anthraquinone Dyes by Surface-Enhanced Raman Spectroscopy Artículo de revista Analytical and Bioanalytical Chemistry, 409 (8), pp. 2221-2228, 2017, ISSN: 1618-2642. Resumen | Enlaces | BibTeX | Etiquetas: anthraquinone, dyestuffs, extraction, lake lake, liquid-liquid madder nanoparticles, pigment, pigments, purple, raman scattering, sers, silver, spectroscopy, surface-enhanced @article{marcaida2017optimization, title = {Optimization of Sample Treatment for the Identification of Anthraquinone Dyes by Surface-Enhanced Raman Spectroscopy}, author = { I. Marcaida and M. Maguregui and H. Morillas and C. Garcia-Florentino and V. Pintus and T. Aguayo and M. Campos-Vallette and J. Madariaga}, url = {/brokenurl#<Go to ISI>://WOS:000395057500024}, doi = {10.1007/s00216-016-0169-6}, issn = {1618-2642}, year = {2017}, date = {2017-01-01}, journal = {Analytical and Bioanalytical Chemistry}, volume = {409}, number = {8}, pages = {2221-2228}, abstract = {The study and characterization of old artifacts such as pigments requires the use of techniques that need a small amount of sample to perform the analysis because of the high value of these samples. In recent years, organic molecules such as anthraquinone dyes have been identified by surface-enhanced Raman spectroscopy (SERS). However, different sample treatments must be applied to isolate the organic dye from the mordant, which produces great fluorescence in the Raman measurements. In this work, optimization of sample treatment for the SERS analysis of anthraquinone dyes was performed. Sample mass, the organic solvent, and its volume were optimized and different slide materials and excitation lasers were compared to choose the best conditions for the identification of the dyes. The optimization of sample treatment resulted in 5 mg of sample as the optimum amount. Further, two consecutive extractions with 0.5 mL of ethyl acetate was the best option for the extraction of the dye. A quartz slide was used instead of a glass slide to reduce background signal, and an excitation laser of 532 nm offers better results than one of 785 nm. The optimized method was applied to the characterization of the dyes used in Pompeian pink and purple lake pigments. Alizarin and purpurin anthraquinone dyes, obtained from madder lake, were identified as the organic colorants. The SERS results were confirmed by those obtained by means of UV-visible spectroscopy.}, keywords = {anthraquinone, dyestuffs, extraction, lake lake, liquid-liquid madder nanoparticles, pigment, pigments, purple, raman scattering, sers, silver, spectroscopy, surface-enhanced}, pubstate = {published}, tppubtype = {article} } The study and characterization of old artifacts such as pigments requires the use of techniques that need a small amount of sample to perform the analysis because of the high value of these samples. In recent years, organic molecules such as anthraquinone dyes have been identified by surface-enhanced Raman spectroscopy (SERS). However, different sample treatments must be applied to isolate the organic dye from the mordant, which produces great fluorescence in the Raman measurements. In this work, optimization of sample treatment for the SERS analysis of anthraquinone dyes was performed. Sample mass, the organic solvent, and its volume were optimized and different slide materials and excitation lasers were compared to choose the best conditions for the identification of the dyes. The optimization of sample treatment resulted in 5 mg of sample as the optimum amount. Further, two consecutive extractions with 0.5 mL of ethyl acetate was the best option for the extraction of the dye. A quartz slide was used instead of a glass slide to reduce background signal, and an excitation laser of 532 nm offers better results than one of 785 nm. The optimized method was applied to the characterization of the dyes used in Pompeian pink and purple lake pigments. Alizarin and purpurin anthraquinone dyes, obtained from madder lake, were identified as the organic colorants. The SERS results were confirmed by those obtained by means of UV-visible spectroscopy. |
Rua, C; Sepulveda, M; Gutierrez, S; Carcamo, J J; Surco-Luque, J; Campos-Vallette, M; Guzman, F; Conti, P; Pereira, M Raman Identification of Pigments in Wall Paintings of the Colonial Period from Bolivian Churches in the Ruta De La Plata Artículo de revista Conservation Science in Cultural Heritage, 17 , pp. 117-137, 2017, ISSN: 1974-4951. Resumen | Enlaces | BibTeX | Etiquetas: ancient, andean art, artworks, breakdown churches, colonial complexes, corrosion, hematite, induced painted paintings, pigments, raman spectra, spectroscopy, sulfate wall @article{RN370, title = {Raman Identification of Pigments in Wall Paintings of the Colonial Period from Bolivian Churches in the Ruta De La Plata}, author = { C. Rua and M. Sepulveda and S. Gutierrez and J.J. Carcamo and J. Surco-Luque and M. Campos-Vallette and F. Guzman and P. Conti and M. Pereira}, url = {/brokenurl#<Go to ISI>://WOS:000428811100008}, issn = {1974-4951}, year = {2017}, date = {2017-01-01}, journal = {Conservation Science in Cultural Heritage}, volume = {17}, pages = {117-137}, abstract = {Micro-Raman spectroscopy was used to analyze and identify pigments and determine the palette of color in wall paintings from four churches of the Colonial Period, in the Bolivian highlands. The ancient churches Santiago de Callapa, Curahuara de Carangas, Nuestra Senora de Copacabana de Andamarca and San Jose de Soracachi were constructed during the 17th and 18th centuries, around the important colonial Ruta de la Plata, between Potosi city and Arica harbor on the Paciic coast of South America. Most pigments used in the wall paintings correspond to inorganic minerals as well as to organic colorants. Fully chlorinated copper phthalocyanine (green), copper phthalocyanine (blue), beta-naphthol (yellow) and benzoimidazolone (red), were identiied in the corresponding colored areas suggesting subsequent recent interventions or restorations. Ground layer materials were also characterized. The present results allow for discussion of the pictorial techniques used in the Andean highland during the colonial period and allow conservators and restorers to make important decisions regarding the type of intervention to perform in the case of these important historical and patrimonial monuments.}, keywords = {ancient, andean art, artworks, breakdown churches, colonial complexes, corrosion, hematite, induced painted paintings, pigments, raman spectra, spectroscopy, sulfate wall}, pubstate = {published}, tppubtype = {article} } Micro-Raman spectroscopy was used to analyze and identify pigments and determine the palette of color in wall paintings from four churches of the Colonial Period, in the Bolivian highlands. The ancient churches Santiago de Callapa, Curahuara de Carangas, Nuestra Senora de Copacabana de Andamarca and San Jose de Soracachi were constructed during the 17th and 18th centuries, around the important colonial Ruta de la Plata, between Potosi city and Arica harbor on the Paciic coast of South America. Most pigments used in the wall paintings correspond to inorganic minerals as well as to organic colorants. Fully chlorinated copper phthalocyanine (green), copper phthalocyanine (blue), beta-naphthol (yellow) and benzoimidazolone (red), were identiied in the corresponding colored areas suggesting subsequent recent interventions or restorations. Ground layer materials were also characterized. The present results allow for discussion of the pictorial techniques used in the Andean highland during the colonial period and allow conservators and restorers to make important decisions regarding the type of intervention to perform in the case of these important historical and patrimonial monuments. |
2016 |
