2018 |
Silva, N; Riveros, A; Yutronic, N; Lang, E; Chornik, B; Guerrero, S; Samitier, J; Jara, P; Kogan, M J Photothermally Controlled Methotrexate Release System Using Beta-Cyclodextrin and Gold Nanoparticles Artículo de revista Nanomaterials, 8 (12), 2018, ISSN: 2079-4991. Resumen | Enlaces | BibTeX | Etiquetas: binding, citrate complex, compound, cyclodextrin, delivery delivery, gold hepatotoxicity, inclusion irradiation, laser, methotrexate, nanoparticles, oxidative photothermal release, stabilization, stress, system, therapy @article{RN392, title = {Photothermally Controlled Methotrexate Release System Using Beta-Cyclodextrin and Gold Nanoparticles}, author = { N. Silva and A. Riveros and N. Yutronic and E. Lang and B. Chornik and S. Guerrero and J. Samitier and P. Jara and M.J. Kogan}, url = {/brokenurl#<Go to ISI>://WOS:000455323100023}, doi = {10.3390/nano8120985}, issn = {2079-4991}, year = {2018}, date = {2018-01-01}, journal = {Nanomaterials}, volume = {8}, number = {12}, abstract = {The inclusion compound (IC) of cyclodextrin (CD) containing the antitumor drug Methotrexate (MTX) as a guest molecule was obtained to increase the solubility of MTX and decrease its inherent toxic effects in nonspecific cells. The IC was conjugated with gold nanoparticles (AuNPs), obtained by a chemical method, creating a ternary intelligent delivery system for MTX molecules, based on the plasmonic properties of the AuNPs. Irradiation of the ternary system, with a laser wavelength tunable with the corresponding surface plasmon of AuNPs, causes local energy dissipation, producing the controlled release of the guest from CD cavities. Finally, cell viability was evaluated using MTS assays for beta-CD/MTX and AuNPs + beta-CD/MTX samples, with and without irradiation, against HeLa tumor cells. The irradiated sample of the ternary system AuNPs + beta-CD/MTX produced a diminution in cell viability attributed to the photothermal release of MTX.}, keywords = {binding, citrate complex, compound, cyclodextrin, delivery delivery, gold hepatotoxicity, inclusion irradiation, laser, methotrexate, nanoparticles, oxidative photothermal release, stabilization, stress, system, therapy}, pubstate = {published}, tppubtype = {article} } The inclusion compound (IC) of cyclodextrin (CD) containing the antitumor drug Methotrexate (MTX) as a guest molecule was obtained to increase the solubility of MTX and decrease its inherent toxic effects in nonspecific cells. The IC was conjugated with gold nanoparticles (AuNPs), obtained by a chemical method, creating a ternary intelligent delivery system for MTX molecules, based on the plasmonic properties of the AuNPs. Irradiation of the ternary system, with a laser wavelength tunable with the corresponding surface plasmon of AuNPs, causes local energy dissipation, producing the controlled release of the guest from CD cavities. Finally, cell viability was evaluated using MTS assays for beta-CD/MTX and AuNPs + beta-CD/MTX samples, with and without irradiation, against HeLa tumor cells. The irradiated sample of the ternary system AuNPs + beta-CD/MTX produced a diminution in cell viability attributed to the photothermal release of MTX. |
Meneses-Franco, A; Campos-Vallette, M; Vasquez, S O; Soto-Bustamante, E A Er-Doped Nanostructured Batio3 for Nir to Visible Upconversion Artículo de revista Materials, 11 (10), 2018, ISSN: 1996-1944. Resumen | Enlaces | BibTeX | Etiquetas: barium crystal, dielectric-properties, erbium, fabrication, ions microstructure, nanoparticle, nanoparticles, nanotechnology, particles, photoluminescent, spectra, technology, titanate, upconversion @article{RN409, title = {Er-Doped Nanostructured Batio3 for Nir to Visible Upconversion}, author = { A. Meneses-Franco and M. Campos-Vallette and S.O. Vasquez and E.A. Soto-Bustamante}, url = {/brokenurl#<Go to ISI>://WOS:000448658400164}, doi = {10.3390/ma11101950}, issn = {1996-1944}, year = {2018}, date = {2018-01-01}, journal = {Materials}, volume = {11}, number = {10}, abstract = {Photoluminescent mechanisms in erbium-doped barium titanate nanoparticle systems were studied. Er3+ ions were introduced into the BaTiO3 lattice by the sol-gel method. The resulting Er3+ concentration was between 0% and 5%, with Ba/Ti ratios of 1.008 and 0.993. The stoichiometry of Ba and Ti concentrations in the lattice influenced the doping mechanism and placement of erbium ions in the lattice structure. Our research shows the existence of a strong correlation between Ba/Ti ratios, erbium concentration, phase structure and doping site location on the upconversion photoluminescence mechanisms. Competing upconversion emissions H-2(11/2)/(S3/2I15/2)-S-4-I-4 at 523 and 548 nm respectively and other photoluminescent mechanisms as (I9/2I11/2)-I-4-I-4 around 4000 nm (2500 cm(-1)) were studied using Raman and emission spectroscopy. The upconversion process is predominant over other photoluminescent decay when the material presents high distortion in the surrounding activator.}, keywords = {barium crystal, dielectric-properties, erbium, fabrication, ions microstructure, nanoparticle, nanoparticles, nanotechnology, particles, photoluminescent, spectra, technology, titanate, upconversion}, pubstate = {published}, tppubtype = {article} } Photoluminescent mechanisms in erbium-doped barium titanate nanoparticle systems were studied. Er3+ ions were introduced into the BaTiO3 lattice by the sol-gel method. The resulting Er3+ concentration was between 0% and 5%, with Ba/Ti ratios of 1.008 and 0.993. The stoichiometry of Ba and Ti concentrations in the lattice influenced the doping mechanism and placement of erbium ions in the lattice structure. Our research shows the existence of a strong correlation between Ba/Ti ratios, erbium concentration, phase structure and doping site location on the upconversion photoluminescence mechanisms. Competing upconversion emissions H-2(11/2)/(S3/2I15/2)-S-4-I-4 at 523 and 548 nm respectively and other photoluminescent mechanisms as (I9/2I11/2)-I-4-I-4 around 4000 nm (2500 cm(-1)) were studied using Raman and emission spectroscopy. The upconversion process is predominant over other photoluminescent decay when the material presents high distortion in the surrounding activator. |
Pinto, C; Lopez, F; Galdámez, A; Barahona, P; Moris, S Vibrational and Optical Properties of Czts Derivatives for Photovoltaic Applications: Synthesis of Cu2znsn1-Xgexs2se2 Compounds Artículo de revista Solid State Sciences, 85 , pp. 76-82, 2018, ISSN: 1293-2558. Resumen | Enlaces | BibTeX | Etiquetas: analysis, band-gap, cu2znsns4, czts, method, nanocrystals, nanoparticles, raman raman-scattering scattering, single-crystals, solar-cells, spectroscopy spray-pyrolysis @article{RN399, title = {Vibrational and Optical Properties of Czts Derivatives for Photovoltaic Applications: Synthesis of Cu2znsn1-Xgexs2se2 Compounds}, author = { C. Pinto and F. Lopez and A. Gald\'{a}mez and P. Barahona and S. Moris}, url = {/brokenurl#<Go to ISI>://WOS:000448954400011}, doi = {10.1016/j.solidstatesciences.2018.09.005}, issn = {1293-2558}, year = {2018}, date = {2018-01-01}, journal = {Solid State Sciences}, volume = {85}, pages = {76-82}, abstract = {Herein, we report the vibrational and optical properties of new Cu2ZnSn1-xGexS2Se2 solid solutions prepared by isomorphic substitution of a fraction of Se by S in Cu2ZnSn1-xGexSe4 (CZTGeSe) through ceramic method. The Raman spectra and x-ray diffraction analysis on samples confirms that they crystallize in Kesterite-type structure. The Raman peaks were analyzed by fitting of the spectra allowing identification the vibrational modes by comparison with experimental and theoretical data from CZTGeSe and CZTGeS end-members. The dependency between the amount of cation and chalcogen substituent in optical characterization shows band gap around of 1.36 eV, close to the optimum value for solar cells with high efficiency.}, keywords = {analysis, band-gap, cu2znsns4, czts, method, nanocrystals, nanoparticles, raman raman-scattering scattering, single-crystals, solar-cells, spectroscopy spray-pyrolysis}, pubstate = {published}, tppubtype = {article} } Herein, we report the vibrational and optical properties of new Cu2ZnSn1-xGexS2Se2 solid solutions prepared by isomorphic substitution of a fraction of Se by S in Cu2ZnSn1-xGexSe4 (CZTGeSe) through ceramic method. The Raman spectra and x-ray diffraction analysis on samples confirms that they crystallize in Kesterite-type structure. The Raman peaks were analyzed by fitting of the spectra allowing identification the vibrational modes by comparison with experimental and theoretical data from CZTGeSe and CZTGeS end-members. The dependency between the amount of cation and chalcogen substituent in optical characterization shows band gap around of 1.36 eV, close to the optimum value for solar cells with high efficiency. |
Dreyse, P; Alarcon, D A; Galdámez, A; González, I; Cortes-Arriagada, D; Castillo, F; Mella, A Influence of the Anion Nature and Alkyl Substituents in the Behavior of Ionic Liquids Derived from Phenylpyridines Artículo de revista Journal of Molecular Structure, 1154 , pp. 382-391, 2018, ISSN: 0022-2860. Resumen | Enlaces | BibTeX | Etiquetas: binding compounds, crystal design electrochemical-cells, emitting energies, gold ion ionic liquids, nanoparticles, pairs phenylpyridiniums, salts, solvents, structure, temperature, transition, transport, water @article{RN402, title = {Influence of the Anion Nature and Alkyl Substituents in the Behavior of Ionic Liquids Derived from Phenylpyridines}, author = { P. Dreyse and D.A. Alarcon and A. Gald\'{a}mez and I. Gonz\'{a}lez and D. Cortes-Arriagada and F. Castillo and A. Mella}, url = {/brokenurl#<Go to ISI>://WOS:000418212000043}, doi = {10.1016/j.molstruc.2017.10.062}, issn = {0022-2860}, year = {2018}, date = {2018-01-01}, journal = {Journal of Molecular Structure}, volume = {1154}, pages = {382-391}, publisher = {2017 Elsevier B.V.}, abstract = {Quaternary alkyl 2-phenylpyridinium and 2-(2,4-difluorophenyl)pyridinium amines with iodide, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions have been fully characterized by H-1 NMR, FT-IR and MALDI mass spectroscopic methods and studied by quantum chemistry calculations. The compounds with bis(trifluoromethylsulfonyl)imide anion can be classified as ionic liquids, because they melt at room temperature. The quaternary amines with iodide and hexafluorophosphate anions are solid at 25 degrees C. The X-ray diffraction characterization of the 2-(2,4-difiuorophenyl)-1-methylphenylpyridinium hexafluorophosphate and 1-ethyl-2-(2,4-difluorophenyl)phenylpyridinium hexafluorophosphate show an extensive series of C-H center dot center dot center dot F, C-F center dot center dot center dot pi and P-F center dot center dot center dot pi it intermolecular interactions, which give rise to a supramolecular network. The relationship between the solid-state structures and the melting points is discussed by the evaluation of the thermal behavior based on experimental data from Differential Scanning Calorimetry (DSC) studies, and also using the analysis of the ion pairs binding energies. These new compounds based on phenylpyridine allow us to grow the diversity of ionic liquids and their crystalline salts, increasing the knowledge about the chemical and physical properties of these ionic species.}, keywords = {binding compounds, crystal design electrochemical-cells, emitting energies, gold ion ionic liquids, nanoparticles, pairs phenylpyridiniums, salts, solvents, structure, temperature, transition, transport, water}, pubstate = {published}, tppubtype = {article} } Quaternary alkyl 2-phenylpyridinium and 2-(2,4-difluorophenyl)pyridinium amines with iodide, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions have been fully characterized by H-1 NMR, FT-IR and MALDI mass spectroscopic methods and studied by quantum chemistry calculations. The compounds with bis(trifluoromethylsulfonyl)imide anion can be classified as ionic liquids, because they melt at room temperature. The quaternary amines with iodide and hexafluorophosphate anions are solid at 25 degrees C. The X-ray diffraction characterization of the 2-(2,4-difiuorophenyl)-1-methylphenylpyridinium hexafluorophosphate and 1-ethyl-2-(2,4-difluorophenyl)phenylpyridinium hexafluorophosphate show an extensive series of C-H center dot center dot center dot F, C-F center dot center dot center dot pi and P-F center dot center dot center dot pi it intermolecular interactions, which give rise to a supramolecular network. The relationship between the solid-state structures and the melting points is discussed by the evaluation of the thermal behavior based on experimental data from Differential Scanning Calorimetry (DSC) studies, and also using the analysis of the ion pairs binding energies. These new compounds based on phenylpyridine allow us to grow the diversity of ionic liquids and their crystalline salts, increasing the knowledge about the chemical and physical properties of these ionic species. |
