2018 |
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. |
Diaz, C; Carrillo, D; Campa, De La R; Soto, A P; Valenzuela, M L Solid-State Synthesis of Lnocl/Ln(2)O(3) (Ln = Eu, Nd) by Using Chitosan and Ps-Co-P4vp as Polymeric Supports Artículo de revista Journal of Rare Earths, 36 (12), pp. 1326-1332, 2018, ISSN: 1002-0721. Resumen | Enlaces | BibTeX | Etiquetas: earths, euocl/eu2o3, lanthanide, lanthanides, luminescence, method, nanocrystals, ndocl, oxides, rare scale solventless supracrystals @article{RN397, title = {Solid-State Synthesis of Lnocl/Ln(2)O(3) (Ln = Eu, Nd) by Using Chitosan and Ps-Co-P4vp as Polymeric Supports}, author = { C. Diaz and D. Carrillo and R. De La Campa and A.P. Soto and M.L. Valenzuela}, url = {/brokenurl#<Go to ISI>://WOS:000451031200013}, doi = {10.1016/j.jre.2018.03.031}, issn = {1002-0721}, year = {2018}, date = {2018-01-01}, journal = {Journal of Rare Earths}, volume = {36}, number = {12}, pages = {1326-1332}, publisher = {2018 Chinese Society of Rare Earths. Published by Elsevier B.V.}, abstract = {A series of lanthanide materials of type LnOCl or Ln(2)O(3) (Ln = Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan LnCl(3) and PS-co-P4VP center dot LnCl(3) were prepared. These macromolecular complexes were treated in solid state at 800 degrees C under air, leading to the corresponding LnOCl or Ln(2)O(3) materials (Ln = Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnCl and/or Ln(2)O(3)) is strongly influenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan center dot LnCl(3) and PS-co-P4VP center dot EuCl3 are used as macromolecular precursors, a mixture of crystalline phases o f both EuOCl and Eu2O3 are obtained. However, when chitosan center dot NdCl3 and PS-co-P4VP center dot NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly influenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios.}, keywords = {earths, euocl/eu2o3, lanthanide, lanthanides, luminescence, method, nanocrystals, ndocl, oxides, rare scale solventless supracrystals}, pubstate = {published}, tppubtype = {article} } A series of lanthanide materials of type LnOCl or Ln(2)O(3) (Ln = Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan LnCl(3) and PS-co-P4VP center dot LnCl(3) were prepared. These macromolecular complexes were treated in solid state at 800 degrees C under air, leading to the corresponding LnOCl or Ln(2)O(3) materials (Ln = Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnCl and/or Ln(2)O(3)) is strongly influenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan center dot LnCl(3) and PS-co-P4VP center dot EuCl3 are used as macromolecular precursors, a mixture of crystalline phases o f both EuOCl and Eu2O3 are obtained. However, when chitosan center dot NdCl3 and PS-co-P4VP center dot NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly influenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios. |
2016 |
Alarcon-Esposito, J; Contreras, R; Tapia, R A; Campodonico, P R Gutmann's Donor Numbers Correctly Assess the Effect of the Solvent on the Kinetics of Snar Reactions in Ionic Liquids Artículo de revista Chemistry-a European Journal, 22 (37), pp. 13347-13351, 2016, ISSN: 0947-6539. Resumen | Enlaces | BibTeX | Etiquetas: anion aromatic aryl azides, basicity, comparison conventional donicity effects, gutmann's ionic lewis liquids, method, nucleophilic-substitution, numbers, parameters, pi-star, polarities, preferential scale solvation, solvatochromic solvents @article{RN328, title = {Gutmann's Donor Numbers Correctly Assess the Effect of the Solvent on the Kinetics of Snar Reactions in Ionic Liquids}, author = { J. Alarcon-Esposito and R. Contreras and R.A. Tapia and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000383763200049}, doi = {10.1002/chem.201602237}, issn = {0947-6539}, year = {2016}, date = {2016-01-01}, journal = {Chemistry-a European Journal}, volume = {22}, number = {37}, pages = {13347-13351}, abstract = {We report