Soto, C; Saavedra, R; Toral, M I; Nacaratte, F; Poza, C Preliminary Studies for Ciclopirox Olamine Determination by Thermal Lens Spectrophotometry Artículo de revista Microchemical Journal, 129 , pp. 36-40, 2016, ISSN: 0026-265x. Resumen | Enlaces | BibTeX | Etiquetas: antimycotic, chromatography, ciclopirox derivatization, flow lens olamine, polarographic-determination, precolumn spectrometry, spectroscopy, thermal @article{soto2016preliminary, title = {Preliminary Studies for Ciclopirox Olamine Determination by Thermal Lens Spectrophotometry}, author = { C. Soto and R. Saavedra and M.I. Toral and F. Nacaratte and C. Poza}, url = {/brokenurl#<Go to ISI>://WOS:000382595300006}, doi = {10.1016/j.microc.2016.06.004}, issn = {0026-265x}, year = {2016}, date = {2016-01-01}, journal = {Microchemical Journal}, volume = {129}, pages = {36-40}, publisher = {2016 Elsevier B.V.}, abstract = {The spectrophotometric kinetic methods are broadly used in the determination of drugs in several types of matrices. Thermal Lens Spectrometry (TLS) has demonstrated to be a sensitive indirect spectrophotometric technique used in the field of applied sciences, such as environmental and biochemical sciences. Ciclopirox olamine (OM) is a synthetic fungicide that inhibits the growth of pathogenic dermatophytes. This work presents the results of CXO determination by TLS, through a kinetic method, based on the CXO oxidation with KMnO4 in alkaline medium to form manganate (MnO42-). The Thermal Lens (TL) effect was generated by a He-Ne laser (TEM00, 20 mW, 632 nm). The TLS measurements were performed on a single beam assembly with a lens of f = 7.5 cm focal distance and 10 Hz modulation frequency. The TL signal from the detector was acquired for each sample. The optimization was at 30 min reaction time, KMnO4 8.0 . 10(-4) mol L-1 and Na2SO4 0.6 mol L-1. Under these conditions a calibration curve was constructed. The analytical features were LOD = 3.40 mu mol L-1 and LOQ = 113 mu mol L-1. To examine accuracy and reliability, the determination method was successfully applied in tap water samples where known amounts of CXO were spiked.}, keywords = {antimycotic, chromatography, ciclopirox derivatization, flow lens olamine, polarographic-determination, precolumn spectrometry, spectroscopy, thermal}, pubstate = {published}, tppubtype = {article} } The spectrophotometric kinetic methods are broadly used in the determination of drugs in several types of matrices. Thermal Lens Spectrometry (TLS) has demonstrated to be a sensitive indirect spectrophotometric technique used in the field of applied sciences, such as environmental and biochemical sciences. Ciclopirox olamine (OM) is a synthetic fungicide that inhibits the growth of pathogenic dermatophytes. This work presents the results of CXO determination by TLS, through a kinetic method, based on the CXO oxidation with KMnO4 in alkaline medium to form manganate (MnO42-). The Thermal Lens (TL) effect was generated by a He-Ne laser (TEM00, 20 mW, 632 nm). The TLS measurements were performed on a single beam assembly with a lens of f = 7.5 cm focal distance and 10 Hz modulation frequency. The TL signal from the detector was acquired for each sample. The optimization was at 30 min reaction time, KMnO4 8.0 . 10(-4) mol L-1 and Na2SO4 0.6 mol L-1. Under these conditions a calibration curve was constructed. The analytical features were LOD = 3.40 mu mol L-1 and LOQ = 113 mu mol L-1. To examine accuracy and reliability, the determination method was successfully applied in tap water samples where known amounts of CXO were spiked. |
Munoz-Perez, J; Leyton, P; Paipa, C; Soto, J P; Brunet, J; Gomez-Jeria, J S; Campos-Vallette, M Raman and Surface Enhanced Raman Scattering Study of the Orientation of Cruciform 9,10-Anthracene Thiophene and Furan Derivatives Deposited on a Gold Colloidal Surface Artículo de revista Journal of Molecular Structure, 1122 , pp. 198-204, 2016, ISSN: 0022-2860. Resumen | Enlaces | BibTeX | Etiquetas: cluster, cruciform, electronics, gold metal molecular monolayers, nanoparticles, pi-systems, polycyclic raman scattering, self-assembled sers, silver, spectroscopy, spectrum, surface-enhanced vibrational-spectra @article{RN331, title = {Raman and Surface Enhanced Raman Scattering Study of the Orientation of Cruciform 9,10-Anthracene Thiophene and Furan Derivatives Deposited on a Gold Colloidal Surface}, author = { J. Munoz-Perez and P. Leyton and C. Paipa and J.P. Soto and J. Brunet and J.S. Gomez-Jeria and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000381167800023}, doi = {10.1016/j.molstruc.2016.06.002}, issn = {0022-2860}, year = {2016}, date = {2016-01-01}, journal = {Journal of Molecular Structure}, volume = {1122}, pages = {198-204}, publisher = {2016 Elsevier B.V.}, abstract = {The 9,10-di(thiophen-2-yl)anthracene (TAT), 9,10-di(furan-2-yl)anthracene (FAF) and 2-[(10-(thiophen-2-yl)anthracen-9-yl)]furan (TAF) cruciform molecular systems were synthesized using one-step coupling reactions and structurally characterized via Raman, infrared, H-1 NMR, C-13 NMR and mass spectroscopies. The orientation of the analytes on a gold colloidal surface was inferred from a surface-enhanced Raman scattering (SERS) study. The metal surface interaction was driven by the S and O atoms of the thiophene and furan alpha-substituents, and the plane of the anthracene fragment remained parallel to the surface. Theoretical calculations based on a simplified molecular model for the analyte-surface interaction provide a good representation of the experimental data.}, keywords = {cluster, cruciform, electronics, gold metal molecular monolayers, nanoparticles, pi-systems, polycyclic raman scattering, self-assembled sers, silver, spectroscopy, spectrum, surface-enhanced vibrational-spectra}, pubstate = {published}, tppubtype = {article} } The 9,10-di(thiophen-2-yl)anthracene (TAT), 9,10-di(furan-2-yl)anthracene (FAF) and 2-[(10-(thiophen-2-yl)anthracen-9-yl)]furan (TAF) cruciform molecular systems were synthesized using one-step coupling reactions and structurally characterized via Raman, infrared, H-1 NMR, C-13 NMR and mass spectroscopies. The orientation of the analytes on a gold colloidal surface was inferred from a surface-enhanced Raman scattering (SERS) study. The metal surface interaction was driven by the S and O atoms of the thiophene and furan alpha-substituents, and the plane of the anthracene fragment remained parallel to the surface. Theoretical calculations based on a simplified molecular model for the analyte-surface interaction provide a good representation of the experimental data. |
Castillo, C; Buono-Core, G; Manzur, C; Yutronic, N; Sierpe, R; Cabello, G; Chornik, B Molybdenum Trioxide Thin Films Doped with Gold Nanoparticles Grown by a Sequential Methodology: Photochemical Metal-Organic Deposition (Pmod) and Dc-Magnetron Sputtering Artículo de revista Journal of the Chilean Chemical Society, 61 (1), pp. 2816-2820, 2016, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: catalysis, diffraction, films, moo3, nanostructures, optical-properties, oxidation, oxide-films, oxides, photoelectron resonance, selective size, spectroscopy, sputtering, support, surface-plasmon temperature, thin x-ray xps @article{RN302, title = {Molybdenum Trioxide Thin Films Doped with Gold Nanoparticles Grown by a Sequential Methodology: Photochemical Metal-Organic Deposition (Pmod) and Dc-Magnetron Sputtering}, author = { C. Castillo and G. Buono-Core and C. Manzur and N. Yutronic and R. Sierpe and G. Cabello and B. Chornik}, url = {/brokenurl#<Go to ISI>://WOS:000378145500014}, doi = {10.4067/S0717-97072016000100014}, issn = {0717-9707}, year = {2016}, date = {2016-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {61}, number = {1}, pages = {2816-2820}, abstract = {Gold nanoparticles (AuNPs) were deposited by DC-magnetron sputtering onto molybdenum trioxide (MoO3) thin films grown by Photochemical Metal-Organic Deposition (PMOD) on Si(100) and borosilicate glass substrates. The chemical, optical and morphology properties of the films were studied by UV/Vis Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). SEM revealed that AuNPs formed after 5 s of sputtering. AuNPs are spherical and have both an average diameter of 18 nm and a relatively narrow size distribution. As the deposition time increases, larger structures are formed by an aggregation of AuNPs. XPS studies of the AuNP/MoO3 films on Si(100) showed the presence of Mo(VI) and Mo(V), which indicated that the films were primarily non-stoichiometric molybdenum oxides. The occurrence of oxygen vacancies in the substrate play an important role to stabilize the AuNPs.}, keywords = {catalysis, diffraction, films, moo3, nanostructures, optical-properties, oxidation, oxide-films, oxides, photoelectron resonance, selective size, spectroscopy, sputtering, support, surface-plasmon temperature, thin x-ray xps}, pubstate = {published}, tppubtype = {article} } Gold nanoparticles (AuNPs) were deposited by DC-magnetron sputtering onto molybdenum trioxide (MoO3) thin films grown by Photochemical Metal-Organic Deposition (PMOD) on Si(100) and borosilicate glass substrates. The chemical, optical and morphology properties of the films were studied by UV/Vis Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). SEM revealed that AuNPs formed after 5 s of sputtering. AuNPs are spherical and have both an average diameter of 18 nm and a relatively narrow size distribution. As the deposition time increases, larger structures are formed by an aggregation of AuNPs. XPS studies of the AuNP/MoO3 films on Si(100) showed the presence of Mo(VI) and Mo(V), which indicated that the films were primarily non-stoichiometric molybdenum oxides. The occurrence of oxygen vacancies in the substrate play an important role to stabilize the AuNPs. |