Vetterlein, C; Vasquez, R; Bolanos, K; Acosta, G A; Guzman, F; Albericio, F; Celis, F; Campos-Vallette, M; Kogan, M J; Araya, E Exploring the Influence of Diels-Alder Linker Length on Photothermal Molecule Release from Gold Nanorods Artículo de revista Colloids and Surfaces B-Biointerfaces, 166 , pp. 323-329, 2018, ISSN: 0927-7765. Resumen | Enlaces | BibTeX | Etiquetas: controlled drug-delivery, effect, enhanced fluorescence, micelles, nanoparticles, peptide photothermal polymeric raman-scattering, release, spatial temporal @article{RN410, title = {Exploring the Influence of Diels-Alder Linker Length on Photothermal Molecule Release from Gold Nanorods}, author = { C. Vetterlein and R. Vasquez and K. Bolanos and G.A. Acosta and F. Guzman and F. Albericio and F. Celis and M. Campos-Vallette and M.J. Kogan and E. Araya}, url = {/brokenurl#<Go to ISI>://WOS:000432505900038}, doi = {10.1016/j.colsurfb.2018.03.021}, issn = {0927-7765}, year = {2018}, date = {2018-01-01}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {166}, pages = {323-329}, publisher = {2018 Elsevier B.V.}, abstract = {We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SEAS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles.}, keywords = {controlled drug-delivery, effect, enhanced fluorescence, micelles, nanoparticles, peptide photothermal polymeric raman-scattering, release, spatial temporal}, pubstate = {published}, tppubtype = {article} } We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SEAS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles. |
2017 |
Moris, S; Silva, N; Saitz-Barria, C; Jara, P; Chornik, B Nanodecoration of Single Crystals of 5,11,17,23-Tetra-Tert-Butyl-25,27-Bis(Cyanomethoxy)-26,28-Dihydroxycalix[4]Arene Artículo de revista Journal of the Chilean Chemical Society, 62 (4), pp. 3772-3778, 2017, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: calixarene crystals, gold nanodecorated, nanoparticles, single @article{RN355, title = {Nanodecoration of Single Crystals of 5,11,17,23-Tetra-Tert-Butyl-25,27-Bis(Cyanomethoxy)-26,28-Dihydroxycalix[4]Arene}, author = { S. Moris and N. Silva and C. Saitz-Barria and P. Jara and B. Chornik}, url = {/brokenurl#<Go to ISI>://WOS:000431863100018}, issn = {0717-9707}, year = {2017}, date = {2017-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {62}, number = {4}, pages = {3772-3778}, abstract = {Single crystals of 1,3-bis(cyanomethoxy)calix[4]arene (1) were grown from Chloroform/Methanol mixture and these were nanodecorated with colloidal gold nanoparticles (AuNps). The single crystals were then characterized by single-crystal X-ray diffraction (XRD) and Scanning Electronic Microscopy (SEM). The nanodecorated crystals were characterized by UV-Visible Absorption Spectroscopy, Transmission Electronic Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). In this work, it is shown that the stabilization of the nanoparticles occurs through of the interactions of these with the nitrile group, maintaining their shape and size.}, keywords = {calixarene crystals, gold nanodecorated, nanoparticles, single}, pubstate = {published}, tppubtype = {article} } Single crystals of 1,3-bis(cyanomethoxy)calix[4]arene (1) were grown from Chloroform/Methanol mixture and these were nanodecorated with colloidal gold nanoparticles (AuNps). The single crystals were then characterized by single-crystal X-ray diffraction (XRD) and Scanning Electronic Microscopy (SEM). The nanodecorated crystals were characterized by UV-Visible Absorption Spectroscopy, Transmission Electronic Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). In this work, it is shown that the stabilization of the nanoparticles occurs through of the interactions of these with the nitrile group, maintaining their shape and size. |
Mendez-Lopez, M; Saldias, C; Urzúa, M; Villalobos, V; Schmidt, M; Radic, D; Leiva, A Polymer-Based Nanocomposites: In Situ Generation and Immobilization of Gold Nanoparticles on Poly(N-Vinyl-2-Pyrrolidone) and Poly(Epsilon-Caprolactone) Thin Films Artículo de revista Journal of Nanoscience and Nanotechnology, 17 (12), pp. 9074-9080, 2017, ISSN: 1533-4880. Resumen | Enlaces | BibTeX | Etiquetas: chemistry, copolymers, films, gold growth metal nanocomposites, nanoparticles, polymer reducing silver stabilization, step synthesis, thin @article{RN365, title = {Polymer-Based Nanocomposites: In Situ Generation and Immobilization of Gold Nanoparticles on Poly(N-Vinyl-2-Pyrrolidone) and Poly(Epsilon-Caprolactone) Thin Films}, author = { M. Mendez-Lopez and C. Saldias and M. Urz\'{u}a and V. Villalobos and M. Schmidt and D. Radic and A. Leiva}, url = {/brokenurl#<Go to ISI>://WOS:000417111000053}, doi = {10.1166/jnn.2017.13868}, issn = {1533-4880}, year = {2017}, date = {2017-01-01}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {17}, number = {12}, pages = {9074-9080}, abstract = {In this work, we report an interesting method for simultaneous obtaining and immobilization of gold nanoparticles onto polymer thin films. Polymer-based nanocomposites were generated by spontaneous adsorption and reduction of Au III ions onto polymeric films surfaces. Poly(N-vinyl-2-pyrrolidone) and poly(epsilon-caprolactone), polymers that have shown their capability to reduce Au III and stabilize the generated gold nanoparticles, were used. The polymer film thickness and hydrophilic or hydrophobic nature of the solid substrate on which the polymers are deposited, directly affect the quantity and characteristics of the gold nanoparticles incorporated in films. Therefore, these parameters can be used to obtain nanocomposites with modulated features. The method presented is a simple route to produce nanocomposites with a high potential for use in diverse technological applications.}, keywords = {chemistry, copolymers, films, gold growth metal nanocomposites, nanoparticles, polymer reducing silver stabilization, step synthesis, thin}, pubstate = {published}, tppubtype = {article} } In this work, we report an interesting method for simultaneous obtaining and immobilization of gold nanoparticles onto polymer thin films. Polymer-based nanocomposites were generated by spontaneous adsorption and reduction of Au III ions onto polymeric films surfaces. Poly(N-vinyl-2-pyrrolidone) and poly(epsilon-caprolactone), polymers that have shown their capability to reduce Au III and stabilize the generated gold nanoparticles, were used. The polymer film thickness and hydrophilic or hydrophobic nature of the solid substrate on which the polymers are deposited, directly affect the quantity and characteristics of the gold nanoparticles incorporated in films. Therefore, these parameters can be used to obtain nanocomposites with modulated features. The method presented is a simple route to produce nanocomposites with a high potential for use in diverse technological applications. |
Campos-Vallette, M; Rodriguez, M J; Chapanoff, M A; Clavijo, E; Gomez-Jeria, J S; Aliaga, A E; Jara, G P; Celis, F; Paipa, C; Leyton, P Sers Spectrum of Red Dyes in the Mapuche Belts from the Beginning of the Xxth Century Artículo de revista Journal of Raman Spectroscopy, 48 (7), pp. 958-965, 2017, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: colloids, dyes dyes, electrospray-ionization, enhanced fibers, ionization mapuche mass-spectrometry, nanoparticles, natural nylon organic pigments, raman-scattering, red sers, silver spectroscopy synthetic trariwe, works-of-art @article{RN367, title = {Sers Spectrum of Red Dyes in the Mapuche Belts from the Beginning of the Xxth Century}, author = { M. Campos-Vallette and M.J. Rodriguez and M.A. Chapanoff and E. Clavijo and J.S. Gomez-Jeria and A.E. Aliaga and G.P. Jara and F. Celis and C. Paipa and P. Leyton}, url = {/brokenurl#<Go to ISI>://WOS:000405111500008}, doi = {10.1002/jrs.5147}, issn = {0377-0486}, year = {2017}, date = {2017-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {48}, number = {7}, pages = {958-965}, publisher = {2017 John Wiley & Sons, Ltd.}, abstract = {Red dyes in seven belts (trariwe) belonging to the Mapuche culture, dated as beginning of the XXth century and stored in Museo Regional de la Araucania, Chile, were studied by using ultraviolet-visible, liquid chromatography coupled to mass spectrometry, Raman and Surface Enhanced Raman Scattering spectroscopies. Red dyes were extracted and analysed; the spectral analysis allowed identifying that the principal red dye in five samples is highly consistent with a commercial synthetic aniline, the azopigment PR57. Another monoazopigment, an orange benzimidazolone, was identified in two samples. A molecular model for the PR57/Ag surface interaction supports the idea that the dye mainly exposes to the metal the carboxylate and sulphonate groups; the red azopigment is oriented rather tilted with the two aromatic rings being almost coplanar to the surface. The electrostatic interactions are the main factor of the PR57/Ag layer interaction.}, keywords = {colloids, dyes dyes, electrospray-ionization, enhanced fibers, ionization mapuche mass-spectrometry, nanoparticles, natural nylon organic pigments, raman-scattering, red sers, silver spectroscopy synthetic trariwe, works-of-art}, pubstate = {published}, tppubtype = {article} } Red dyes in seven belts (trariwe) belonging to the Mapuche culture, dated as beginning of the XXth century and stored in Museo Regional de la Araucania, Chile, were studied by using ultraviolet-visible, liquid chromatography coupled to mass spectrometry, Raman and Surface Enhanced Raman Scattering spectroscopies. Red dyes were extracted and analysed; the spectral analysis allowed identifying that the principal red dye in five samples is highly consistent with a commercial synthetic aniline, the azopigment PR57. Another monoazopigment, an orange benzimidazolone, was identified in two samples. A molecular model for the PR57/Ag surface interaction supports the idea that the dye mainly exposes to the metal the carboxylate and sulphonate groups; the red azopigment is oriented rather tilted with the two aromatic rings being almost coplanar to the surface. The electrostatic interactions are the main factor of the PR57/Ag layer interaction. |
