2013 |
Ormazabal-Toledo, R; Contreras, R; Campodonico, P R Reactivity Indices Profile: A Companion Tool of the Potential Energy Surface for the Analysis of Reaction Mechanisms. Nucleophilic Aromatic Substitution Reactions as Test Case Artículo de revista Journal of Organic Chemistry, 78 (3), pp. 1091-1097, 2013, ISSN: 0022-3263. Resumen | Enlaces | BibTeX | Etiquetas: aprotic-solvent, electrophilicity hardness hydrogen-bonds, index, ortho-para ratio, secondary-amines @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} } 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. |
2012 |
Soto-Delgado, J; Aizman, A; Contreras, R; Domingo, L R On the Catalytic Effect of Water in the Intramolecular Diels-Alder Reaction of Quinone Systems: A Theoretical Study Artículo de revista Molecules, 17 (11), pp. 13687-13703, 2012, ISSN: 1420-3049. Resumen | Enlaces | BibTeX | Etiquetas: catalysis, characterization, chemistry density dft dft, diels-alder difference electrophilicity, functionals, index, indices, intramolecular local molecules, polar quantitative reactions, reactivity regioselectivity, solvent, thermochemistry, water @article{sotodelgado2012catalytic, title = {On the Catalytic Effect of Water in the Intramolecular Diels-Alder Reaction of Quinone Systems: A Theoretical Study}, author = { J. Soto-Delgado and A. Aizman and R. Contreras and L.R. Domingo}, url = {/brokenurl#<Go to ISI>://WOS:000311428400087}, doi = {10.3390/molecules171113687}, issn = {1420-3049}, year = {2012}, date = {2012-01-01}, journal = {Molecules}, volume = {17}, number = {11}, pages = {13687-13703}, abstract = {The mechanism of the intramolecular Diels-Alder (IMDA) reaction of benzoquinone 1, in the absence and in the presence of three water molecules, 1w, has been studied by means of density functional theory (DFT) methods, using the M05-2X and B3LYP functionals for exploration of the potential energy surface (PES). The energy and geometrical results obtained are complemented with a population analysis using the NBO method, and an analysis based on the global, local and group electrophilicity and nucleophilicity indices. Both implicit and explicit solvation emphasize the increase of the polarity of the reaction and the reduction of activation free energies associated with the transition states (TSs) of this IMDA process. These results are reinforced by the analysis of the reactivity indices derived from the conceptual DFT, which show that the increase of the electrophilicity of the quinone framework by the hydrogen-bond formation correctly explains the high polar character of this intramolecular process. Large polarization at the TSs promoted by hydrogen-bonds and implicit solvation by water together with a high electrophilicity-nucleophilicity difference consistently explains the catalytic effects of water molecules.}, keywords = {catalysis, characterization, chemistry density dft dft, diels-alder difference electrophilicity, functionals, index, indices, intramolecular local molecules, polar quantitative reactions, reactivity regioselectivity, solvent, thermochemistry, water}, pubstate = {published}, tppubtype = {article} } The mechanism of the intramolecular Diels-Alder (IMDA) reaction of benzoquinone 1, in the absence and in the presence of three water molecules, 1w, has been studied by means of density functional theory (DFT) methods, using the M05-2X and B3LYP functionals for exploration of the potential energy surface (PES). The energy and geometrical results obtained are complemented with a population analysis using the NBO method, and an analysis based on the global, local and group electrophilicity and nucleophilicity indices. Both implicit and explicit solvation emphasize the increase of the polarity of the reaction and the reduction of activation free energies associated with the transition states (TSs) of this IMDA process. These results are reinforced by the analysis of the reactivity indices derived from the conceptual DFT, which show that the increase of the electrophilicity of the quinone framework by the hydrogen-bond formation correctly explains the high polar character of this intramolecular process. Large polarization at the TSs promoted by hydrogen-bonds and implicit solvation by water together with a high electrophilicity-nucleophilicity difference consistently explains the catalytic effects of water molecules. |
2011 |
Mendizabal, F; Donoso, D; Burgos, D Theoretical Study of the Protonation of [Pt-3(Mu-L)(3)(L ')(3)] (L = Co, So2, Cnh; L ' = Ph3, Cnh) Artículo de revista Chemical Physics Letters, 514 (4-6), pp. 374-378, 2011, ISSN: 0009-2614. Resumen | Enlaces | BibTeX | Etiquetas: approximation, chemistry, cluster complexes, electrophilicity hydride, index, molecules, systems, units @article{mendizabal2011theoretical, title = {Theoretical Study of the Protonation of [Pt-3(Mu-L)(3)(L ')(3)] (L = Co, So2, Cnh; L ' = Ph3, Cnh)}, author = { F. Mendizabal and D. Donoso and D. Burgos}, url = {/brokenurl#<Go to ISI>://WOS:000295831700035}, doi = {10.1016/j.cplett.2011.08.068}, issn = {0009-2614}, year = {2011}, date = {2011-01-01}, journal = {Chemical Physics Letters}, volume = {514}, number = {4-6}, pages = {374-378}, publisher = {2011 Elsevier B. V.}, abstract = {Ab initio calculations suggest that a series of clusters of the [Pt-3(mu-L)(3)(L')(3)(mu(3)-H](+) type (L = CO, SO2, CNH; L' = PH3, CNH) are stable. We have studied these clusters at the HF, MP2, B3LYP, PBE and TPSS theory levels. The magnitude of the interaction energies and distances indicates a substantial covalent character of the Pt-3-H bond, confirmed by orbital diagrams. In addition, the Fukui index of electrophilic attack and electrophilicity index on the unprotonated clusters were used to explore possible sites where chemical reactivity may play a role.}, keywords = {approximation, chemistry, cluster complexes, electrophilicity hydride, index, molecules, systems, units}, pubstate = {published}, tppubtype = {article} } Ab initio calculations suggest that a series of clusters of the [Pt-3(mu-L)(3)(L')(3)(mu(3)-H](+) type (L = CO, SO2, CNH; L' = PH3, CNH) are stable. We have studied these clusters at the HF, MP2, B3LYP, PBE and TPSS theory levels. The magnitude of the interaction energies and distances indicates a substantial covalent character of the Pt-3-H bond, confirmed by orbital diagrams. In addition, the Fukui index of electrophilic attack and electrophilicity index on the unprotonated clusters were used to explore possible sites where chemical reactivity may play a role. |
2013 |
Reactivity Indices Profile: A Companion Tool of the Potential Energy Surface for the Analysis of Reaction Mechanisms. Nucleophilic Aromatic Substitution Reactions as Test Case Artículo de revista Journal of Organic Chemistry, 78 (3), pp. 1091-1097, 2013, ISSN: 0022-3263. |
2012 |
On the Catalytic Effect of Water in the Intramolecular Diels-Alder Reaction of Quinone Systems: A Theoretical Study Artículo de revista Molecules, 17 (11), pp. 13687-13703, 2012, ISSN: 1420-3049. |
2011 |
Theoretical Study of the Protonation of [Pt-3(Mu-L)(3)(L ')(3)] (L = Co, So2, Cnh; L ' = Ph3, Cnh) Artículo de revista Chemical Physics Letters, 514 (4-6), pp. 374-378, 2011, ISSN: 0009-2614. |