2015 |
Vera, A M; Carcamo, J J; Aliaga, A E; Gomez-Jeria, J S; Kogan, M J; Campos-Vallette, M Interaction of the Clpffd Peptide with Gold Nanospheres. A Raman, Surface Enhanced Raman Scattering and Theoretical Study Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 134 , pp. 251-256, 2015, ISSN: 1386-1425. Resumen | Enlaces | BibTeX | Etiquetas: alzheimer-disease, anti-aggregation approximations, assemblies, beta-amyloid, calculations, clpffd extended hartree-fock htickel molecular-orbital nanoparticles, of peptide peptide, protein, sers, silver, spectroscopy, stability theories, theory type @article{RN262, title = {Interaction of the Clpffd Peptide with Gold Nanospheres. A Raman, Surface Enhanced Raman Scattering and Theoretical Study}, author = { A.M. Vera and J.J. Carcamo and A.E. Aliaga and J.S. Gomez-Jeria and M.J. Kogan and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000342718700034}, doi = {10.1016/j.saa.2014.06.116}, issn = {1386-1425}, year = {2015}, date = {2015-01-01}, journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy}, volume = {134}, pages = {251-256}, publisher = {2014 Elsevier B.V.}, abstract = {In a previous work we demonstrated that toxic aggregates of the protein beta-amyloid (ATA beta) involved in the Alzheimer's disease (AD) can be destabilized upon electromagnetic irradiation of the peptide Cys-Leu-Pro-Phe-Phe-Asp (CLPFFD) adsorbed on gold nanospheres (AuNSs). For a selective recognition of the therapeutic target (i.e. ATA beta) of AD by the conjugates peptide-nanoparticle it is relevant to understand how the interaction between attached ligands and nanoparticles occurs. In this work a surface enhanced Raman scattering spectroscopy (SERS) study of the interactions of CLPFFD with AuNSs of 10 nm average diameter was carried out. The SERS data suggest that phenylalanine displays its aromatic ring coplanar to the surface which is supported by theoretical data obtained from molecular mechanics (MM) and Extended Huckel Theory (EHT) calculations.}, keywords = {alzheimer-disease, anti-aggregation approximations, assemblies, beta-amyloid, calculations, clpffd extended hartree-fock htickel molecular-orbital nanoparticles, of peptide peptide, protein, sers, silver, spectroscopy, stability theories, theory type}, pubstate = {published}, tppubtype = {article} } In a previous work we demonstrated that toxic aggregates of the protein beta-amyloid (ATA beta) involved in the Alzheimer's disease (AD) can be destabilized upon electromagnetic irradiation of the peptide Cys-Leu-Pro-Phe-Phe-Asp (CLPFFD) adsorbed on gold nanospheres (AuNSs). For a selective recognition of the therapeutic target (i.e. ATA beta) of AD by the conjugates peptide-nanoparticle it is relevant to understand how the interaction between attached ligands and nanoparticles occurs. In this work a surface enhanced Raman scattering spectroscopy (SERS) study of the interactions of CLPFFD with AuNSs of 10 nm average diameter was carried out. The SERS data suggest that phenylalanine displays its aromatic ring coplanar to the surface which is supported by theoretical data obtained from molecular mechanics (MM) and Extended Huckel Theory (EHT) calculations. |
2014 |
Bahamonde-Padilla, V E; Lopez-Cascales, J J; Araya-Maturana, R; Martinez-Cifuentes, M; Weiss-Lopez, B Thermodynamics and (Hnmr)-H-2 Study on the Insertion of Small Quinones into a Discotic Nematic Lyotropic Liquid Crystal Artículo de revista Chemphyschem, 15 (7), pp. 1422-1431, 2014, ISSN: 1439-4235. Resumen | Enlaces | BibTeX | Etiquetas: aqueous-solution, crystals, derivatives, dynamics, ewald, force-field, free-energy, lipid-bilayer, liquid membrane, mesh micelle microviscosity, molecular molecular-dynamics nmr particle quinones, resonance, simulations, spectroscopy @article{RN213, title = {Thermodynamics and (Hnmr)-H-2 Study on the Insertion of Small Quinones into a Discotic Nematic Lyotropic Liquid Crystal}, author = { V.E. Bahamonde-Padilla and J.J. Lopez-Cascales and R. Araya-Maturana and M. Martinez-Cifuentes and B. Weiss-Lopez}, url = {/brokenurl#<Go to ISI>://WOS:000335515900018}, doi = {10.1002/cphc.201301146}, issn = {1439-4235}, year = {2014}, date = {2014-01-01}, journal = {Chemphyschem}, volume = {15}, number = {7}, pages = {1422-1431}, abstract = {A detailed description of the distribution, interaction, and dynamics of molecules with biological activity dissolved in a hydrophobic bilayer, a simple model of a biological membrane, provides valuable information for a better understanding of drug functioning, which can be very useful in drug design. Here we present an H-2 NMR and molecular dynamics study on the insertion, distribution, interactions, and thermodynamics of two biologically active molecules, 9,10-dihydroxy-4,4-dimethyl-1,4,5,8-tetrahydroanthracen-1-one (HQ), with anticancer activity, and 4,4-dimethyl-1,4,5,8,9,10-hexahydroanthracen-1,9,10-trione (Q) a fungicide, dissolved in a nematic discotic lyotropic liquid crystal (ndllc) composed of sodium dodecylsulphate (SDS), decanol (DecOH) and Na2SO4 in water. H-2 NMR quadrupole splittings ((Q)) and longitudinal relaxation times (T-1) from HQ-d(6), Q-d(4), DecOH--d(2), partially deuterated water, and SDS-d(25) were measured and several molecular dynamics trajectories were also calculated. In particular, G, H, and S profiles for the process of both molecules crossing the bilayer were estimated. It was evidenced that the insertion of both molecules into the aggregate is a spontaneous process, and the molecules are mainly distributed in the internal side of the interface. Addition of HQ or Q decreased the mobility of all aggregate components, but this effect was more pronounced for HQ. The rotational correlation time of Q allowed an estimate of 5.3 cP for the microviscosity inside the ndllc aggregate, in the order of previously measured values in similar environments. Both guest molecules display similar free-energy profiles for the process of crossing the bilayer, with a calculated barrier height of 25 and 36 kJmol(-1) for HQ and Q, respectively.}, keywords = {aqueous-solution, crystals, derivatives, dynamics, ewald, force-field, free-energy, lipid-bilayer, liquid membrane, mesh micelle microviscosity, molecular molecular-dynamics nmr particle quinones, resonance, simulations, spectroscopy}, pubstate = {published}, tppubtype = {article} } A detailed description of the distribution, interaction, and dynamics of molecules with biological activity dissolved in a hydrophobic bilayer, a simple model of a biological membrane, provides valuable information for a better understanding of drug functioning, which can be very useful in drug design. Here we present an H-2 NMR and molecular dynamics study on the insertion, distribution, interactions, and thermodynamics of two biologically active molecules, 9,10-dihydroxy-4,4-dimethyl-1,4,5,8-tetrahydroanthracen-1-one (HQ), with anticancer activity, and 4,4-dimethyl-1,4,5,8,9,10-hexahydroanthracen-1,9,10-trione (Q) a fungicide, dissolved in a nematic discotic lyotropic liquid crystal (ndllc) composed of sodium dodecylsulphate (SDS), decanol (DecOH) and Na2SO4 in water. H-2 NMR quadrupole splittings ((Q)) and longitudinal relaxation times (T-1) from HQ-d(6), Q-d(4), DecOH--d(2), partially deuterated water, and SDS-d(25) were measured and several molecular dynamics trajectories were also calculated. In particular, G, H, and S profiles for the process of both molecules crossing the bilayer were estimated. It was evidenced that the insertion of both molecules into the aggregate is a spontaneous process, and the molecules are mainly distributed in the internal side of the interface. Addition of HQ or Q decreased the mobility of all aggregate components, but this effect was more pronounced for HQ. The rotational correlation time of Q allowed an estimate of 5.3 cP for the microviscosity inside the ndllc aggregate, in the order of previously measured values in similar environments. Both guest molecules display similar free-energy profiles for the process of crossing the bilayer, with a calculated barrier height of 25 and 36 kJmol(-1) for HQ and Q, respectively. |