Diaz, C; Valenzuela, M L; Bobadilla, D; Laguna-Bercero, M A Bimetallic Au//Ag Alloys inside Sio2 Using a Solid-State Method Artículo de revista Journal of Cluster Science, 28 (5), pp. 2809-2815, 2017, ISSN: 1040-7278. Resumen | Enlaces | BibTeX | Etiquetas: au/ag fabrication inside method, nanocrystals, nanoparticles, nanostructures, sio2, state supracrystals @article{RN361, title = {Bimetallic Au//Ag Alloys inside Sio2 Using a Solid-State Method}, author = { C. Diaz and M.L. Valenzuela and D. Bobadilla and M.A. Laguna-Bercero}, url = {/brokenurl#<Go to ISI>://WOS:000410837600032}, doi = {10.1007/s10876-017-1261-6}, issn = {1040-7278}, year = {2017}, date = {2017-01-01}, journal = {Journal of Cluster Science}, volume = {28}, number = {5}, pages = {2809-2815}, abstract = {Bimetallic Au/Ag nanostructures have been included inside SiO2 by pyrolysis of the macromolecular complexes Chitosan center dot(MLn/M'Ln)(n)center dot SiO2 and PSP-4-PVP center dot(MLn/M'Ln)(n)center dot SiO2 with MLn = AuCl3 and M'Ln = Ag(CF3SO3). The structural characterization was performed by XRD (X-ray diffraction of powder) and UV-Vis, and the microstructural characterization was done by SEM/EDS analysis HRTEM. The resulting products from the pyrolytic precursors PSP-4-PVP center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:1 (1), PSP-4-PVP center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:5 (2), Chitosan center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:1 (3) and Chitosan center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:5 (4) were Au/Ag//SiO2, Au//SiO2 and Ag//SiO2 as well as isolated Au and Ag, depending on the polymeric precursor. The Chitosan polymer precursor induces mainly Ag and Ag/SiO2 nanostructures, while PSP-4-PVP induces mainly Au/Ag//SiO2 nanostructures. This can be explained by the facility to link Ag+ to the NH2 and OH groups of Chitosan than to the pyridine of PSP-4-PVP. On the contrary, Au3+ exhibits most coordination ability to pyridine groups of PSP-4-PVP than NH2- and OH-groups of Chitosan. EDS mapping analysis indicates a uniform distribution of the Au/Ag nanostructure inside the SiO2 matrix. Using reflectance diffuse analysis, the plasmon is consistent with the Au/Ag alloys structure.}, keywords = {au/ag fabrication inside method, nanocrystals, nanoparticles, nanostructures, sio2, state supracrystals}, pubstate = {published}, tppubtype = {article} } Bimetallic Au/Ag nanostructures have been included inside SiO2 by pyrolysis of the macromolecular complexes Chitosan center dot(MLn/M'Ln)(n)center dot SiO2 and PSP-4-PVP center dot(MLn/M'Ln)(n)center dot SiO2 with MLn = AuCl3 and M'Ln = Ag(CF3SO3). The structural characterization was performed by XRD (X-ray diffraction of powder) and UV-Vis, and the microstructural characterization was done by SEM/EDS analysis HRTEM. The resulting products from the pyrolytic precursors PSP-4-PVP center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:1 (1), PSP-4-PVP center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:5 (2), Chitosan center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:1 (3) and Chitosan center dot(AuCl3/AgSO3CF3)(n)center dot SiO2 1:5 (4) were Au/Ag//SiO2, Au//SiO2 and Ag//SiO2 as well as isolated Au and Ag, depending on the polymeric precursor. The Chitosan polymer precursor induces mainly Ag and Ag/SiO2 nanostructures, while PSP-4-PVP induces mainly Au/Ag//SiO2 nanostructures. This can be explained by the facility to link Ag+ to the NH2 and OH groups of Chitosan than to the pyridine of PSP-4-PVP. On the contrary, Au3+ exhibits most coordination ability to pyridine groups of PSP-4-PVP than NH2- and OH-groups of Chitosan. EDS mapping analysis indicates a uniform distribution of the Au/Ag nanostructure inside the SiO2 matrix. Using reflectance diffuse analysis, the plasmon is consistent with the Au/Ag alloys structure. |
Aliaga, J A; Zepeda, T N; Pawelec, B N; Araya, J F; Antunez-Garcia, J; Farias, M H; Fuentes, S; Galvan, D; Alonso-Nunez, G; González, G Microspherical Res2 as a High-Performance Hydrodesulfurization Catalyst Artículo de revista Catalysis Letters, 147 (5), pp. 1243-1251, 2017, ISSN: 1011-372x. Resumen | Enlaces | BibTeX | Etiquetas: carbon, catalysis, composites, dichalcogenides, disulfide, evolution, heterogeneous hidrodesulfurization, hydrodeoxygenation, hydrogen molybdenum-disulfide, nanoparticles, nanosized rhenium solvothermal sulfide, sulfides, synthesis, technetium transition-metal @article{RN349, title = {Microspherical Res2 as a High-Performance Hydrodesulfurization Catalyst}, author = { J.A. Aliaga and T.N. Zepeda and B.N. Pawelec and J.F. Araya and J. Antunez-Garcia and M.H. Farias and S. Fuentes and D. Galvan and G. Alonso-Nunez and G. Gonz\'{a}lez}, url = {/brokenurl#<Go to ISI>://WOS:000400356200016}, doi = {10.1007/s10562-017-2024-6}, issn = {1011-372x}, year = {2017}, date = {2017-01-01}, journal = {Catalysis Letters}, volume = {147}, number = {5}, pages = {1243-1251}, abstract = {An unsupported microspherical ReS2 catalyst, consisting in self-assembled nano-layers, was evaluated in the hydrodesulfurization (HDS) of 3-methylthiophene showing an excellent catalytic activity. The samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. These techniques revealed that the rhenium disulfide layers are confined to a 3D hierarchical structure with different stacking, slab size and bending, according to the annealing temperature (400 or 800 A degrees C). The presence of a defect-rich structure in the microspheres, with short and randomly-orientated ReS2 slabs, results in the exposure of additional edge sites, which improve the catalytic performance of this material. This microspherical ReS2 composite, with good HDS performance, is a promising catalyst for the desulfurization of fuel oils; the solvothermal reaction conditions are also useful to tune and create exotic morphologies for the design of new ReS2 catalysts.}, keywords = {carbon, catalysis, composites, dichalcogenides, disulfide, evolution, heterogeneous hidrodesulfurization, hydrodeoxygenation, hydrogen molybdenum-disulfide, nanoparticles, nanosized rhenium solvothermal sulfide, sulfides, synthesis, technetium transition-metal}, pubstate = {published}, tppubtype = {article} } An unsupported microspherical ReS2 catalyst, consisting in self-assembled nano-layers, was evaluated in the hydrodesulfurization (HDS) of 3-methylthiophene showing an excellent catalytic activity. The samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. These techniques revealed that the rhenium disulfide layers are confined to a 3D hierarchical structure with different stacking, slab size and bending, according to the annealing temperature (400 or 800 A degrees C). The presence of a defect-rich structure in the microspheres, with short and randomly-orientated ReS2 slabs, results in the exposure of additional edge sites, which improve the catalytic performance of this material. This microspherical ReS2 composite, with good HDS performance, is a promising catalyst for the desulfurization of fuel oils; the solvothermal reaction conditions are also useful to tune and create exotic morphologies for the design of new ReS2 catalysts. |
Diaz, C; Valenzuela, M L; Laguna-Bercero, M A; Orera, A; Bobadilla, D; Abarca, S; Pena, O Synthesis and Magnetic Properties of Nanostructured Metallic Co, Mn and Ni Oxide Materials Obtained from Solid-State Metal-Macromolecular Complex Precursors Artículo de revista Rsc Advances, 7 (44), pp. 27729-27736, 2017, ISSN: 2046-2069. Resumen | Enlaces | BibTeX | Etiquetas: chemistry, chitosan, co3o4 crystal-structure, decomposition, gold nanocomposites, nanocrystals, nanoparticles, size, supracrystals @article{RN362, title = {Synthesis and Magnetic Properties of Nanostructured Metallic Co, Mn and Ni Oxide Materials Obtained from Solid-State Metal-Macromolecular Complex Precursors}, author = { C. Diaz and M.L. Valenzuela and M.A. Laguna-Bercero and A. Orera and D. Bobadilla and S. Abarca and O. Pena}, url = {/brokenurl#<Go to ISI>://WOS:000402166600064}, doi = {10.1039/c7ra00782e}, issn = {2046-2069}, year = {2017}, date = {2017-01-01}, journal = {Rsc Advances}, volume = {7}, number = {44}, pages = {27729-27736}, abstract = {The simple reaction of chitosan with metallic salts yields (chitosan) (MLn)(x)}, keywords = {chemistry, chitosan, co3o4 crystal-structure, decomposition, gold nanocomposites, nanocrystals, nanoparticles, size, supracrystals}, pubstate = {published}, tppubtype = {article} } The simple reaction of chitosan with metallic salts yields (chitosan) (MLn)(x) |
2016 |
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. |
Silva, N; Munoz, C; Diaz-Marcos, J; Samitier, J; Yutronic, N; Kogan, M J; Jara, P In Situ Visualization of the Local Photothermal Effect Produced on Alpha-Cyclodextrin Inclusion Compound Associated with Gold Nanoparticles Artículo de revista Nanoscale Research Letters, 11 , pp. 1-8, 2016, ISSN: 1556-276x. Resumen | Enlaces | BibTeX | Etiquetas: compound, cyclodextrin gold guest heating, inclusion metal migration, monolayers, nanoparticles, nanorods, nanotechnology, optical-properties, plasmonic therapy @article{RN300, title = {In Situ Visualization of the Local Photothermal Effect Produced on Alpha-Cyclodextrin Inclusion Compound Associated with Gold Nanoparticles}, author = { N. Silva and C. Munoz and J. Diaz-Marcos and J. Samitier and N. Yutronic and M.J. Kogan and P. Jara}, url = {/brokenurl#<Go to ISI>://WOS:000373961200001}, doi = {10.1186/s11671-016-1322-z}, issn = {1556-276x}, year = {2016}, date = {2016-01-01}, journal = {Nanoscale Research Letters}, volume = {11}, pages = {1-8}, abstract = {Evidence of guest migration in alpha-cyclodextrin-octylamine (alpha-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix).}, keywords = {compound, cyclodextrin gold guest heating, inclusion metal migration, monolayers, nanoparticles, nanorods, nanotechnology, optical-properties, plasmonic therapy}, pubstate = {published}, tppubtype = {article} } Evidence of guest migration in alpha-cyclodextrin-octylamine (alpha-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix). |
Miranda-Rojas, S; Salazar-Molina, R; Kastner, J; Arratia-Perez, R; Mendizabal, F Theoretical Exploration of Seleno and Tellurophenols as Promising Alternatives to Sulfur Ligands for Anchoring to Gold (111) Materials Artículo de revista Rsc Advances, 6 (6), pp. 4458-4468, 2016, ISSN: 2046-2069. Resumen | Enlaces | BibTeX | Etiquetas: basis-sets, chain-length, charge-transfer, chemistry, complexes, interface, monolayers, nanoparticles, pseudopotentials, self-assembled tellurium titanium @article{RN306, title = {Theoretical Exploration of Seleno and Tellurophenols as Promising Alternatives to Sulfur Ligands for Anchoring to Gold (111) Materials}, author = { S. Miranda-Rojas and R. Salazar-Molina and J. Kastner and R. Arratia-Perez and F. Mendizabal}, url = {/brokenurl#<Go to ISI>://WOS:000369510500023}, doi = {10.1039/c5ra21964g}, issn = {2046-2069}, year = {2016}, date = {2016-01-01}, journal = {Rsc Advances}, volume = {6}, number = {6}, pages = {4458-4468}, abstract = {It is widely known that sulfur ligands, such as alkanethiols or phenothiols and their derivatives, are useful anchor systems for gold materials due to the high affinity of sulfur to gold surfaces. In this study we use DFT calculations and a 42-atom gold cluster model to study the interaction between selenophenol and tellurophenol-derivatives with the Au(111) surface to gain information towards potential new gold-based materials. We modulated the interaction strength by controlling the charge transfer process of a particular interaction by chemically modifying the ligands. To obtain a complete analysis, we studied the ligands in their protonated, anionic and radical states aiming to cover the three possibilities in which these may interact with the gold cluster. In order to get a deeper insight into the nature of the interaction we used several analysis techniques such as energy decomposition analysis (EDA), non-covalent interactions (NCI) and natural population analysis (NPA). Our results reveal that tellurium in the anionic state provides complexes of better thermodynamic stability by similar to 12.0 kcal mol, when compared with the strongest sulfur-gold complex, also in the anionic state. Furthermore, this indicates that the anionic ligand is probably the dominant state for both selenium and tellurium as observed previously for sulfur. The extent to which the interaction strength could be controlled directly depends on the state of the anchor atom. In our case the anionic state is the most suitable for tuning the interaction. Finally, our main findings suggest that exchanging sulfur with selenium or tellurium involves an important increase of the interaction strength, thus, making these selenophenol and tellurophenol derivatives attractive for the development of new functional materials.}, keywords = {basis-sets, chain-length, charge-transfer, chemistry, complexes, interface, monolayers, nanoparticles, pseudopotentials, self-assembled tellurium titanium}, pubstate = {published}, tppubtype = {article} } It is widely known that sulfur ligands, such as alkanethiols or phenothiols and their derivatives, are useful anchor systems for gold materials due to the high affinity of sulfur to gold surfaces. In this study we use DFT calculations and a 42-atom gold cluster model to study the interaction between selenophenol and tellurophenol-derivatives with the Au(111) surface to gain information towards potential new gold-based materials. We modulated the interaction strength by controlling the charge transfer process of a particular interaction by chemically modifying the ligands. To obtain a complete analysis, we studied the ligands in their protonated, anionic and radical states aiming to cover the three possibilities in which these may interact with the gold cluster. In order to get a deeper insight into the nature of the interaction we used several analysis techniques such as energy decomposition analysis (EDA), non-covalent interactions (NCI) and natural population analysis (NPA). Our results reveal that tellurium in the anionic state provides complexes of better thermodynamic stability by similar to 12.0 kcal mol, when compared with the strongest sulfur-gold complex, also in the anionic state. Furthermore, this indicates that the anionic ligand is probably the dominant state for both selenium and tellurium as observed previously for sulfur. The extent to which the interaction strength could be controlled directly depends on the state of the anchor atom. In our case the anionic state is the most suitable for tuning the interaction. Finally, our main findings suggest that exchanging sulfur with selenium or tellurium involves an important increase of the interaction strength, thus, making these selenophenol and tellurophenol derivatives attractive for the development of new functional materials. |
