Publicaciones 2011-2020

@article{RN419,
title = {How Meaningful Is the Halogen Bonding in 1-Ethyl-3-Methyl Imidazolium-Based Ionic Liquids for Co2 Capture?},
author = { L. Lodeiro and R. Contreras and R. Ormazabal-Toledo},
url = {/brokenurl#<Go to ISI>://WOS:000442437700011},
doi = {10.1021/acs.jpcb.8b04990},
issn = {1520-6106},
year = {2018},
date = {2018-01-01},
journal = {Journal of Physical Chemistry B},
volume = {122},
number = {32},
pages = {7907-7914},
abstract = {We report on several parameters that can be used to describe the 1-ethyl-3-methyl-4,5-(X-2)imidazolium cations (where X = H, Br, and I) within the Canongia-Lopez and Padua Force Field (CL&P) framework. Geometrical parameters like intramolecular distances and radial distribution functions are close to the experimental structure. Density values obtained with our force field are within the expected ones from CL&P calculations in related systems. This information is used to simulate through molecular dynamics the solubilization of CO2 by these ILs. For pure ILs, the addition of halides in position 4 and 5 promotes an enhanced hydrogen bond interaction at position 2 with the oxygen atoms in the anion. It is found that CO2 should be in the interstices of the anion-cation 3D network with longer distances than those found in other reports at ab initio levels, suggesting that halogen bond, if present, may be not the driving force interaction in these systems. Therefore, it seems that CO2 interacts linearly via an oxygen atom with the cation and with the anion through a pi-stacking or hydrogen-bonded fashions. Solvation enthalpies compare well with the experimental data, thereby suggesting that halogenated ILs dissolve more efficiently in CO2 than C(2)C(1)Im(+) derivatives. This result suggests that halogenated ILs can be considered as reliable candidates for CO2 capture.},
keywords = {atmospheric carbon-dioxide, co2, conversion, dynamics, field, hydrogen-bonds, mechanism molecular-force reactivity, solubility, solvents},
pubstate = {published},
tppubtype = {article}
}

@article{RN327,
title = {On the Mechanism of Co2 Electro-Cycloaddition to Propylene Oxides},
author = { S. Gallardo-Fuentes and R. Contreras and M. Isaacs and J. Honores and D. Quezada and E. Landaeta and R. Ormazabal-Toledo},
url = {/brokenurl#<Go to ISI>://WOS:000389089200013},
doi = {10.1016/j.jcou.2016.06.007},
issn = {2212-9820},
year = {2016},
date = {2016-01-01},
journal = {Journal of Co2 Utilization},
volume = {16},
pages = {114-120},
publisher = {2016 Elsevier Ltd.},
abstract = {We herein present a systematic study on the mechanism of CO2 electro-cycloaddition to propylene oxide, using both experimental and theoretical procedures. The study considers the analysis of mild and sustainable conditions to obtain cyclic carbonates from CO2 recycling. Within the electrochemical approach, the application of an overpotential in the reaction enhances the reaction yield significantly with respect to the thermal pathway. The quantum-mechanical approach provides relevant information about the reaction mechanism. Specifically, the use of the Lewis acid catalyst Mg2+ in the presence of the [C(4)C(1)Im][Br] ionic liquid provides the best condition for the electro-synthesis. The theoretical predictions were confirmed by a new set of experiments.},
keywords = {atmospheric calculations, capture carbonate catalyst co2 co2, complexes, conversion, cyclic density dioxide, efficient electro-cycloaddition, electrochemical functional high-capacity, ionic liquids, mechanism, reaction recovery, reduction, salen synthesis, system},
pubstate = {published},
tppubtype = {article}
}

@article{RN251,
title = {Substituents Role in Zinc Phthalocyanine Derivatives Used as Dye-Sensitized Solar Cells. A Theoretical Study Using Density Functional Theory},
author = { C. Linares-Flores and F. Mendizabal and R. Arratia-Perez and N. Inostroza and C. Orellana},
url = {/brokenurl#<Go to ISI>://WOS:000365814400033},
doi = {10.1016/j.cplett.2015.09.025},
issn = {0009-2614},
year = {2015},
date = {2015-01-01},
journal = {Chemical Physics Letters},
volume = {639},
pages = {172-177},
publisher = {2015 Elsevier B.V.},
abstract = {A series of zinc phthalocyanine dyes with different electron-donating and electron-withdrawing substituents and using the COOH as the anchor group that interacts with the semiconductor (TiO2) surface, were studied employing DFT and TDDFT methodologies. Their HOMO and LUMO orbital energies and, the redox mediator position would facilitate the injection process toward the conduction band of TiO2. We tested the effect of some electron-donating or electron-withdrawing substituents over zinc phthalocyanine dyes in terms of the Hammett parameters (Sigma sigma). We obtained a linear correlation between the substituents properties versus the free energy change of the electron-injection (Delta G(inject)) process.},
keywords = {approximation, conversion, electronic-structure, hammett organic-dyes, parameters, porphyrins properties, spectroscopic states, surface, tio2},
pubstate = {published},
tppubtype = {article}
}

@article{RN36h,
title = {A Preparative Method for the Purification of Isopenicillin N from Genetically Blocked Acremonium Chrysogenum Strain Td189: Studies on the Degradation Kinetics and Storage Conditions},
author = { I. Vaca and J. Casqueiro and R.V. Ullan and A. Rumbero and R. Chavez and J.F. Martin},
url = {/brokenurl#<Go to ISI>://WOS:000292090800006},
doi = {10.1038/ja.2011.30},
issn = {0021-8820},
year = {2011},
date = {2011-01-01},
journal = {Journal of Antibiotics},
volume = {64},
number = {6},
pages = {447-451},
abstract = {A protocol for preparative isopenicillin N (IPN) purification, a highly interesting and hitherto unavailable intermediate of the penicillin and cephalosporin biosynthetic pathway due to its high unstability, is described. Culture broths of Acremonium chrysogenum TD189, a strain blocked in cephalosporin biosynthesis that accumulates this metabolite, were treated with acetone and filtered though charcoal and a hydrophobic resin in a single step as tandem columns. The cleared broth was then lyophilized and passed though a Sephadex G-25 column. The last step was the purification to homogeneity of IPN in a semipreparative HPLC equipment and, optionally, a desalting step by Sephadex G-10 column. Once purified, a complete analysis of the stability of the compound and the conditions for its long-term storage was carried out. Our results suggest a first-order model for IPN decomposition for all the pH and temperature analyzed. IPN is more stable at neutral pH, and once lyophilized, can be stored under vacuum and -75 degrees C with a half-life of 770 days. The Journal of Antibiotics (2011); published online 27 April 2011},
keywords = {biosynthesis, cephalosporin-c, chrysogenum, conversion, hplc, isopenicillin liquid-chromatography n, natural-products, penicillium-chrysogenum, purification, stability, storage, system temperature},
pubstate = {published},
tppubtype = {article}
}