Ogalde, J P; Salas, C O; Lara, N; Leyton, P; Paipa, C; Campos-Vallette, M; Arriaza, B Multi-Instrumental Identification of Orpiment in Archaeological Mortuary Contexts Artículo de revista Journal of the Chilean Chemical Society, 59 (3), pp. 2571-2573, 2014, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: ceramics, chile, chorrillos, color, glass manuscripts, northern pararealgar, persian pigments, raman raman, realgar, sem-edx, spectra, spectroscopy @article{RN210, title = {Multi-Instrumental Identification of Orpiment in Archaeological Mortuary Contexts}, author = { J.P. Ogalde and C.O. Salas and N. Lara and P. Leyton and C. Paipa and M. Campos-Vallette and B. Arriaza}, url = {/brokenurl#<Go to ISI>://WOS:000347833800010}, doi = {10.4067/S0717-97072014000300010}, issn = {0717-9707}, year = {2014}, date = {2014-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {59}, number = {3}, pages = {2571-2573}, abstract = {This paper reports on an unknown yellowish mineral compound found in an archaeological context from Chorrillos cemetery (Calama, Chile) dating to the Early Formative period (800 - 200 B.C.). We used optic microscopy, SEM, EDX, H-1-RMN, C-13-RMN, and infrared (IR) and Raman spectroscopy to tease out the chemical and molecular composition of the sample. The microscopic images show amorphous yellowish granulates with heterogeneous chemical surfaces. H-1-RMN and C-13-RMN negative results show that the sample is free of organic matter. The SEM and EDX indicate the presence of arsenic and sulfur in the sample. The IR and Raman analyses suggest the presence of orpiment which is a toxic yellow arsenic sulfide mineral.}, keywords = {ceramics, chile, chorrillos, color, glass manuscripts, northern pararealgar, persian pigments, raman raman, realgar, sem-edx, spectra, spectroscopy}, pubstate = {published}, tppubtype = {article} } This paper reports on an unknown yellowish mineral compound found in an archaeological context from Chorrillos cemetery (Calama, Chile) dating to the Early Formative period (800 - 200 B.C.). We used optic microscopy, SEM, EDX, H-1-RMN, C-13-RMN, and infrared (IR) and Raman spectroscopy to tease out the chemical and molecular composition of the sample. The microscopic images show amorphous yellowish granulates with heterogeneous chemical surfaces. H-1-RMN and C-13-RMN negative results show that the sample is free of organic matter. The SEM and EDX indicate the presence of arsenic and sulfur in the sample. The IR and Raman analyses suggest the presence of orpiment which is a toxic yellow arsenic sulfide mineral. |
Araya, C; Jaque, J; Naranjo, N; Icaza, M; Clavijo, E; Aguayo, T; Campos-Vallette, M Raman Characterization of Pigments in Painted Beams and a Wall Painting Discovered in the San Francisco Church in Santiago, Chile Artículo de revista Spectroscopy Letters, 47 (3), pp. 177-183, 2014, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: analyses, binding copper, corrosion, ft-raman, identification, lead library, media, microchemical minerals, mural painting, polychrome, raman spectra, spectroscopy, wood @article{RN211, title = {Raman Characterization of Pigments in Painted Beams and a Wall Painting Discovered in the San Francisco Church in Santiago, Chile}, author = { C. Araya and J. Jaque and N. Naranjo and M. Icaza and E. Clavijo and T. Aguayo and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000329200400003}, doi = {10.1080/00387010.2013.788521}, issn = {0038-7010}, year = {2014}, date = {2014-01-01}, journal = {Spectroscopy Letters}, volume = {47}, number = {3}, pages = {177-183}, abstract = {A material characterization of two artworks discovered in the San Francisco Church, Santiago, Chile, was performed using micro-Raman spectroscopy. Structural painted beams and a wall painting that belong to the same time period, between the end of the 17th and 19th centuries, were analyzed. The cross-section samples of both artworks were characterized and animal protein was identified in the ground layer in both cases. The supporting material of the beams was identified as cypress wood, and a rag paper layer was used as a base for the paint layer, which is composed mainly of a white ground layer on which the color was subsequently added; the yellow pigments are orpiment and chrome yellow; the green color probably arises from a mixture of orpiment, red lead, ultramarine blue, and calcite. A complete analysis of the materials using complementary techniques such as microchemistry and optical microscopy indicates that the mural was painted using a mixed technique and that organic and inorganic pigments were used. The identification of the synthetic pigment ultramarine blue in some blue areas of the wall revealed a modification of the wall painting in the 19th century; dark blue areas resulted from a mixture of indigo, palygorskite, and lazurite.}, keywords = {analyses, binding copper, corrosion, ft-raman, identification, lead library, media, microchemical minerals, mural painting, polychrome, raman spectra, spectroscopy, wood}, pubstate = {published}, tppubtype = {article} } A material characterization of two artworks discovered in the San Francisco Church, Santiago, Chile, was performed using micro-Raman spectroscopy. Structural painted beams and a wall painting that belong to the same time period, between the end of the 17th and 19th centuries, were analyzed. The cross-section samples of both artworks were characterized and animal protein was identified in the ground layer in both cases. The supporting material of the beams was identified as cypress wood, and a rag paper layer was used as a base for the paint layer, which is composed mainly of a white ground layer on which the color was subsequently added; the yellow pigments are orpiment and chrome yellow; the green color probably arises from a mixture of orpiment, red lead, ultramarine blue, and calcite. A complete analysis of the materials using complementary techniques such as microchemistry and optical microscopy indicates that the mural was painted using a mixed technique and that organic and inorganic pigments were used. The identification of the synthetic pigment ultramarine blue in some blue areas of the wall revealed a modification of the wall painting in the 19th century; dark blue areas resulted from a mixture of indigo, palygorskite, and lazurite. |
2013 |