Aliaga, A E; Leyton, P; Clavijo, E; Campos-Vallette, M Fluorescence and Surface-Enhanced Vibrational Spectroscopies of Lawsone and Plumbagin Artículo de revista Spectroscopy Letters, 49 (5), pp. 326-335, 2016, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: behavior, calculations, enhanced fluorescence, infrared-absorption, lawsone, nanoparticles, plumbagin, quinones raman raman-scattering, reduction, scattering, selection, sers, silver spectrum, surface theoretical @article{RN318, title = {Fluorescence and Surface-Enhanced Vibrational Spectroscopies of Lawsone and Plumbagin}, author = { A.E. Aliaga and P. Leyton and E. Clavijo and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000405754400002}, doi = {10.1080/00387010.2016.1146772}, issn = {0038-7010}, year = {2016}, date = {2016-01-01}, journal = {Spectroscopy Letters}, volume = {49}, number = {5}, pages = {326-335}, abstract = {The natural dyes lawsone and plumbagin (1,4-naphthoquinones) were studied by using fluorescence, Raman, infrared (IR), surface-enhanced Raman scattering (SERS), and surface-enhanced IR absorption. From the absorption spectrum, it was possible to infer that the enol-lawsone tautomer concentration decreases in silver colloidal solution. Plumbagin dimers, both in water and in silver colloidal solution, were identified from the fluorescence band profile and surface-SERS spectrum. The SERS spectrum of lawsone was obtained by using silver colloidal solution after 12-hour settle; the keto and enol lawsone silver colloid interaction occurs. The assignment of Raman and IR bands of both dyes was calculated with density functional theory calculations. Only a monomeric structure of lawsone interacting with a silver cluster model was predicted. The monomer adopts a nearly coplanar orientation onto the silver surface; the shortest distance is 3.2 angstrom, suggesting an electrostatic interaction.}, keywords = {behavior, calculations, enhanced fluorescence, infrared-absorption, lawsone, nanoparticles, plumbagin, quinones raman raman-scattering, reduction, scattering, selection, sers, silver spectrum, surface theoretical}, pubstate = {published}, tppubtype = {article} } The natural dyes lawsone and plumbagin (1,4-naphthoquinones) were studied by using fluorescence, Raman, infrared (IR), surface-enhanced Raman scattering (SERS), and surface-enhanced IR absorption. From the absorption spectrum, it was possible to infer that the enol-lawsone tautomer concentration decreases in silver colloidal solution. Plumbagin dimers, both in water and in silver colloidal solution, were identified from the fluorescence band profile and surface-SERS spectrum. The SERS spectrum of lawsone was obtained by using silver colloidal solution after 12-hour settle; the keto and enol lawsone silver colloid interaction occurs. The assignment of Raman and IR bands of both dyes was calculated with density functional theory calculations. Only a monomeric structure of lawsone interacting with a silver cluster model was predicted. The monomer adopts a nearly coplanar orientation onto the silver surface; the shortest distance is 3.2 angstrom, suggesting an electrostatic interaction. |
Garrido, C; Weiss-Lopez, B; Campos-Vallette, M Surface-Enhanced Raman Scattering Activity of Negatively Charged Bio-Analytes from a Modified Silver Colloid Artículo de revista Spectroscopy Letters, 49 (1), pp. 11-18, 2016, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: bio-analytes, charged colloidal fluorescein, nanoparticles, negatively peptides, raman reduction scattering, sers, silver spectroscopy, surface, surface-enhanced @article{RN323, title = {Surface-Enhanced Raman Scattering Activity of Negatively Charged Bio-Analytes from a Modified Silver Colloid}, author = { C. Garrido and B. Weiss-Lopez and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000364784800003}, doi = {10.1080/00387010.2015.1046606}, issn = {0038-7010}, year = {2016}, date = {2016-01-01}, journal = {Spectroscopy Letters}, volume = {49}, number = {1}, pages = {11-18}, abstract = {A modification to the traditional synthesis of reduced silver metal nanoparticles with hydroxylamine hydrochloride is proposed. The new colloid, obtained by decreasing the concentration of hydroxide and chloride ions, is stable in a large pH range. The low negative surface charge density of the nanoparticles allowed to obtain surface-enhanced Raman scattering (SERS) spectral activity of bio-analytes containing negatively charged groups in aqueous solution. The new colloidal system, characterized by electronic spectroscopy, atomic force microscopy, and zeta potential measurements, was used in the SERS study of the bio-analytes aspartic acid, four oligopeptides, one polypeptide and a probe, the organic dye fluorescein.}, keywords = {bio-analytes, charged colloidal fluorescein, nanoparticles, negatively peptides, raman reduction scattering, sers, silver spectroscopy, surface, surface-enhanced}, pubstate = {published}, tppubtype = {article} } A modification to the traditional synthesis of reduced silver metal nanoparticles with hydroxylamine hydrochloride is proposed. The new colloid, obtained by decreasing the concentration of hydroxide and chloride ions, is stable in a large pH range. The low negative surface charge density of the nanoparticles allowed to obtain surface-enhanced Raman scattering (SERS) spectral activity of bio-analytes containing negatively charged groups in aqueous solution. The new colloidal system, characterized by electronic spectroscopy, atomic force microscopy, and zeta potential measurements, was used in the SERS study of the bio-analytes aspartic acid, four oligopeptides, one polypeptide and a probe, the organic dye fluorescein. |
2015 |
Aliaga, J A; Araya, J F; Lozano, H; Benavente, E; Alonso-Nunez, G; González, G An Easy One-Pot Solvothermal Synthesis of Poorly Crystalline Solid Res2/C Microspheres Artículo de revista Materials Chemistry and Physics, 151 , pp. 372-377, 2015, ISSN: 0254-0584. Resumen | Enlaces | BibTeX | Etiquetas: amorphous carbon chalcogenides, composite growth-mechanism, material, nanoparticles, reduction, rhenium sulfide, technetium, temperature @article{aliaga2015onepot, title = {An Easy One-Pot Solvothermal Synthesis of Poorly Crystalline Solid Res2/C Microspheres}, author = { J.A. Aliaga and J.F. Araya and H. Lozano and E. Benavente and G. Alonso-Nunez and G. Gonz\'{a}lez}, url = {/brokenurl#<Go to ISI>://WOS:000348263600051}, doi = {10.1016/j.matchemphys.2014.12.012}, issn = {0254-0584}, year = {2015}, date = {2015-01-01}, journal = {Materials Chemistry and Physics}, volume = {151}, pages = {372-377}, publisher = {2014 Elsevier B.V.}, abstract = {Dense microspheres consisting of poorly crystalline ReS2 embedded in carbon were synthesized with a high yield via a facile one-pot solvothermal route, by reacting dirhenium decacarbonyl, elemental sulfur and an aromatic solvent (benzene, toluene or p-xylene) for 24 h at 180 degrees C. X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Fourier transform infrared spectroscopy (Fr-IR) techniques were used to characterize the samples. The resulting microspheres were dense, with average diameters between 0.79 and 1.40 mu m, had smooth surfaces and were constructed of ReS2 sheet-like structures with 4.5-9.8 wt % of structural amorphous carbon, which is retained as a textural stabilizer after calcination at 800 degrees C. The synthesis was repeated using isopropanol and cyclohexane, whose products were agglomerated grains and botryoidal quasi-spherical particles, respectively. A possible formation mechanism of ReS2/C microspheres was preliminarily presented, in order to clarify the mechanistic differences between the rhenium carbonyl and other transition metal carbonyls used in similar syntheses.}, keywords = {amorphous carbon chalcogenides, composite growth-mechanism, material, nanoparticles, reduction, rhenium sulfide, technetium, temperature}, pubstate = {published}, tppubtype = {article} } Dense microspheres consisting of poorly crystalline ReS2 embedded in carbon were synthesized with a high yield via a facile one-pot solvothermal route, by reacting dirhenium decacarbonyl, elemental sulfur and an aromatic solvent (benzene, toluene or p-xylene) for 24 h at 180 degrees C. X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Fourier transform infrared spectroscopy (Fr-IR) techniques were used to characterize the samples. The resulting microspheres were dense, with average diameters between 0.79 and 1.40 mu m, had smooth surfaces and were constructed of ReS2 sheet-like structures with 4.5-9.8 wt % of structural amorphous carbon, which is retained as a textural stabilizer after calcination at 800 degrees C. The synthesis was repeated using isopropanol and cyclohexane, whose products were agglomerated grains and botryoidal quasi-spherical particles, respectively. A possible formation mechanism of ReS2/C microspheres was preliminarily presented, in order to clarify the mechanistic differences between the rhenium carbonyl and other transition metal carbonyls used in similar syntheses. |
Solar, P; González, G; Vilos, C; Herrera, N; Juica, N; Moreno, M; Simon, F; Velásquez, L Multifunctional polymeric nanoparticles doubly loaded with SPION and ceftiofur retain their physical and biological properties Artículo de revista Journal of Nanobiotechnology, 13 , 2015, ISSN: 1477-3155. Resumen | Enlaces | BibTeX | Etiquetas: ceftiofur, delivery, drug drug-delivery, magnetic micelles, nanoparticles, phbv, polymeric release spion, superparamagnetic @article{solar2015multifunctional, title = {Multifunctional polymeric nanoparticles doubly loaded with SPION and ceftiofur retain their physical and biological properties}, author = { P. Solar and G. Gonz\'{a}lez and C. Vilos and N. Herrera and N. Juica and M. Moreno and F. Simon and L. Vel\'{a}squez}, doi = {Mult10.1186/s12951-015-0077-5}, issn = {1477-3155}, year = {2015}, date = {2015-01-01}, journal = {Journal of Nanobiotechnology}, volume = {13}, abstract = {Advances in nanostructure materials are leading to novel strategies for drug delivery and targeting, contrast media for magnetic resonance imaging (MRI), agents for hyperthermia and nanocarriers. Superparamagnetic iron oxide nanoparticles (SPIONs) are useful for all of these applications, and in drug-release systems, SPIONs allow for the localization, direction and concentration of drugs, providing a broad range of therapeutic applications. In this work, we developed and characterized polymeric nanoparticles based on poly (3-hydroxybutyric acid-co-hydroxyvaleric acid) (PHBV) functionalized with SPIONs and/or the antibiotic ceftiofur. These nanoparticles can be used in multiple biomedical applications, and the hybrid SPION-ceftiofur nanoparticles (PHBV/SPION/CEF) can serve as a multifunctional platform for the diagnosis and treatment of cancer and its associated bacterial infections., Results: Morphological examination using transmission electron microscopy (TEM) showed nanoparticles with a spherical shape and a core-shell structure. The particle size was evaluated using dynamic light scattering (DLS), which revealed a diameter of 243.0 +/- 17 nm. The efficiency of encapsulation (45.5 +/- 0.6% w/v) of these polymeric nanoparticles was high, and their components were evaluated using spectroscopy. UV-VIS, FTIR and DSC showed that all of the nanoparticles contained the desired components, and these compounds interacted to form a nanocomposite. Using the agar diffusion method and live/dead bacterial viability assays, we demonstrated that these nanoparticles have antimicrobial properties against Escherichia coli, and they retain their magnetic properties as measured using a vibrating sample magnetometer (VSM). Cytotoxicity was assessed in HepG2 cells using live/dead viability assays and MTS, and these assays showed low cytotoxicity with IC50 > 10 mg/mL nanoparticles., Conclusions: Our results indicate that hybrid and multifunctional PHBV/SPION/CEF nanoparticles are suitable as a superparamagnetic drug delivery system that can guide, concentrate and site-specifically release drugs with antibacterial activity.