Ill‐defined chemical concepts: The problem of quantification

Grunenberg, Jörg

doi:10.1002/qua.25359

Cited by 60 publications

(49 citation statements)

References 61 publications

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“…An underlying theme of the above questions has been the gap that exists, in general, between quantitative quantum theory and chemical concepts. In this context, we agree with the comment by Grunenberg “I am not writing against the use of qualitative chemical concepts per se, but against their quantification. In many cases, qualitative concepts even in combination with nonperfect experiments led to real progress in chemistry.…”

Section: Question 3: How Can One Use the Results Of A Partition Schemsupporting

confidence: 84%

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Nine questions on energy decomposition analysis

Andrés

Ayers

Boto³

et al. 2019

J Comput Chem

126

123

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The paper collects the answers of the authors to the following questions: Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes? Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts? How can one use the results of a partition scheme to improve the clarity of definitions of concepts? Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the “natural selection” process? To what extent does/can/should investigated systems influence the choice of a particular partition scheme? Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general? Is there any interest in developing common benchmarks and test sets for cross‐validation of methods? Is it possible to contemplate a unified partition scheme (let us call it the “standard model” of partitioning), that is proper for all applications in chemistry, in the foreseeable future or even in principle? In the end, science is about experiments and the real world. Can one, therefore, use any experiment or experimental data be used to favor one partition scheme over another? © 2019 Wiley Periodicals, Inc.

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Section: Question 3: How Can One Use the Results Of A Partition Schemsupporting

confidence: 84%

“…As Solà remarked recently: “My usual answer is that the most fruitful concepts in chemistry share the same lack of strict definition …”

Section: Question 2: Does the Adoption Of A Given Partition Scheme Immentioning

confidence: 99%

Nine questions on energy decomposition analysis

Andrés

Ayers

Boto³

et al. 2019

J Comput Chem

126

123

View full text Add to dashboard Cite

show abstract

“…Like many other concepts in chemistry, aromaticity has not been precisely defined. 1 In practice, however, it is determined enumeratively on the basis of distinctive properties of aromatic species. These properties regard inter alia increased stability with respect to the (linear) unsaturated counterparts without cyclic delocalization of p-electrons (energetic criterion), 2 vanishing or significantly reduced alternation of bond lengths (structural criterion), 3 and large magnetic anisotropies accompanied by abnormal chemical shifts (magnetic criterion).…”

Section: Introductionmentioning

confidence: 99%

The electron density of delocalized bonds (EDDB) applied for quantifying aromaticity

Szczepanik

Andrzejak

Dominikowska

et al. 2017

Phys. Chem. Chem. Phys.

165

145

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In this study the recently developed electron density of delocalized bonds (EDDB) is used to define a new measure of aromaticity in molecular rings. The relationships between bond-length alternation, electron delocalization and diatropicity of the induced ring current are investigated for a test set of representative molecular rings by means of correlation and principal component analyses involving the most popular aromaticity descriptors based on structural, electronic, and magnetic criteria. Additionally, a qualitative comparison is made between EDDB and the magnetically induced ring-current density maps from the ipsocentric approach for a series of linear acenes. Special emphasis is given to the comparative study of the description of cyclic delocalization of electrons in a wide range of organic aromatics in terms of the kekulean multicenter index KMCI and the newly proposed EDDB k index.

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“…For some of these researchers, only if all these effects are disentangled, that is, only if we are able to obtain the energy cost of going from the ground‐state molecule to the fragments‐in‐the‐molecule, will we be able to define an appropriate intrinsic bond energy (IBE). Because these IBEs necessarily rest on more or less arbitrary prescriptions to define the fragments‐in‐the‐molecule, there is not much hope in using energy‐derived bond strengths, others say …”

Section: Introductionmentioning

confidence: 99%

Real‐Space In Situ Bond Energies: Toward A Consistent Energetic Definition of Bond Strength

Menéndez-Crespo

Costales

Francisco

et al. 2018

Chemistry A European J

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A rigorous definition of intrinsic bond strength based on the partitioning of a molecule into real-space fragments is presented. Using the domains provided by the quantum theory of atoms-in-molecules (QTAIM) together with the interacting quantum atoms (IQA) energetic decomposition, we show how an in situ bond strength, matching all the requirements of an intrinsic bond energy, can be defined between each pair of fragments. Total atomization or fragmentation energies are shown to be equal to the sum of these in situ bond energies (ISBEs) if the energies of the fragments are measured with respect to their in-the-molecule state. These energies usually lie above the ground state of the isolated fragments by quantities identified with the standard fragment relaxation or deformation energies, which are also provided by the protocol. Deformation energies bridge dissociation energies with ISBEs, and can be dissected by using well-known tools of real-space theories of chemical bonding. Similarly, ISBEs can be partitioned into ionic and covalent contributions, and this feature adds to the chemical appeal of the procedure. All the energetic quantities examined are observable and amenable, in principle, to experimental determination. Several systems, exemplifying the role of each energetic term presented herein, are used to show the power of the approach.

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Ill‐defined chemical concepts: The problem of quantification

Cited by 60 publications

References 61 publications

Nine questions on energy decomposition analysis

Nine questions on energy decomposition analysis

The electron density of delocalized bonds (EDDB) applied for quantifying aromaticity

Real‐Space In Situ Bond Energies: Toward A Consistent Energetic Definition of Bond Strength

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