Aguayo, T; Garrido, C; Clavijo, E; Gomez-Jeria, J S; Monasterio, C A; Icaza, M; Moraga, F E; Campos-Vallette, M Raman and Surface Enhanced Raman Scattering of a Black Dyed Silk Artículo de revista Journal of Raman Spectroscopy, 44 (9), pp. 1238-1245, 2013, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: aromatic-hydrocarbons, art, dye, fibroin, gagags, microscopy, model, nmr polycyclic raman, resonance sers, silk, spectroscopy @article{RN153, title = {Raman and Surface Enhanced Raman Scattering of a Black Dyed Silk}, author = { T. Aguayo and C. Garrido and E. Clavijo and J.S. Gomez-Jeria and C.A. Monasterio and M. Icaza and F.E. Moraga and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000323784900005}, doi = {10.1002/jrs.4348}, issn = {0377-0486}, year = {2013}, date = {2013-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {44}, number = {9}, pages = {1238-1245}, publisher = {2013 John Wiley & Sons, Ltd.}, abstract = {The Raman and surface enhanced Raman scattering (SERS) spectra of a black dyed silk sample (BDS) were registered. The spectral analysis was performed on the basis of Raman and SERS spectral data of isolated samples of Bombyx mori silk fibroin, its motif peptide component (GAGAGS) and the synthetic reactive black 5 dye (RB5). The macro FT-Raman spectrum of the silk sample is consistent with a silk II-Cp crystalline fraction of Bombyx mori silk fibroin; the SERS spectrum is highly consistent with conformational modifications of the fibroin due to the interactions with the Ag nanoparticles. The GAGAGS peptide sequence dominates the Raman spectrum of the silk. The SERS spectrum of the peptide suggests a random coil conformation imposed by the surface interaction; the serine residue in the new conformation is exposed to the surface. Quantum chemical calculations for a model of the GAGAGS-Ag surface predict a nearly extended conformation at the Ag surface. The Raman spectrum of the dye was analysed, and a complete band assignment was proposed; it was not possible to propose a preferential orientation or organization of the molecule on the metal surface. Quantum chemical calculations for a model of the dye interacting with a silver surface predict a rather coplanar orientation of the RB5 on the Ag metal surface. The Raman spectrum of the BDS sample is dominated by signals from the dye; the general spectral behaviour indicates that the dye mainly interacts with the silk through the sulphone (-SO2-) and sulphonate (-SO2-O-) groups. Besides the presence of dye signals, mainly ascribed to the sulphone and sulphonate bands, the SERS spectrum of the BDS sample also displays bands belonging to the amino acids alanine, glycine, serine and particularly tyrosine.}, keywords = {aromatic-hydrocarbons, art, dye, fibroin, gagags, microscopy, model, nmr polycyclic raman, resonance sers, silk, spectroscopy}, pubstate = {published}, tppubtype = {article} } The Raman and surface enhanced Raman scattering (SERS) spectra of a black dyed silk sample (BDS) were registered. The spectral analysis was performed on the basis of Raman and SERS spectral data of isolated samples of Bombyx mori silk fibroin, its motif peptide component (GAGAGS) and the synthetic reactive black 5 dye (RB5). The macro FT-Raman spectrum of the silk sample is consistent with a silk II-Cp crystalline fraction of Bombyx mori silk fibroin; the SERS spectrum is highly consistent with conformational modifications of the fibroin due to the interactions with the Ag nanoparticles. The GAGAGS peptide sequence dominates the Raman spectrum of the silk. The SERS spectrum of the peptide suggests a random coil conformation imposed by the surface interaction; the serine residue in the new conformation is exposed to the surface. Quantum chemical calculations for a model of the GAGAGS-Ag surface predict a nearly extended conformation at the Ag surface. The Raman spectrum of the dye was analysed, and a complete band assignment was proposed; it was not possible to propose a preferential orientation or organization of the molecule on the metal surface. Quantum chemical calculations for a model of the dye interacting with a silver surface predict a rather coplanar orientation of the RB5 on the Ag metal surface. The Raman spectrum of the BDS sample is dominated by signals from the dye; the general spectral behaviour indicates that the dye mainly interacts with the silk through the sulphone (-SO2-) and sulphonate (-SO2-O-) groups. Besides the presence of dye signals, mainly ascribed to the sulphone and sulphonate bands, the SERS spectrum of the BDS sample also displays bands belonging to the amino acids alanine, glycine, serine and particularly tyrosine. |
Diaz, C; Garcia, C; Iturriaga-Vasquez, P; Aguirre, M J; Muena, J P; Contreras, R; Ormazabal-Toledo, R; Isaacs, M Experimental and Theoretical Study on the Oxidation Mechanism of Dopamine in N-Octyl Pyridinium Based Ionic Liquids-Carbon Paste Modified Electrodes Artículo de revista Electrochimica Acta, 111 , pp. 846-854, 2013, ISSN: 0013-4686. Resumen | Enlaces | BibTeX | Etiquetas: behavior, detection, disk dopamine electrochemical electrode, electrodes, impedance impedance, insights, ionic liquids-carbon mechanism, metabolites, oxidation paste rat rotating separation, spectroscopy, striatum @article{RN129, title = {Experimental and Theoretical Study on the Oxidation Mechanism of Dopamine in N-Octyl Pyridinium Based Ionic Liquids-Carbon Paste Modified Electrodes}, author = { C. Diaz and C. Garcia and P. Iturriaga-Vasquez and M.J. Aguirre and J.P. Muena and R. Contreras and R. Ormazabal-Toledo and M. Isaacs}, url = {/brokenurl#<Go to ISI>://WOS:000329531100111}, doi = {10.1016/j.electacta.2013.08.103}, issn = {0013-4686}, year = {2013}, date = {2013-01-01}, journal = {Electrochimica Acta}, volume = {111}, pages = {846-854}, publisher = {2013 Elsevier Ltd.}, abstract = {This work describes the influence of n-octyl pyridinium cations based ionicliquids-carbon paste modified electrodes on the oxidation mechanism of dopamine. Ionic liquids formed by hexafluorophosphate anion and n-octyl pyridinium [R-OPy](+); R= CH3, H, CF3, where ionic liquids containing CH3 and CF3 are new products, were synthesized and characterized. Modified carbon paste electrodes with these salts were characterized by electrochemicalimpedance spectroscopy and cyclic voltammetry. Electrochemical oxidation of dopamine was studied in PBS buffer solution at pH = 7.4. The influence of the ionic liquids in the oxidation of dopamine was studied by cyclic voltammetry and rotating disk electrode. The results show that typical carbon paste electrode presents an electrochemical/chemical mechanism; whereas [OPy]PF6 and [CF3-OPy]PF6 modified electrodes present an electrochemical/chemical/electrochemical mechanism. The experimental study is complemented with a theoretical analysis of substituent effects in terms of the molecular electrostatic potential, Mulliken population analysis and second order perturbation theory probed at the cation moiety of the IL These indices consistently show an electron density accumulation at the ipso position of the pyridinium moiety of the IL that is in agreement with the electrochemical characterization.}, keywords = {behavior, detection, disk dopamine electrochemical electrode, electrodes, impedance impedance, insights, ionic liquids-carbon mechanism, metabolites, oxidation paste rat rotating separation, spectroscopy, striatum}, pubstate = {published}, tppubtype = {article} } This work describes the influence of n-octyl pyridinium cations based ionicliquids-carbon paste modified electrodes on the oxidation mechanism of dopamine. Ionic liquids formed by hexafluorophosphate anion and n-octyl pyridinium [R-OPy](+); R= CH3, H, CF3, where ionic liquids containing CH3 and CF3 are new products, were synthesized and characterized. Modified carbon paste electrodes with these salts were characterized by electrochemicalimpedance spectroscopy and cyclic voltammetry. Electrochemical oxidation of dopamine was studied in PBS buffer solution at pH = 7.4. The influence of the ionic liquids in the oxidation of dopamine was studied by cyclic voltammetry and rotating disk electrode. The results show that typical carbon paste electrode presents an electrochemical/chemical mechanism; whereas [OPy]PF6 and [CF3-OPy]PF6 modified electrodes present an electrochemical/chemical/electrochemical mechanism. The experimental study is complemented with a theoretical analysis of substituent effects in terms of the molecular electrostatic potential, Mulliken population analysis and second order perturbation theory probed at the cation moiety of the IL These indices consistently show an electron density accumulation at the ipso position of the pyridinium moiety of the IL that is in agreement with the electrochemical characterization. |