}, keywords = {ceftiofur, delivery, drug drug-delivery, magnetic micelles, nanoparticles, phbv, polymeric release spion, superparamagnetic}, pubstate = {published}, tppubtype = {article} } Advances in nanostructure materials are leading to novel strategies for drug delivery and targeting, contrast media for magnetic resonance imaging (MRI), agents for hyperthermia and nanocarriers. Superparamagnetic iron oxide nanoparticles (SPIONs) are useful for all of these applications, and in drug-release systems, SPIONs allow for the localization, direction and concentration of drugs, providing a broad range of therapeutic applications. In this work, we developed and characterized polymeric nanoparticles based on poly (3-hydroxybutyric acid-co-hydroxyvaleric acid) (PHBV) functionalized with SPIONs and/or the antibiotic ceftiofur. These nanoparticles can be used in multiple biomedical applications, and the hybrid SPION-ceftiofur nanoparticles (PHBV/SPION/CEF) can serve as a multifunctional platform for the diagnosis and treatment of cancer and its associated bacterial infections., Results: Morphological examination using transmission electron microscopy (TEM) showed nanoparticles with a spherical shape and a core-shell structure. The particle size was evaluated using dynamic light scattering (DLS), which revealed a diameter of 243.0 +/- 17 nm. The efficiency of encapsulation (45.5 +/- 0.6% w/v) of these polymeric nanoparticles was high, and their components were evaluated using spectroscopy. UV-VIS, FTIR and DSC showed that all of the nanoparticles contained the desired components, and these compounds interacted to form a nanocomposite. Using the agar diffusion method and live/dead bacterial viability assays, we demonstrated that these nanoparticles have antimicrobial properties against Escherichia coli, and they retain their magnetic properties as measured using a vibrating sample magnetometer (VSM). Cytotoxicity was assessed in HepG2 cells using live/dead viability assays and MTS, and these assays showed low cytotoxicity with IC50 > 10 mg/mL nanoparticles., Conclusions: Our results indicate that hybrid and multifunctional PHBV/SPION/CEF nanoparticles are suitable as a superparamagnetic drug delivery system that can guide, concentrate and site-specifically release drugs with antibacterial activity. |
Diaz, C; Barrera, G; Segovia, M; Valenzuela, M L; Osiak, M; O'dwyer, C Crystallizing Vanadium Pentoxide Nanostructures in the Solid-State Using Modified Block Copolymer and Chitosan Complexes Artículo de revista Journal of Nanomaterials, 10.1155/2015/105157 , 2015, ISSN: 1687-4110. Resumen | Enlaces | BibTeX | Etiquetas: electrochemical gold growth, intercalation, mechanisms, nanocomposites, nanoparticles, optical-properties, photoluminescence, precursors, properties, ruthenium @article{RN255, title = {Crystallizing Vanadium Pentoxide Nanostructures in the Solid-State Using Modified Block Copolymer and Chitosan Complexes}, author = { C. Diaz and G. Barrera and M. Segovia and M.L. Valenzuela and M. Osiak and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000354681800001}, doi = {10.1155/2015/105157}, issn = {1687-4110}, year = {2015}, date = {2015-01-01}, journal = {Journal of Nanomaterials}, volume = {10.1155/2015/105157}, abstract = {A systematic study of the synthesis of V2O5 nanostructured materials using macromolecular PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes is presented. It is demonstrated that various coordination degrees of the metal into the polymeric chain specifically influence the product formation after pyrolysis. PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes were prepared by simple coordination reaction of VCl3 with the respective polymer inmolar ratios 1 : 1, 1 : 5, and 1 : 10 metal/polymer and characterized by elemental analysis, IR spectroscopy, and TGA/DSC analysis. Solid-state thermolysis of these precursors at several temperatures under air results in nanostructured V2O5 using all precursors. The size and shape of the nanostructured V2O5 depend on the nature of the polymer. For the chitosan center dot(VCl3)(y) precursors sub-10nm nanocrystals are formed. The calcination process, involved in the preparation method, produces V2O5 with photoluminescence in the visible light region, suggesting the possible application in oxygen sensing devices.}, keywords = {electrochemical gold growth, intercalation, mechanisms, nanocomposites, nanoparticles, optical-properties, photoluminescence, precursors, properties, ruthenium}, pubstate = {published}, tppubtype = {article} } A systematic study of the synthesis of V2O5 nanostructured materials using macromolecular PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes is presented. It is demonstrated that various coordination degrees of the metal into the polymeric chain specifically influence the product formation after pyrolysis. PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes were prepared by simple coordination reaction of VCl3 with the respective polymer inmolar ratios 1 : 1, 1 : 5, and 1 : 10 metal/polymer and characterized by elemental analysis, IR spectroscopy, and TGA/DSC analysis. Solid-state thermolysis of these precursors at several temperatures under air results in nanostructured V2O5 using all precursors. The size and shape of the nanostructured V2O5 depend on the nature of the polymer. For the chitosan center dot(VCl3)(y) precursors sub-10nm nanocrystals are formed. The calcination process, involved in the preparation method, produces V2O5 with photoluminescence in the visible light region, suggesting the possible application in oxygen sensing devices. |
2014 |
Diaz, C; Platoni, S; Molina, A; Valenzuela, M L; Geaney, H; O'dwyer, C Novel Solid-State Route to Nanostructured Tin, Zinc and Cerium Oxides as Potential Materials for Sensors Artículo de revista Journal of Nanoscience and Nanotechnology, 14 (9), pp. 6748-6753, 2014, ISSN: 1533-4880. Resumen | Enlaces | BibTeX | Etiquetas: ceo2, cerium complex, gold metal-oxide, nanoparticles, nanostructures, oxide, polyphosphazenes, ruthenium, sensors, solid state, synthesis, tem, tin zinc @article{RN201, title = {Novel Solid-State Route to Nanostructured Tin, Zinc and Cerium Oxides as Potential Materials for Sensors}, author = { C. Diaz and S. Platoni and A. Molina and M.L. Valenzuela and H. Geaney and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000335873900035}, doi = {10.1166/jnn.2014.9350}, issn = {1533-4880}, year = {2014}, date = {2014-01-01}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {14}, number = {9}, pages = {6748-6753}, abstract = {Solid-state sensor nanostructured materials (SnO2, ZnO and CeO2) have been prepared by pyrolysis of macromolecular complexes: PSP-co-4-PVP center dot (SnCl2)(n), PSP-co-4-PVP center dot (ZnCl2)(n) and PSP-co-4-PVP center dot (Ce(NO3)(3))(n) in several molar ratios under air at 800 degrees C. The as-prepared nanostructured SnO2 exhibits morphologies and particle sizes which are dependent upon the molar ratio of the SnCl2:PSP-co-4-PVR When a larger weight fraction of the inorganic salt in the precursor mixture is used (1:10 > 1:5 > 1.1) larger crystalline crystals are found for each oxide. For ZnO and CeO2 agglomerates of morphologies from the respective hexagonal and cubic structures were observed with typical sizes of 30-50 nm in both cases for a precursor mixture ratio of 1:1.}, keywords = {ceo2, cerium complex, gold metal-oxide, nanoparticles, nanostructures, oxide, polyphosphazenes, ruthenium, sensors, solid state, synthesis, tem, tin zinc}, pubstate = {published}, tppubtype = {article} } Solid-state sensor nanostructured materials (SnO2, ZnO and CeO2) have been prepared by pyrolysis of macromolecular complexes: PSP-co-4-PVP center dot (SnCl2)(n), PSP-co-4-PVP center dot (ZnCl2)(n) and PSP-co-4-PVP center dot (Ce(NO3)(3))(n) in several molar ratios under air at 800 degrees C. The as-prepared nanostructured SnO2 exhibits morphologies and particle sizes which are dependent upon the molar ratio of the SnCl2:PSP-co-4-PVR When a larger weight fraction of the inorganic salt in the precursor mixture is used (1:10 > 1:5 > 1.1) larger crystalline crystals are found for each oxide. For ZnO and CeO2 agglomerates of morphologies from the respective hexagonal and cubic structures were observed with typical sizes of 30-50 nm in both cases for a precursor mixture ratio of 1:1. |
Aliaga, J A; Araya, J F; Villarroel, R; Lozano, H; Alonso-Nunez, G; González, G Rhenium and Molybdenum Poorly Crystalline Disulfides and Their Mesophases with Hexadecylamine Artículo de revista Journal of Coordination Chemistry, 67 (23-24), pp. 3884-3893, 2014, ISSN: 0095-8972. Resumen | Enlaces | BibTeX | Etiquetas: amorphous autogenic carbon, composite deposition, elevated-temperature, in-situ materials, molybdenum mos2, nanoparticles, pressure, rhenium storage sulfide @article{RN198, title = {Rhenium and Molybdenum Poorly Crystalline Disulfides and Their Mesophases with Hexadecylamine}, author = { J.A. Aliaga and J.F. Araya and R. Villarroel and H. Lozano and G. Alonso-Nunez and G. Gonz\'{a}lez}, url = {/brokenurl#<Go to ISI>://WOS:000345454600011}, doi = {10.1080/00958972.2014.975220}, issn = {0095-8972}, year = {2014}, date = {2014-01-01}, journal = {Journal of Coordination Chemistry}, volume = {67}, number = {23-24}, pages = {3884-3893}, abstract = {Sulfides of molybdenum and rhenium poorly crystalline were prepared by solvothermal oxidative decarbonylation of the respective metal carbonyls with sulfur using p-xylene as solvent. The same reaction, but in presence of hexadecylamine (HDA), was used for preparing the nanocomposites MoS2/HDA and ReS2/HDA. The products were analyzed by X-ray diffraction analysis, scanning electron microscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy. The products, MoS2 and ReS2, are structurally similar but morphologically different: small undefined particles (150-300nm) and well-defined, almost perfect microspheres (0.4-2.8m), respectively. Preparations containing HDA lead to the corresponding layered nanocomposites. MoS2/HDA is a dark solid easily separable from the reaction mixture, while ReS2/HDA remains as a suspension in p-xylene, from which it is obtained by evaporating the solvent under vacuum. Both are layered species with basal spacing of 33.8 angstrom (Mo) and 30.4 angstrom (Re), respectively. The preparation of thin films of ReS2/HDA from its suspension by evaporating the solvent in the air produces small cylindrical particles of about 0.4x1.0m in size. Differences in the behavior of Mo and Re derivatives are discussed considering the coordination of the metal and the electronic structures of both metal disulfides.}, keywords = {amorphous autogenic carbon, composite deposition, elevated-temperature, in-situ materials, molybdenum mos2, nanoparticles, pressure, rhenium storage sulfide}, pubstate = {published}, tppubtype = {article} } Sulfides of molybdenum and rhenium poorly crystalline were prepared by solvothermal oxidative decarbonylation of the respective metal carbonyls with sulfur using p-xylene as solvent. The same reaction, but in presence of hexadecylamine (HDA), was used for preparing the nanocomposites MoS2/HDA and ReS2/HDA. The products were analyzed by X-ray diffraction analysis, scanning electron microscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy. The products, MoS2 and ReS2, are structurally similar but morphologically different: small undefined particles (150-300nm) and well-defined, almost perfect microspheres (0.4-2.8m), respectively. Preparations containing HDA lead to the corresponding layered nanocomposites. MoS2/HDA is a dark solid easily separable from the reaction mixture, while ReS2/HDA remains as a suspension in p-xylene, from which it is obtained by evaporating the solvent under vacuum. Both are layered species with basal spacing of 33.8 angstrom (Mo) and 30.4 angstrom (Re), respectively. The preparation of thin films of ReS2/HDA from its suspension by evaporating the solvent in the air produces small cylindrical particles of about 0.4x1.0m in size. Differences in the behavior of Mo and Re derivatives are discussed considering the coordination of the metal and the electronic structures of both metal disulfides. |
