Publicaciones 2011-2020

@article{RN420,
title = {Activation of Electrophile/Nucleophile Pair by a Nucleophilic and Electrophilic Solvation in a Snar Reaction},
author = { B. Sanchez and C. Calderon and R.A. Tapia and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000447985400001},
doi = {10.3389/fchem.2018.00509},
issn = {2296-2646},
year = {2018},
date = {2018-01-01},
journal = {Frontiers in Chemistry},
volume = {6},
abstract = {Nucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile.},
keywords = {anion aromatic-substitution catalysis, effect, effects, electronic ionic liquids, mixtures, organic-reactions, potentials preferential reactions, secondary-amines, solvation, solvent solvent, temperature theory},
pubstate = {published},
tppubtype = {article}
}

@article{RN273,
title = {Changes in the Snar Reaction Mechanism Brought About by Preferential Solvation},
author = { J. Alarcon-Esposito and R.A. Tapia and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000365328000069},
doi = {10.1039/c5ra20779g},
issn = {2046-2069},
year = {2015},
date = {2015-01-01},
journal = {Rsc Advances},
volume = {5},
number = {120},
pages = {99322-99328},
abstract = {We herein report an experimental and theoretical study on preferential solvation effects for the reactions of 1-fluoro and 1-chloro-2,4-dinitrobenzene towards morpholine in acetonitrile, water and mixtures of them of varying compositions. A detailed kinetic study opens the possibility of analyzing preferential solvation and reaction rates. The kinetic study was complemented with an exploration of the potential energy surface in order to analyze the nature of the molecular interactions. For the fluorine derivative, this analysis reveals that the solvation of the TS in the mode TS1F-water/MeCN clearly outweighs the solvation of TS1F-MeCN/water, thereby suggesting that there is preferential solvation in favor of the aqueous phase.},
keywords = {aminolysis, benzenesulfonates, binary ionic liquids, mixtures, molecules, nucleophilic-substitution pathways reactions, regioselectivity, secondary-amines, solvent},
pubstate = {published},
tppubtype = {article}
}

@article{RN224,
title = {Mechanistic Pathways of Aromatic Nucleophilic Substitution in Conventional Solvents and Ionic Liquids},
author = { M. Gazitua and R.A. Tapia and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000336821000059},
doi = {10.1039/c4nj00130c},
issn = {1144-0546},
year = {2014},
date = {2014-01-01},
journal = {New Journal of Chemistry},
volume = {38},
number = {6},
pages = {2611-2618},
abstract = {Solvation effects on the reaction mechanism of the title reactions have been kinetically evaluated in 21 conventional solvents and 17 ionic liquids. Solvent polarity affects the catalyzed and non-catalyzed SNAr pathways differently. The ambiphilic character of water and formamide, which act as a hydrogen bond donor/acceptor, induces nucleophilic activation at the nitrogen center of the nucleophile. The ionic liquid EMIMDCN appears to be the best solvent for the SNAr route probably due to the high polarizability of the dicyanamide anion.},
keywords = {aminolysis aryl azides, benzenesulfonates, kinetics, rationalization, regioselectivity, secondary-amines, solvation},
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{RN167,
title = {Specific Nucleophile-Electrophile Interactions in Nucleophilic Aromatic Substitutions},
author = { R. Ormazabal-Toledo and R. Contreras and R.A. Tapia and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000316011300012},
doi = {10.1039/c3ob27450k},
issn = {1477-0520},
year = {2013},
date = {2013-01-01},
journal = {Organic & Biomolecular Chemistry},
volume = {11},
number = {14},
pages = {2302-2309},
abstract = {We herein report results obtained from an integrated experimental and theoretical study on aromatic nucleophilic substitution (SNAr) reactions of a series of amines towards 1-fluoro-2,4-dinitrobenzene in water. Specific nucleophile-electrophile interactions in the title reactions have been kinetically evaluated. The whole series undergoes SNAr reactions where the formation of the Meisenheimer complex is rate determining. Theoretical studies concerning specific interactions are discussed in detail. It is found that H-bonding effects along the intrinsic reaction coordinate profile promote the activation of both the electrophile and the nucleophile. Using these results, it is possible to establish a hierarchy of reactivity that is in agreement with the experimental data. Second order energy perturbation energy analysis highlights the strong interaction between the ortho-nitro group and the acidic hydrogen atom of the amine. The present study strongly suggests that any theoretical analysis must be performed at the activated transition state structure, because the static model developed around the reactant states hides most of the relevant specific interactions that characterize the aromatic substitution process.},
keywords = {base binary catalysis, group, groups, leaving mechanism, mixtures, nitro ortho-para ratio, reactions, secondary-amines, snar solvent},
pubstate = {published},
tppubtype = {article}
}

@article{RN166,
title = {Reactivity Indices Profile: A Companion Tool of the Potential Energy Surface for the Analysis of Reaction Mechanisms. Nucleophilic Aromatic Substitution Reactions as Test Case},
author = { R. Ormazabal-Toledo and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000314558300028},
doi = {10.1021/jo3025048},
issn = {0022-3263},
year = {2013},
date = {2013-01-01},
journal = {Journal of Organic Chemistry},
volume = {78},
number = {3},
pages = {1091-1097},
abstract = {We herein report on the usefulness of the reactivity indices profiles along a reaction coordinate. The model is tested to fully describe the reaction mechanism of the title reactions. Group nucleophilicity and electrophilicity profiles help describe the bond-breaking/bond-formation processes and the intramolecular electron density reorganization. The reactivity indices' profile analysis is consistently complemented with hydrogen bonding (HB) effects along the reaction coordinate: the final outcome of the reaction is determined by the stage at which the HB complex can be formed. Transition-state structures located for six reactions studied, including the charged nucleophile thiocyanate, show that the main stabilizing interaction is that formed between the hydrogen atom of the nucleophile and the o-NO2 group. This result discards the role of HB interaction between the nucleophile and the leaving group previously proposed in the literature.},
keywords = {aprotic-solvent, electrophilicity hardness hydrogen-bonds, index, ortho-para ratio, secondary-amines},
pubstate = {published},
tppubtype = {article}
}