Garrido, C; Aguayo, T; Clavijo, E; Gomez-Jeria, J S; Campos-Vallette, M The Effect of the Ph on the Interaction of L-Arginine with Colloidal Silver Nanoparticles. A Raman and Sers Study Artículo de revista Journal of Raman Spectroscopy, 44 (8), pp. 1105-1110, 2013, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: amino-acids, aromatic-hydrocarbons, enhanced extended huckel hydrochloride l-arginine, l-lysine, polycyclic potential protein, raman scattering scattering, spectra, spectroscopy, surface surface, temperature, theory zeta @article{RN154, title = {The Effect of the Ph on the Interaction of L-Arginine with Colloidal Silver Nanoparticles. A Raman and Sers Study}, author = { C. Garrido and T. Aguayo and E. Clavijo and J.S. Gomez-Jeria and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000323180700006}, doi = {10.1002/jrs.4331}, issn = {0377-0486}, year = {2013}, date = {2013-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {44}, number = {8}, pages = {1105-1110}, publisher = {2013 John Wiley & Sons, Ltd.}, abstract = {Raman and surface enhanced Raman scattering (SERS) spectroscopies were used to study the pH effect (7 to 9) on the interaction of arginine (Arg) with colloidal Ag nanoparticles (AgNps). A new methodology was implemented in order to obtain reproducible SERS spectra in solution. The dependence of the Arg concentration on the stability of the AgNps is discussed. A pH increasing of the colloidal solution to the limits of the Arg pKa(2) value induces a preferential and stable Arg-metal interaction. potential measurements of the Arg-AgNps system at different pH conditions studied provide information about the Arg-AgNps interaction; the pH increasing favors the interaction. SERS spectra at pH 7 indicate that the molecule interacts with the Ag surface only through the guanidinium fragment. By increasing the pH to 9, the molecule adopts a new conformation on the surface; the metal-analyte interaction is verified through the guanidinium, carboxylate and the aliphatic moieties. In addition, theoretical calculations performed by using the extended Huckel method for a model of Arg interacting with an Ag surface support the observed SERS results.}, keywords = {amino-acids, aromatic-hydrocarbons, enhanced extended huckel hydrochloride l-arginine, l-lysine, polycyclic potential protein, raman scattering scattering, spectra, spectroscopy, surface surface, temperature, theory zeta}, pubstate = {published}, tppubtype = {article} } Raman and surface enhanced Raman scattering (SERS) spectroscopies were used to study the pH effect (7 to 9) on the interaction of arginine (Arg) with colloidal Ag nanoparticles (AgNps). A new methodology was implemented in order to obtain reproducible SERS spectra in solution. The dependence of the Arg concentration on the stability of the AgNps is discussed. A pH increasing of the colloidal solution to the limits of the Arg pKa(2) value induces a preferential and stable Arg-metal interaction. potential measurements of the Arg-AgNps system at different pH conditions studied provide information about the Arg-AgNps interaction; the pH increasing favors the interaction. SERS spectra at pH 7 indicate that the molecule interacts with the Ag surface only through the guanidinium fragment. By increasing the pH to 9, the molecule adopts a new conformation on the surface; the metal-analyte interaction is verified through the guanidinium, carboxylate and the aliphatic moieties. In addition, theoretical calculations performed by using the extended Huckel method for a model of Arg interacting with an Ag surface support the observed SERS results. |
2012 |
Carcamo, J J; Aliaga, A E; Clavijo, E; Branes, M; Campos-Vallette, M Raman Study of the Shockwave Effect on Collagens Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 86 , pp. 360-365, 2012, ISSN: 1386-1425. Resumen | Enlaces | BibTeX | Etiquetas: amino-acids, collagens, conformation, dependence, infrared-spectra, raman, scattering, shockwaves, spectroscopy, time tissues @article{carcamo2012raman, title = {Raman Study of the Shockwave Effect on Collagens}, author = { J.J. Carcamo and A.E. Aliaga and E. Clavijo and M. Branes and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000300515500052}, doi = {10.1016/j.saa.2011.10.049}, issn = {1386-1425}, year = {2012}, date = {2012-01-01}, journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy}, volume = {86}, pages = {360-365}, publisher = {2011 Elsevier B.V.}, abstract = {The Raman spectra (1800-200 cm(-1)) of isolated dried collagen types land ill were recorded at different times after shockwave (SW) application in aqueous media. SWs were applied in a single session. One week after the SW application the vibrational data analysis indicates changes in the conformation of the collagens; orientational changes are also inferred. During the next three weeks collagens tended to recover the conformation and orientation existing before SW application.}, keywords = {amino-acids, collagens, conformation, dependence, infrared-spectra, raman, scattering, shockwaves, spectroscopy, time tissues}, pubstate = {published}, tppubtype = {article} } The Raman spectra (1800-200 cm(-1)) of isolated dried collagen types land ill were recorded at different times after shockwave (SW) application in aqueous media. SWs were applied in a single session. One week after the SW application the vibrational data analysis indicates changes in the conformation of the collagens; orientational changes are also inferred. During the next three weeks collagens tended to recover the conformation and orientation existing before SW application. |
Garrido, C; Aliaga, A E; Gomez-Jeria, J S; Carcamo, J J; Clavijo, E; Campos-Vallette, M Interaction of the C-Terminal Peptide from Pigeon Cytochrome C with Silver Nanoparticles. A Raman, Sers and Theoretical Study Artículo de revista Vibrational Spectroscopy, 61 , pp. 94-98, 2012, ISSN: 0924-2031. Resumen | Enlaces | BibTeX | Etiquetas: amino-acids, approximations aromatic-hydrocarbons, charge, enhanced extended hartree-fock huckel hydrophobicity, molecular-orbital net pcc87-104 peptide, polycyclic proteins, raman raman, scattering, spectroscopy, surface, surface-enhanced theories, theory, type @article{garrido2012interaction, title = {Interaction of the C-Terminal Peptide from Pigeon Cytochrome C with Silver Nanoparticles. A Raman, Sers and Theoretical Study}, author = { C. Garrido and A.E. Aliaga and J.S. Gomez-Jeria and J.J. Carcamo and E. Clavijo and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000304686400014}, doi = {10.1016/j.vibspec.2012.01.011}, issn = {0924-2031}, year = {2012}, date = {2012-01-01}, journal = {Vibrational Spectroscopy}, volume = {61}, pages = {94-98}, publisher = {2012 Elsevier B.V.}, abstract = {The Raman and surface-enhanced Raman scattering (SERS) spectra of the C-terminal peptide of pigeon cytochrome C (PCC87-104). were recorded. This peptide is widely used to study the immune response in vivo. Hydrophobicity and net charge parameters of PCC87-104, allowed prediction of the nature of its interaction with colloidal nanostructured silver surfaces. The SERS spectrum provided information about the organization and orientation of PCC87-104 on the surface of silver nanoparticles (AgNPs). The batch to batch reproducible SERS spectra were obtained by adding the colloidal AgNPs solution onto the dried analyte sample. On the basis of the SERS information and the analysis of the net charge of each amino acid residue in the peptide sequence, it is concluded that the interaction of the peptide and the AgNPs is mainly induced and oriented by the lysine residues. The spectroscopic results are supported by quantum chemical calculations, performed by using Extended Huckel theory for a model of PCC87-104 interacting with a silver surface.}, keywords = {amino-acids, approximations aromatic-hydrocarbons, charge, enhanced extended hartree-fock huckel hydrophobicity, molecular-orbital net pcc87-104 peptide, polycyclic proteins, raman raman, scattering, spectroscopy, surface, surface-enhanced theories, theory, type}, pubstate = {published}, tppubtype = {article} } The Raman and surface-enhanced Raman scattering (SERS) spectra of the C-terminal peptide of pigeon cytochrome C (PCC87-104). were recorded. This peptide is widely used to study the immune response in vivo. Hydrophobicity and net charge parameters of PCC87-104, allowed prediction of the nature of its interaction with colloidal nanostructured silver surfaces. The SERS spectrum provided information about the organization and orientation of PCC87-104 on the surface of silver nanoparticles (AgNPs). The batch to batch reproducible SERS spectra were obtained by adding the colloidal AgNPs solution onto the dried analyte sample. On the basis of the SERS information and the analysis of the net charge of each amino acid residue in the peptide sequence, it is concluded that the interaction of the peptide and the AgNPs is mainly induced and oriented by the lysine residues. The spectroscopic results are supported by quantum chemical calculations, performed by using Extended Huckel theory for a model of PCC87-104 interacting with a silver surface. |