2013 |
Campos, C; Munoz, M; Barrientos-Poblete, L; Lang, E; Jara, P; Sobrados, I; Yutronic, N Adhesion of Gold and Silver Nanoparticles onto Urea-Alkylamine Inclusion Compounds Artículo de revista Journal of Inclusion Phenomena and Macrocyclic Chemistry, 75 (1-2), pp. 165-173, 2013, ISSN: 1388-3127. Resumen | Enlaces | BibTeX | Etiquetas: alpha-cyclodextrin, amine aspects, compounds, dynamics gold guests, inclusion molecules, nanoparticle, nanoparticles, reduction, silver structural temperature, thiourea, urea x-ray-diffraction @article{RN137, title = {Adhesion of Gold and Silver Nanoparticles onto Urea-Alkylamine Inclusion Compounds}, author = { C. Campos and M. Munoz and L. Barrientos-Poblete and E. Lang and P. Jara and I. Sobrados and N. Yutronic}, url = {/brokenurl#<Go to ISI>://WOS:000314898300018}, doi = {10.1007/s10847-012-0157-1}, issn = {1388-3127}, year = {2013}, date = {2013-01-01}, journal = {Journal of Inclusion Phenomena and Macrocyclic Chemistry}, volume = {75}, number = {1-2}, pages = {165-173}, abstract = {We report the synthesis and characterization of a new series of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests, as well as the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes. X-ray diffraction confirms the inclusion process of the amine in the urea cavities. The structures determined for the three complexes correspond to a hexagonal channel structure with space group P6(1)22. Alkylamine-urea stoichiometric ratios in all cases satisfy the relationship 1:3n (n = 2 for octylamine and 3 for decylamine and dodecylamine), determined by elemental analysis. The deposition of gold and silver nanoparticles by the magnetron sputtering technique onto microcrystals of the complexes was analyzed by Diffuse Reflectance Spectroscopy, showing characteristic surface plasmon resonance for metal nanoparticles. Transmission electron microscopy demonstrates the presence of metal nanoparticles (MNPs) in a size range between 5 and 60 nm for gold and between 5 and 20 nm for silver, and furthermore, in some cases it shows vestiges of a hexagonal arrangement of the MNPs. X-ray diffraction and IR measurements demonstrate that the basic structure of the matrix remains unchanged after the MNPs adhesion. IR also shows increased broadening and intensity of the characteristic NH2 bending frequencies (1,597 cm(-1)) when the MNPs interact with the inclusion compounds. We conclude that the interactions between the inclusion compounds and metal nanoparticles occurs mainly through the amino groups of the guest molecules that can emerge from the entrance of the inclusion compound cavities attracted by the metallic nanoparticles, in opposition to the restoring van der Waals interactions present inside channels, which increase with increasing chain length of the guest molecules., Schematic representation of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests and the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes.}, keywords = {alpha-cyclodextrin, amine aspects, compounds, dynamics gold guests, inclusion molecules, nanoparticle, nanoparticles, reduction, silver structural temperature, thiourea, urea x-ray-diffraction}, pubstate = {published}, tppubtype = {article} } We report the synthesis and characterization of a new series of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests, as well as the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes. X-ray diffraction confirms the inclusion process of the amine in the urea cavities. The structures determined for the three complexes correspond to a hexagonal channel structure with space group P6(1)22. Alkylamine-urea stoichiometric ratios in all cases satisfy the relationship 1:3n (n = 2 for octylamine and 3 for decylamine and dodecylamine), determined by elemental analysis. The deposition of gold and silver nanoparticles by the magnetron sputtering technique onto microcrystals of the complexes was analyzed by Diffuse Reflectance Spectroscopy, showing characteristic surface plasmon resonance for metal nanoparticles. Transmission electron microscopy demonstrates the presence of metal nanoparticles (MNPs) in a size range between 5 and 60 nm for gold and between 5 and 20 nm for silver, and furthermore, in some cases it shows vestiges of a hexagonal arrangement of the MNPs. X-ray diffraction and IR measurements demonstrate that the basic structure of the matrix remains unchanged after the MNPs adhesion. IR also shows increased broadening and intensity of the characteristic NH2 bending frequencies (1,597 cm(-1)) when the MNPs interact with the inclusion compounds. We conclude that the interactions between the inclusion compounds and metal nanoparticles occurs mainly through the amino groups of the guest molecules that can emerge from the entrance of the inclusion compound cavities attracted by the metallic nanoparticles, in opposition to the restoring van der Waals interactions present inside channels, which increase with increasing chain length of the guest molecules., Schematic representation of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests and the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes. |
Diaz, C; Carriedo, G; Valenzuela, M L; Zuniga, L; O'dwyer, C Solid State Pathways to Complex Shape Evolution and Tunable Porosity During Metallic Crystal Growth Artículo de revista Scientific Reports, 3 , 2013, ISSN: 2045-2322. Resumen | Enlaces | BibTeX | Etiquetas: carbon gold nanocrystals, nanoparticles, silver @article{RN145, title = {Solid State Pathways to Complex Shape Evolution and Tunable Porosity During Metallic Crystal Growth}, author = { C. Diaz and G. Carriedo and M.L. Valenzuela and L. Zuniga and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000324229300005}, doi = {10.1038/srep02642}, issn = {2045-2322}, year = {2013}, date = {2013-01-01}, journal = {Scientific Reports}, volume = {3}, abstract = {Growing complex metallic crystals, supported high index facet nanocrystal composites and tunable porosity metals, and exploiting factors that influence shape and morphology is crucial in many exciting developments in chemistry, catalysis, biotechnology and nanoscience. Assembly, organization and ordered crystallization of nanostructures into complex shapes requires understanding of the building blocks and their association, and this relationship can define the many physical properties of crystals and their assemblies. Understanding crystal evolution pathways is required for controlled deposition onto surfaces. Here, complex metallic crystals on the nano-and microscale, carbon supported nanoparticles, and spinodal porous noble metals with defined inter-feature distances in 3D, are accomplished in the solid-state for Au, Ag, Pd, and Re. Bottom-up growth and positioning is possible through competitive coarsening of mobile nanoparticles and their site-specific crystallization in a nucleation-dewetted matrix. Shape evolution, density and growth mechanism of complex metallic crystals and porous metals can be imaged during growth.}, keywords = {carbon gold nanocrystals, nanoparticles, silver}, pubstate = {published}, tppubtype = {article} } Growing complex metallic crystals, supported high index facet nanocrystal composites and tunable porosity metals, and exploiting factors that influence shape and morphology is crucial in many exciting developments in chemistry, catalysis, biotechnology and nanoscience. Assembly, organization and ordered crystallization of nanostructures into complex shapes requires understanding of the building blocks and their association, and this relationship can define the many physical properties of crystals and their assemblies. Understanding crystal evolution pathways is required for controlled deposition onto surfaces. Here, complex metallic crystals on the nano-and microscale, carbon supported nanoparticles, and spinodal porous noble metals with defined inter-feature distances in 3D, are accomplished in the solid-state for Au, Ag, Pd, and Re. Bottom-up growth and positioning is possible through competitive coarsening of mobile nanoparticles and their site-specific crystallization in a nucleation-dewetted matrix. Shape evolution, density and growth mechanism of complex metallic crystals and porous metals can be imaged during growth. |
Diaz, C; Valenzuela, M L; Caceres, S; O'dwyer, C Solution and Surfactant-Free Growth of Supported High Index Facet Sers Active Nanoparticles of Rhenium by Phase Demixing Artículo de revista Journal of Materials Chemistry A, 1 (5), pp. 1566-1572, 2013, ISSN: 2050-7488. Resumen | Enlaces | BibTeX | Etiquetas: excitation gold graphene, morphology, nanocatalysts, nanocrystals, nanoparticles, precursors @article{RN144, title = {Solution and Surfactant-Free Growth of Supported High Index Facet Sers Active Nanoparticles of Rhenium by Phase Demixing}, author = { C. Diaz and M.L. Valenzuela and S. Caceres and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000314640100008}, doi = {10.1039/c2ta00262k}, issn = {2050-7488}, year = {2013}, date = {2013-01-01}, journal = {Journal of Materials Chemistry A}, volume = {1}, number = {5}, pages = {1566-1572}, abstract = {Stable, high-index facet Re nanoparticles have been grown by a solid state synthetic method, negating the need for solutions or surfactants to control seeding, supracrystallization and NP shape. By using mixtures of K[ReO4] and the cyclic triphosphazene [NP(O2C12H8)](3), high-index facet nanoparticles and nanocrystals similar to 3 nm in size can be seeded and grown from drop-cast films and powders due to phase demixing of the metallopolymer. NP dispersions are formed directly within a carbon support that liquefies, allowing NP coarsening and ripening, and the eventual formation of a solidified graphitic support filled with crystals. Successful growth of mesoscale supracrystals of Re also occurs from ripening of nucleated NP seeds, incubated within a solidified and partially dewetted solid support that patterns the surface. The supported Re NP dispersions also exhibit surface enhanced Raman scattering within a graphitic matrix.}, keywords = {excitation gold graphene, morphology, nanocatalysts, nanocrystals, nanoparticles, precursors}, pubstate = {published}, tppubtype = {article} } Stable, high-index facet Re nanoparticles have been grown by a solid state synthetic method, negating the need for solutions or surfactants to control seeding, supracrystallization and NP shape. By using mixtures of K[ReO4] and the cyclic triphosphazene [NP(O2C12H8)](3), high-index facet nanoparticles and nanocrystals similar to 3 nm in size can be seeded and grown from drop-cast films and powders due to phase demixing of the metallopolymer. NP dispersions are formed directly within a carbon support that liquefies, allowing NP coarsening and ripening, and the eventual formation of a solidified graphitic support filled with crystals. Successful growth of mesoscale supracrystals of Re also occurs from ripening of nucleated NP seeds, incubated within a solidified and partially dewetted solid support that patterns the surface. The supported Re NP dispersions also exhibit surface enhanced Raman scattering within a graphitic matrix. |