an experimental study on the effect of solvents on the model SNAr reaction between 1-chloro-2,4dinitrobenzene and morpholine in a series of pure ionic liquids (IL). A significant catalytic effect is observed with reference to the same reaction run in water, acetonitrile, and other conventional solvents. The series of IL considered include the anions, NTf2-, DCN-, SCN-, CF3SO3-, PF6-, and FAP(-) with the series of cations 1-butyl-3-methyl-imidazolium ([BMIM]+), 1-ethyl-3-methyl-imidazolium ([ EMIM]+), 1-butyl2,3- dimethyl-imidazolium ([BM2(I)M](+)), and 1-butyl-1-methyl-pyrrolidinium ([BMPyr](+)). The observed solvent effects can be attributed to an "anion effect". The anion effect appears related to the anion size (polarizability) and their hydrogenbonding (HB) abilities to the substrate. These results have been confirmed by performing a comparison of the rate constants with Gutmann's donicity numbers (DNs). The good correlation between rate constants and DN emphasizes the major role of charge transfer from the anion to the substrate.}, keywords = {anion aromatic aryl azides, basicity, comparison conventional donicity effects, gutmann's ionic lewis liquids, method, nucleophilic-substitution, numbers, parameters, pi-star, polarities, preferential scale solvation, solvatochromic solvents}, pubstate = {published}, tppubtype = {article} } We report an experimental study on the effect of solvents on the model SNAr reaction between 1-chloro-2,4dinitrobenzene and morpholine in a series of pure ionic liquids (IL). A significant catalytic effect is observed with reference to the same reaction run in water, acetonitrile, and other conventional solvents. The series of IL considered include the anions, NTf2-, DCN-, SCN-, CF3SO3-, PF6-, and FAP(-) with the series of cations 1-butyl-3-methyl-imidazolium ([BMIM]+), 1-ethyl-3-methyl-imidazolium ([ EMIM]+), 1-butyl2,3- dimethyl-imidazolium ([BM2(I)M](+)), and 1-butyl-1-methyl-pyrrolidinium ([BMPyr](+)). The observed solvent effects can be attributed to an "anion effect". The anion effect appears related to the anion size (polarizability) and their hydrogenbonding (HB) abilities to the substrate. These results have been confirmed by performing a comparison of the rate constants with Gutmann's donicity numbers (DNs). The good correlation between rate constants and DN emphasizes the major role of charge transfer from the anion to the substrate. |
2014 |
Soto, C; Otipka, R; Toral, M I; Pino, D; Contreras, D; Yanez, J Journal of the Chilean Chemical Society, 59 (2), pp. 2485-2489, 2014, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: alpha-ethinyl chlormadinone derivative electrode estradiol, ethinylestradiol, formulations, gestodene, human least-squares, liquid-chromatography, mass-spectrometry, method, oral-contraceptives, performance pharmaceutical plasma, screening spectrophotometry, tandem @article{RN174, title = {Determination and Co-Estimate of the Chlormadinone Acetate and 17 Alpha-Ethinyl Estradiol in Pharmaceutical Formulation and Drinking Water Samples by Digital Derivative Spectophotometry}, author = { C. Soto and R. Otipka and M.I. Toral and D. Pino and D. Contreras and J. Yanez}, url = {/brokenurl#<Go to ISI>://WOS:000342613100019}, doi = {10.4067/S0717-97072014000200019}, issn = {0717-9707}, year = {2014}, date = {2014-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {59}, number = {2}, pages = {2485-2489}, abstract = {In this work are presented two methods for the simultaneous determination of 17 alpha-ethinylestradiol (EEL) and chlormadinone acetate (CMA) by second order derivative spectrophotometry., The first analytical method proposed is based in the dissolution and extraction of both drugs in acetonitrile. The solution was directly evaluated by second order derivative spectrophotometry with a smoothing factor of 8,000 and a scale factor of 10,000. The determination of EEL and CMA was carried out to 296,6 and 291.8 nm, respectively. The