Leyton, P; Saladino, R; Crestini, C; Campos-Vallette, M; Paipa, C; Berrios, A; Fuentes, S; Zarate, R A Influence of Tio2 on Prebiotic Thermal Synthesis of the Gly-Gln Polymer Artículo de revista Amino Acids, 42 (6), pp. 2079-2088, 2012, ISSN: 0939-4451. Resumen | Enlaces | BibTeX | Etiquetas: amino-acids, chemistry, condensation conditions, crystalline diketopiperazine, dioxide, dynamics, earth formation ft-ir glutamic glycine, peptide prebiotic primitive reaction, self-disproportionation, spectra, spectroscopy, synthesis, thermal titanium vibrational @article{RN29d, title = {Influence of Tio2 on Prebiotic Thermal Synthesis of the Gly-Gln Polymer}, author = { P. Leyton and R. Saladino and C. Crestini and M. Campos-Vallette and C. Paipa and A. Berrios and S. Fuentes and R.A. Zarate}, url = {/brokenurl#<Go to ISI>://WOS:000304150300004}, doi = {10.1007/s00726-011-0939-6}, issn = {0939-4451}, year = {2012}, date = {2012-01-01}, journal = {Amino Acids}, volume = {42}, number = {6}, pages = {2079-2088}, abstract = {The role of the titanium dioxide (rutile and anatase) with and without room light on the thermal synthesis of the glycine--glutamine (Gly-Gln) polymer is described. The efficiency in percentage of polymerization with room light was increased in 6% in the presence of rutile and in 23% in the presence of anatase. The thermal synthesis in the molten state was carried out in the absence and presence of both oxides. In all cases, the vibrational spectra showed characteristic group frequencies corresponding to a polypeptide structure. No spectral differences were observed by room light effect on the polymer on rutile. However, the polymer obtained in the presence of anatase and room light shows spectral changes associated with the formation of shorter new abundant and conformationally different species compared with the original polymer. The SEM-EDX characterization of the solid phase involved in the thermal synthesis showed that the morphology of the polypeptide is different in the presence of rutile compared to anatase. The SDS-PAGE and GPC results suggest that smaller chains are formed in the presence of both oxides and the distribution of the size and weight of each polymer molecule is completely different when the condensation is performed in the presence of anatase or rutile. Nuclear magnetic resonance analyses confirmed the incorporation of both Gly and Gln residues in the polymers, with a prevalence of Gly. Both possible sequences -GlyGln- and -GlnGly- were also detected.}, keywords = {amino-acids, chemistry, condensation conditions, crystalline diketopiperazine, dioxide, dynamics, earth formation ft-ir glutamic glycine, peptide prebiotic primitive reaction, self-disproportionation, spectra, spectroscopy, synthesis, thermal titanium vibrational}, pubstate = {published}, tppubtype = {article} } The role of the titanium dioxide (rutile and anatase) with and without room light on the thermal synthesis of the glycine--glutamine (Gly-Gln) polymer is described. The efficiency in percentage of polymerization with room light was increased in 6% in the presence of rutile and in 23% in the presence of anatase. The thermal synthesis in the molten state was carried out in the absence and presence of both oxides. In all cases, the vibrational spectra showed characteristic group frequencies corresponding to a polypeptide structure. No spectral differences were observed by room light effect on the polymer on rutile. However, the polymer obtained in the presence of anatase and room light shows spectral changes associated with the formation of shorter new abundant and conformationally different species compared with the original polymer. The SEM-EDX characterization of the solid phase involved in the thermal synthesis showed that the morphology of the polypeptide is different in the presence of rutile compared to anatase. The SDS-PAGE and GPC results suggest that smaller chains are formed in the presence of both oxides and the distribution of the size and weight of each polymer molecule is completely different when the condensation is performed in the presence of anatase or rutile. Nuclear magnetic resonance analyses confirmed the incorporation of both Gly and Gln residues in the polymers, with a prevalence of Gly. Both possible sequences -GlyGln- and -GlnGly- were also detected. |
Carcamo, J J; Aliaga, A E; Clavijo, E; Branes, M; Campos-Vallette, M Raman and Surface-Enhanced Raman Scattering in the Study of Human Rotator Cuff Tissues after Shock Wave Treatment Artículo de revista Journal of Raman Spectroscopy, 43 (2), pp. 248-254, 2012, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: amino-acids, collagen, collagens, cuff, gold infrared-spectra, nanoparticles, raman, rotator sers, shockwaves, silver, single-molecule, spectroscopy @article{RN39i, title = {Raman and Surface-Enhanced Raman Scattering in the Study of Human Rotator Cuff Tissues after Shock Wave Treatment}, author = { J.J. Carcamo and A.E. Aliaga and E. Clavijo and M. Branes and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000300836900011}, doi = {10.1002/jrs.3019}, issn = {0377-0486}, year = {2012}, date = {2012-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {43}, number = {2}, pages = {248-254}, publisher = {2011 John Wiley & Sons, Ltd.}, abstract = {Important improvements of diseases of the rotator cuff supraspinatus tendons are seen after shock wave (SW) treatment. Neo-angiogenesis stimulation and hypercellularization result from short periods of treatment. The present work is an attempt to provide a first approach to these bioprocesses, most likely associated with structural aspects resulting from biochemical changes brought about by the SW. Immunohistochemical data indicate that collagen areas in the tissues are influenced the most by the SW. Presence of additional collagens I and III by the SW treatment is inferred from an observed increase of the tissue's tinctorial properties. The tools selected for our studies are Raman spectroscopy and the ultrasensitive surface-enhanced Raman scattering (SERS). Here we extract information from 1016 SERS spectra of 52 biopsies of human tendon tissues on Ag nanoparticles before and after the SW treatment. The spectral information is analyzed on the basis of Raman and SERS data of collagen types I and III and their most abundant amino acid components. SERS spectra of tissues reveal the presence of characteristic modes related mainly to amino acids. It has been found that the main differences between both tissue samples could be correlated with the structural conformational aspects of collagen.}, keywords = {amino-acids, collagen, collagens, cuff, gold infrared-spectra, nanoparticles, raman, rotator sers, shockwaves, silver, single-molecule, spectroscopy}, pubstate = {published}, tppubtype = {article} } Important improvements of diseases of the rotator cuff supraspinatus tendons are seen after shock wave (SW) treatment. Neo-angiogenesis stimulation and hypercellularization result from short periods of treatment. The present work is an attempt to provide a first approach to these bioprocesses, most likely associated with structural aspects resulting from biochemical changes brought about by the SW. Immunohistochemical data indicate that collagen areas in the tissues are influenced the most by the SW. Presence of additional collagens I and III by the SW treatment is inferred from an observed increase of the tissue's tinctorial properties. The tools selected for our studies are Raman spectroscopy and the ultrasensitive surface-enhanced Raman scattering (SERS). Here we extract information from 1016 SERS spectra of 52 biopsies of human tendon tissues on Ag nanoparticles before and after the SW treatment. The spectral information is analyzed on the basis of Raman and SERS data of collagen types I and III and their most abundant amino acid components. SERS spectra of tissues reveal the presence of characteristic modes related mainly to amino acids. It has been found that the main differences between both tissue samples could be correlated with the structural conformational aspects of collagen. |