Diaz, C; Valenzuela, M L; Caceres, S; Diaz, R; O'dwyer, C Solvent and Stabilizer Free Growth of Ag and Pd Nanoparticles Using Metallic Salts/Cyclotriphosphazenes Mixtures Artículo de revista Materials Chemistry and Physics, 143 (1), pp. 124-132, 2013, ISSN: 0254-0584. Resumen | Enlaces | BibTeX | Etiquetas: annealing, derivatives, electron gold, mechanical-behavior, metals, microscopy, nanoparticles, nanorods organometallic palladium polyphosphazenes, precursors, properties, pyrolysis, shape-controlled solid-state surface synthesis, thermolytic transformation @article{RN146, title = {Solvent and Stabilizer Free Growth of Ag and Pd Nanoparticles Using Metallic Salts/Cyclotriphosphazenes Mixtures}, author = { C. Diaz and M.L. Valenzuela and S. Caceres and R. Diaz and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000327684100017}, doi = {10.1016/j.matchemphys.2013.08.034}, issn = {0254-0584}, year = {2013}, date = {2013-01-01}, journal = {Materials Chemistry and Physics}, volume = {143}, number = {1}, pages = {124-132}, publisher = {2013 Elsevier B.V.}, abstract = {Cyclotriphosphazene is used as a sacrificial solid-state template to synthesize a range of Ag and Pd nanoparticles with diverse geometries by thermal treatment using MLn/N3P3(O2C12H8)(3) mixtures. The Pd and Ag nanoparticles are synthesized by solid-state pyrolysis of AgPPh3[CF3SO3]/N3P3(O2C12H8)(3) and PdCl2/N3P3(O2C12H8)(3) mixtures with molar relationships of 1:1, 1:5 and 1:10 respectively, in air and at 800 degrees C. The morphology of the as-prepared nanoparticles is found to depend on the molar ratio of the precursor mixture, the preparation method and of the nature of the metal. Ag and Pd, microcrystals were thermally grown on Si from the respective 1:1 precursors while that metal foams were grown from 1:5 ratios precursors on SiO2 wafers. High resolution transmission electron microscopy investigations reveal in most cases small crystals of Pd. HRSTEM measurements indicate that the formation of the Pd and Ag nanoparticles occurs through a phase demixing and dewetting mechanism. This approach has potential to be a useful and facile method to prepare metallic nanoparticles without requiring solutions or surfactants for application in electronic, catalytic and sensor materials and devices.}, keywords = {annealing, derivatives, electron gold, mechanical-behavior, metals, microscopy, nanoparticles, nanorods organometallic palladium polyphosphazenes, precursors, properties, pyrolysis, shape-controlled solid-state surface synthesis, thermolytic transformation}, pubstate = {published}, tppubtype = {article} } Cyclotriphosphazene is used as a sacrificial solid-state template to synthesize a range of Ag and Pd nanoparticles with diverse geometries by thermal treatment using MLn/N3P3(O2C12H8)(3) mixtures. The Pd and Ag nanoparticles are synthesized by solid-state pyrolysis of AgPPh3[CF3SO3]/N3P3(O2C12H8)(3) and PdCl2/N3P3(O2C12H8)(3) mixtures with molar relationships of 1:1, 1:5 and 1:10 respectively, in air and at 800 degrees C. The morphology of the as-prepared nanoparticles is found to depend on the molar ratio of the precursor mixture, the preparation method and of the nature of the metal. Ag and Pd, microcrystals were thermally grown on Si from the respective 1:1 precursors while that metal foams were grown from 1:5 ratios precursors on SiO2 wafers. High resolution transmission electron microscopy investigations reveal in most cases small crystals of Pd. HRSTEM measurements indicate that the formation of the Pd and Ag nanoparticles occurs through a phase demixing and dewetting mechanism. This approach has potential to be a useful and facile method to prepare metallic nanoparticles without requiring solutions or surfactants for application in electronic, catalytic and sensor materials and devices. |
Herrera, B; Adura, C; Yutronic, N; Kogan, M J; Jara, P Selective Nanodecoration of Modified Cyclodextrin Crystals with Gold Nanorods Artículo de revista Journal of Colloid and Interface Science, 389 , pp. 42-45, 2013, ISSN: 0021-9797. Resumen | Enlaces | BibTeX | Etiquetas: alpha-cyclodextrin, cationic complex compound, compounds, cyclodextrin, deposition, gold inclusion nanodecoration, nanoparticles, nanorods, surfactants @article{RN138, title = {Selective Nanodecoration of Modified Cyclodextrin Crystals with Gold Nanorods}, author = { B. Herrera and C. Adura and N. Yutronic and M.J. Kogan and P. Jara}, url = {/brokenurl#<Go to ISI>://WOS:000310763900006}, doi = {10.1016/j.jcis.2012.08.027}, issn = {0021-9797}, year = {2013}, date = {2013-01-01}, journal = {Journal of Colloid and Interface Science}, volume = {389}, pages = {42-45}, publisher = {2012 Elsevier Inc.}, abstract = {Gold nanorods (AuNRs) stabilized by cetyltrimethylammonium bromide (CTAB) were deposited onto crystals of alpha-cyclodextrin (alpha-CD) inclusion compounds (ICs) that contained octanethiol (OT) as guest molecules. The nanodecoration was produced specifically at the 001 crystal planes through interaction between the -SH groups of the ICs and the AuNRs.}, keywords = {alpha-cyclodextrin, cationic complex compound, compounds, cyclodextrin, deposition, gold inclusion nanodecoration, nanoparticles, nanorods, surfactants}, pubstate = {published}, tppubtype = {article} } Gold nanorods (AuNRs) stabilized by cetyltrimethylammonium bromide (CTAB) were deposited onto crystals of alpha-cyclodextrin (alpha-CD) inclusion compounds (ICs) that contained octanethiol (OT) as guest molecules. The nanodecoration was produced specifically at the 001 crystal planes through interaction between the -SH groups of the ICs and the AuNRs. |
Miranda-Rojas, S; Munoz-Castro, A; Arratia-Perez, R; Mendizabal, F Theoretical Insights into the Adsorption of Neutral, Radical and Anionic Thiophenols on Gold(111) Artículo de revista Physical Chemistry Chemical Physics, 15 (46), pp. 20363-20370, 2013, ISSN: 1463-9076. Resumen | Enlaces | BibTeX | Etiquetas: basis-sets, chemisorption, complexes dft, electronic-structure, gold interface, metallic monolayers, nanoparticles, self-assembled surfaces @article{RN141, title = {Theoretical Insights into the Adsorption of Neutral, Radical and Anionic Thiophenols on Gold(111)}, author = { S. Miranda-Rojas and A. Munoz-Castro and R. Arratia-Perez and F. Mendizabal}, url = {/brokenurl#<Go to ISI>://WOS:000326747200048}, doi = {10.1039/c3cp53591f}, issn = {1463-9076}, year = {2013}, date = {2013-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {15}, number = {46}, pages = {20363-20370}, abstract = {The interaction of thiol and thiolate containing molecules with gold (S-Au) has gained increasing interest because of its applications in molecular electronic devices and catalysis. In this context, the enhanced conductivity of thiophenol compared to alkanethiol represents an opportunity to develop more sensitive and selective gold-based devices by incorporating molecules with the aryl-thiol moiety into their structures. As has been proposed earlier, the thiol moiety is deprotonated after binding to gold, hence, we present here a comparative study of the S-Au bond strength between several neutral and deprotonated aromatic-sulfur systems in their anionic and radical forms with a detailed description of the nature of this interaction. The study was performed by means of computational chemistry methods, using a cluster of 42 Au atoms as a model of the Au(111) surface that allowed us to provide new chemical insights to control the S-Au interface interaction strength. Our results revealed that the thiophenols-gold interaction is mainly dispersive where the interaction energies range between 31 and 43 kcal mol(-1). The radical and anionic thiophenolates-gold interaction increases due to a strong charge transfer character, depicting interaction energies in the range of 50 to 55 kcal mol(-1) and 62 to 92 kcal mol(-1), respectively. These results suggest that for the anionic thiophenolate the binding strength can be tailored according to the electron-donor capabilities of the ligand which in turn can be finely tuned by several substituents. Our results are of possible impact for the design of new devices.}, keywords = {basis-sets, chemisorption, complexes dft, electronic-structure, gold interface, metallic monolayers, nanoparticles, self-assembled surfaces}, pubstate = {published}, tppubtype = {article} } The interaction of thiol and thiolate containing molecules with gold (S-Au) has gained increasing interest because of its applications in molecular electronic devices and catalysis. In this context, the enhanced conductivity of thiophenol compared to alkanethiol represents an opportunity to develop more sensitive and selective gold-based devices by incorporating molecules with the aryl-thiol moiety into their structures. As has been proposed earlier, the thiol moiety is deprotonated after binding to gold, hence, we present here a comparative study of the S-Au bond strength between several neutral and deprotonated aromatic-sulfur systems in their anionic and radical forms with a detailed description of the nature of this interaction. The study was performed by means of computational chemistry methods, using a cluster of 42 Au atoms as a model of the Au(111) surface that allowed us to provide new chemical insights to control the S-Au interface interaction strength. Our results revealed that the thiophenols-gold interaction is mainly dispersive where the interaction energies range between 31 and 43 kcal mol(-1). The radical and anionic thiophenolates-gold interaction increases due to a strong charge transfer character, depicting interaction energies in the range of 50 to 55 kcal mol(-1) and 62 to 92 kcal mol(-1), respectively. These results suggest that for the anionic thiophenolate the binding strength can be tailored according to the electron-donor capabilities of the ligand which in turn can be finely tuned by several substituents. Our results are of possible impact for the design of new devices. |
Diaz, C; Valenzuela, M L; Bobadilla, D Bimetallic Au/Ag Metal Superstructures from Macromolecular Metal Complexes in Solid-State Artículo de revista Journal of the Chilean Chemical Society, 58 (4), pp. 1994-1997, 2013, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: and au complexes, derivatives, fabrication, gold, macromolecular metallic morphology, nanocrystals, nanoparticles, organometallic polyphosphazenes, precursors, pyrolysis pyrolysis, superstructures, thermolytic transformation @article{RN143, title = {Bimetallic Au/Ag Metal Superstructures from Macromolecular Metal Complexes in Solid-State}, author = { C. Diaz and M.L. Valenzuela and D. Bobadilla}, url = {/brokenurl#<Go to ISI>://WOS:000331238800015}, doi = {10.4067/S0717-97072013000400019}, issn = {0717-9707}, year = {2013}, date = {2013-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {58}, number = {4}, pages = {1994-1997}, abstract = {Novel bimetallic Au/Ag superstructures have been prepared from solid-state pyrolysis of the macromolecular complexes Chitosan( MLn/M'Ln)(n) y PSP-4-PVPx(MLn/M'Ln)(n) with MLn = AuCl3 and M'Ln = Ag(CF3SO3). The characterization was made from XRD (X-ray diffraction of powder), SEM and EDS analysis. Morphologies are influenced by both the nature of the polymer and the metal/polymer, molar ratio of the polymer precursor. EDS analysis suggests a core/shell Au/Ag structure for the materials. A probable mechanism of the formation of these superstructures is discussed. Although separated reports of metallic superstructures of Au or Ag have been recently described, the here reported are the first bimetallic Au/Ag.}, keywords = {and au complexes, derivatives, fabrication, gold, macromolecular metallic morphology, nanocrystals, nanoparticles, organometallic polyphosphazenes, precursors, pyrolysis pyrolysis, superstructures, thermolytic transformation}, pubstate = {published}, tppubtype = {article} } Novel bimetallic Au/Ag superstructures have been prepared from solid-state pyrolysis of the macromolecular complexes Chitosan( MLn/M'Ln)(n) y PSP-4-PVPx(MLn/M'Ln)(n) with MLn = AuCl3 and M'Ln = Ag(CF3SO3). The characterization was made from XRD (X-ray diffraction of powder), SEM and EDS analysis. Morphologies are influenced by both the nature of the polymer and the metal/polymer, molar ratio of the polymer precursor. EDS analysis suggests a core/shell Au/Ag structure for the materials. A probable mechanism of the formation of these superstructures is discussed. Although separated reports of metallic superstructures of Au or Ag have been recently described, the here reported are the first bimetallic Au/Ag. |
2012 |
