Characterization of Elementary Chemical Processes by Catastrophe Theory

Krokidis, Xénophon; Noury, Stéphane; Silvi, Bernard

doi:10.1021/jp9711508

Cited by 394 publications

(500 citation statements)

References 19 publications

(25 reference statements)

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“…When trying to achieve a better understanding of bonding changes in organic reactions, the socalled BET [21] has proven to be a very useful methodological tool. This quantum-chemical methodology makes it possible to understand the bonding changes along a reaction path and, thus, to establish the nature of the electronic rearrangement associated with a given molecular mechanism [30].…”

Section: Bet Study Of the 32ca Reaction Of Ai 1b With Ethylenementioning

confidence: 99%

“…Considering that the simplest AI 1b has a different activation energy towards ethylene 3 than that shown by AY 1a and Ni 1c, two TACs with a different electronic structure (see Scheme 3), an MEDT study of the 32CA reactions of the simplest AI 1b with ethylene 3 and with electron-deficient (ED) dicyanoethylene (DCE) 6, a strongly electrophilic ethylene, is herein carried out in order to establish the structure and reactivity of this TAC (see Scheme 5). Together with an electron localisation function (ELF) characterisation of the electronic structure of the simplest AI 1b, a Bonding Evolution Theory [21] (BET) study of both reactions is performed in order to characterise the molecular mechanisms and to explain the activation energies implied in these cycloadditions. …”

Section: Introductionmentioning

confidence: 99%

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A Molecular Electron Density Theory Study of the Reactivity of Azomethine Imine in [3+2] Cycloaddition Reactions

Domingo

Ríos‐Gutiérrez

2017

Preprint

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Abstract:The electronic structure and the participation of the simplest azomethine imine (AI) in [3+2] cycloaddition (32CA) reactions have been analysed within the Molecular Electron Density Theory (MEDT) using DFT calculations at the MPWB1K/6-311G(d) level. Electron localisation function (ELF) topological analysis reveals that AI has a pseudoradical structure, while the conceptual DFT reactivity indices characterise this TAC as a moderate electrophile and a good nucleophile. The non-polar 32CA reaction of AI with ethylene takes place through a one-step mechanism with low activation energy, 5.3 kcal/mol -1 . A bonding evolution theory (BET) study indicates that this reaction takes place through a non-concerted [2n+2τ] mechanism in which the C−C bond formation is clearly anticipated prior to the C−N one. On the other hand, the polar 32CA reaction of AI with dicyanoethylene takes place through a two-stage one-step mechanism. Now, the more favourable regioisomeric transition state structure (TS) is located 8.5 kcal·mol -1 below the reagents, in complete agreement with the high polar character of the TS. The current MEDT study makes it possible to extend Domingo's classification of 32CA reactions to a new pra-type of reactivity.

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Section: Bet Study Of the 32ca Reaction Of Ai 1b With Ethylenementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Molecular Electron Density Theory Study of the Reactivity of Azomethine Imine in [3+2] Cycloaddition Reactions

Domingo

Ríos‐Gutiérrez

2017

Preprint

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“…[84][85][86][87] However, the applicability of QTAIM to the study of reaction mechanisms rapidly appeared to be mostly limited to intramolecular processes because there is no topological change in the charge density gradient field when a diatom dissociates. Bader's methodology has been further revised by Krokidis et al [88] who used the ELF instead of the charge density. Thus, the topological analysis of the ELF [62,63,89] is becoming increasingly popular in the characterization of chemical bonding in systems ranging from clusters in the gas phase to solids.…”

Section: The Bonding Evolution Theorymentioning

confidence: 99%

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

Andrés

González-Navarrete

Safont

2014

Int J of Quantum Chemistry

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A chemical reaction can be understood in terms of geometrical changes of the molecular structures and reordering of the electronic densities involved in the process; therefore, identifying structural and electronic density changes taking place along the reaction coordinate renders valuable information on reaction mechanism. Understanding the atomic rearrangements that occur during chemical reactions is of great importance, and this perspective aims to highlight the major developments in quantum chemical topology analysis, based on the combination of electron localization function and catastrophe theory as useful tools in elucidating the bonding and reactivity patterns of molecules. It reveals all the expected, but still ambiguous, elements of electronic structure extensively used by chemists. The chemical bonds determine chemical reactivity, and this technique offers the possibility of their visualization, allowing chemists to understand how atoms bond, how and where bonds are broken/ formed along a given reaction pathway at a most fundamental level, and so, better following and understanding the changes in the bond pattern. Their results clearly herald a new era, in which the atomic imaging of chemical bonds will constitute a new method for examining chemical structures and reaction mechanisms. The important feature of this procedure is that in practice the scope of its values is systemindependent. In addition, from a practical point of view, it is cheap to calculate and implement because wave functions are the required input, which are easily available from standard calculations. To capture these results two reaction mechanisms: isomerization of C(BH) 2 carbene and the thermal cycloheptatriene-norcaradiene isomerizations have been selected, indicating both the generality and utility of this type of analysis.

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“…The caustic-symmetry correspondence is rigorously demonstrated within both complementary frames, the geometric as well as the ondulatory frame. The findings of this work could be useful in the application of the catastrophe theory to other areas beyond the optical beams since the fold and cusp catastrophes are a powerful tool in diverse areas of chemistry [25,26], physics [27][28][29], and cosmology [30,31], in addition to other sciences such as medicine [32,33].…”

Section: Introductionmentioning

confidence: 99%

Caustics, catastrophes, and symmetries in curved beams

et al. 2015

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In this paper, a meaningful classification of optical caustic beams in two dimensions is presented. It is demonstrated that the phase symmetry of the beam's angular spectrum governs the optical catastrophe, which describes the wave properties of ray singularities, for cusp (symmetric phase) and fold (antisymmetric phase) caustics. In contrast to the established idea, the caustic classification arises from the phase symmetry rather than from the phase power, thus breaking the commonly accepted concept that fold and cusp caustics are related to the Airy and Pearcey functions, respectively. Nevertheless, the role played by the spectral phase power is to control the degree of caustic curvature. These findings provide straightforward engineering of caustic beams by addressing the spectral phase into a spatial light modulator or glass plate.

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Characterization of Elementary Chemical Processes by Catastrophe Theory

Cited by 394 publications

References 19 publications

A Molecular Electron Density Theory Study of the Reactivity of Azomethine Imine in [3+2] Cycloaddition Reactions

A Molecular Electron Density Theory Study of the Reactivity of Azomethine Imine in [3+2] Cycloaddition Reactions

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

Caustics, catastrophes, and symmetries in curved beams

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