detection limits (3.3 sigma criterion) for EEL and CMA were 6.9 x 10(-7) and 9.8 x 10(-8) mol/L, respectively., Furthermore, a study of the effect of the excipients containing in the pharmaceutical formulation was included. Polyvidone presents greater tendency to produce interference, but its spectral bands are located between 215 and 240 nm, so these bands do not interferes spectrally in the simultaneous determination of EEL and CMA. Both drugs were extracted from the pharmaceutical formulation with acetonitrile, obtaining a good recovery relative to the nominal content., The second method is a screening method and was applied in fortified drinking water. In this method, drugs were extracted in chloroform, which was then removed with N-2 and the residue was redissolved in acetonitrile. Due to the difference in the procedure in relation to the pharmaceutical formulation a new analytical parameters were obtained. For EEL this parameters were very similar to those obtained directly in solution, however these were higher for CMA, which could be attributed to that under these conditions was found a higher standard deviation of the blank. Recoveries of fortified samples were 81.8 +/- 1.5% and 101.1 +/- 0.73% for EEL and CMA, respectively.}, keywords = {alpha-ethinyl chlormadinone derivative electrode estradiol, ethinylestradiol, formulations, gestodene, human least-squares, liquid-chromatography, mass-spectrometry, method, oral-contraceptives, performance pharmaceutical plasma, screening spectrophotometry, tandem}, pubstate = {published}, tppubtype = {article} } In this work are presented two methods for the simultaneous determination of 17 alpha-ethinylestradiol (EEL) and chlormadinone acetate (CMA) by second order derivative spectrophotometry., The first analytical method proposed is based in the dissolution and extraction of both drugs in acetonitrile. The solution was directly evaluated by second order derivative spectrophotometry with a smoothing factor of 8,000 and a scale factor of 10,000. The determination of EEL and CMA was carried out to 296,6 and 291.8 nm, respectively. The detection limits (3.3 sigma criterion) for EEL and CMA were 6.9 x 10(-7) and 9.8 x 10(-8) mol/L, respectively., Furthermore, a study of the effect of the excipients containing in the pharmaceutical formulation was included. Polyvidone presents greater tendency to produce interference, but its spectral bands are located between 215 and 240 nm, so these bands do not interferes spectrally in the simultaneous determination of EEL and CMA. Both drugs were extracted from the pharmaceutical formulation with acetonitrile, obtaining a good recovery relative to the nominal content., The second method is a screening method and was applied in fortified drinking water. In this method, drugs were extracted in chloroform, which was then removed with N-2 and the residue was redissolved in acetonitrile. Due to the difference in the procedure in relation to the pharmaceutical formulation a new analytical parameters were obtained. For EEL this parameters were very similar to those obtained directly in solution, however these were higher for CMA, which could be attributed to that under these conditions was found a higher standard deviation of the blank. Recoveries of fortified samples were 81.8 +/- 1.5% and 101.1 +/- 0.73% for EEL and CMA, respectively. |
2018 |
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. |
Solid-State Synthesis of Lnocl/Ln(2)O(3) (Ln = Eu, Nd) by Using Chitosan and Ps-Co-P4vp as Polymeric Supports Artículo de revista Journal of Rare Earths, 36 (12), pp. 1326-1332, 2018, ISSN: 1002-0721. |
2016 |
Gutmann's Donor Numbers Correctly Assess the Effect of the Solvent on the Kinetics of Snar Reactions in Ionic Liquids Artículo de revista Chemistry-a European Journal, 22 (37), pp. 13347-13351, 2016, ISSN: 0947-6539. |
2014 |
Journal of the Chilean Chemical Society, 59 (2), pp. 2485-2489, 2014, ISSN: 0717-9707. |