Barrientos-Poblete, L; Allende-González, P; Orellana, C; Jara, P Ordered Arrangements of Metal Nanoparticles on Alpha-Cyclodextrin Inclusion Complexes by Magnetron Sputtering Artículo de revista Inorganica Chimica Acta, 380 , pp. 372-377, 2012, ISSN: 0020-1693. Resumen | Enlaces | BibTeX | Etiquetas: catalysis, colloids, gold guest host interaction, magnetron metal metal-guest molecules, monolayer, nanoparticles, nanostructures, particles, size, sputtering, stabilization, supramolecular surface @article{RN81, title = {Ordered Arrangements of Metal Nanoparticles on Alpha-Cyclodextrin Inclusion Complexes by Magnetron Sputtering}, author = { L. Barrientos-Poblete and P. Allende-Gonz\'{a}lez and C. Orellana and P. Jara}, url = {/brokenurl#<Go to ISI>://WOS:000300180100050}, doi = {10.1016/j.ica.2011.10.032}, issn = {0020-1693}, year = {2012}, date = {2012-01-01}, journal = {Inorganica Chimica Acta}, volume = {380}, pages = {372-377}, publisher = {2011 Elsevier B.V.}, abstract = {An ordered self-assembly of copper, silver and gold nanoparticles onto crystal faces of alpha-cyclodextrin/1-octanethiol and 2 alpha-cyclodextrin/1-octylamine inclusion complexes by means of physical vapor deposition (magnetron sputtering) has been achieved. The preferential deposition on the (001) plane of the supramolecular crystal occurs because the -SH and -NH2 groups from the guest molecules found within the alpha-cyclodextrin protrude into that plane. These functional groups form a two-dimensional hexagonal lattice that interacts with the metal nanoparticles, arranging them in an ordered way.}, keywords = {catalysis, colloids, gold guest host interaction, magnetron metal metal-guest molecules, monolayer, nanoparticles, nanostructures, particles, size, sputtering, stabilization, supramolecular surface}, pubstate = {published}, tppubtype = {article} } An ordered self-assembly of copper, silver and gold nanoparticles onto crystal faces of alpha-cyclodextrin/1-octanethiol and 2 alpha-cyclodextrin/1-octylamine inclusion complexes by means of physical vapor deposition (magnetron sputtering) has been achieved. The preferential deposition on the (001) plane of the supramolecular crystal occurs because the -SH and -NH2 groups from the guest molecules found within the alpha-cyclodextrin protrude into that plane. These functional groups form a two-dimensional hexagonal lattice that interacts with the metal nanoparticles, arranging them in an ordered way. |
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. |
Diaz, C; Valenzuela, M L; Garrido, D; Aguirre, P Sol-Gel Incorporation of Organometallic Compounds into Silica: Useful Precursors to Metallic Nanostructured Materials Artículo de revista Journal of the Chilean Chemical Society, 57 (2), pp. 1155-1162, 2012, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: bridged magnetic-properties, materials, matrix, mesoporous molecular nanoclusters nanocomposites, nanoparticles, nanostructured, nanowires, organic-inorganic polysilsesquioxanes, precursors, pyrophosphates, silica, sol-gel, source thermolytic transformation @article{RN87, title = {Sol-Gel Incorporation of Organometallic Compounds into Silica: Useful Precursors to Metallic Nanostructured Materials}, author = { C. Diaz and M.L. Valenzuela and D. Garrido and P. Aguirre}, url = {/brokenurl#<Go to ISI>://WOS:000305169800021}, issn = {0717-9707}, year = {2012}, date = {2012-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {57}, number = {2}, pages = {1155-1162}, abstract = {Inclusion of the organometallic MLn = [HOC5H4N center dot Cp2TiCl][PF6] (I), HOC5H4N center dot W(CO)(5) (2), HOC5H4N center dot Mo(CO)(5) (3), [HOC6H4CH2CN center dot Cp2TiCl][PF6] (4), HOC6H4CH2CN center dot W(CO)(5) (5) and HOC6H4CH2CN center dot Mo(CO)(5) (6) into amorphous silica using the gelator precursor TEOS and N3P3N-H[CH2](3)Si[OEt](3)(6) afford the gels (MLn)(SiO2)(n). The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800 degrees C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N2P3NH[CH2](3)Si[OEt](3) as gelator. TEm images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables.}, keywords = {bridged magnetic-properties, materials, matrix, mesoporous molecular nanoclusters nanocomposites, nanoparticles, nanostructured, nanowires, organic-inorganic polysilsesquioxanes, precursors, pyrophosphates, silica, sol-gel, source thermolytic transformation}, pubstate = {published}, tppubtype = {article} } Inclusion of the organometallic MLn = [HOC5H4N center dot Cp2TiCl][PF6] (I), HOC5H4N center dot W(CO)(5) (2), HOC5H4N center dot Mo(CO)(5) (3), [HOC6H4CH2CN center dot Cp2TiCl][PF6] (4), HOC6H4CH2CN center dot W(CO)(5) (5) and HOC6H4CH2CN center dot Mo(CO)(5) (6) into amorphous silica using the gelator precursor TEOS and N3P3N-H[CH2](3)Si[OEt](3)(6) afford the gels (MLn)(SiO2)(n). The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800 degrees C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N2P3NH[CH2](3)Si[OEt](3) as gelator. TEm images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables. |
Diaz, C; Valenzuela, M L; Lavayen, V; O'dwyer, C Layered Graphitic Carbon Host Formation During Liquid-Free Solid State Growth of Metal Pyrophosphates Artículo de revista Inorganic Chemistry, 51 (11), pp. 6228-6236, 2012, ISSN: 0020-1669. Resumen | Enlaces | BibTeX | Etiquetas: characterization, nanocomposites, nanoparticles, nanotubes, nanowires precursor, pyrolysis, spectroscopic @article{RN89, title = {Layered Graphitic Carbon Host Formation During Liquid-Free Solid State Growth of Metal Pyrophosphates}, author = { C. Diaz and M.L. Valenzuela and V. Lavayen and C. O'dwyer}, url = {/brokenurl#<Go to ISI>://WOS:000304728500029}, doi = {10.1021/ic300767h}, issn = {0020-1669}, year = {2012}, date = {2012-01-01}, journal = {Inorganic Chemistry}, volume = {51}, number = {11}, pages = {6228-6236}, abstract = {We report a successful ligand- and liquid-free solid state route to form metal pyrophosphates within a layered graphitic carbon matrix through a single step approach involving pyrolysis of previously synthesized organometallic derivatives of a cyclotriphosphazene. In this case, we show how single crystal Mn2P2O7 can be formed on either the micro- or the nanoscale in the complete absence of solvents or solutions by an efficient combustion process using rationally designed macromolecular trimer precursors, and present evidence and a mechanism for layered graphite host formation. Using in situ Raman spectroscopy, infrared spectroscopy, X-ray diffraction, high resolution electron microscopy, thermogravimetric and differential scanning calorimetric analysis, and near-edge X-ray absorption fine structure examination, we monitor the formation process of a layered, graphitic carbon in the matrix. The identification of thermally and electrically conductive graphitic carbon host formation is important for the further development of this general ligand-free synthetic approach for inorganic nanocrystal growth in the solid state, and can be extended to form a range of transition metals pyrophosphates. For important energy storage applications, the method gives the ability to form oxide and (pyro)phosphates within a conductive, intercalation possible, graphitic carbon as host-guest composites directly on substrates for high rate Li-ion battery and emerging alternative positive electrode materials.}, keywords = {characterization, nanocomposites, nanoparticles, nanotubes, nanowires precursor, pyrolysis, spectroscopic}, pubstate = {published}, tppubtype = {article} } We report a successful ligand- and liquid-free solid state route to form metal pyrophosphates within a layered graphitic carbon matrix through a single step approach involving pyrolysis of previously synthesized organometallic derivatives of a cyclotriphosphazene. In this case, we show how single crystal Mn2P2O7 can be formed on either the micro- or the nanoscale in the complete absence of solvents or solutions by an efficient combustion process using rationally designed macromolecular trimer precursors, and present evidence and a mechanism for layered graphite host formation. Using in situ Raman spectroscopy, infrared spectroscopy, X-ray diffraction, high resolution electron microscopy, thermogravimetric and differential scanning calorimetric analysis, and near-edge X-ray absorption fine structure examination, we monitor the formation process of a layered, graphitic carbon in the matrix. The identification of thermally and electrically conductive graphitic carbon host formation is important for the further development of this general ligand-free synthetic approach for inorganic nanocrystal growth in the solid state, and can be extended to form a range of transition metals pyrophosphates. For important energy storage applications, the method gives the ability to form oxide and (pyro)phosphates within a conductive, intercalation possible, graphitic carbon as host-guest composites directly on substrates for high rate Li-ion battery and emerging alternative positive electrode materials. |
2011 |
Osorio-Roman, I O; Ortega-Vasquez, V; Vargas, V; Aroca, R F Surface-Enhanced Spectra on D-Gluconic Acid Coated Silver Nanoparticles Artículo de revista Applied Spectroscopy, 65 (8), pp. 838-843, 2011, ISSN: 0003-7028. Resumen | Enlaces | BibTeX | Etiquetas: coated d-gluconic emission, enhanced film fluorescence, luminescence, nanoparticles, nanopartides, plasmon raman resonance scattering, see, serrs, silver surface-enhanced @article{RN48, title = {Surface-Enhanced Spectra on D-Gluconic Acid Coated Silver Nanoparticles}, author = { I.O. Osorio-Roman and V. Ortega-Vasquez and V. Vargas and R.F. Aroca}, url = {/brokenurl#<Go to ISI>://WOS:000293206800002}, doi = {10.1366/11-06279}, issn = {0003-7028}, year = {2011}, date = {2011-01-01}, journal = {Applied Spectroscopy}, volume = {65}, number = {8}, pages = {838-843}, abstract = {Coated silver (Ag) colloids synthesized with D-glucose permit the observation of surface-enhanced fluorescence (SEF) and surface-enhanced resonance Raman scattering (SERRS) of the rhodamine B (RhB) molecule. The organic coating formed during the synthesis of the Ag nanostructures was identified by its surface-enhanced Raman scattering (SERS) spectrum as D-gluconic acid. The RhB molecule is used to exemplify the distance dependence of SEF and SERRS on the coated Ag nanostructures. The fluorescence enhancement factor for RhB on D-gluconic acid coated silver nanoparticles was determined experimentally and estimated using a simple model. Further support for the plasmon enhancement is obtained from the fact that the measured fluorescence lifetime of RhB on the silver coated with D-gluconic acid is shorter than that found on a glass surface. A very modest enhancement factor is obtained, as expected for very short distance between RhB and the metal surface. Given the very thin metal fluorophore separation, estimated from the size of the D-gluconic acid, the energy transfer or fluorescence quenching is still efficient and the SEF enhancement is just overcoming the energy transfer. Therefore, both SEF and SERRS are observed. Notably, the aggregation of coated nanoparticles also increases the enhancement factor for SEF.}, keywords = {coated d-gluconic emission, enhanced film fluorescence, luminescence, nanoparticles, nanopartides, plasmon raman resonance scattering, see, serrs, silver surface-enhanced}, pubstate = {published}, tppubtype = {article} } Coated silver (Ag) colloids synthesized with D-glucose permit the observation of surface-enhanced fluorescence (SEF) and surface-enhanced resonance Raman scattering (SERRS) of the rhodamine B (RhB) molecule. The organic coating formed during the synthesis of the Ag nanostructures was identified by its surface-enhanced Raman scattering (SERS) spectrum as D-gluconic acid. The RhB molecule is used to exemplify the distance dependence of SEF and SERRS on the coated Ag nanostructures. The fluorescence enhancement factor for RhB on D-gluconic acid coated silver nanoparticles was determined experimentally and estimated using a simple model. Further support for the plasmon enhancement is obtained from the fact that the measured fluorescence lifetime of RhB on the silver coated with D-gluconic acid is shorter than that found on a glass surface. A very modest enhancement factor is obtained, as expected for very short distance between RhB and the metal surface. Given the very thin metal fluorophore separation, estimated from the size of the D-gluconic acid, the energy transfer or fluorescence quenching is still efficient and the SEF enhancement is just overcoming the energy transfer. Therefore, both SEF and SERRS are observed. Notably, the aggregation of coated nanoparticles also increases the enhancement factor for SEF. |
Publicaciones 2011-2020
