Publicaciones 2011-2020

@article{RN421,
title = {Solvent Effect on a Model Snar Reaction in Ionic Liquid/Water Mixtures at Different Compositions},
author = { B. Sanchez and C. Calderon and C. Garrido and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000435298100034},
doi = {10.1039/c7nj04820c},
issn = {1144-0546},
year = {2018},
date = {2018-01-01},
journal = {New Journal of Chemistry},
volume = {42},
number = {12},
pages = {9645-9650},
abstract = {The reaction of phenyl 2,4,6-trinitrophenyl ether and piperidine was kinetically evaluated in BMIMBF4/water mixtures as the reaction media. This study shows the dramatic effect of the mixture composition on the reacting pair and its reaction rate, highlighting two strongly demarcated zones. The first one, rich in water, is characterized by strong variations in the rate coefficient values, suggesting the presence of preferential solvent effects in the aqueous phase. The second zone shows high rate coefficient values independent of the composition of the solvent mixture, suggesting predominant anion solvent effects. These results were validated using fluorescence spectroscopy and the Kamlet-Taft parameter.},
keywords = {aromatic binary-mixtures, catalysis, kinetics liquids, mixed-solvents, molecules, nitro-group, nucleophilic-substitution, preferential solvation, water},
pubstate = {published},
tppubtype = {article}
}

@article{RN376,
title = {Iso-Solvation Effects in Mixtures of Ionic Liquids on the Kinetics of a Model Snar Reaction},
author = { J. Alarcon-Esposito and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000414440000030},
doi = {10.1039/c7nj03246c},
issn = {1144-0546},
year = {2017},
date = {2017-01-01},
journal = {New Journal of Chemistry},
volume = {41},
number = {22},
pages = {13435-13441},
abstract = {The SNAr reaction between 1-chloro-2,4-dinitrobenzene and morpholine was used as a model system to study solvation effects in a series of mixtures involving imidazolium based ionic liquids. Iso-solvation regimes (i.e. a solvent composition regime where the solute is being solvated by approximately the same number of different solvent molecules in the mixture) are reported for the first time in ionic liquid mixtures, for 4 mixtures including [EMIM][SCN][DCN], [BMIM][DCN][BF4], [BMIM][BF4][PF6] and [BMIM][PF6][FAP]. The results show that for significant changes in composition, the rate coefficients remain approximately constant. An additional interesting result is that the mixture [BMIM][BF4][PF6] (in the proportion of 0.9 for the molar fraction of BMIMBF4) shows a slightly better kinetic performance as compared to pure BMIMBF4 and BMIMPF6. Finally, for the [EMIM][SCN][DCN] mixture, an increasing proportion of EMIMSCN with respect to EMIMDCN results in a decrease in the rate coefficient within the range of (0.1-0.75) for the molar fraction of EMIMSCN. This result may be traced to competition between the anions [SCN-] and [DCN-] towards the reaction center driven by the basicity of the reaction medium.},
keywords = {alpha, aromatic behavior, binary-mixtures, comparison method, nucleophilic-substitution, parameters, preferential probes, scale solvation, solvatochromic solvents},
pubstate = {published},
tppubtype = {article}
}

@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}
}

@article{RN225,
title = {Site Activation Effects Promoted by Intramolecular Hydrogen Bond Interactions in Snar Reactions},
author = { S. Gallardo-Fuentes and R.A. Tapia and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000340500300025},
doi = {10.1039/c4ra04725g},
issn = {2046-2069},
year = {2014},
date = {2014-01-01},
journal = {Rsc Advances},
volume = {4},
number = {58},
pages = {30638-30643},
abstract = {The nucleophilic aromatic substitution reaction of benzohydrazide derivatives towards 2-chloro-5nitropyrimidine is used as model system to experimentally and theoretically show that intramolecular hydrogen-bond formation operates as a perturbation that elicits a dual response at the reaction center of the transition state (TS) structure, by enhancing the electrophilicity of the pyrimidine moiety and the nucleophilicity of the nitrogen atom of the benzohydrazide fragment. The electronic mechanism can therefore be described as a (non-local) site activation problem.},
keywords = {aromatic electrophilicity, functionals, markovnikov model molecules, nucleophilic-substitution, potentials, reactivity, regioselectivity rule, secondary-amines, solvent},
pubstate = {published},
tppubtype = {article}
}

@article{RN163,
title = {Hydrogen Bond Contribution to Preferential Solvation in Snar Reactions},
author = { R. Ormazabal-Toledo and J.G. Santos and P. Rios and E.A. Castro and P.R. Campodonico and R. Contreras},
url = {/brokenurl#<Go to ISI>://WOS:000319649800012},
doi = {10.1021/jp4005295},
issn = {1520-6106},
year = {2013},
date = {2013-01-01},
journal = {Journal of Physical Chemistry B},
volume = {117},
number = {19},
pages = {5908-5915},
abstract = {Preferential solvation in aromatic nucleophilic substitution reactions is discussed using a kinetic study complemented with quantum chemical calculations. The model system is the reaction of a series of secondary alicyclic amines toward phenyl 2,4,6-trinitrophenyl ether in aqueous ethanol mixtures of different compositions. From solvent effect studies, it is found that only piperidine is sensitive to solvation effects, a result that may be traced to the polarity of the solvent composition in the ethanol/water mixture, which points to a specific electrophilic solvation in the aqueous phase.},
keywords = {amines aromatic behavior, binary chemical ether, kinetics, mixtures, molecules, nucleophilic-substitution, piperidine, probes, solvent},
pubstate = {published},
tppubtype = {article}
}