2011 |
Aguayo, T; Clavijo, E; Eisner, F; Ossa-Izquierdo, C; Campos-Vallette, M Raman Spectroscopy in the Diagnosis of the Wall Painting History of Concepcion, Chile Artículo de revista Journal of Raman Spectroscopy, 42 (12), pp. 2143-2148, 2011, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: analysis, art, calcium, conservation, cultural-heritage, fluorescence ft-raman, identification, nondestructive of painting, pigment pigments, raman spectra, spectroscopy, wall work @article{RN40b, title = {Raman Spectroscopy in the Diagnosis of the Wall Painting History of Concepcion, Chile}, author = { T. Aguayo and E. Clavijo and F. Eisner and C. Ossa-Izquierdo and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000298581500013}, doi = {10.1002/jrs.2978}, issn = {0377-0486}, year = {2011}, date = {2011-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {42}, number = {12}, pages = {2143-2148}, publisher = {2011 John Wiley & Sons, Ltd.}, abstract = {Pigments and fresco-related materials from the wall painting Historia de Concepcion by Gregorio De La Fuente in Concepcion, Chile were identified by Raman microscopy. The pigments were compared with those obtained from the artist's studio, and results allowed inference about subsequent interventions. Materials coming from processes such as salt efflorescence were also studied. The results contribute to the diagnosis of the current conservation state of the wall painting for its future restoration.}, keywords = {analysis, art, calcium, conservation, cultural-heritage, fluorescence ft-raman, identification, nondestructive of painting, pigment pigments, raman spectra, spectroscopy, wall work}, pubstate = {published}, tppubtype = {article} } Pigments and fresco-related materials from the wall painting Historia de Concepcion by Gregorio De La Fuente in Concepcion, Chile were identified by Raman microscopy. The pigments were compared with those obtained from the artist's studio, and results allowed inference about subsequent interventions. Materials coming from processes such as salt efflorescence were also studied. The results contribute to the diagnosis of the current conservation state of the wall painting for its future restoration. |
Leyton, P; Zarate, R A; Fuentes, S; Paipa, C; Gomez-Jeria, J S; Leyton, Y Influence of Aluminum Oxide on the Prebiotic Thermal Synthesis of Gly-Glu-(Gly-Glu)(N) Polymer Artículo de revista Biosystems, 104 (2-3), pp. 118-126, 2011, ISSN: 0303-2647. Resumen | Enlaces | BibTeX | Etiquetas: amino-acid-sequences, analysis, bond chemistry, conditions, crystalline diketopiperazine, earth formation formation, glutamic glycine ir-spectra, peptide prebiotic primitive pyroglutamic reaction, spectroscopy, synthesis, thermal vibrational @article{RN27d, title = {Influence of Aluminum Oxide on the Prebiotic Thermal Synthesis of Gly-Glu-(Gly-Glu)(N) Polymer}, author = { P. Leyton and R.A. Zarate and S. Fuentes and C. Paipa and J.S. Gomez-Jeria and Y. Leyton}, url = {/brokenurl#<Go to ISI>://WOS:000290194500006}, doi = {10.1016/j.biosystems.2011.01.008}, issn = {0303-2647}, year = {2011}, date = {2011-01-01}, journal = {Biosystems}, volume = {104}, number = {2-3}, pages = {118-126}, publisher = {2011 Elsevier Ireland Ltd.}, abstract = {The effect of the aluminum oxide on the thermal synthesis of the glycine-glutamic acid (Gly-Glu-(Gly-Glu)(n) polymer is described. The thermal synthesis in the molten state was carried out in the absence and presence of the oxide. In both cases, the vibrational spectra showed characteristic group frequencies corresponding predominantly to a Gly-Glu-(Gly-Glu)(n) sequence in the polymeric structure. The theoretical spectral data support the experimental proposed Gly-Glu-(Gly-Glu)(n) sequence for the polymer. The SEM-EDX characterization of the solid phase involved in the thermal synthesis showed that the aluminum oxide participates as a site for nucleation and growth of the polymer, explaining the increase of 25% efficiency in the presence of aluminum oxide. Electrophoresis data show shorter polypeptide chains in the presence of aluminum oxide.}, keywords = {amino-acid-sequences, analysis, bond chemistry, conditions, crystalline diketopiperazine, earth formation formation, glutamic glycine ir-spectra, peptide prebiotic primitive pyroglutamic reaction, spectroscopy, synthesis, thermal vibrational}, pubstate = {published}, tppubtype = {article} } The effect of the aluminum oxide on the thermal synthesis of the glycine-glutamic acid (Gly-Glu-(Gly-Glu)(n) polymer is described. The thermal synthesis in the molten state was carried out in the absence and presence of the oxide. In both cases, the vibrational spectra showed characteristic group frequencies corresponding predominantly to a Gly-Glu-(Gly-Glu)(n) sequence in the polymeric structure. The theoretical spectral data support the experimental proposed Gly-Glu-(Gly-Glu)(n) sequence for the polymer. The SEM-EDX characterization of the solid phase involved in the thermal synthesis showed that the aluminum oxide participates as a site for nucleation and growth of the polymer, explaining the increase of 25% efficiency in the presence of aluminum oxide. Electrophoresis data show shorter polypeptide chains in the presence of aluminum oxide. |
Diaz-Fleming, G; Celis, F; Campos-Vallette, M; Aliaga, A E; Escobar, M; Koch, R Raman, Infrared, Sers and Theoretical Study of 3-(1-Phenylpropan-2-Ylamino) Propanenitrile, Fenproporex Artículo de revista Journal of Raman Spectroscopy, 42 (7), pp. 1497-1504, 2011, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: calculations, density-functional dft elements, fenproporex, gold, infrared, raman, scattering, sers, silver, spectroscopy, surface-enhanced temperature theory @article{RN41f, title = {Raman, Infrared, Sers and Theoretical Study of 3-(1-Phenylpropan-2-Ylamino) Propanenitrile, Fenproporex}, author = { G. Diaz-Fleming and F. Celis and M. Campos-Vallette and A.E. Aliaga and M. Escobar and R. Koch}, url = {/brokenurl#<Go to ISI>://WOS:000293001000003}, doi = {10.1002/jrs.2882}, issn = {0377-0486}, year = {2011}, date = {2011-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {42}, number = {7}, pages = {1497-1504}, publisher = {2011 John Wiley & Sons, Ltd.}, abstract = {Infrared, Raman and surface-enhanced Raman scattering (SERS) spectra of 3-(1-phenylpropan-2-ylamino) propanenitrile (fenproporex) have been recorded. Density functional theory (DFT) with the B3LYP functional was used for optimizations of ground state geometries and simulation of Raman and SERS vibrational spectra of this molecule. Bands of the vibrational spectra were assigned in detail. The comparison of SERS spectra obtained by using colloidal silver and gold nanoparticles with the corresponding Raman spectrum reveals enhancement and shifts in bands, suggesting a possible partial charge-transfer mechanism in the SERS effect. Information about the orientation of fenproporex on the nanometer-sized metal structures is also obtained.}, keywords = {calculations, density-functional dft elements, fenproporex, gold, infrared, raman, scattering, sers, silver, spectroscopy, surface-enhanced temperature theory}, pubstate = {published}, tppubtype = {article} } Infrared, Raman and surface-enhanced Raman scattering (SERS) spectra of 3-(1-phenylpropan-2-ylamino) propanenitrile (fenproporex) have been recorded. Density functional theory (DFT) with the B3LYP functional was used for optimizations of ground state geometries and simulation of Raman and SERS vibrational spectra of this molecule. Bands of the vibrational spectra were assigned in detail. The comparison of SERS spectra obtained by using colloidal silver and gold nanoparticles with the corresponding Raman spectrum reveals enhancement and shifts in bands, suggesting a possible partial charge-transfer mechanism in the SERS effect. Information about the orientation of fenproporex on the nanometer-sized metal structures is also obtained. |
Publicaciones 2011-2020
